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Woods JG, Achten E, Asllani I, Bolar DS, Dai W, Detre JA, Fan AP, Fernández-Seara M, Golay X, Günther M, Guo J, Hernandez-Garcia L, Ho ML, Juttukonda MR, Lu H, MacIntosh BJ, Madhuranthakam AJ, Mutsaerts HJ, Okell TW, Parkes LM, Pinter N, Pinto J, Qin Q, Smits M, Suzuki Y, Thomas DL, Van Osch MJ, Wang DJJ, Warnert EA, Zaharchuk G, Zelaya F, Zhao M, Chappell MA. Recommendations for quantitative cerebral perfusion MRI using multi-timepoint arterial spin labeling: Acquisition, quantification, and clinical applications. Magn Reson Med 2024; 92:469-495. [PMID: 38594906 PMCID: PMC11142882 DOI: 10.1002/mrm.30091] [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: 08/31/2023] [Revised: 02/09/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024]
Abstract
Accurate assessment of cerebral perfusion is vital for understanding the hemodynamic processes involved in various neurological disorders and guiding clinical decision-making. This guidelines article provides a comprehensive overview of quantitative perfusion imaging of the brain using multi-timepoint arterial spin labeling (ASL), along with recommendations for its acquisition and quantification. A major benefit of acquiring ASL data with multiple label durations and/or post-labeling delays (PLDs) is being able to account for the effect of variable arterial transit time (ATT) on quantitative perfusion values and additionally visualize the spatial pattern of ATT itself, providing valuable clinical insights. Although multi-timepoint data can be acquired in the same scan time as single-PLD data with comparable perfusion measurement precision, its acquisition and postprocessing presents challenges beyond single-PLD ASL, impeding widespread adoption. Building upon the 2015 ASL consensus article, this work highlights the protocol distinctions specific to multi-timepoint ASL and provides robust recommendations for acquiring high-quality data. Additionally, we propose an extended quantification model based on the 2015 consensus model and discuss relevant postprocessing options to enhance the analysis of multi-timepoint ASL data. Furthermore, we review the potential clinical applications where multi-timepoint ASL is expected to offer significant benefits. This article is part of a series published by the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group, aiming to guide and inspire the advancement and utilization of ASL beyond the scope of the 2015 consensus article.
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Affiliation(s)
- Joseph G. Woods
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Eric Achten
- Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium
| | - Iris Asllani
- Department of Neuroscience, University of Sussex, UK and Department of Biomedical Engineering, Rochester Institute of Technology, USA
| | - Divya S. Bolar
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Weiying Dai
- Department of Computer Science, State University of New York at Binghamton, Binghamton, NY, USA, 13902
| | - John A. Detre
- Department of Neurology, University of Pennsylvania, 3 Dulles Building, 3400 Spruce Street, Philadelphia, PA 19104 USA
| | - Audrey P. Fan
- Department of Biomedical Engineering, Department of Neurology, University of California Davis, Davis, CA, USA
| | - Maria Fernández-Seara
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain; IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Xavier Golay
- UCL Queen Square Institute of Neurology, University College London, London, UK; Gold Standard Phantoms, UK
| | - Matthias Günther
- Imaging Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
- Departments of Physics and Electrical Engineering, University of Bremen, Bremen, Germany
| | - Jia Guo
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | | | - Mai-Lan Ho
- Department of Radiology, University of Missouri, Columbia, MO, USA. ORCID: 0000-0002-9455-1350
| | - Meher R. Juttukonda
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bradley J. MacIntosh
- Hurvitz Brain Sciences Program, Centre for Brain Resilience & Recovery, Sunnybrook Research Institute, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Computational Radiology & Artificial Intelligence unit, Oslo University Hospital, Oslo, Norway
| | - Ananth J. Madhuranthakam
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Henk-Jan Mutsaerts
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Radiology and Nuclear Medicine, Amsterdam, The Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, The Netherlands
| | - Thomas W. Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Laura M. Parkes
- School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, UK
| | - Nandor Pinter
