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Bergs J, Morr AS, Silva RV, Infante-Duarte C, Sack I. The Networking Brain: How Extracellular Matrix, Cellular Networks, and Vasculature Shape the In Vivo Mechanical Properties of the Brain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402338. [PMID: 38874205 DOI: 10.1002/advs.202402338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/22/2024] [Indexed: 06/15/2024]
Abstract
Mechanically, the brain is characterized by both solid and fluid properties. The resulting unique material behavior fosters proliferation, differentiation, and repair of cellular and vascular networks, and optimally protects them from damaging shear forces. Magnetic resonance elastography (MRE) is a noninvasive imaging technique that maps the mechanical properties of the brain in vivo. MRE studies have shown that abnormal processes such as neuronal degeneration, demyelination, inflammation, and vascular leakage lead to tissue softening. In contrast, neuronal proliferation, cellular network formation, and higher vascular pressure result in brain stiffening. In addition, brain viscosity has been reported to change with normal blood perfusion variability and brain maturation as well as disease conditions such as tumor invasion. In this article, the contributions of the neuronal, glial, extracellular, and vascular networks are discussed to the coarse-grained parameters determined by MRE. This reductionist multi-network model of brain mechanics helps to explain many MRE observations in terms of microanatomical changes and suggests that cerebral viscoelasticity is a suitable imaging marker for brain disease.
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Affiliation(s)
- Judith Bergs
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Anna S Morr
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Rafaela V Silva
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité - Universitätsmedizin Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
- Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Carmen Infante-Duarte
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité - Universitätsmedizin Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
- Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
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Ishida S, Fujiwara Y, Matta Y, Takei N, Kanamoto M, Kimura H, Tsujikawa T. Enhanced parameter estimation in multiparametric arterial spin labeling using artificial neural networks. Magn Reson Med 2024. [PMID: 38852172 DOI: 10.1002/mrm.30184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024]
Abstract
PURPOSE Multiparametric arterial spin labeling (MP-ASL) can quantify cerebral blood flow (CBF) and arterial cerebral blood volume (CBVa). However, its accuracy is compromised owing to its intrinsically low SNR, necessitating complex and time-consuming parameter estimation. Deep neural networks (DNNs) offer a solution to these limitations. Therefore, we aimed to develop simulation-based DNNs for MP-ASL and compared the performance of a supervised DNN (DNNSup), physics-informed unsupervised DNN (DNNUns), and the conventional lookup table method (LUT) using simulation and in vivo data. METHODS MP-ASL was performed twice during resting state and once during the breath-holding task. First, the accuracy and noise immunity were evaluated in the first resting state. Second, CBF and CBVa values were statistically compared between the first resting state and the breath-holding task using the Wilcoxon signed-rank test and Cliff's delta. Finally, reproducibility of the two resting states was assessed. RESULTS Simulation and first resting-state analyses demonstrated that DNNSup had higher accuracy, noise immunity, and a six-fold faster computation time than LUT. Furthermore, all methods detected task-induced CBF and CBVa elevations, with the effect size being larger with the DNNSup (CBF, p = 0.055, Δ = 0.286; CBVa, p = 0.008, Δ = 0.964) and DNNUns (CBF, p = 0.039, Δ = 0.286; CBVa, p = 0.008, Δ = 1.000) than that with LUT (CBF, p = 0.109, Δ = 0.214; CBVa, p = 0.008, Δ = 0.929). Moreover, all the methods exhibited comparable and satisfactory reproducibility. CONCLUSION DNNSup outperforms DNNUns and LUT with respect to estimation performance and computation time.
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Affiliation(s)
- Shota Ishida
- Department of Radiological Technology, Faculty of Medical Sciences, Kyoto College of Medical Science, Nantan, Japan
| | - Yasuhiro Fujiwara
- Department of Medical Image Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yuki Matta
- Radiological Center, University of Fukui Hospital, Eiheiji, Japan
| | | | | | - Hirohiko Kimura
- Faculty of Medical Sciences, University of Fukui, Fukui, Japan
- Radiology Section, National Health Insurance Echizen-cho Ota Hospital, Echizen, Japan
| | - Tetsuya Tsujikawa
- Department of Radiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
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Gu C, Li Y, Cao D, Miao X, Paez AG, Sun Y, Cai J, Li W, Li X, Pillai JJ, Earley CJ, van Zijl PC, Hua J. On the optimization of 3D inflow-based vascular-space-occupancy (iVASO) MRI for the quantification of arterial cerebral blood volume (CBVa). Magn Reson Med 2024; 91:1893-1907. [PMID: 38115573 PMCID: PMC10950541 DOI: 10.1002/mrm.29971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 12/21/2023]
Abstract
PURPOSE The inflow-based vascular-space-occupancy (iVASO) MRI was originally developed in a single-slice mode to measure arterial cerebral blood volume (CBVa). When vascular crushers are applied in iVASO, the signals can be sensitized predominantly to small pial arteries and arterioles. The purpose of this study is to perform a systematic optimization and evaluation of a 3D iVASO sequence on both 3 T and 7 T for the quantification of CBVa values in the human brain. METHODS Three sets of experiments were performed in three separate cohorts. (1) 3D iVASO MRI protocols were compared to single-slice iVASO, and the reproducibility of whole-brain 3D iVASO MRI was evaluated. (2) The effects from different vascular crushers in iVASO were assessed. (3) 3D iVASO MRI results were evaluated in arterial and venous blood vessels identified using ultrasmall-superparamagnetic-iron-oxides-enhanced MRI to validate its arterial origin. RESULTS 3D iVASO scans showed signal-to-noise ratio (SNR) and CBVa measures consistent with single-slice iVASO with reasonable intrasubject reproducibility. Among the iVASO scans performed with different vascular crushers, the whole-brain 3D iVASO scan with a motion-sensitized-driven-equilibrium preparation with two binomial refocusing pulses and an effective TE of 50 ms showed the best suppression of macrovascular signals, with a relatively low specific absorption rate. When no vascular crusher was applied, the CBVa maps from 3D iVASO scans showed large CBVa values in arterial vessels but well-suppressed signals in venous vessels. CONCLUSION A whole-brain 3D iVASO MRI scan was optimized for CBVa measurement in the human brain. When only microvascular signals are desired, a motion-sensitized-driven-equilibrium-based vascular crusher with binomial refocusing pulses can be applied in 3D iVASO.
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Affiliation(s)
- Chunming Gu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Yinghao Li
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Di Cao
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Xinyuan Miao
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Adrian G. Paez
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Yuanqi Sun
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Jitong Cai
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Wenbo Li
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Xu Li
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Jay J. Pillai
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Division of Neuroradiology, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Christopher J. Earley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Peter C.M. van Zijl
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Jun Hua
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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Favilla CG, Carter S, Hartl B, Gitlevich R, Mullen MT, Yodh AG, Baker WB, Konecky S. Validation of the Openwater wearable optical system: cerebral hemodynamic monitoring during a breath-hold maneuver. NEUROPHOTONICS 2024; 11:015008. [PMID: 38464864 PMCID: PMC10923543 DOI: 10.1117/1.nph.11.1.015008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/10/2024] [Accepted: 02/13/2024] [Indexed: 03/12/2024]
Abstract
Significance Bedside cerebral blood flow (CBF) monitoring has the potential to inform and improve care for acute neurologic diseases, but technical challenges limit the use of existing techniques in clinical practice. Aim Here, we validate the Openwater optical system, a novel wearable headset that uses laser speckle contrast to monitor microvascular hemodynamics. Approach We monitored 25 healthy adults with the Openwater system and concurrent transcranial Doppler (TCD) while performing a breath-hold maneuver to increase CBF. Relative blood flow (rBF) was derived from changes in speckle contrast, and relative blood volume (rBV) was derived from changes in speckle average intensity. Results A strong correlation was observed between beat-to-beat optical rBF and TCD-measured cerebral blood flow velocity (CBFv), R = 0.79 ; the slope of the linear fit indicates good agreement, 0.87 (95% CI: 0.83 - 0.92 ). Beat-to-beat rBV and CBFv were also strongly correlated, R = 0.72 , but as expected the two variables were not proportional; changes in rBV were smaller than CBFv changes, with linear fit slope of 0.18 (95% CI: 0.17 to 0.19). Further, strong agreement was found between rBF and CBFv waveform morphology and related metrics. Conclusions This first in vivo validation of the Openwater optical system highlights its potential as a cerebral hemodynamic monitor, but additional validation is needed in disease states.
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Affiliation(s)
- Christopher G. Favilla
- University of Pennsylvania, Department of Neurology, Philadelphia, Pennsylvania, United States
| | - Sarah Carter
- University of Pennsylvania, Department of Neurology, Philadelphia, Pennsylvania, United States
| | - Brad Hartl
- Openwater, San Francisco, California, United States
| | - Rebecca Gitlevich
- University of Pennsylvania, Department of Neurology, Philadelphia, Pennsylvania, United States
| | - Michael T. Mullen
- Temple University, Department of Neurology, Philadelphia, Pennsylvania, United States
| | - Arjun G. Yodh
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
| | - Wesley B. Baker
- Children’s Hospital of Philadelphia, Department of Neurology, Philadelphia, Pennsylvania, United States
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Favilla CG, Carter S, Hartl B, Gitlevich R, Mullen MT, Yodh AG, Baker WB, Konecky S. Validation of the Openwater wearable optical system: cerebral hemodynamic monitoring during a breath hold maneuver. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.10.11.23296612. [PMID: 37873126 PMCID: PMC10592983 DOI: 10.1101/2023.10.11.23296612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Bedside cerebral blood flow (CBF) monitoring has the potential to inform and improve care for acute neurologic diseases, but technical challenges limit the use of existing techniques in clinical practice. Here we validate the Openwater optical system, a novel wearable headset that uses laser speckle contrast to monitor microvascular hemodynamics. We monitored 25 healthy adults with the Openwater system and concurrent transcranial Doppler (TCD) while performing a breath-hold maneuver to increase CBF. Relative blood flow (rBF) was derived from the changes in speckle contrast, and relative blood volume (rBV) was derived from the changes in speckle average intensity. A strong correlation was observed between beat-to-beat optical rBF and TCD-measured cerebral blood flow velocity (CBFv), R=0.79; the slope of the linear fit indicates good agreement, 0.87 (95% CI:0.83-0.92). Beat-to-beat rBV and CBFv were strongly correlated, R=0.72, but as expected the two variables were not proportional; changes in rBV were smaller than CBFv changes, with linear fit slope of 0.18 (95% CI:0.17-0.19). Further, strong agreement was found between rBF and CBFv waveform morphology and related metrics. This first in vivo validation of the Openwater optical system highlights its potential as a cerebral hemodynamic monitor, but additional validation is needed in disease states.
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Uludağ K. Physiological modeling of the BOLD signal and implications for effective connectivity: A primer. Neuroimage 2023; 277:120249. [PMID: 37356779 DOI: 10.1016/j.neuroimage.2023.120249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/12/2023] [Accepted: 06/23/2023] [Indexed: 06/27/2023] Open
Abstract
In this primer, I provide an overview of the physiological processes that contribute to the observed BOLD signal (i.e., the generative biophysical model), including their time course properties within the framework of the physiologically-informed dynamic causal modeling (P-DCM). The BOLD signal is primarily determined by the change in paramagnetic deoxygenated hemoglobin, which results from combination of changes in oxygen metabolism, and cerebral blood flow and volume. Specifically, the physiological origin of the so-called BOLD signal "transients" will be discussed, including the initial overshoot, steady-state activation and the post-stimulus undershoot. I argue that incorrect physiological assumptions in the generative model of the BOLD signal can lead to incorrect inferences pertaining to both local neuronal activity and effective connectivity between brain regions. In addition, I introduce the recent laminar BOLD signal model, which extends P-DCM to cortical depths-resolved BOLD signals, allowing for laminar neuronal activity to be determined using high-resolution fMRI data.
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Affiliation(s)
- Kâmil Uludağ
- Krembil Brain Institute, University Health Network Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Center for Neuroscience Imaging Research, Institute for Basic Science & Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
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Biondetti E, Cho J, Lee H. Cerebral oxygen metabolism from MRI susceptibility. Neuroimage 2023; 276:120189. [PMID: 37230206 PMCID: PMC10335841 DOI: 10.1016/j.neuroimage.2023.120189] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/26/2023] [Accepted: 05/23/2023] [Indexed: 05/27/2023] Open
Abstract
This article provides an overview of MRI methods exploiting magnetic susceptibility properties of blood to assess cerebral oxygen metabolism, including the tissue oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO2). The first section is devoted to describing blood magnetic susceptibility and its effect on the MRI signal. Blood circulating in the vasculature can have diamagnetic (oxyhemoglobin) or paramagnetic properties (deoxyhemoglobin). The overall balance between oxygenated and deoxygenated hemoglobin determines the induced magnetic field which, in turn, modulates the transverse relaxation decay of the MRI signal via additional phase accumulation. The following sections of this review then illustrate the principles underpinning susceptibility-based techniques for quantifying OEF and CMRO2. Here, it is detailed whether these techniques provide global (OxFlow) or local (Quantitative Susceptibility Mapping - QSM, calibrated BOLD - cBOLD, quantitative BOLD - qBOLD, QSM+qBOLD) measurements of OEF or CMRO2, and what signal components (magnitude or phase) and tissue pools they consider (intravascular or extravascular). Validations studies and potential limitations of each method are also described. The latter include (but are not limited to) challenges in the experimental setup, the accuracy of signal modeling, and assumptions on the measured signal. The last section outlines the clinical uses of these techniques in healthy aging and neurodegenerative diseases and contextualizes these reports relative to results from gold-standard PET.
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Affiliation(s)
- Emma Biondetti
- Department of Neuroscience, Imaging and Clinical Sciences, "D'Annunzio University" of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, "D'Annunzio University" of Chieti-Pescara, Chieti, Italy
| | - Junghun Cho
- Department of Biomedical Engineering, University at Buffalo, The State University of New York, New York, USA
| | - Hyunyeol Lee
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, Republic of Korea; Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Waddle SL, Garza M, Ying C, Davis LT, Jordan LC, An H, Donahue MJ. Vascular space occupancy asymmetric spin echo (VASO-ASE) for non-invasive quantification of cerebral oxygen extraction fraction. Magn Reson Med 2023; 90:211-221. [PMID: 36880522 PMCID: PMC10149592 DOI: 10.1002/mrm.29618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/30/2022] [Accepted: 01/27/2023] [Indexed: 03/08/2023]
Abstract
PURPOSE Asymmetric spin echo (ASE) MRI is a method for measuring regional oxygen extraction fraction (OEF); however, extravascular tissue models have been shown to under-estimate OEF. The hypothesis investigated here is that the addition of a vascular-space-occupancy (VASO) pre-pulse will more fully suppress blood water signal and provide global OEF values more consistent with physiological expectation and 15 O positron emission tomography (PET)-validated T2 -relaxation-under-spin-tagging (TRUST) OEF measures. METHODS Healthy adults (n = 14; age = 27.7 ± 5.2 y; sex = 7/7 male/female) were scanned at 3.0T. Multi-echo ASE without inter-readout refocusing (ASERF- ), multi-echo ASE with inter-readout refocusing (ASERF+ ), and single-echo VASO-ASE were acquired twice each with common spatial resolution = 3.44 × 3.44 × 3.0 mm and τ = 0-20 ms (interval = 0.5 ms). TRUST was acquired twice sequentially for independent global OEF assessment (τCPMG = 10 ms; effective TEs = 0, 40, 80, and 160 ms; spatial resolution = 3.4 × 3.4 × 5 mm). OEF intraclass-correlation-coefficients (ICC), summary statistics, and group-wise differences were assessed (Wilcoxon rank-sum; significance: two-sided p < 0.05). RESULTS ASERF+ (OEF = 36.8 ± 1.9%) and VASO-ASE (OEF = 34.4 ± 2.3%) produced OEF values similar to TRUST (OEF = 36.5 ± 4.6%, human calibration model; OEF = 32.7 ± 4.9%, bovine calibration model); however, ASERF- yielded lower OEF (OEF = 26.1 ± 1.0%; p < 0.01) relative to TRUST. VASO-ASE (ICC = 0.61) yielded lower ICC compared to other ASE variants (ICC >0.89). CONCLUSION VASO-ASE and TRUST provide similar OEF values; however, VASO-ASE spatial coverage and repeatability improvements are required.
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Affiliation(s)
- Spencer L. Waddle
- Department of Neurology, Vanderbilt University Medical Center, Nashville ,TN, USA
| | - Maria Garza
- Department of Neurology, Vanderbilt University Medical Center, Nashville ,TN, USA
| | - Chunwei Ying
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - L. Taylor Davis
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lori C. Jordan
- Department of Neurology, Vanderbilt University Medical Center, Nashville ,TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hongyu An
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Manus J. Donahue
- Department of Neurology, Vanderbilt University Medical Center, Nashville ,TN, USA
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
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Elabasy A, Suhonen M, Rajna Z, Hosni Y, Kananen J, Annunen J, Ansakorpi H, Korhonen V, Seppänen T, Kiviniemi V. Respiratory brain impulse propagation in focal epilepsy. Sci Rep 2023; 13:5222. [PMID: 36997658 PMCID: PMC10063583 DOI: 10.1038/s41598-023-32271-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023] Open
Abstract
Respiratory brain pulsations pertaining to intra-axial hydrodynamic solute transport are markedly altered in focal epilepsy. We used optical flow analysis of ultra-fast functional magnetic resonance imaging (fMRI) data to investigate the velocity characteristics of respiratory brain impulse propagation in patients with focal epilepsy treated with antiseizure medication (ASM) (medicated patients with focal epilepsy; ME, n = 23), drug-naïve patients with at least one seizure (DN, n = 19) and matched healthy control subjects (HC, n = 75). We detected in the two patient groups (ME and DN) several significant alterations in the respiratory brain pulsation propagation velocity, which showed a bidirectional change dominated by a reduction in speed. Furthermore, the respiratory impulses moved more in reversed or incoherent directions in both patient groups vs. the HC group. The speed reductions and directionality changes occurred in specific phases of the respiratory cycle. In conclusion, irrespective of medication status, both patient groups showed incoherent and slower respiratory brain impulses, which may contribute to epileptic brain pathology by hindering brain hydrodynamics.
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Affiliation(s)
- Ahmed Elabasy
- Center for Machine Vision and Signal Analysis, University of Oulu, 90014, Oulu, Finland.
- Oulu Functional NeuroImaging, Diagnostic Radiology, Medical Research Center/HTS, Oulu University Hospital, 90029, Oulu, Finland.
| | - Mia Suhonen
- Medical Imaging, Physics and Technology, University of Oulu, 90029, Oulu, Finland.
- Oulu Functional NeuroImaging, Diagnostic Radiology, Medical Research Center/HTS, Oulu University Hospital, 90029, Oulu, Finland.
| | - Zalan Rajna
- Center for Machine Vision and Signal Analysis, University of Oulu, 90014, Oulu, Finland
| | - Youssef Hosni
- Center for Machine Vision and Signal Analysis, University of Oulu, 90014, Oulu, Finland
- Oulu Functional NeuroImaging, Diagnostic Radiology, Medical Research Center/HTS, Oulu University Hospital, 90029, Oulu, Finland
| | - Janne Kananen
- Medical Imaging, Physics and Technology, University of Oulu, 90029, Oulu, Finland
- Oulu Functional NeuroImaging, Diagnostic Radiology, Medical Research Center/HTS, Oulu University Hospital, 90029, Oulu, Finland
- Clinical Neurophysiology, Oulu University Hospital, 90029 OYS, Oulu, Finland
| | - Johanna Annunen
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, 90029, Oulu, Finland
- Neurocenter, Neurology, Oulu University Hospital, Member of ERN EpiCARE, 90029, Oulu, Finland
- MRC, Oulu University Hospital, 90029, Oulu, Finland
| | - Hanna Ansakorpi
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, 90029, Oulu, Finland
| | - Vesa Korhonen
- Medical Imaging, Physics and Technology, University of Oulu, 90029, Oulu, Finland
- Oulu Functional NeuroImaging, Diagnostic Radiology, Medical Research Center/HTS, Oulu University Hospital, 90029, Oulu, Finland
| | - Tapio Seppänen
- Center for Machine Vision and Signal Analysis, University of Oulu, 90014, Oulu, Finland
| | - Vesa Kiviniemi
- Medical Imaging, Physics and Technology, University of Oulu, 90029, Oulu, Finland.
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Domogo AA, Reinstrup P, Ottesen JT. Mechanistic-mathematical modeling of intracranial pressure (ICP) profiles over a single heart cycle. The fundament of the ICP curve form. J Theor Biol 2023; 564:111451. [PMID: 36907263 DOI: 10.1016/j.jtbi.2023.111451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/31/2022] [Accepted: 02/28/2023] [Indexed: 03/13/2023]
Abstract
The intracranial pressure (ICP) curve with its different peaks has been comprehensively studied, but the exact physiological mechanisms behind its morphology has not been revealed. If the pathophysiology behind deviations from the normal ICP curve form could be identified, it could be vital information to diagnose and treat each single patient. A mathematical model of the hydrodynamics in the intracranial cavity over single heart cycles was developed. A Windkessel model approach was generalized but the unsteady Bernoulli equation was utilized for blood flow and CSF flow. This is a modification of earlier models using the extended and simplified classical Windkessel analogies to a model that is based on mechanisms rooted in the laws of physics. The improved model was calibrated with patient data for cerebral arterial inflow, venous outflow, cerebrospinal fluid (CSF), and ICP over one heart cycle from 10 neuro-intensive care unit patients. A priori model parameter values were obtained by considering patient data and values taken from earlier studies. These values were used as an initial guess for an iterated constrained-ODE (ordinary differential equation) optimization problem with cerebral arterial inflow data as input into the system of ODEs. The optimization routine found patient-specific model parameter values that produced model ICP curves that showed excellent agreement with clinical measurements while model venous and CSF flow were within a physiologically acceptable range. The improved model and the automated optimization routine gave better model calibration results compared to previous studies. Moreover, patient-specific values of physiologically important parameters like intracranial compliance, arterial and venous elastance, and venous outflow resistance were determined. The model was used to simulate intracranial hydrodynamics and to explain the underlying mechanisms of the ICP curve morphology. Sensitivity analysis showed that the order of the three main peaks of the ICP curve was affected by a decrease in arterial elastance, a large increase in resistance to arteriovenous flow, an increase in venous elastance, or a decrease in resistance to CSF flow in the foramen magnum; and the frequency of oscillations were notably affected by intracranial elastance. In particular, certain pathological peak patterns were caused by these changes in physiological parameters. To the best of our knowledge, there are no other mechanism-based models associating the pathological peak patterns to variation of the physiological parameters.
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Affiliation(s)
- Andrei A Domogo
- Department of Mathematics and Computer Science, University of the Philippines Baguio, Baguio City 2600, Philippines; IMFUFA, Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark.
| | - Peter Reinstrup
- Intensive and Perioperative Care, Skåne University Hospital, Lund, Sweden.
| | - Johnny T Ottesen
- Center for Mathematical Modeling - Human Health and Disease (COMMAND), Roskilde University, 4000 Roskilde, Denmark; IMFUFA, Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark.
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11
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Pardridge WM. Physiologically Based Pharmacokinetic Model of Brain Delivery of Plasma Protein Bound Drugs. Pharm Res 2023; 40:661-674. [PMID: 36829100 PMCID: PMC10036418 DOI: 10.1007/s11095-023-03484-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/10/2023] [Indexed: 02/26/2023]
Abstract
INTRODUCTION A physiologically based pharmacokinetic (PBPK) model is developed that focuses on the kinetic parameters of drug association and dissociation with albumin, alpha-1 acid glycoprotein (AGP), and brain tissue proteins, as well as drug permeability at the blood-brain barrier, drug metabolism, and brain blood flow. GOAL The model evaluates the extent to which plasma protein-mediated uptake (PMU) of drugs by brain influences the concentration of free drug both within the brain capillary compartment in vivo and the brain compartment. The model also studies the effect of drug binding to brain tissue proteins on the concentration of free drug in brain. METHODS The steady state and non-steady state PBPK models are comprised of 11-12 variables, and 18-23 parameters, respectively. Two model drugs are analyzed: propranolol, which undergoes modest PMU from the AGP-bound pool, and imipramine, which undergoes a high degree of PMU from both the albumin-bound and AGP-bound pools in plasma. RESULTS The free propranolol concentration in brain is under-estimated 2- to fourfold by in vitro measurements of free plasma propranolol, and the free imipramine concentration in brain is under-estimated by 18- to 31-fold by in vitro measurements of free imipramine in plasma. The free drug concentration in brain in vivo is independent of drug binding to brain tissue proteins. CONCLUSIONS In vitro measurement of free drug concentration in plasma under-estimates the free drug in brain in vivo if PMU in vivo from either the albumin and/or the AGP pools in plasma takes place at the BBB surface.
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12
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Zhao X, Wright A, Goertz DE. An optical and acoustic investigation of microbubble cavitation in small channels under therapeutic ultrasound conditions. ULTRASONICS SONOCHEMISTRY 2023; 93:106291. [PMID: 36640460 PMCID: PMC9852793 DOI: 10.1016/j.ultsonch.2023.106291] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/22/2022] [Accepted: 01/04/2023] [Indexed: 06/04/2023]
Abstract
Therapeutic focused ultrasound in combination with encapsulated microbubbles is being widely investigated for its ability to elicit bioeffects in the microvasculature, such as transient permeabilization for drug delivery or at higher pressures to achieve 'antivascular' effects. While it is well established that the behaviors of microbubbles are altered when they are situated within sufficiently small vessels, there is a paucity of data examining how the bubble population dynamics and emissions change as a function of channel (vessel) diameter over a size range relevant to therapeutic ultrasound, particularly at pressures relevant to antivascular ultrasound. Here we use acoustic emissions detection and high-speed microscopy (10 kframes/s) to examine the behavior of a polydisperse clinically employed agent (Definity®) in wall-less channels as their diameters are scaled from 1200 to 15 µm. Pressures are varied from 0.1 to 3 MPa using either a 5 ms pulse or a sequence of 0.1 ms pulses spaced at 1 ms, both of which have been previously employed in an in vivo context. With increasing pressure, the 1200 µm channel - on the order of small arteries and veins - exhibited inertial cavitation, 1/2 subharmonics and 3/2 ultraharmonics, consistent with numerous previous reports. The 200 and 100 µm channels - in the size range of larger microvessels less affected by therapeutic focused ultrasound - exhibited a distinctly different behavior, having muted development of 1/2 subharmonics and 3/2 ultraharmonics and reduced persistence. These were associated with radiation forces displacing bubbles to the distal wall and inducing clusters that then rapidly dissipated along with emissions. As the diameter transitioned to 50 and then 15 µm - a size regime that is most relevant to therapeutic focused ultrasound - there was a higher threshold for the onset of inertial cavitation as well as subharmonics and ultraharmonics, which importantly had more complex orders that are not normally reported. Clusters also occurred in these channels (e.g. at 3 MPa, the mean lateral and axial sizes were 23 and 72 µm in the 15 µm channel; 50 and 90 µm in the 50 µm channel), however in this case they occupied the entire lumens and displaced the wall boundaries. Damage to the 15 µm channel was observed for both pulse types, but at a lower pressure for the long pulse. Experiments conducted with a 'nanobubble' (<0.45 µm) subpopulation of Definity followed broadly similar features to 'native' Definity, albeit at a higher pressure threshold for inertial cavitation. These results provide new insights into the behavior of microbubbles in small vessels at higher pressures and have implications for therapeutic focused ultrasound cavitation monitoring and control.