- Dent Neurologic Institute, Buffalo, New York, USA; University at Buffalo Neurosurgery, Buffalo, New York, USA
| | - Joana Pinto
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Marion Smits
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Medical Delta, Delft, The Netherlands
- Erasmus MC Cancer Institute, Erasmus MC, Rotterdam, NL
| | - Yuriko Suzuki
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - David L. Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Matthias J.P. Van Osch
- C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Danny JJ Wang
- Laboratory of FMRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Esther A.H. Warnert
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Erasmus MC, Rotterdam, NL
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Fernando Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Moss Zhao
- Department of Radiology, Stanford University, Stanford, CA, USA
- Maternal & Child Health Research Institute, Stanford University, Stanford, CA, USA
| | - Michael A. Chappell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
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Mahmud SZ, Denney TS, Bashir A. Non-contrast estimate of blood-brain barrier permeability in humans using arterial spin labeling and magnetization transfer at 7 T. NMR IN BIOMEDICINE 2023; 36:e4908. [PMID: 36650646 DOI: 10.1002/nbm.4908] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 12/17/2022] [Accepted: 01/16/2023] [Indexed: 06/15/2023]
Abstract
Blood-brain barrier (BBB) dysfunction is associated with a number of central nervous system diseases. This study demonstrates the application of a novel noninvasive technique to measure the BBB permeability in the human brain at 7 T. The technique exploits the fact that, when tissue macromolecules are saturated by off-resonance RF pulse, the intravascular and the extravascular (tissue) water experience different magnetization transfer effects. This principle was combined with arterial spin labeling to distinguish between the intravascular and the tissue water, and was used to calculate perfusion, water extraction fraction (E), and BBB permeability surface area product for water (PS). Simultaneous coregistered magnetization transfer ratio maps were also generated that can provide valuable additional information. Eighteen healthy volunteers (seven females), age = 27 ± 11 years and weight = 65 ± 9 kg, participated in the study. Average perfusion was 67 ± 5 and 29 ± 4 ml/100 g/min (p < 0.05); and E was 0.921 ± 0.025 and 0.962 ± 0.015 (p < 0.05) in the gray matter (GM) and the white matter (WM), respectively. PS was higher in the GM (171 ± 20 ml/100 g/min) compared with the WM (95 ± 18 ml/100 g/min) (p < 0.05). The parameters exhibited good reliability with test re-test experiments. The sensitivity of this technique was demonstrated by 200 mg caffeine intake, which resulted in a decrease in the resting PS by ~31%.
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Affiliation(s)
- Sultan Z Mahmud
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
| | - Thomas S Denney
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
| | - Adil Bashir
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
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Hernandez‐Garcia L, Aramendía‐Vidaurreta V, Bolar DS, Dai W, Fernández‐Seara MA, Guo J, Madhuranthakam AJ, Mutsaerts H, Petr J, Qin Q, Schollenberger J, Suzuki Y, Taso M, Thomas DL, van Osch MJP, Woods J, Zhao MY, Yan L, Wang Z, Zhao L, Okell TW. Recent Technical Developments in ASL: A Review of the State of the Art. Magn Reson Med 2022; 88:2021-2042. [PMID: 35983963 PMCID: PMC9420802 DOI: 10.1002/mrm.29381] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 05/31/2022] [Accepted: 06/18/2022] [Indexed: 12/11/2022]
Abstract
This review article provides an overview of a range of recent technical developments in advanced arterial spin labeling (ASL) methods that have been developed or adopted by the community since the publication of a previous ASL consensus paper by Alsop et al. It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine Perfusion Study Group. Here, we focus on advancements in readouts and trajectories, image reconstruction, noise reduction, partial volume correction, quantification of nonperfusion parameters, fMRI, fingerprinting, vessel selective ASL, angiography, deep learning, and ultrahigh field ASL. We aim to provide a high level of understanding of these new approaches and some guidance for their implementation, with the goal of facilitating the adoption of such advances by research groups and by MRI vendors. Topics outside the scope of this article that are reviewed at length in separate articles include velocity selective ASL, multiple-timepoint ASL, body ASL, and clinical ASL recommendations.