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Affiliation(s)
- Xiaoxiao Zhao
- Department of Medical Biophysics, University of Toronto, M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada.
| | - Alex Wright
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada
| | - David E Goertz
- Department of Medical Biophysics, University of Toronto, M5G 1L7, Canada; Sunnybrook Research Institute, 2075 Bayview Ave, Toronto M4N 3M5, Canada.
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13
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Dixon B, Sharkey JM, Teo EJ, Grace SA, Savage JS, Udy A, Smith P, Hellerstedt J, Santamaria JD. Assessment of a Non-Invasive Brain Pulse Monitor to Measure Intra-Cranial Pressure Following Acute Brain Injury. MEDICAL DEVICES (AUCKLAND, N.Z.) 2023; 16:15-26. [PMID: 36718229 PMCID: PMC9883992 DOI: 10.2147/mder.s398193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/13/2023] [Indexed: 01/26/2023]
Abstract
Background Intracranial pressure (ICP) monitoring requires placing a hole in the skull through which an invasive pressure monitor is inserted into the brain. This approach has risks for the patient and is expensive. We have developed a non-invasive brain pulse monitor that uses red light to detect a photoplethysmographic (PPG) signal arising from the blood vessels on the brain's cortical surface. The brain PPG and the invasive ICP waveform share morphological features which may allow measurement of the intracranial pressure. Methods We enrolled critically ill patients with an acute brain injury with invasive ICP monitoring to assess the new monitor. A total of 24 simultaneous invasive ICP and brain pulse monitor PPG measurements were undertaken in 12 patients over a range of ICP levels. Results The waveform morphologies were similar for the invasive ICP and brain pulse monitor PPG approach. Both methods demonstrated a progressive increase in the amplitude of P2 relative to P1 with increasing ICP levels. An automated algorithm was developed to assess the PPG morphological features in relation to the ICP level. A correlation was demonstrated between the brain pulse waveform morphology and ICP levels, R2=0.66, P < 0.001. Conclusion The brain pulse monitor's PPG waveform demonstrated morphological features were similar to the invasive ICP waveform over a range of ICP levels, these features may provide a method to measure ICP levels. Trial Registration ACTRN12620000828921.
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Affiliation(s)
- Barry Dixon
- Cyban Pty Ltd, Melbourne, VIC, Australia,Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Australia,Department of Medicine, University of Melbourne, Melbourne, Vic, Australia,Correspondence: Barry Dixon, Department of Critical Care Medicine, St Vincent’s Hospital (Melbourne), 41 Victoria Parade, Fitzroy, VIC, 3065, Australia, Tel +61 3 9231 4425, Email
| | | | - Elliot J Teo
- Cyban Pty Ltd, Melbourne, VIC, Australia,Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Australia
| | | | | | - Andrew Udy
- Department of Critical Care Medicine, The Alfred Hospital, Melbourne, Australia
| | - Paul Smith
- Department of Neurosurgery, St Vincent’s Hospital, Melbourne, Australia,University of Melbourne Medical School, Melbourne, Vic, Australia
| | | | - John D Santamaria
- Department of Critical Care Medicine, St Vincent’s Hospital, Melbourne, Australia
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14
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Delvecchio G, Gritti D, Squarcina L, Brambilla P. Neurovascular alterations in bipolar disorder: A review of perfusion weighted magnetic resonance imaging studies. J Affect Disord 2022; 316:254-272. [PMID: 35940377 DOI: 10.1016/j.jad.2022.07.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 07/08/2022] [Accepted: 07/22/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bipolar Disorder (BD) is a severe chronic psychiatric disorder whose aetiology is still largely unknown. However, increasing literature reported the involvement of neurovascular factors in the pathophysiology of BD, suggesting that a measure of Cerebral Blood Flow (CBF) could be an important biomarker of the illness. Therefore, since, to date, Magnetic Resonance Perfusion Weighted Imaging (PWI) techniques, such as Dynamic Susceptibility Contrast (DSC) and Arterial Spin Labelling (ASL), are the most common approaches that allow non-invasive in-vivo perfusion measurements,this review aims to summarize the results from all PWI studies that evaluated the CBF in BD. METHODS A bibliographic search in PubMed up until May 2021 was performed. 16 PWI studies that used DSC or ASL sequences met our inclusion criteria. RESULTS Overall, the results supported the presence of hyper-perfusion in the cingulate cortex and fronto-temporal regions, as well as the presence of hypo-perfusion in the cerebellum in BD, compared with both healthy controls and patients with unipolar depression. CBF changes after cognitive and aerobic training, as well as in relation with other physiological, clinical, and neurocognitive variables were also reported. LIMITATIONS The heterogeneity across the studies, in terms of experimental designs, sample selection, and methodological approach employed, limited the studies' comparison. CONCLUSIONS These findings showed CBF alterations in the cingulate cortex, fronto-temporal regions, and cerebellum in BD, suggesting that CBF may be an important pathophysiological marker of BD that merits further investigation to clarify the extent of neurovascular alterations.
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Affiliation(s)
- Giuseppe Delvecchio
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
| | - Davide Gritti
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Letizia Squarcina
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Paolo Brambilla
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
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15
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Akbari A, Bollmann S, Ali TS, Barth M. Modelling the depth-dependent VASO and BOLD responses in human primary visual cortex. Hum Brain Mapp 2022; 44:710-726. [PMID: 36189837 PMCID: PMC9842911 DOI: 10.1002/hbm.26094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/05/2022] [Accepted: 08/07/2022] [Indexed: 01/25/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) using a blood-oxygenation-level-dependent (BOLD) contrast is a common method for studying human brain function noninvasively. Gradient-echo (GRE) BOLD is highly sensitive to the blood oxygenation change in blood vessels; however, the spatial signal specificity can be degraded due to signal leakage from activated lower layers to superficial layers in depth-dependent (also called laminar or layer-specific) fMRI. Alternatively, physiological variables such as cerebral blood volume using the VAscular-Space-Occupancy (VASO) contrast have shown higher spatial specificity compared to BOLD. To better understand the physiological mechanisms such as blood volume and oxygenation changes and to interpret the measured depth-dependent responses, models are needed which reflect vascular properties at this scale. For this purpose, we extended and modified the "cortical vascular model" previously developed to predict layer-specific BOLD signal changes in human primary visual cortex to also predict a layer-specific VASO response. To evaluate the model, we compared the predictions with experimental results of simultaneous VASO and BOLD measurements in a group of healthy participants. Fitting the model to our experimental data provided an estimate of CBV change in different vascular compartments upon neural activity. We found that stimulus-evoked CBV change mainly occurs in small arterioles, capillaries, and intracortical arteries and that the contribution from venules and ICVs is smaller. Our results confirm that VASO is less susceptible to large vessel effects compared to BOLD, as blood volume changes in intracortical arteries did not substantially affect the resulting depth-dependent VASO profiles, whereas depth-dependent BOLD profiles showed a bias towards signal contributions from intracortical veins.
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Affiliation(s)
- Atena Akbari
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia
| | - Saskia Bollmann
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia
| | - Tonima S. Ali
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia
| | - Markus Barth
- Centre for Advanced ImagingUniversity of QueenslandBrisbaneAustralia,ARC Training Centre for Innovation in Biomedical Imaging TechnologyThe University of QueenslandBrisbaneAustralia,School of Information Technology and Electrical EngineeringThe University of QueenslandBrisbaneQueenslandAustralia
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16
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Qin Q, Alsop DC, Bolar DS, Hernandez‐Garcia L, Meakin J, Liu D, Nayak KS, Schmid S, van Osch MJP, Wong EC, Woods JG, Zaharchuk G, Zhao MY, Zun Z, Guo J. Velocity-selective arterial spin labeling perfusion MRI: A review of the state of the art and recommendations for clinical implementation. Magn Reson Med 2022; 88:1528-1547. [PMID: 35819184 PMCID: PMC9543181 DOI: 10.1002/mrm.29371] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/16/2022] [Accepted: 06/08/2022] [Indexed: 12/11/2022]
Abstract
This review article provides an overview of the current status of velocity-selective arterial spin labeling (VSASL) perfusion MRI and is part of a wider effort arising from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. Since publication of the 2015 consensus paper on arterial spin labeling (ASL) for cerebral perfusion imaging, important advancements have been made in the field. The ASL community has, therefore, decided to provide an extended perspective on various aspects of technical development and application. Because VSASL has the potential to become a principal ASL method because of its unique advantages over traditional approaches, an in-depth discussion was warranted. VSASL labels blood based on its velocity and creates a magnetic bolus immediately proximal to the microvasculature within the imaging volume. VSASL is, therefore, insensitive to transit delay effects, in contrast to spatially selective pulsed and (pseudo-) continuous ASL approaches. Recent technical developments have improved the robustness and the labeling efficiency of VSASL, making it a potentially more favorable ASL approach in a wide range of applications where transit delay effects are of concern. In this review article, we (1) describe the concepts and theoretical basis of VSASL; (2) describe different variants of VSASL and their implementation; (3) provide recommended parameters and practices for clinical adoption; (4) describe challenges in developing and implementing VSASL; and (5) describe its current applications. As VSASL continues to undergo rapid development, the focus of this review is to summarize the fundamental concepts of VSASL, describe existing VSASL techniques and applications, and provide recommendations to help the clinical community adopt VSASL.
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Affiliation(s)
- Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - David C. Alsop
- Department of RadiologyBeth Israel Deaconess Medical Center and Harvard Medical SchoolBostonMassachusettsUSA
| | - Divya S. Bolar
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | | | - James Meakin
- Department of Radiology, Nuclear Medicine and AnatomyRadboud University Medical CenterNijmegenThe Netherlands
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Krishna S. Nayak
- Magnetic Resonance Engineering Laboratory, Ming Hsieh Department of Electrical EngineeringUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Sophie Schmid
- C.J. Gorter Center for high field MRI, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Matthias J. P. van Osch
- C.J. Gorter Center for high field MRI, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Eric C. Wong
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | - Joseph G. Woods
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | - Greg Zaharchuk
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
| | - Moss Y. Zhao
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
| | - Zungho Zun
- Department of RadiologyWeill Cornell MedicineNew YorkNew YorkUSA
| | - Jia Guo
- Department of BioengineeringUniversity of California RiversideRiversideCaliforniaUSA
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17
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Zhang WT, Chao THH, Yang Y, Wang TW, Lee SH, Oyarzabal EA, Zhou J, Nonneman R, Pegard NC, Zhu H, Cui G, Shih YYI. Spectral fiber photometry derives hemoglobin concentration changes for accurate measurement of fluorescent sensor activity. CELL REPORTS METHODS 2022; 2:100243. [PMID: 35880016 PMCID: PMC9308135 DOI: 10.1016/j.crmeth.2022.100243] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/08/2022] [Accepted: 06/08/2022] [Indexed: 12/22/2022]
Abstract
Fiber photometry is an emerging technique for recording fluorescent sensor activity in the brain. However, significant hemoglobin absorption artifacts in fiber photometry data may be misinterpreted as sensor activity changes. Because hemoglobin exists widely in the brain, and its concentration varies temporally, such artifacts could impede the accuracy of photometry recordings. Here we present use of spectral photometry and computational methods to quantify photon absorption effects by using activity-independent fluorescence signals, which can be used to derive oxy- and deoxy-hemoglobin concentration changes. Although these changes are often temporally delayed compared with the fast-responding fluorescence spikes, we found that erroneous interpretation may occur when examining pharmacology-induced sustained changes and that sometimes hemoglobin absorption could flip the GCaMP signal polarity. We provide hemoglobin-based correction methods to restore fluorescence signals and compare our results with other commonly used approaches. We also demonstrated the utility of spectral fiber photometry for delineating regional differences in hemodynamic response functions.
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Affiliation(s)
- Wei-Ting Zhang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yue Yang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sung-Ho Lee
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Esteban A. Oyarzabal
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jingheng Zhou
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Randy Nonneman
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nicolas C. Pegard
- Department of Applied Physical Sciences, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hongtu Zhu
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Guohong Cui
- In Vivo Neurobiology Group, Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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18
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Brighi C, Verburg N, Koh ES, Walker A, Chen C, Pillay S, de Witt Hamer PC, Aly F, Holloway LC, Keall PJ, Waddington DE. Repeatability of radiotherapy dose-painting prescriptions derived from a multiparametric magnetic resonance imaging model of glioblastoma infiltration. Phys Imaging Radiat Oncol 2022; 23:8-15. [PMID: 35734265 PMCID: PMC9207284 DOI: 10.1016/j.phro.2022.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/03/2022] Open
Abstract
Magnetic resonance imaging was used to derive dose-painting prescriptions in glioma. Dose prescriptions derived from magnetic resonance imaging are highly repeatable. Dose-painting plans are more repeatable than their dose prescriptions.
Background and purpose Glioblastoma (GBM) patients have a dismal prognosis. Tumours typically recur within months of surgical resection and post-operative chemoradiation. Multiparametric magnetic resonance imaging (mpMRI) biomarkers promise to improve GBM outcomes by identifying likely regions of infiltrative tumour in tumour probability (TP) maps. These regions could be treated with escalated dose via dose-painting radiotherapy to achieve higher rates of tumour control. Crucial to the technical validation of dose-painting using imaging biomarkers is the repeatability of the derived dose prescriptions. Here, we quantify repeatability of dose-painting prescriptions derived from mpMRI. Materials and methods TP maps were calculated with a clinically validated model that linearly combined apparent diffusion coefficient (ADC) and relative cerebral blood volume (rBV) or ADC and relative cerebral blood flow (rBF) data. Maps were developed for 11 GBM patients who received two mpMRI scans separated by a short interval prior to chemoradiation treatment. A linear dose mapping function was applied to obtain dose-painting prescription (DP) maps for each session. Voxel-wise and group-wise repeatability metrics were calculated for parametric, TP and DP maps within radiotherapy margins. Results DP maps derived from mpMRI were repeatable between imaging sessions (ICC > 0.85). ADC maps showed higher repeatability than rBV and rBF maps (Wilcoxon test, p = 0.001). TP maps obtained from the combination of ADC and rBF were the most stable (median ICC: 0.89). Conclusions Dose-painting prescriptions derived from a mpMRI model of tumour infiltration have a good level of repeatability and can be used to generate reliable dose-painting plans for GBM patients.
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19
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Chiarelli AM, Germuska M, Chandler H, Stickland R, Patitucci E, Biondetti E, Mascali D, Saxena N, Khot S, Steventon J, Foster C, Rodríguez-Soto AE, Englund E, Murphy K, Tomassini V, Wehrli FW, Wise RG. A flow-diffusion model of oxygen transport for quantitative mapping of cerebral metabolic rate of oxygen (CMRO 2) with single gas calibrated fMRI. J Cereb Blood Flow Metab 2022; 42:1192-1209. [PMID: 35107026 PMCID: PMC9207485 DOI: 10.1177/0271678x221077332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
One promising approach for mapping CMRO2 is dual-calibrated functional MRI (dc-fMRI). This method exploits the Fick Principle to combine estimates of CBF from ASL, and OEF derived from BOLD-ASL measurements during arterial O2 and CO2 modulations. Multiple gas modulations are required to decouple OEF and deoxyhemoglobin-sensitive blood volume. We propose an alternative single gas calibrated fMRI framework, integrating a model of oxygen transport, that links blood volume and CBF to OEF and creates a mapping between the maximum BOLD signal, CBF and OEF (and CMRO2). Simulations demonstrated the method's viability within physiological ranges of mitochondrial oxygen pressure, PmO2, and mean capillary transit time. A dc-fMRI experiment, performed on 20 healthy subjects using O2 and CO2 challenges, was used to validate the approach. The validation conveyed expected estimates of model parameters (e.g., low PmO2), with spatially uniform OEF maps (grey matter, GM, OEF spatial standard deviation ≈ 0.13). GM OEF estimates obtained with hypercapnia calibrated fMRI correlated with dc-fMRI (r = 0.65, p = 2·10-3). For 12 subjects, OEF measured with dc-fMRI and the single gas calibration method were correlated with whole-brain OEF derived from phase measures in the superior sagittal sinus (r = 0.58, p = 0.048; r = 0.64, p = 0.025 respectively). Simplified calibrated fMRI using hypercapnia holds promise for clinical application.
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Affiliation(s)
- Antonio M Chiarelli
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Michael Germuska
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Hannah Chandler
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Rachael Stickland
- Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Eleonora Patitucci
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Emma Biondetti
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Daniele Mascali
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Neeraj Saxena
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Sharmila Khot
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Jessica Steventon
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Catherine Foster
- Wales Institute of Social and Economic Research and Data (WISERD), School of Social Sciences, Cardiff University, Cardiff, UK
| | - Ana E Rodríguez-Soto
- Department of Radiology, University of California, San Diego, La Jolla, California, USA
| | - Erin Englund
- Department of Radiology, University of Colorado, Aurora, Colorado, USA
| | - Kevin Murphy
- Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Valentina Tomassini
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK.,MS Centre, Dept of Clinical Neurology, SS. Annunziata University Hospital, Chieti, Italy.,Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.,Helen Durham Centre for Neuroinflammation, University Hospital of Wales, Cardiff, UK
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard G Wise
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
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20
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Chen JJ, Uthayakumar B, Hyder F. Mapping oxidative metabolism in the human brain with calibrated fMRI in health and disease. J Cereb Blood Flow Metab 2022; 42:1139-1162. [PMID: 35296177 PMCID: PMC9207484 DOI: 10.1177/0271678x221077338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Conventional functional MRI (fMRI) with blood-oxygenation level dependent (BOLD) contrast is an important tool for mapping human brain activity non-invasively. Recent interest in quantitative fMRI has renewed the importance of oxidative neuroenergetics as reflected by cerebral metabolic rate of oxygen consumption (CMRO2) to support brain function. Dynamic CMRO2 mapping by calibrated fMRI require multi-modal measurements of BOLD signal along with cerebral blood flow (CBF) and/or volume (CBV). In human subjects this "calibration" is typically performed using a gas mixture containing small amounts of carbon dioxide and/or oxygen-enriched medical air, which are thought to produce changes in CBF (and CBV) and BOLD signal with minimal or no CMRO2 changes. However non-human studies have demonstrated that the "calibration" can also be achieved without gases, revealing good agreement between CMRO2 changes and underlying neuronal activity (e.g., multi-unit activity and local field potential). Given the simpler set-up of gas-free calibrated fMRI, there is evidence of recent clinical applications for this less intrusive direction. This up-to-date review emphasizes technological advances for such translational gas-free calibrated fMRI experiments, also covering historical progression of the calibrated fMRI field that is impacting neurological and neurodegenerative investigations of the human brain.
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Affiliation(s)
- J Jean Chen
- Medical Biophysics, University of Toronto, Toronto, Canada.,Rotman Research Institute, Baycrest, Toronto, Canada
| | - Biranavan Uthayakumar
- Medical Biophysics, University of Toronto, Toronto, Canada.,Sunnybrook Research Institute, Toronto, Canada
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, USA.,Department of Radiology, Yale University, New Haven, Connecticut, USA.,Quantitative Neuroscience with Magnetic Resonance (QNMR) Research Program, Yale University, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
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21
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Lansdell TA, Chambers LC, Dorrance AM. Endothelial Cells and the Cerebral Circulation. Compr Physiol 2022; 12:3449-3508. [PMID: 35766836 DOI: 10.1002/cphy.c210015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.
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Affiliation(s)
- Theresa A Lansdell
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Laura C Chambers
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
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22
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Jiang D, Lu H. Cerebral oxygen extraction fraction MRI: Techniques and applications. Magn Reson Med 2022; 88:575-600. [PMID: 35510696 PMCID: PMC9233013 DOI: 10.1002/mrm.29272] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/20/2022] [Accepted: 03/29/2022] [Indexed: 12/20/2022]
Abstract
The human brain constitutes 2% of the body's total mass but uses 20% of the oxygen. The rate of the brain's oxygen utilization can be derived from a knowledge of cerebral blood flow and the oxygen extraction fraction (OEF). Therefore, OEF is a key physiological parameter of the brain's function and metabolism. OEF has been suggested to be a useful biomarker in a number of brain diseases. With recent advances in MRI techniques, several MRI-based methods have been developed to measure OEF in the human brain. These MRI OEF techniques are based on the T2 of blood, the blood signal phase, the magnetic susceptibility of blood-containing voxels, the effect of deoxyhemoglobin on signal behavior in extravascular tissue, and the calibration of the BOLD signal using gas inhalation. Compared to 15 O PET, which is considered the "gold standard" for OEF measurement, MRI-based techniques are non-invasive, radiation-free, and are more widely available. This article provides a review of these emerging MRI-based OEF techniques. We first briefly introduce the role of OEF in brain oxygen homeostasis. We then review the methodological aspects of different categories of MRI OEF techniques, including their signal mechanisms, acquisition methods, and data analyses. The strengths and limitations of the techniques are discussed. Finally, we review key applications of these techniques in physiological and pathological conditions.
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Affiliation(s)
- Dengrong Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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23
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Bollmann S, Mattern H, Bernier M, Robinson SD, Park DJ, Speck O, Polimeni JR. Imaging of the pial arterial vasculature of the human brain in vivo using high-resolution 7T time-of-flight angiography. eLife 2022; 11:71186. [PMID: 35486089 PMCID: PMC9150892 DOI: 10.7554/elife.71186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 04/28/2022] [Indexed: 11/30/2022] Open
Abstract
The pial arterial vasculature of the human brain is the only blood supply to the neocortex, but quantitative data on the morphology and topology of these mesoscopic arteries (diameter 50–300 µm) remains scarce. Because it is commonly assumed that blood flow velocities in these vessels are prohibitively slow, non-invasive time-of-flight magnetic resonance angiography (TOF-MRA)—which is well suited to high 3D imaging resolutions—has not been applied to imaging the pial arteries. Here, we provide a theoretical framework that outlines how TOF-MRA can visualize small pial arteries in vivo, by employing extremely small voxels at the size of individual vessels. We then provide evidence for this theory by imaging the pial arteries at 140 µm isotropic resolution using a 7 Tesla (T) magnetic resonance imaging (MRI) scanner and prospective motion correction, and show that pial arteries one voxel width in diameter can be detected. We conclude that imaging pial arteries is not limited by slow blood flow, but instead by achievable image resolution. This study represents the first targeted, comprehensive account of imaging pial arteries in vivo in the human brain. This ultra-high-resolution angiography will enable the characterization of pial vascular anatomy across the brain to investigate patterns of blood supply and relationships between vascular and functional architecture.
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Affiliation(s)
- Saskia Bollmann
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
| | - Hendrik Mattern
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Michaël Bernier
- Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, United States
| | - Simon D Robinson
- Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
| | - Daniel J Park
- Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, United States
| | - Oliver Speck
- German Center for Neurodegenerative Diseases, Magdeburg, Germany
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24
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Duckworth H, Azor A, Wischmann N, Zimmerman KA, Tanini I, Sharp DJ, Ghajari M. A Finite Element Model of Cerebral Vascular Injury for Predicting Microbleeds Location. Front Bioeng Biotechnol 2022; 10:860112. [PMID: 35519616 PMCID: PMC9065595 DOI: 10.3389/fbioe.2022.860112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
Finite Element (FE) models of brain mechanics have improved our understanding of the brain response to rapid mechanical loads that produce traumatic brain injuries. However, these models have rarely incorporated vasculature, which limits their ability to predict the response of vessels to head impacts. To address this shortcoming, here we used high-resolution MRI scans to map the venous system anatomy at a submillimetre resolution. We then used this map to develop an FE model of veins and incorporated it in an anatomically detailed FE model of the brain. The model prediction of brain displacement at different locations was compared to controlled experiments on post-mortem human subject heads, yielding over 3,100 displacement curve comparisons, which showed fair to excellent correlation between them. We then used the model to predict the distribution of axial strains and strain rates in the veins of a rugby player who had small blood deposits in his white matter, known as microbleeds, after sustaining a head collision. We hypothesised that the distribution of axial strain and strain rate in veins can predict the pattern of microbleeds. We reconstructed the head collision using video footage and multi-body dynamics modelling and used the predicted head accelerations to load the FE model of vascular injury. The model predicted large axial strains in veins where microbleeds were detected. A region of interest analysis using white matter tracts showed that the tract group with microbleeds had 95th percentile peak axial strain and strain rate of 0.197 and 64.9 s−1 respectively, which were significantly larger than those of the group of tracts without microbleeds (0.163 and 57.0 s−1). This study does not derive a threshold for the onset of microbleeds as it investigated a single case, but it provides evidence for a link between strain and strain rate applied to veins during head impacts and structural damage and allows for future work to generate threshold values. Moreover, our results suggest that the FE model has the potential to be used to predict intracranial vascular injuries after TBI, providing a more objective tool for TBI assessment and improving protection against it.
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Affiliation(s)
- Harry Duckworth
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Adriana Azor
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Nikolaus Wischmann
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
| | - Karl A. Zimmerman
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Ilaria Tanini
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- Industrial Engineering Department, University of Florence, Florence, Italy
| | - David J. Sharp
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
- Care Research and Technology Centre, Dementia Research Institute, London, United Kingdom
| | - Mazdak Ghajari
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- *Correspondence: Mazdak Ghajari,
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25
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Abstract
The brain harbors a unique ability to, figuratively speaking, shift its gears. During wakefulness, the brain is geared fully toward processing information and behaving, while homeostatic functions predominate during sleep. The blood-brain barrier establishes a stable environment that is optimal for neuronal function, yet the barrier imposes a physiological problem; transcapillary filtration that forms extracellular fluid in other organs is reduced to a minimum in brain. Consequently, the brain depends on a special fluid [the cerebrospinal fluid (CSF)] that is flushed into brain along the unique perivascular spaces created by astrocytic vascular endfeet. We describe this pathway, coined the term glymphatic system, based on its dependency on astrocytic vascular endfeet and their adluminal expression of aquaporin-4 water channels facing toward CSF-filled perivascular spaces. Glymphatic clearance of potentially harmful metabolic or protein waste products, such as amyloid-β, is primarily active during sleep, when its physiological drivers, the cardiac cycle, respiration, and slow vasomotion, together efficiently propel CSF inflow along periarterial spaces. The brain's extracellular space contains an abundance of proteoglycans and hyaluronan, which provide a low-resistance hydraulic conduit that rapidly can expand and shrink during the sleep-wake cycle. We describe this unique fluid system of the brain, which meets the brain's requisites to maintain homeostasis similar to peripheral organs, considering the blood-brain-barrier and the paths for formation and egress of the CSF.