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Affiliation(s)
| | | | - Divya S. Bolar
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of California at San DiegoSan DiegoCaliforniaUSA
| | - Weiying Dai
- Department of Computer ScienceState University of New York at BinghamtonBinghamtonNYUSA
| | | | - Jia Guo
- Department of BioengineeringUniversity of California RiversideRiversideCaliforniaUSA
| | | | - Henk Mutsaerts
- Department of Radiology & Nuclear MedicineAmsterdam University Medical Center, Amsterdam NeuroscienceAmsterdamThe Netherlands
| | - Jan Petr
- Helmholtz‐Zentrum Dresden‐RossendorfInstitute of Radiopharmaceutical Cancer ResearchDresdenGermany
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins UniversityBaltimoreMarylandUSA
| | | | - Yuriko Suzuki
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
| | - Manuel Taso
- Division of MRI research, RadiologyBeth Israel Deaconess Medical Center and Harvard Medical SchoolBostonMassachusettsUSA
| | - David L. Thomas
- Department of Brain Repair and RehabilitationUCL Queen Square Institute of NeurologyLondonUnited Kingdom
| | - Matthias J. P. van Osch
- C.J. Gorter Center for high field MRI, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Joseph Woods
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
- Department of RadiologyUniversity of CaliforniaLa JollaCaliforniaUSA
| | - Moss Y. Zhao
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
| | - Lirong Yan
- Department of Radiology, Feinberg School of MedicineNorthwestern UniversityChicagoIllinoisUSA
| | - Ze Wang
- Department of Diagnostic Radiology and Nuclear MedicineUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Li Zhao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument ScienceZhejiang UniversityZhejiangPeople's Republic of China
| | - Thomas W. Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
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Okada T, Fujimoto K, Fushimi Y, Akasaka T, Thuy DHD, Shima A, Sawamoto N, Oishi N, Zhang Z, Funaki T, Nakamoto Y, Murai T, Miyamoto S, Takahashi R, Isa T. Neuroimaging at 7 Tesla: a pictorial narrative review. Quant Imaging Med Surg 2022; 12:3406-3435. [PMID: 35655840 PMCID: PMC9131333 DOI: 10.21037/qims-21-969] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/05/2022] [Indexed: 01/26/2024]
Abstract
Neuroimaging using the 7-Tesla (7T) human magnetic resonance (MR) system is rapidly gaining popularity after being approved for clinical use in the European Union and the USA. This trend is the same for functional MR imaging (MRI). The primary advantages of 7T over lower magnetic fields are its higher signal-to-noise and contrast-to-noise ratios, which provide high-resolution acquisitions and better contrast, making it easier to detect lesions and structural changes in brain disorders. Another advantage is the capability to measure a greater number of neurochemicals by virtue of the increased spectral resolution. Many structural and functional studies using 7T have been conducted to visualize details in the white matter and layers of the cortex and hippocampus, the subnucleus or regions of the putamen, the globus pallidus, thalamus and substantia nigra, and in small structures, such as the subthalamic nucleus, habenula, perforating arteries, and the perivascular space, that are difficult to observe at lower magnetic field strengths. The target disorders for 7T neuroimaging range from tumoral diseases to vascular, neurodegenerative, and psychiatric disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, major depressive disorder, and schizophrenia. MR spectroscopy has also been used for research because of its increased chemical shift that separates overlapping peaks and resolves neurochemicals more effectively at 7T than a lower magnetic field. This paper presents a narrative review of these topics and an illustrative presentation of images obtained at 7T. We expect 7T neuroimaging to provide a new imaging biomarker of various brain disorders.