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Affiliation(s)
- Martin Kaag Rasmussen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
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26
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Xiao X, Liu X, Liang W, Han LY, Li XD, Guo LJ, He WL, Liu XM, Zhou J, Cai Q, Xu YK, Tan XL, Wu YK. Conventional MRI Features of Central Nervous System Embryonal Tumor, Not Otherwise Specified in Adults: Comparison with Glioblastoma. Acad Radiol 2022; 29 Suppl 3:S44-S51. [PMID: 33504445 DOI: 10.1016/j.acra.2021.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 11/01/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this study was to explore conventional MRI features that can accurately differentiate central nervous system embryonal tumor, not otherwise specified (CNS ETNOS) from glioblastoma (GBM) in adults. MATERIALS AND METHODS Preoperative conventional MRI images of 30 CNS ETNOS and 98 GBMs were analyzed by neuroradiologists retrospectively to identify valuable MRI features. Five blinded neuroradiologists independently reviewed all these MRI images, and scored MRI features on a five-point scale. Kendall's coefficient of concordance was used to measure inter-rater agreement. Diagnostic value was assessed by the area under the curve (AUC) of receiver operating curve, and sensitivity and specificity were also calculated. RESULTS Seven MRI features, including isointensity on T1WI, T2WI, and FLAIR, ill-defined margin, severe peritumoral edema, ring enhancement, and broad-based attachment sign, were helpful for the differential diagnosis of these two entities. Among these features, ring enhancement showed the highest inter-rater concordance (0.80). Ring enhancement showed the highest AUC value (0.79), followed by severe peritumoral edema (0.67). The combination of seven features showed the highest AUC value (0.86), followed by that of three features (ill-defined margin, severe peritumoral edema, and ring enhancement) (0.83). CONCLUSION Enhancement pattern, peritumoral edema, and margin are valuable for the discrimination between CNS ETNOS and GBM in adults.
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27
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Toro EF, Celant M, Zhang Q, Contarino C, Agarwal N, Linninger A, Müller LO. Cerebrospinal fluid dynamics coupled to the global circulation in holistic setting: Mathematical models, numerical methods and applications. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3532. [PMID: 34569188 PMCID: PMC9285081 DOI: 10.1002/cnm.3532] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
This paper presents a mathematical model of the global, arterio-venous circulation in the entire human body, coupled to a refined description of the cerebrospinal fluid (CSF) dynamics in the craniospinal cavity. The present model represents a substantially revised version of the original Müller-Toro mathematical model. It includes one-dimensional (1D), non-linear systems of partial differential equations for 323 major blood vessels and 85 zero-dimensional, differential-algebraic systems for the remaining components. Highlights include the myogenic mechanism of cerebral blood regulation; refined vasculature for the inner ear, the brainstem and the cerebellum; and viscoelastic, rather than purely elastic, models for all blood vessels, arterial and venous. The derived 1D parabolic systems of partial differential equations for all major vessels are approximated by hyperbolic systems with stiff source terms following a relaxation approach. A major novelty of this paper is the coupling of the circulation, as described, to a refined description of the CSF dynamics in the craniospinal cavity, following Linninger et al. The numerical solution methodology employed to approximate the hyperbolic non-linear systems of partial differential equations with stiff source terms is based on the Arbitrary DERivative Riemann problem finite volume framework, supplemented with a well-balanced formulation, and a local time stepping procedure. The full model is validated through comparison of computational results against published data and bespoke MRI measurements. Then we present two medical applications: (i) transverse sinus stenoses and their relation to Idiopathic Intracranial Hypertension; and (ii) extra-cranial venous strictures and their impact in the inner ear circulation, and its implications for Ménière's disease.
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Affiliation(s)
| | - Morena Celant
- Department of MathematicsUniversity of TrentoTrentoItaly
| | - Qinghui Zhang
- Laboratory of Applied Mathematics, DICAMUniversity of TrentoTrentoItaly
| | | | | | - Andreas Linninger
- Department of BioengineeringUniversity of Illinois at ChicagoChicagoIllinoisUSA
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28
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Liu H, Zhang C, Xu J, Jin J, Cheng L, Miao X, Wu Q, Wei Z, Liu P, Lu H, van Zijl PCM, Ross CA, Hua J, Duan W. Huntingtin silencing delays onset and slows progression of Huntington's disease: a biomarker study. Brain 2021; 144:3101-3113. [PMID: 34043007 PMCID: PMC8634120 DOI: 10.1093/brain/awab190] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/19/2021] [Accepted: 04/29/2021] [Indexed: 01/29/2023] Open
Abstract
Huntington's disease is a dominantly inherited, fatal neurodegenerative disorder caused by a CAG expansion in the huntingtin (HTT) gene, coding for pathological mutant HTT protein (mHTT). Because of its gain-of-function mechanism and monogenic aetiology, strategies to lower HTT are being actively investigated as disease-modifying therapies. Most approaches are currently targeted at the manifest stage, where clinical outcomes are used to evaluate the effectiveness of therapy. However, as almost 50% of striatal volume has been lost at the time of onset of clinical manifest, it would be preferable to begin therapy in the premanifest period. An unmet challenge is how to evaluate therapeutic efficacy before the presence of clinical symptoms as outcome measures. To address this, we aim to develop non-invasive sensitive biomarkers that provide insight into therapeutic efficacy in the premanifest stage of Huntington's disease. In this study, we mapped the temporal trajectories of arteriolar cerebral blood volumes (CBVa) using inflow-based vascular-space-occupancy (iVASO) MRI in the heterozygous zQ175 mice, a full-length mHTT expressing and slowly progressing model with a premanifest period as in human Huntington's disease. Significantly elevated CBVa was evident in premanifest zQ175 mice prior to motor deficits and striatal atrophy, recapitulating altered CBVa in human premanifest Huntington's disease. CRISPR/Cas9-mediated non-allele-specific HTT silencing in striatal neurons restored altered CBVa in premanifest zQ175 mice, delayed onset of striatal atrophy, and slowed the progression of motor phenotype and brain pathology. This study-for the first time-shows that a non-invasive functional MRI measure detects therapeutic efficacy in the premanifest stage and demonstrates long-term benefits of a non-allele-selective HTT silencing treatment introduced in the premanifest Huntington's disease.
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Affiliation(s)
- Hongshuai Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chuangchuang Zhang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jing Jin
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Liam Cheng
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xinyuan Miao
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qian Wu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhiliang Wei
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hanzhang Lu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peter C M van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jun Hua
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wenzhen Duan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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29
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Cho J, Zhang J, Spincemaille P, Zhang H, Hubertus S, Wen Y, Jafari R, Zhang S, Nguyen TD, Dimov AV, Gupta A, Wang Y. QQ-NET - using deep learning to solve quantitative susceptibility mapping and quantitative blood oxygen level dependent magnitude (QSM+qBOLD or QQ) based oxygen extraction fraction (OEF) mapping. Magn Reson Med 2021; 87:1583-1594. [PMID: 34719059 DOI: 10.1002/mrm.29057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/01/2021] [Accepted: 10/07/2021] [Indexed: 01/17/2023]
Abstract
PURPOSE To improve accuracy and speed of quantitative susceptibility mapping plus quantitative blood oxygen level-dependent magnitude (QSM+qBOLD or QQ) -based oxygen extraction fraction (OEF) mapping using a deep neural network (QQ-NET). METHODS The 3D multi-echo gradient echo images were acquired in 34 ischemic stroke patients and 4 healthy subjects. Arterial spin labeling and diffusion weighted imaging (DWI) were also performed in the patients. NET was developed to solve the QQ model inversion problem based on Unet. QQ-based OEF maps were reconstructed with previously introduced temporal clustering, tissue composition, and total variation (CCTV) and NET. The results were compared in simulation, ischemic stroke patients, and healthy subjects using a two-sample Kolmogorov-Smirnov test. RESULTS In the simulation, QQ-NET provided more accurate and precise OEF maps than QQ-CCTV with 150 times faster reconstruction speed. In the subacute stroke patients, OEF from QQ-NET had greater contrast-to-noise ratio (CNR) between DWI-defined lesions and their unaffected contralateral normal tissue than with QQ-CCTV: 1.9 ± 1.3 vs 6.6 ± 10.7 (p = 0.03). In healthy subjects, both QQ-CCTV and QQ-NET provided uniform OEF maps. CONCLUSION QQ-NET improves the accuracy of QQ-based OEF with faster reconstruction.
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Affiliation(s)
- Junghun Cho
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Jinwei Zhang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Hang Zhang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Simon Hubertus
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Yan Wen
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Ramin Jafari
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Shun Zhang
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Alexey V Dimov
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
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Xu S, Yang Q, Chen M, Deng P, Zhuang R, Sun Z, Li C, Yan Z, Zhang Y, Jia J. Capturing Neuroplastic Changes after iTBS in Patients with Post-Stroke Aphasia: A Pilot fMRI Study. Brain Sci 2021; 11:brainsci11111451. [PMID: 34827450 PMCID: PMC8615629 DOI: 10.3390/brainsci11111451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Intermittent theta-burst stimulation (iTBS) is a high-efficiency transcranial magnetic stimulation (TMS) paradigm that has been applied to post-stroke aphasia (PSA). However, its efficacy mechanisms have not been clarified. This study aimed to explore the immediate effects of iTBS of the primary motor cortex (M1) of the affected hemisphere, on the functional activities and connectivity of the brains of PSA patients. A total of 16 patients with aphasia after stroke received iTBS with 800 pulses for 300 s. All patients underwent motor, language, and cognitive assessments and resting-state functional MRI scans immediately before and after the iTBS intervention. Regional, seed-based connectivity, and graph-based measures were used to test the immediate functional effects of the iTBS intervention, including the fractional amplitude of low-frequency fluctuation (fALFF), degree centrality (DC), and functional connectivity (FC) of the left M1 area throughout the whole brain. The results showed that after one session of iTBS intervention, the fALFF, DC, and FC values changed significantly in the patients' brains. Specifically, the DC values were significantly higher in the right middle frontal gyrus and parts of the left parietal lobe (p < 0.05), while fALFF values were significantly lower in the right medial frontal lobe and parts of the left intracalcarine cortex (p < 0.05), and the strength of the functional connectivity between the left M1 area and the left superior frontal gyrus was reduced (p < 0.05). Our findings provided preliminary evidences that the iTBS on the ipsilesional M1 could induce neural activity and functional connectivity changes in the motor, language, and other brain regions in patients with PSA, which may promote neuroplasticity and functional recovery.
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Affiliation(s)
- Shuo Xu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China; (S.X.); (Q.Y.); (M.C.)
| | - Qing Yang
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China; (S.X.); (Q.Y.); (M.C.)
| | - Mengye Chen
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China; (S.X.); (Q.Y.); (M.C.)
| | - Panmo Deng
- Department of Rehabilitation Medicine, Jingan District Central Hospital Affiliated to Fudan University, Shanghai 200040, China;
| | - Ren Zhuang
- Department of Rehabilitation Medicine, Changzhou Dean Hospital, Changzhou 213000, China;
| | - Zengchun Sun
- Sichuan Bayi Rehabilitation Center, Affiliated Sichuan Provincial Rehabilitation Hospital of Chengdu University of TCM, Chengdu 610075, China;
| | - Chong Li
- Faculty of Sport and Science, Shanghai University of Sport, Shanghai 200040, China;
| | - Zhijie Yan
- The Third Affiliated Hospital, Xinxiang Medical University, Xinxiang 453003, China;
| | - Yongli Zhang
- Institute of Rehabilitation, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China;
| | - Jie Jia
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China; (S.X.); (Q.Y.); (M.C.)
- Correspondence: ; Tel.: +86-136-1172-2357
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31
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Ishida S, Kimura H, Takei N, Fujiwara Y, Matsuda T, Kanamoto M, Matta Y, Kosaka N, Kidoya E. Separating spin compartments in arterial spin labeling using delays alternating with nutation for tailored excitation (DANTE) pulse: A validation study using T 2 -relaxometry and application to arterial cerebral blood volume imaging. Magn Reson Med 2021; 87:1329-1345. [PMID: 34687085 DOI: 10.1002/mrm.29052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/31/2021] [Accepted: 09/30/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE To clarify the type of spin compartment in arterial spin labeling (ASL) that is eliminated by delays alternating with nutation for tailored excitation (DANTE) pulse using T2 -relaxometry, and to demonstrate the feasibility of arterial cerebral blood volume (CBVa ) imaging using DANTE-ASL in combination with a simplified two-compartment model. METHOD The DANTE and T2 -preparation modules were combined into a single ASL sequence. T2 values under the application of DANTE were determined to evaluate changes in T2 , along with the post-labeling delay (PLD) and the relationship between transit time without DANTE (TTnoVS ) and T2 . The reference tissue T2 (T2_ref ) was also obtained. Subsequently, the DANTE module was embedded into the Hadamard-encoded ASL. Cerebral blood flow (CBF) and CBVa were computed using two Hadamard-encoding datasets (with and without DANTE) in a rest and breath-holding (BH) task. RESULTS While T2 without DANTE (T2_noVS ) decreased as the PLD increased, T2 with DANTE (T2_DANTE ) was equivalent to T2_ref and did not change with the PLD. Although there was a significant positive correlation between TTnoVS and T2_noVS with short PLD, T2_DANTE was not correlated with TTnoVS nor PLD. Baseline CBVa values obtained at rest were 0.64 ± 0.12, 0.64 ± 0.11, and 0.58 ± 0.15 mL/100 g for anterior, middle, and posterior cerebral arteries, respectively. Significant CBF and CBVa elevations were observed in the BH task. CONCLUSION Microvascular compartment signals were eliminated from the total ASL signals by DANTE. CBVa can be measured using Hadamard-encoded DANTE-ASL in combination with a simplified two-compartment model.
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Affiliation(s)
- Shota Ishida
- Radiological Center, University of Fukui Hospital, Eiheiji, Fukui, Japan
| | - Hirohiko Kimura
- Department of Radiology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Fukui, Japan
| | - Naoyuki Takei
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
| | - Yasuhiro Fujiwara
- Department of Medical Image Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Tsuyoshi Matsuda
- Division of Ultra-high Field MRI, Institute for Biomedical Science, Iwate Medical University, Iwate, Japan
| | - Masayuki Kanamoto
- Radiological Center, University of Fukui Hospital, Eiheiji, Fukui, Japan
| | - Yuki Matta
- Radiological Center, University of Fukui Hospital, Eiheiji, Fukui, Japan
| | - Nobuyuki Kosaka
- Department of Radiology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Fukui, Japan
| | - Eiji Kidoya
- Radiological Center, University of Fukui Hospital, Eiheiji, Fukui, Japan
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Scerrati A, De Bonis P, Zamboni P, Dones F, Fontanella M, Cenzato M, Visani J, Bianchi F, Zanin L, Cavallo MA, Sturiale CL. A New Insight in Nonaneurysmal Subarachnoid Hemorrhage: the Potential Role of the Internal Jugular Veins. J Neurol Surg A Cent Eur Neurosurg 2021; 83:344-350. [PMID: 34687035 DOI: 10.1055/s-0041-1733895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Causes of the nonaneurysmal subarachnoid hemorrhage (na-SAH) are still debated. Many studies confirmed the possible involvement of the intracranial venous system, in particular variants of the basal vein of Rosenthal. STUDY OBJECT The aim of this study is to investigate the role of extracranial venous system, in particular the jugular drainage, in the na-SAH pathophysiology. MATERIALS AND METHODS This is a multicenter retrospective study including patients suffering from na-SAH who were radiologically screened to exclude vascular malformations. The course of the internal jugular veins was evaluated to reveal any stenosis (caliber reduction >80%). Particular attention was paid at the passage between the styloid process and the arch of C1 to detect possible compression. As a control group, we enrolled patients who underwent CT angiograms and/or cerebral DSAs in the past 2 years. RESULTS We included 194 patients. The na-SAH group consisted of 94 patients, whereas the control group consisted of 100 patients. Fifty patients of the control group underwent a CT angiography for an ischemic cerebrovascular disease or trauma and 50 patients for an SAH due to a ruptured aneurysm. A significant jugular stenosis was found in 49 (52.1%) patients in the na-SAH group and in 18 (18%) patients in the control group. At univariate and multivariate analysis, the difference was statistically significant (p < 0.0001). CONCLUSIONS This is the first study investigating the correlation between jugular stenosis and the occurrence of na-SAH. The impaired venous outflow due to reduced venous caliber could result in an engorgement of the upstream intracranial veins with transient hypertensive phases facilitating ruptures. Further larger prospective studies are necessary to confirm these data.
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Affiliation(s)
- Alba Scerrati
- Dipartimento di Morfologia, Azienda Ospedaliera Sant'Anna, UOC di Neurochirurgia, Chirurgia e Medicina Sperimentale, Università di Ferrara, Ferrara, Italy
| | - Pasquale De Bonis
- Department of Neurosurgery, University of Ferrara, Ferrara, Emilia-Romagna, Italy
| | - Paolo Zamboni
- Department of Vascular Surgery, University of Ferrara, Ferrara, Emilia-Romagna, Italy
| | - Flavia Dones
- Dipartimento di Morfologia, Azienda Ospedaliera Sant'Anna, UOC di Neurochirurgia, Chirurgia e Medicina Sperimentale, Università di Ferrara, Ferrara, Italy
| | - Marco Fontanella
- Neurosurgery Department of Medical and Surgical Specialties, Radiological Sciences and Public Health University of Brescia, Brescia, Italy
| | - Marco Cenzato
- Department of Neurosurgery, Ospedale Niguarda Ca Granda, Milano, Lombardia, Italy
| | - Jacopo Visani
- Dipartimento di Morfologia, Azienda Ospedaliera Sant'Anna, UOC di Neurochirurgia, Chirurgia e Medicina Sperimentale, Università di Ferrara, Ferrara, Italy
| | - Federico Bianchi
- Department of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Luca Zanin
- Department of Neurosurgery, University of Brescia, Brescia, Lombardia, Italy
| | - Michele Alessandro Cavallo
- Dipartimento di Morfologia, Azienda Ospedaliera Sant'Anna, UOC di Neurochirurgia, Chirurgia e Medicina Sperimentale, Università di Ferrara, Ferrara, Italy
| | - Carmelo Lucio Sturiale
- Department of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
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Imaging faster neural dynamics with fast fMRI: A need for updated models of the hemodynamic response. Prog Neurobiol 2021; 207:102174. [PMID: 34525404 DOI: 10.1016/j.pneurobio.2021.102174] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 07/30/2021] [Accepted: 09/08/2021] [Indexed: 12/20/2022]
Abstract
Fast fMRI enables the detection of neural dynamics over timescales of hundreds of milliseconds, suggesting it may provide a new avenue for studying subsecond neural processes in the human brain. The magnitudes of these fast fMRI dynamics are far greater than predicted by canonical models of the hemodynamic response. Several studies have established nonlinear properties of the hemodynamic response that have significant implications for fast fMRI. We first review nonlinear properties of the hemodynamic response function that may underlie fast fMRI signals. We then illustrate the breakdown of canonical hemodynamic response models in the context of fast neural dynamics. We will then argue that the canonical hemodynamic response function is not likely to reflect the BOLD response to neuronal activity driven by sparse or naturalistic stimuli or perhaps to spontaneous neuronal fluctuations in the resting state. These properties suggest that fast fMRI is capable of tracking surprisingly fast neuronal dynamics, and we discuss the neuroscientific questions that could be addressed using this approach.
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34
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Yin Y, Shu S, Qin L, Shan Y, Gao JH, Lu J. Effects of mild hypoxia on oxygen extraction fraction responses to brain stimulation. J Cereb Blood Flow Metab 2021; 41:2216-2228. [PMID: 33563081 PMCID: PMC8393298 DOI: 10.1177/0271678x21992896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Characterizing the effect of limited oxygen availability on brain metabolism during brain activation is an essential step towards a better understanding of brain homeostasis and has obvious clinical implications. However, how the cerebral oxygen extraction fraction (OEF) depends on oxygen availability during brain activation remains unclear, which is mostly attributable to the scarcity and safety of measurement techniques. Recently, a magnetic resonance imaging (MRI) method that enables noninvasive and dynamic measurement of the OEF has been developed and confirmed to be applicable to functional MRI studies. Using this novel method, the present study investigated the motor-evoked OEF response in both normoxia (21% O2) and hypoxia (12% O2). Our results showed that OEF activation decreased in the brain areas involved in motor task execution. Decreases in the motor-evoked OEF response were greater under hypoxia (-21.7% ± 5.5%) than under normoxia (-11.8% ± 3.7%) and showed a substantial decrease as a function of arterial oxygen saturation. These findings suggest a different relationship between oxygen delivery and consumption during hypoxia compared to normoxia. This methodology may provide a new perspective on the effects of mild hypoxia on brain function.
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Affiliation(s)
- Yayan Yin
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China
| | - Su Shu
- Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China.,Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Lang Qin
- Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China.,Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yi Shan
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China
| | - Jia-Hong Gao
- Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China.,Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,McGovern Institution for Brain Research, Peking University, Beijing, China
| | - Jie Lu
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China.,Department of Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
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AMPK-Regulated Astrocytic Lactate Shuttle Plays a Non-Cell-Autonomous Role in Neuronal Survival. Cell Rep 2021; 32:108092. [PMID: 32877674 PMCID: PMC7531170 DOI: 10.1016/j.celrep.2020.108092] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 07/01/2020] [Accepted: 08/07/2020] [Indexed: 12/18/2022] Open
Abstract
Lactate is used as an energy source by producer cells or shuttled to neighboring cells and tissues. Both glucose and lactate fulfill the bioenergetic demand of neurons, the latter imported from astrocytes. The contribution of astrocytic lactate to neuronal bioenergetics and the mechanisms of astrocytic lactate production are incompletely understood. Through in vivo1H magnetic resonance spectroscopy, 13C glucose mass spectroscopy, and electroencephalographic and molecular studies, here we show that the energy sensor AMP activated protein kinase (AMPK) regulates neuronal survival in a non-cell-autonomous manner. Ampk-null mice are deficient in brain lactate and are seizure prone. Ampk deletion in astroglia, but not neurons, causes neuronal loss in both mammalian and fly brains. Mechanistically, astrocytic AMPK phosphorylated and destabilized thioredoxin-interacting protein (TXNIP), enabling expression and surface translocation of the glucose transporter GLUT1, glucose uptake, and lactate production. Ampk loss in astrocytes causes TXNIP hyperstability, GLUT1 misregulation, inadequate glucose metabolism, and neuronal loss. Muraleedharan et al. demonstrate that AMPK is required for astrocytic glycolysis, lactate production, and lactate shuttle as an energy source to neurons such that AMPK loss in glia causes non-cell-autonomous neuronal loss in the mammalian and fly brain.
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36
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Jordan LC, DeBaun MR, Donahue MJ. Advances in neuroimaging to improve care in sickle cell disease. Lancet Neurol 2021; 20:398-408. [PMID: 33894194 DOI: 10.1016/s1474-4422(20)30490-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/26/2022]
Abstract
Sickle cell disease is associated with progressive and increased neurological morbidity throughout the lifespan. In people with sickle cell anaemia (the most common and severe type of sickle cell disease), silent cerebral infarcts are found in more than a third of adolescents by age 18 years and roughly half of young adults by age 30 years, many of whom have cognitive impairment despite having few or no conventional stroke risk factors. Common anatomical neuroimaging in individuals with sickle disease can assess structural brain injury, such as stroke and silent cerebral infarcts; however, emerging advanced neuroimaging methods can provide novel insights into the pathophysiology of sickle cell disease, including insights into the cerebral haemodynamic and metabolic contributors of neurological injury. Advanced neuroimaging methods, particularly methods that report on aberrant cerebral blood flow and oxygen delivery, have potential for triaging patients for appropriate disease-modifying or curative therapies before they have irreversible neurological injury, and for confirming the benefit of new therapies on brain health in clinical trials.
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Affiliation(s)
- Lori C Jordan
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Michael R DeBaun
- Department of Pediatrics, Vanderbilt-Meharry Center of Excellence in Sickle Cell Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Manus J Donahue
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
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37
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Li W, Liu D, van Zijl PCM, Qin Q. Three-dimensional whole-brain mapping of cerebral blood volume and venous cerebral blood volume using Fourier transform-based velocity-selective pulse trains. Magn Reson Med 2021; 86:1420-1433. [PMID: 33955583 DOI: 10.1002/mrm.28815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/28/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE To develop 3D MRI methods for cerebral blood volume (CBV) and venous cerebral blood volume (vCBV) estimation with whole-brain coverage using Fourier transform-based velocity-selective (FT-VS) pulse trains. METHODS For CBV measurement, FT-VS saturation pulse trains were used to suppress static tissue, whereas CSF contamination was corrected voxel-by-voxel using a multi-readout acquisition and a fast CSF T2 scan. The vCBV mapping was achieved by inserting an arterial-nulling module that included a FT-VS inversion pulse train. Using these methods, CBV and vCBV maps were obtained on 6 healthy volunteers at 3 T. RESULTS The mean CBV and vCBV values in gray matter and white matter in different areas of the brain showed high correlation (r = 0.95 and P < .0001). The averaged CBV and vCBV values of the whole brain were 5.4 ± 0.6 mL/100 g and 2.5 ± 0.3 mL/100 g in gray matter, and 2.6 ± 0.5 mL/100 g and 1.5 ± 0.2 mL/100 g in white matter, respectively, comparable to the literature. CONCLUSION The feasibility of FT-VS-based CBV and vCBV estimation was demonstrated for 3D acquisition with large spatial coverage.
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Affiliation(s)
- Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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38
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Haacke EM, Ge Y, Sethi SK, Buch S, Zamboni P. An Overview of Venous Abnormalities Related to the Development of Lesions in Multiple Sclerosis. Front Neurol 2021; 12:561458. [PMID: 33981281 PMCID: PMC8107266 DOI: 10.3389/fneur.2021.561458] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 03/26/2021] [Indexed: 12/21/2022] Open
Abstract
The etiology of multiple sclerosis (MS) is currently understood to be autoimmune. However, there is a long history and growing evidence for disrupted vasculature and flow within the disease pathology. A broad review of the literature related to vascular effects in MS revealed a suggestive role for abnormal flow in the medullary vein system. Evidence for venous involvement in multiple sclerosis dates back to the early pathological work by Charcot and Bourneville, in the mid-nineteenth century. Pioneering work by Adams in the 1980s demonstrated vasculitis within the walls of veins and venules proximal to active MS lesions. And more recently, magnetic resonance imaging (MRI) has been used to show manifestations of the central vein as a precursor to the development of new MS lesions, and high-resolution MRI using Ferumoxytol has been used to reveal the microvasculature that has previously only been demonstrated in cadaver brains. Both approaches may shed new light into the structural changes occurring in MS lesions. The material covered in this review shows that multiple pathophysiological events may occur sequentially, in parallel, or in a vicious circle which include: endothelial damage, venous collagenosis and fibrin deposition, loss of vessel compliance, venous hypertension, perfusion reduction followed by ischemia, medullary vein dilation and local vascular remodeling. We come to the conclusion that a potential source of MS lesions is due to locally disrupted flow which in turn leads to remodeling of the medullary veins followed by endothelial damage with the subsequent escape of glial cells, cytokines, etc. These ultimately lead to the cascade of inflammatory and demyelinating events which ensue in the course of the disease.