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Affiliation(s)
- Tomohisa Okada
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koji Fujimoto
- Department of Real World Data Research and Development, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasutaka Fushimi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Thai Akasaka
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Dinh H. D. Thuy
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Shima
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobukatsu Sawamoto
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Naoya Oishi
- Medial Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Zhilin Zhang
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takeshi Funaki
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuji Nakamoto
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Toshiya Murai
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tadashi Isa
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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5
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Damato EG, Flak TA, Mayes RS, Strohl KP, Ziganti AM, Abdollahifar A, Flask CA, LaManna JC, Decker MJ. Neurovascular and cortical responses to hyperoxia: enhanced cognition and electroencephalographic activity despite reduced perfusion. J Physiol 2020; 598:3941-3956. [PMID: 33174711 DOI: 10.1113/jp279453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Extreme aviation is accompanied by ever-present risks of hypobaric hypoxia and decompression sickness. Neuroprotection against those hazards is conferred through fractional inspired oxygen ( F I , O 2 ) concentrations of 60-100% (hyperoxia). Hyperoxia reduces global cerebral perfusion (gCBF), increases reactive oxygen species within the brain and leads to cell death within the hippocampus. However, an understanding of hyperoxia's effect on cortical activity and concomitant levels of cognitive performance is lacking. This limits our understanding of whether hyperoxia could lower the brain's threshold of tolerance to physiological stressors inherent to extreme aviation, such as high gravitational forces. This study aimed to quantify the impact of hyperoxia upon global cerebral perfusion (gCBF), cognitive performance and cortical electroencephalography (EEG). Hyperoxia evoked a rapid reduction in gCBF, yet cognitive performance and vigilance were enhanced. EEG measurements revealed enhanced alpha power, suggesting less desynchrony, within the cortical temporal regions. Collectively, this work suggests hyperoxia-induced brain hypoperfusion is accompanied by enhanced cognitive processing and cortical arousal. ABSTRACT Extreme aviators continually inspire hyperoxic gas to mitigate risk of hypoxia and decompression injury. This neuroprotection carries a physiological cost: reduced cerebral perfusion (CBF). As reduced CBF may increase vulnerability to ever-present physiological challenges during extreme aviation, we defined the magnitude and duration of hyperoxia-induced changes in CBF, cortical electrical activity and cognition in 30 healthy males and females. Magnetic resonance imaging with pulsed arterial spin labelling provided serial measurements of global CBF (gCBF), first during exposure to 21% inspired oxygen ( F I , O 2 ) followed by a 30-min exposure to 100% F I , O 2 . High-density EEG facilitated characterization of cortical activity during assessment of cognitive performance, also measured during exposure to 21% and 100% F I , O 2 . Acid-base physiology was measured with arterial blood gases. We found that exposure to 100% F I , O 2 reduced gCBF to 63% of baseline values across all participants. Cognitive performance testing at 21% F I , O 2 was accompanied by increased theta and beta power with decreased alpha power across multiple cortical areas. During cognitive testing at 100% F I , O 2 , alpha activity was less desynchronized within the temporal regions than at 21% F I , O 2 . The collective hyperoxia-induced changes in gCBF, cognitive performance and EEG were similar across observed partial pressures of arterial oxygen ( P a O 2 ), which ranged between 276-548 mmHg, and partial pressures of arterial carbon dioxide ( P aC O 2 ), which ranged between 34-50 mmHg. Sex did not influence gCBF response to 100% F I , O 2 . Our findings suggest hyperoxia-induced reductions in gCBF evoke enhanced levels of cortical arousal and cognitive processing, similar to those occurring during a perceived threat.
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Affiliation(s)
- Elizabeth G Damato
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,School of Nursing, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Tod A Flak
- Bioautomatix, LLC, Shaker Heights, OH, 44122, USA
| | - Ryan S Mayes
- United States Air Force, 711th Human Performance Wing, USAF School of Aerospace Medicine, Wright-Patterson AFB, OH, 45433, USA
| | - Kingman P Strohl
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,Louis Stokes Cleveland Veterans Administration Medical Center, Cleveland, OH, 44106, USA
| | - Aemilee M Ziganti
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Alireza Abdollahifar
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Chris A Flask
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Radiology, School of Medicine, Cleveland, OH, 44106, USA
| | - Joseph C LaManna
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Michael J Decker
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
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6
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Tong Y, Jezzard P, Okell TW, Clarke WT. Improving PCASL at ultra-high field using a VERSE-guided parallel transmission strategy. Magn Reson Med 2020; 84:777-786. [PMID: 31971634 PMCID: PMC7216913 DOI: 10.1002/mrm.28173] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/02/2019] [Accepted: 12/24/2019] [Indexed: 11/16/2022]
Abstract
Purpose To improve the labeling efficiency of pseudo‐continuous arterial spin labeling (PCASL) at 7T using parallel transmission (pTx). Methods Five healthy subjects were scanned on an 8‐channel‐transmit 7T human MRI scanner. Time‐of‐flight (TOF) angiography was acquired to identify regions of interest (ROIs) around the 4 major feeding arteries to the brain, and B1+ and B0 maps were acquired in the labeling plane for tagging pulse design. Complex weights of the labeling pulses for each of the 8 transmit channels were calculated to produce a homogenous radiofrequency (RF) ‐shimmed labeling across the ROIs. Variable‐Rate Selective Excitation (VERSE) pulses were also implemented as a part of the labeling pulse train. Whole‐brain perfusion‐weighted images were acquired under conditions of RF shimming, VERSE with RF shimming, and standard circularly polarized (CP) mode. The same subjects were scanned on a 3T scanner for comparison. Results In simulation, VERSE with RF shimming improved the flip‐angles across the ROIs in the labeling plane by 90% compared with CP mode. VERSE with RF shimming improved the temporal signal‐to‐noise ratio by 375% compared with CP mode, but did not outperform a matched 3T sequence with a matched flip‐angle. Conclusion We have demonstrated improved PCASL tagging at 7T using VERSE with RF shimming on a commercial head coil under conservative SAR limits at 7T. However, improvements of 7T over 3T may require strategies with less conservative SAR restrictions.
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Affiliation(s)
- Yan Tong
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - Peter Jezzard
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - Thomas W Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - William T Clarke
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
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7
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Cho J, Zhang S, Kee Y, Spincemaille P, Nguyen TD, Hubertus S, Gupta A, Wang Y. Cluster analysis of time evolution (CAT) for quantitative susceptibility mapping (QSM) and quantitative blood oxygen level-dependent magnitude (qBOLD)-based oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO 2 ) mapping. Magn Reson Med 2019; 83:844-857. [PMID: 31502723 DOI: 10.1002/mrm.27967] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/07/2019] [Accepted: 08/04/2019] [Indexed: 01/01/2023]
Abstract
PURPOSE To improve the accuracy of QSM plus quantitative blood oxygen level-dependent magnitude (QSM + qBOLD or QQ)-based mapping of the oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2 ) using cluster analysis of time evolution (CAT). METHODS 3D multi-echo gradient echo and arterial spin labeling images were acquired in 11 healthy subjects and 5 ischemic stroke patients. DWI was also carried out on patients. CAT was developed for analyzing signal evolution over TE. QQ-based OEF and CMRO2 were reconstructed with and without CAT, and results were compared using region of interest analysis and a paired t-test. RESULTS Simulations demonstrated that CAT substantially reduced noise error in QQ-based OEF. In healthy subjects, QQ-based OEF appeared less noisy and more uniform with CAT than without CAT; average OEF with and without CAT in cortical gray matter was 32.7 ± 4.0% and 37.9 ± 4.5%, with corresponding CMRO2 of 148.4 ± 23.8 and 171.4 ± 22.4 μmol/100 g/min, respectively. In patients, regions of low OEF were confined within the ischemic lesions defined on DWI when using CAT, which was not observed without CAT. CONCLUSION The cluster analysis of time evolution (CAT) significantly improves the robustness of QQ-based OEF against noise.