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Affiliation(s)
- E. Mark Haacke
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Yulin Ge
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, United States
| | - Sean K. Sethi
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Sagar Buch
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Paolo Zamboni
- Vascular Diseases Center, University of Ferrara, Ferrara, Italy
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Kashyap S, Ivanov D, Havlicek M, Huber L, Poser BA, Uludağ K. Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T. PLoS One 2021; 16:e0250504. [PMID: 33901230 PMCID: PMC8075193 DOI: 10.1371/journal.pone.0250504] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
Laminar fMRI at ultra-high magnetic field strength is typically carried out using the Blood Oxygenation Level-Dependent (BOLD) contrast. Despite its unrivalled sensitivity to detecting activation, the BOLD contrast is limited in its spatial specificity due to signals stemming from intra-cortical ascending and pial veins. Alternatively, regional changes in perfusion (i.e., cerebral blood flow through tissue) are colocalised to neuronal activation, which can be non-invasively measured using Arterial Spin Labelling (ASL) MRI. In addition, ASL provides a quantitative marker of neuronal activation in terms of perfusion signal, which is simultaneously acquired along with the BOLD signal. However, ASL for laminar imaging is challenging due to the lower SNR of the perfusion signal and higher RF power deposition i.e., specific absorption rate (SAR) of ASL sequences. In the present study, we present for the first time in humans, isotropic sub-millimetre spatial resolution functional perfusion images using Flow-sensitive Alternating Inversion Recovery (FAIR) ASL with a 3D-EPI readout at 7 T. We show that robust statistical activation maps can be obtained with perfusion-weighting in a single session. We observed the characteristic BOLD amplitude increase towards the superficial laminae, and, in apparent discrepancy, the relative perfusion profile shows a decrease of the amplitude and the absolute perfusion profile a much smaller increase towards the cortical surface. Considering the draining vein effect on the BOLD signal using model-based spatial “convolution”, we show that the empirically measured perfusion and BOLD profiles are, in fact, consistent with each other. This study demonstrates that laminar perfusion fMRI in humans is feasible at 7 T and that caution must be exercised when interpreting BOLD signal laminar profiles as direct representation of the cortical distribution of neuronal activity.
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Affiliation(s)
- Sriranga Kashyap
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Centre (M-BIC), Maastricht University, Maastricht, The Netherlands
- * E-mail: (SK); (DI)
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Centre (M-BIC), Maastricht University, Maastricht, The Netherlands
- * E-mail: (SK); (DI)
| | - Martin Havlicek
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Laurentius Huber
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Centre (M-BIC), Maastricht University, Maastricht, The Netherlands
| | - Benedikt A. Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Centre (M-BIC), Maastricht University, Maastricht, The Netherlands
| | - Kâmil Uludağ
- Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University, Suwon, South Korea
- Department of Biomedical Engineering, N Center, Sungkyunkwan University, Suwon, South Korea
- Techna Institute & Koerner Scientist in MR Imaging, University Health Network, Toronto, Canada
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40
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Decreased Muscular Perfusion in Dermatomyositis: Initial Results Detected by Inflow-Based Vascular-Space-Occupancy MRI. AJR Am J Roentgenol 2021; 216:1588-1595. [PMID: 33787295 DOI: 10.2214/ajr.20.23045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. This study aimed to determine whether inflow-based vascular-space-occupancy (iVASO) MRI could reproducibly quantify skeletal muscle perfusion and differentiate patients with dermatomyositis (DM) from healthy subjects. MATERIALS AND METHODS. A total of 25 patients with DM and 22 healthy volunteers underwent iVASO MRI in a 3-T MRI scanner. Maximum and mean arteriolar muscle blood volume (MBV) values of four subgroups of muscles (normal muscles, morphologically normal-appearing muscles, edematous muscles, and atrophic or fat-infiltrated muscles) were obtained. Maximum and mean arteriolar MBV values were compared among the different subgroups, and repeat testing was performed in 20 subjects to assess reproducibility. RESULTS. Compared with normal muscles in healthy subjects, morphologically normal-appearing muscles, edematous muscles, and atrophic or fat-infiltrated muscles in patients with DM showed a significant decrease of both maximum and mean arteriolar MBV (p < .001). Both parameters were significantly lower in atrophic or fat-infiltrated muscles than in morphologically normal-appearing and edematous muscles (p < .001). ROC AUCs for discriminating patients with DM from healthy volunteers were 0.842 and 0.812 for maximum and mean arteriolar MBV values, respectively. As a measure of test-retest studies, the intraclass correlation coefficients (ICCs) were 0.990 (95% CI, 0.986-0.993) and 0.990 (95% CI, 0.987-0.993) for maximum and mean arteriolar MBV, respectively. For interobserver reproducibility, the ICCs were 0.989 (95% CI, 0.986-0.991) and 0.980 (95% CI, 0.975-0.983), respectively. CONCLUSION. iVASO MRI can reproducibly quantify arteriolar MBV in the thigh and discriminate between healthy volunteers and patients with DM.
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Cao H, Xiao X, Hua J, Huang G, He W, Qin J, Wu Y, Li X. The Added Value of Inflow-Based Vascular-Space-Occupancy and Diffusion-Weighted Imaging in Preoperative Grading of Gliomas. NEURODEGENER DIS 2021; 20:123-130. [PMID: 33735873 DOI: 10.1159/000512545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 10/26/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The present study aimed to study whether combined inflow-based vascular-space-occupancy (iVASO) MR imaging (MRI) and diffusion-weighted imaging (DWI) improve the diagnostic accuracy in the preoperative grading of gliomas. METHODS Fifty-one patients with histopathologically confirmed diffuse gliomas underwent preoperative structural MRI, iVASO, and DWI. We performed 2 qualitative consensus reviews: (1) structural MR images alone and (2) structural MR images with iVASO and DWI. Relative arteriolar cerebral blood volume (rCBVa) and minimum apparent diffusion coefficient (mADC) were compared between low-grade and high-grade gliomas. Receiver operating characteristic (ROC) curve analysis was performed to compare the tumor grading efficiency of rCBVa, mADC, and the combination of the two parameters. RESULTS Two observers diagnosed accurate tumor grade in 40 of 51 (78.4%) patients in the first review and in 46 of 51 (90.2%) in the second review. Both rCBVa and mADC showed significant differences between low-grade and high-grade gliomas. ROC analysis gave a threshold value of 1.52 for rCBVa and 0.85 × 10-3 mm2/s for mADC to provide a sensitivity and specificity of 88.0 and 81.2% and 100.0 and 68.7%, respectively. The area under the ROC curve (AUC) was 0.87 and 0.85 for rCBVa and mADC, respectively. The combination of rCBVa and mADC values increased the AUC to 0.92. CONCLUSION The combined application of iVASO and DWI may improve the diagnostic accuracy of glioma grading.
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Affiliation(s)
- Haimei Cao
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiang Xiao
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Hua
- Neurosection, Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Meghalaya, USA.,Department of Radiology, F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Meghalaya, USA
| | - Guanglong Huang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Wenle He
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jie Qin
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuankui Wu
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China,
| | - Xiaodan Li
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
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Narciso L, Ssali T, Iida H, St Lawrence K. A non-invasive reference-based method for imaging the cerebral metabolic rate of oxygen by PET/MR: theory and error analysis. Phys Med Biol 2021; 66:065009. [PMID: 33596555 DOI: 10.1088/1361-6560/abe737] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Positron emission tomography (PET) remains the gold standard for quantitative imaging of the cerebral metabolic rate of oxygen (CMRO2); however, it is an invasive and complex procedure that requires accounting for recirculating [15O]H2O (RW) and the cerebral blood volume (CBV). This study presents a non-invasive reference-based technique for imaging CMRO2 that was developed for PET/magnetic resonance imaging (MRI) with the goal of simplifying the PET procedure while maintaining its ability to quantify metabolism. The approach is to use whole-brain (WB) measurements of oxygen extraction fraction (OEF) and cerebral blood flow (CBF) to calibrate [15O]O2-PET data, thereby avoiding the need for invasive arterial sampling. Here we present the theoretical framework, along with error analyses, sensitivity to PET noise and inaccuracies in input parameters, and initial assessment on PET data acquired from healthy participants. Simulations showed that neglecting RW and CBV corrections caused errors in CMRO2 of less than ±10% for changes in regional OEF of ±25%. These predictions were supported by applying the reference-based approach to PET data, which resulted in remarkably similar CMRO2 images to those generated by analyzing the same data using a modeling approach that incorporated the arterial input functions and corrected for CBV contributions. Significant correlations were observed between regional CMRO2 values from the two techniques (slope = 1.00 ± 0.04, R 2 > 0.98) with no significant differences found for integration times of 3 and 5 min. In summary, results demonstrate the feasibility of producing quantitative CMRO2 images by PET/MRI without the need for invasive blood sampling.
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Affiliation(s)
- Lucas Narciso
- Lawson Health Research Institute, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Tracy Ssali
- Lawson Health Research Institute, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Hidehiro Iida
- University of Turku and Turku PET Centre, Turku, Finland.,National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Keith St Lawrence
- Lawson Health Research Institute, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada
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He W, Li X, Hua J, Liao S, Guo L, Xiao X, Liu X, Zhou J, Wang W, Xu Y, Wu Y. Noninvasive Assessment of O(6)-Methylguanine-DNA Methyltransferase Promoter Methylation Status in World Health Organization Grade II-IV Glioma Using Histogram Analysis of Inflow-Based Vascular-Space-Occupancy Combined with Structural Magnetic Resonance Imaging. J Magn Reson Imaging 2021; 54:227-236. [PMID: 33590929 DOI: 10.1002/jmri.27514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation is an important prognostic factor for gliomas and is associated with tumor angiogenesis. Arteriolar cerebral blood volume (CBVa) obtained from inflow-based vascular-space-occupancy (iVASO) magnetic resonance imaging (MRI) is assumed to be an indicator of tumor microvasculature. Its preoperative predictive ability for MGMT promoter methylation remains unclear. PURPOSE To investigate the role of iVASO-CBVa histogram features in determining MGMT promoter methylation status of grade II-IV gliomas. STUDY TYPE Retrospective SUBJECTS: Forty-six patients consisting of 20 MGMT methylated and 26 unmethylated gliomas. FIELD STRENGTH/SEQUENCE 3.0 T magnetic resonance images containing iVASO MRI, T1 -weighted image (T1 WI), T2 -weighted image, T2 -weighted fluid attenuated inversion recovery image images, and enhanced T1 WI. ASSESSMENT Sixteen structural imaging features were visually evaluated on structural MRI and 14 CBVa histogram features were extracted from iVASO-CBVa maps. STATISTICAL TESTS Imaging features were screened and ranked using Fisher's exact test, Mann-Whitney U-test, and randomforest algorithm. Features with higher importance were selected to develop logistic regression models to determine MGMT methylation status. Receiver operating characteristics (ROC) curve with the area under the curve (AUC) and leave-one-out cross-validation (LOOCV) were used to assess effectiveness and stability. RESULTS The top two CBVa histogram features were root mean squared (RMS) and variance. The top two structural imaging features were contrast-enhancing component of the tumor (CET) location and tumor location. Both the CBVa model of RMS and variance (ROC, AUC = 0.867; LOOCV, AUC = 0.819) and the model of structural features (ROC, AUC = 0.882; LOOCV, AUC = 0.802) accurately identified MGMT methylation. The fusion model of CBVa RMS and CET location improved diagnostic performance (ROC, AUC = 0.931; LOOCV, AUC =0.906). DATA CONCLUSION: iVASO-CBVa has potential in evaluating MGMT methylation status in grade II-IV gliomas. LEVEL OF EVIDENCE 4 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Wenle He
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Radiology, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Xiaodan Li
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Hua
- Neurosection, Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Shukun Liao
- Division of CT & MR, Radiology Department, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Liuji Guo
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiang Xiao
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaomin Liu
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Zhou
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Wensheng Wang
- Department of Radiology, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Yikai Xu
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuankui Wu
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, China
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Guo L, Li X, Cao H, Hua J, Mei Y, Pillai JJ, Wu Y. Inflow-based vascular-space-occupancy (iVASO) might potentially predict IDH mutation status and tumor grade in diffuse cerebral gliomas. J Neuroradiol 2021; 49:267-274. [PMID: 33482231 DOI: 10.1016/j.neurad.2021.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/13/2020] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
PURPOSE The aim of the study is to assess the diagnostic performance of inflow-based vascular-space-occupancy (iVASO) MR imaging for differentiating glioblastomas (grade IV, GBM) and lower-grade diffuse gliomas (grade II and III, LGG) and its potential to predict IDH mutation status. METHODS One hundred and two patients with diffuse cerebral glioma (56 males; median age, 43.5 years) underwent iVASO and dynamic susceptibility contrast (DSC) MR imaging. The iVASO-derived arteriolar cerebral blood volume (CBVa), relative CBVa (rCBVa), and the DSC-derived relative cerebral blood volume (rCBV) were obtained, and these measurements were compared between the GBM group (n = 43) and the LGG group (n = 59) and between the IDH-mutation group (n = 54) and the IDH-wild group (n = 48). RESULTS Significant correlation was observed between rCBV and CBVa (P < 0.001) or rCBVa (P < 0.001). Both CBVa (P < 0.001) and rCBVa (P < 0.001) were higher in the GBM group. Both CBVa (P < 0.001) and rCBVa (P < 0.001) were lower in the IDH-mutation group compared to the IDH-wild group. Receiver operating characteristic analyses showed the area under curve (AUC) of 0.95 with CBVa and 0.97 with rCBVa in differentiating GBM from LGG. The AUCs were 0.82 and 0.85 for CBVa and rCBVa in predicting IDH gene status, respectively, which were lower than that of rCBV (AUC = 0.90). Combined rCBV and rCBVa significantly improved the diagnostic performance (AUC = 0.95). CONCLUSIONS iVASO MR imaging has the potential to predict IDH mutation and grade in glioma.
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Affiliation(s)
- Liuji Guo
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, PR China
| | - Xiaodan Li
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, PR China
| | - Haimei Cao
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, PR China
| | - Jun Hua
- Neurosection, Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Yingjie Mei
- China International Center, Philips Healthcare, Guangzhou, PR China
| | - Jay J Pillai
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuankui Wu
- Department of Medical Imaging, Nanfang Hospital, Southern Medical University, Guangzhou, PR China.