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Affiliation(s)
- Junghun Cho
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Shun Zhang
- Department of Radiology, Weill Cornell Medical College, New York, New York
- Department of Radiology, Tongji Hospital, Wuhan, China
| | - Youngwook Kee
- Department of Radiology, Weill Cornell Medical College, New York, New York
| | | | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York
| | - Simon Hubertus
- Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, New York
| | - Yi Wang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
- Department of Radiology, Weill Cornell Medical College, New York, New York
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8
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Carone D, Harston GWJ, Garrard J, De Angeli F, Griffanti L, Okell TW, Chappell MA, Kennedy J. ICA-based denoising for ASL perfusion imaging. Neuroimage 2019; 200:363-372. [PMID: 31276796 PMCID: PMC6711457 DOI: 10.1016/j.neuroimage.2019.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/20/2022] Open
Abstract
Arterial Spin Labelling (ASL) imaging derives a perfusion image by tracing the accumulation of magnetically labeled blood water in the brain. As the image generated has an intrinsically low signal to noise ratio (SNR), multiple measurements are routinely acquired and averaged, at a penalty of increased scan duration and opportunity for motion artefact. However, this strategy alone might be ineffective in clinical settings where the time available for acquisition is limited and patient motion are increased. This study investigates the use of an Independent Component Analysis (ICA) approach for denoising ASL data, and its potential for automation. 72 ASL datasets (pseudo-continuous ASL; 5 different post-labeling delays: 400, 800, 1200, 1600, 2000 m s; total volumes = 60) were collected from thirty consecutive acute stroke patients. The effects of ICA-based denoising (manual and automated) where compared to two different denoising approaches, aCompCor, a Principal Component-based method, and Enhancement of Automated Blood Flow Estimates (ENABLE), an algorithm based on the removal of corrupted volumes. Multiple metrics were used to assess the changes in the quality of the data following denoising, including changes in cerebral blood flow (CBF) and arterial transit time (ATT), SNR, and repeatability. Additionally, the relationship between SNR and number of repetitions acquired was estimated before and after denoising the data. The use of an ICA-based denoising approach resulted in significantly higher mean CBF and ATT values (p < 0.001), lower CBF and ATT variance (p < 0.001), increased SNR (p < 0.001), and improved repeatability (p < 0.05) when compared to the raw data. The performance of manual and automated ICA-based denoising was comparable. These results went beyond the effects of aCompCor or ENABLE. Following ICA-based denoising, the SNR was higher using only 50% of the ASL-dataset collected than when using the whole raw data. The results show that ICA can be used to separate signal from noise in ASL data, improving the quality of the data collected. In fact, this study suggests that the acquisition time could be reduced by 50% without penalty to data quality, something that merits further study. Independent component classification and regression can be carried out either manually, following simple criteria, or automatically. ICA can be used to separate signal from noise in ASL data, improving data quality. Automated denoising reproduces the improvement seen by a manual approach. ICA based denoising is superior to PCA or volume censoring approaches. ASL acquisition time could be reduced by 50% without penalty to data quality.
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Affiliation(s)
- D Carone
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; Laboratory of Experimental Stroke Research, Department of Surgery and Translational Medicine, University of Milano Bicocca, Milan Center of Neuroscience, Monza, Italy
| | - G W J Harston
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - J Garrard
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - F De Angeli
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; Laboratory of Experimental Stroke Research, Department of Surgery and Translational Medicine, University of Milano Bicocca, Milan Center of Neuroscience, Monza, Italy
| | - L Griffanti
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - T W Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - M A Chappell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom; Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, United Kingdom
| | - J Kennedy
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.
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9
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Woods JG, Chappell MA, Okell TW. A general framework for optimizing arterial spin labeling MRI experiments. Magn Reson Med 2019; 81:2474-2488. [PMID: 30588656 PMCID: PMC6492260 DOI: 10.1002/mrm.27580] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 09/21/2018] [Accepted: 10/02/2018] [Indexed: 11/22/2022]
Abstract
PURPOSE Arterial spin labeling (ASL) MRI is a non-invasive perfusion imaging technique that is inherently SNR limited, so scan protocols ideally need to be rigorously optimized to provide the most accurate measurements. A general framework is presented for optimizing ASL experiments to achieve optimal accuracy for perfusion estimates and, if required, other hemodynamic parameters, within a fixed scan time. The effectiveness of this framework is then demonstrated by optimizing the post-labeling delays (PLDs) of a multi-PLD pseudo-continuous ASL experiment and validating the improvement using simulations and in vivo data. THEORY AND METHODS A simple framework is proposed based on the use of the Cramér-Rao lower bound to find the protocol design which minimizes the predicted parameter estimation errors. Protocols were optimized for cerebral blood flow (CBF) accuracy or both CBF and arterial transit time (ATT) accuracy and compared to a conventional multi-PLD protocol, with evenly spaced PLDs, and a single-PLD protocol, using simulations and in vivo experiments in healthy volunteers. RESULTS Simulations and in vivo data agreed extremely well with the predicted performance of all protocols. For the in vivo experiments, optimizing for just CBF resulted in a 48% and 15% decrease in CBF errors, relative to the reference multi-PLD and single-PLD protocols, respectively. Optimizing for both CBF and ATT reduced CBF errors by 37%, without a reduction in ATT accuracy, relative to the reference multi-PLD protocol. CONCLUSION The presented framework can effectively design ASL experiments to minimize measurement errors based on the requirements of the scan.
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Affiliation(s)
- Joseph G. Woods
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
| | - Michael A. Chappell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
- Institute of Biomedical Engineering, Department of EngineeringUniversity of OxfordOxfordUnited Kingdom
| | - Thomas W. Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
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10
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Dury RJ, Falah Y, Gowland PA, Evangelou N, Bright MG, Francis ST. Ultra-high-field arterial spin labelling MRI for non-contrast assessment of cortical lesion perfusion in multiple sclerosis. Eur Radiol 2018; 29:2027-2033. [PMID: 30280247 PMCID: PMC6420612 DOI: 10.1007/s00330-018-5707-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/09/2018] [Accepted: 08/06/2018] [Indexed: 11/27/2022]
Abstract
Objectives To assess the feasibility of using an optimised ultra-high-field high-spatial-resolution low-distortion arterial spin labelling (ASL) MRI acquisition to measure focal haemodynamic pathology in cortical lesions (CLs) in multiple sclerosis (MS). Methods Twelve MS patients (eight female, mean age 50 years; range 35–64 years) gave informed consent and were scanned on a 7 Tesla Philips Achieva scanner. Perfusion data were collected at multiple post-labelling delay times using a single-slice flow-sensitive alternating inversion recovery ASL protocol with a balanced steady-state free precession readout scheme. CLs were identified using a high-resolution Phase-Sensitive Inversion Recovery (PSIR) scan. Significant differences in perfusion within CLs compared to immediately surrounding normal appearing grey matter (NAGMlocal) and total cortical normal appearing grey matter (NAGMcortical) were assessed using paired t-tests. Results Forty CLs were identified in PSIR scans that overlapped with the ASL acquisition coverage. After excluding lesions due to small size or intravascular contamination, 27 lesions were eligible for analysis. Mean perfusion was 40 ± 25 ml/100 g/min in CLs, 53 ± 12 ml/100 g/min in NAGMlocal, and 53 ± 8 ml/100 g/min in NAGMcortical. CL perfusion was significantly reduced by 23 ± 9% (mean ± SE, p = 0.013) and 26 ± 9% (p = 0.006) relative to NAGMlocal and NAGMcortical perfusion, respectively. Conclusion This is the first ASL MRI study quantifying CL perfusion in MS at 7 Tesla, demonstrating that an optimised ASL acquisition is sensitive to focal haemodynamic pathology previously observed using dynamic susceptibility contrast MRI. ASL requires no exogenous contrast agent, making it a more appropriate tool to monitor longitudinal perfusion changes in MS, providing a new window to study lesion development. Key Points • Perfusion can be quantified within cortical lesions in multiple sclerosis using an optimised high spatial resolution arterial spin Labelling MRI acquisition at ultra-high-field. • The majority of cortical lesions assessed using arterial spin labelling are hypo-perfused compared to normal appearing grey matter, in agreement with dynamic susceptibility contrast MRI literature. • Arterial spin labelling MRI, which does not involve the injection of a contrast agent, is a safe and appropriate technique for repeat scanning of an individual patient.
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Affiliation(s)
- Richard J Dury
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Yasser Falah
- Clinical Neurology, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Penny A Gowland
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Nikos Evangelou
- Clinical Neurology, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Molly G Bright
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK. .,Clinical Neurology, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK. .,Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 1100, Chicago, IL, 60611, USA. .,Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, 60208, USA.
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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11
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Cho J, Kee Y, Spincemaille P, Nguyen TD, Zhang J, Gupta A, Zhang S, Wang Y. Cerebral metabolic rate of oxygen (CMRO 2 ) mapping by combining quantitative susceptibility mapping (QSM) and quantitative blood oxygenation level-dependent imaging (qBOLD). Magn Reson Med 2018. [PMID: 29516537 DOI: 10.1002/mrm.27135] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To map the cerebral metabolic rate of oxygen (CMRO2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. THEORY AND METHODS 3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. RESULTS The average CMRO2 value in cortical gray matter across subjects were 140.4 ± 14.9, 134.1 ± 12.5, and 184.6 ± 17.9 μmol/100 g/min, with corresponding OEFs of 30.9 ± 3.4%, 30.0 ± 1.8%, and 40.9 ± 2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. CONCLUSION Quantitative CMRO2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude.