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Tsvetanov KA, Henson RNA, Rowe JB. Separating vascular and neuronal effects of age on fMRI BOLD signals. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190631. [PMID: 33190597 PMCID: PMC7741031 DOI: 10.1098/rstb.2019.0631] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2020] [Indexed: 12/14/2022] Open
Abstract
Accurate identification of brain function is necessary to understand the neurobiology of cognitive ageing, and thereby promote well-being across the lifespan. A common tool used to investigate neurocognitive ageing is functional magnetic resonance imaging (fMRI). However, although fMRI data are often interpreted in terms of neuronal activity, the blood oxygenation level-dependent (BOLD) signal measured by fMRI includes contributions of both vascular and neuronal factors, which change differentially with age. While some studies investigate vascular ageing factors, the results of these studies are not well known within the field of neurocognitive ageing and therefore vascular confounds in neurocognitive fMRI studies are common. Despite over 10 000 BOLD-fMRI papers on ageing, fewer than 20 have applied techniques to correct for vascular effects. However, neurovascular ageing is not only a confound in fMRI, but an important feature in its own right, to be assessed alongside measures of neuronal ageing. We review current approaches to dissociate neuronal and vascular components of BOLD-fMRI of regional activity and functional connectivity. We highlight emerging evidence that vascular mechanisms in the brain do not simply control blood flow to support the metabolic needs of neurons, but form complex neurovascular interactions that influence neuronal function in health and disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Kamen A. Tsvetanov
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Richard N. A. Henson
- Department of Psychiatry, University of Cambridge, Cambridge CB2 0SP, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | - James B. Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
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Buch S, Subramanian K, Jella PK, Chen Y, Wu Z, Shah K, Bernitsas E, Ge Y, Haacke EM. Revealing vascular abnormalities and measuring small vessel density in multiple sclerosis lesions using USPIO. Neuroimage Clin 2020; 29:102525. [PMID: 33338965 PMCID: PMC7750444 DOI: 10.1016/j.nicl.2020.102525] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND PURPOSE Multiple Sclerosis (MS) is a progressive, inflammatory, neuro-degenerative disease of the central nervous system (CNS) characterized by a wide range of histopathological features including vascular abnormalities. In this study, an ultra-small superparamagnetic iron oxide (USPIO) contrast agent, Ferumoxytol, was administered to induce an increase in susceptibility for both arteries and veins to help better reveal the cerebral microvasculature. The purpose of this work was to examine the presence of vascular abnormalities and vascular density in MS lesions using high-resolution susceptibility weighted imaging (SWI). METHODS Six subjects with relapsing remitting MS (RRMS, age = 47.3 ± 11.8 years with 3 females and 3 males) and fourteen age-matched healthy controls were scanned at 3 T with SWI acquired before and after the infusion of Ferumoxytol. Composite data was generated by registering the FLAIR data to the high resolution SWI data in order to highlight the vascular information in MS lesions. Both the central vein sign (CVS) and, a new measure, the multiple vessel sign (MVS) were identified, along with any vascular abnormalities, in the lesions on pre- and post-contrast SWI-FLAIR fusion data. The small vessel density within the periventricular normal-appearing white matter (NAWM) and the periventricular lesions were compared for all subjects. RESULTS Averaged across two independent raters, a total of 530 lesions were identified across all patients. The total number of lesions with vascularity on pre- and post-contrast data were 287 and 488, respectively. The lesions with abnormal vascular behavior were broken up into following categories: small lesions appearing only at the vessel boundary; dilated vessels within the lesions; and developmental venous angiomas. These vessel abnormalities observed within lesions increased from 55 on pre-contrast data to 153 on post-contrast data. Finally, across all the patients, the periventricular lesional vessel density was significantly higher (p < 0.05) than that of the periventricular NAWM. CONCLUSIONS By inducing a super-paramagnetic susceptibility in the blood using Ferumoxytol, the vascular abnormalities in the RRMS patients were revealed and small vessel densities were obtained. This approach has the potential to monitor the venous vasculature present in MS lesions, catalogue their characteristics and compare the vascular structures spatially to the presence of lesions. These enhanced vascular features may provide new insight into the pathophysiology of MS.
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Affiliation(s)
- Sagar Buch
- Department of Radiology, Wayne State University, Detroit, MI, USA
| | | | - Pavan K Jella
- Department of Radiology, Wayne State University, Detroit, MI, USA
| | - Yongsheng Chen
- Department of Neurology, Wayne State University, Detroit, MI, USA
| | - Zhen Wu
- Department of Radiology, Wayne State University, Detroit, MI, USA
| | - Kamran Shah
- Department of Radiology, Wayne State University, Detroit, MI, USA
| | | | - Yulin Ge
- Center for Biomedical Imaging, Department of Radiology, NYU Grossman School of Medicine, New York, NY, USA
| | - E Mark Haacke
- Department of Radiology, Wayne State University, Detroit, MI, USA; Department of Neurology, Wayne State University, Detroit, MI, USA.
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Kallab M, Hommer N, Tan B, Pfister M, Schlatter A, Werkmeister RM, Chua J, Schmidl D, Schmetterer L, Garhöfer G. Plexus-specific effect of flicker-light stimulation on the retinal microvasculature assessed with optical coherence tomography angiography. Am J Physiol Heart Circ Physiol 2020; 320:H23-H28. [PMID: 33275537 DOI: 10.1152/ajpheart.00495.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In neural tissues, the coupling between neural activity and blood flow is a physiological key principle in blood flow regulation. We used optical coherence tomography angiography to investigate stimulus-evoked hemodynamic responses in different microvascular layers of the human retina. Twenty-two healthy subjects were included. Vessel density before and during light stimulation was measured using optical coherence tomography angiography and assessed for the superficial, intermediate, and deep capillary plexus of the retinal circulation. Volumetric blood flow was measured using a custom-built Doppler optical coherence tomography system. Our results show that flicker stimulation induced a significant increase in the vessel density of +9.9 ± 6.7% in the superficial capillary plexus, +6.6 ± 1.7% in the intermediate capillary plexus, and +4.9 ± 2.3% in the deep capillary plexus. The hyperemic response of the superficial capillary plexus was significantly higher compared to the intermediate capillary plexus (P = 0.02) and deep capillary plexus (P = 0.002). Volumetric retinal blood flow increased by +39.9 ± 34.9% in arteries and by +29.8 ± 16.8% in veins. In conclusion, we showed a strong increase in the retinal microvascular density in response to light stimulation, with the most pronounced effect in the superficial capillary plexus. This is compatible with the hypothesis that the microvasculature exerts an important function in mediating functional hyperemia in humans.NEW & NOTEWORTHY We present vessel density alterations in response to flicker stimulation using optical coherence tomography angiography and identified the superficial capillary plexus as the layer with the most pronounced effect. This points out the physiological importance of the microvasculature in mediating functional hyperemia and suggests a fine-tuned plexus-specific mechanism to meet cellular metabolic demands.
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Affiliation(s)
- Martin Kallab
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Nikolaus Hommer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore.,Institute of Health Technology, Nanyang Technological University, Singapore
| | - Martin Pfister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Ocular and Dermal Effects of Thiomers, Medical University of Vienna, Vienna, Austria.,Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Andreas Schlatter
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Department of Ophthalmology, Vienna Institute for Research in Ocular Surgery-Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore.,Institute of Health Technology, Nanyang Technological University, Singapore.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore.,Institute of Clinical and Experimental Ophthalmology, Basel, Switzerland
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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Paez AG, Gu C, Rajan S, Miao X, Cao D, Kamath V, Bakker A, Unschuld PG, Pantelyat AY, Rosenthal LS, Hua J. Differential Changes in Arteriolar Cerebral Blood Volume between Parkinson's Disease Patients with Normal and Impaired Cognition and Mild Cognitive Impairment (MCI) Patients without Movement Disorder - An Exploratory Study. Tomography 2020; 6:333-342. [PMID: 33364423 PMCID: PMC7744190 DOI: 10.18383/j.tom.2020.00033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cognitive impairment amongst Parkinson's disease (PD) patients is highly prevalent and associated with an increased risk of dementia. There is growing evidence that altered cerebrovascular functions contribute to cognitive impairment. Few studies have compared cerebrovascular changes in PD patients with normal and impaired cognition and those with mild-cognitive-impairment (MCI) without movement disorder. Here, we investigated arteriolar-cerebral-blood-volume (CBVa), an index reflecting the homeostasis of the most actively regulated segment in the microvasculature, using advanced MRI in various brain regions in PD and MCI patients and matched controls. Our goal is to find brain regions with altered CBVa that are specific to PD with normal and impaired cognition, and MCI-without-movement-disorder, respectively. In PD patients with normal cognition (n=10), CBVa was significantly decreased in the substantia nigra, caudate and putamen when compared to controls. In PD patients with impaired cognition (n=6), CBVa showed a decreasing trend in the substantia nigra, caudate and putamen, but was significantly increased in the presupplementary motor area and intracalcarine gyrus compared to controls. In MCI-patients-without-movement-disorder (n=18), CBVa was significantly increased in the caudate, putamen, hippocampus and lingual gyrus compared to controls. These findings provide important information for efforts towards developing biomarkers for the evaluation of potential risk of PD dementia (PDD) in PD patients. The current study is limited in sample size and therefore is exploratory in nature. The data from this pilot study will serve as the basis for power analysis for subsequent studies to further investigate and validate the current findings.
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Affiliation(s)
- Adrian G. Paez
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
- Neurosection, Division of MR Research, Department of Radiology
| | - Chunming Gu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
- Neurosection, Division of MR Research, Department of Radiology
| | - Suraj Rajan
- Department of Neurology; and
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD; and
| | - Xinyuan Miao
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
- Neurosection, Division of MR Research, Department of Radiology
| | - Di Cao
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
- Neurosection, Division of MR Research, Department of Radiology
- Department of Biomedical Engineering
| | - Vidyulata Kamath
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD; and
| | - Arnold Bakker
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD; and
| | - Paul G. Unschuld
- Department of Psychogeriatric Medicine, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | | | | | - Jun Hua
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD
- Neurosection, Division of MR Research, Department of Radiology
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Zhang Y, Yin Y, Li H, Gao JH. Measurement of CMRO 2 and its relationship with CBF in hypoxia with an extended calibrated BOLD method. J Cereb Blood Flow Metab 2020; 40:2066-2080. [PMID: 31665954 PMCID: PMC7786846 DOI: 10.1177/0271678x19885124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) are physiological parameters that not only reflect brain health and disease but also jointly contribute to blood oxygen level-dependent (BOLD) signals. Nevertheless, unsolved issues remain concerning the CBF-CMRO2 relationship in the working brain under various oxygen conditions. In particular, the CMRO2 responses to functional tasks in hypoxia are less studied. We extended the calibrated BOLD model to incorporate CMRO2 measurements in hypoxia. The extended model, which was cross-validated with a multicompartment BOLD model, considers the influences of the reduced arterial saturation level and increased baseline cerebral blood volume (CBV) and deoxyhemoglobin concentration on the changes of BOLD signals in hypoxia. By implementing a pulse sequence to simultaneously acquire the CBV-, CBF- and BOLD-weighted signals, we investigated the effects of mild hypoxia on the CBF and CMRO2 responses to graded visual stimuli. Compared with normoxia, mild hypoxia caused significant alterations in both the amplitude and the trend of the CMRO2 responses but did not impact the corresponding CBF responses. Our observations suggested that the flow-metabolism coupling strategies in the brain during mild hypoxia were different from those during normoxia.
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Affiliation(s)
- Yaoyu Zhang
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yayan Yin
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China
| | - Huanjie Li
- School of Biomedical Engineering, Dalian University of Technology, Dalian, China
| | - Jia-Hong Gao
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Beijing City Key Lab for Medical Physics and Engineering, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing, China.,McGovern Institute for Brain Research, Peking University, Beijing, China
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Lee H, Wehrli FW. Venous cerebral blood volume mapping in the whole brain using venous-spin-labeled 3D turbo spin echo. Magn Reson Med 2020; 84:1991-2003. [PMID: 32243708 DOI: 10.1002/mrm.28262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/27/2020] [Accepted: 02/29/2020] [Indexed: 11/12/2022]
Abstract
PURPOSE Venous cerebral blood volume (CBVv ) is a major contributor to BOLD contrast, and therefore is an important parameter for understanding the underlying mechanism. Here, we propose a velocity-selective venous spin labeling (VS-VSL)-prepared 3D turbo spin echo pulse sequence for whole-brain baseline CBVv mapping. METHODS Unlike previous CBVv measurement techniques that exploit the interrelationship between BOLD signals and CBVv , in the proposed VS-VSL technique both arterial blood and cerebrospinal fluid (CSF) signals were suppressed before the VS pulse train for exclusive labeling of venous blood, while a single-slab 3D turbo spin echo readout was used because of its relative immunity to magnetic field variations. Furthermore, two approximations were made to the VS-VSL signal model for simplified derivation of CBVv . In vivo studies were performed at 3T field strength in 8 healthy subjects. The performance of the proposed VS-VSL method in baseline CBVv estimation was first evaluated in comparison to the existing, hyperoxia-based method. Then, data were also acquired using VS-VSL under hypercapnic and hyperoxic gas breathing challenges for further validation of the technique. RESULTS The proposed technique yielded physiologically plausible baseline CBVv values, and when compared with the hyperoxia-based method, showed no statistical difference. Furthermore, data acquired using VS-VSL yielded average CBVv of 2.89%/1.78%, 3.71%/2.29%, and 2.88%/1.76% for baseline, hypercapnia, and hyperoxia, respectively, in gray/white matter regions. As expected, hyperoxia had negligible effect (P > .8), whereas hypercapnia demonstrated vasodilation (P << .01). CONCLUSION Upon further validation of the quantification model, the method is expected to have merit for 3D CBVv measurements across the entire brain.
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Affiliation(s)
- Hyunyeol Lee
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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