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Affiliation(s)
- Junghun Cho
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Youngwook Kee
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Pascal Spincemaille
- 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
| | - Jingwei Zhang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Shun Zhang
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Radiology, Tongji Hospital, Wuhan, China
| | - Yi Wang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Department of Radiology, Weill Cornell Medical College, New York, New York, USA
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12
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Advances in MR angiography with 7T MRI: From microvascular imaging to functional angiography. Neuroimage 2018; 168:269-278. [DOI: 10.1016/j.neuroimage.2017.01.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 01/03/2017] [Accepted: 01/09/2017] [Indexed: 01/15/2023] Open
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13
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Poser BA, Setsompop K. Pulse sequences and parallel imaging for high spatiotemporal resolution MRI at ultra-high field. Neuroimage 2018; 168:101-118. [PMID: 28392492 PMCID: PMC5630499 DOI: 10.1016/j.neuroimage.2017.04.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/01/2017] [Accepted: 04/03/2017] [Indexed: 12/18/2022] Open
Abstract
The SNR and CNR benefits of ultra-high field (UHF) have helped push the envelope of achievable spatial resolution in MRI. For applications based on susceptibility contrast where there is a large CNR gain, high quality sub-millimeter resolution imaging is now being routinely performed, particularly in fMRI and phase imaging/QSM. This has enabled the study of structure and function of very fine-scale structures in the brain. UHF has also helped push the spatial resolution of many other MRI applications as will be outlined in this review. However, this push in resolution comes at a cost of a large encoding burden leading to very lengthy scans. Developments in parallel imaging with controlled aliasing and the move away from 2D slice-by-slice imaging to much more SNR-efficient simultaneous multi-slice (SMS) and 3D acquisitions have helped address this issue. In particular, these developments have revolutionized the efficiency of UHF MRI to enable high spatiotemporal resolution imaging at an order of magnitude faster acquisition. In addition to describing the main approaches to these techniques, this review will also outline important key practical considerations in using these methods in practice. Furthermore, new RF pulse design to tackle the B1+ and SAR issues of UHF and the increased SAR and power requirement of SMS RF pulses will also be touched upon. Finally, an outlook into new developments of smart encoding in more dimensions, particularly through using better temporal/across-contrast encoding and reconstruction will be described. Just as controlled aliasing fully exploits spatial encoding in parallel imaging to provide large multiplicative gains in accelerations, the complimentary use of these new approaches in temporal and across-contrast encoding are expected to provide exciting opportunities for further large gains in efficiency to further push the spatiotemporal resolution of MRI.
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Affiliation(s)
- Benedikt A Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.
| | - Kawin Setsompop
- Department of Radiology, Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
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14
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Intact hemisphere and corpus callosum compensate for visuomotor functions after early visual cortex damage. Proc Natl Acad Sci U S A 2017; 114:E10475-E10483. [PMID: 29133428 PMCID: PMC5715784 DOI: 10.1073/pnas.1714801114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unilateral damage to the primary visual cortex (V1) leads to clinical blindness in the opposite visual hemifield, yet nonconscious ability to transform unseen visual input into motor output can be retained, a condition known as "blindsight." Here we combined psychophysics, functional magnetic resonance imaging, and tractography to investigate the functional and structural properties that enable the developing brain to partly overcome the effects of early V1 lesion in one blindsight patient. Visual stimuli appeared in either the intact or blind hemifield and simple responses were given with either the left or right hand, thereby creating conditions where visual input and motor output involve the same or opposite hemisphere. When the V1-damaged hemisphere was challenged by incoming visual stimuli, or controlled manual responses to these unseen stimuli, the corpus callosum (CC) dynamically recruited areas in the visual dorsal stream and premotor cortex of the intact hemisphere to compensate for altered visuomotor functions. These compensatory changes in functional brain activity were paralleled by increased connections in posterior regions of the CC, where fibers connecting homologous areas of the parietal cortex course.
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15
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Ivanov D, Gardumi A, Haast RA, Pfeuffer J, Poser BA, Uludağ K. Comparison of 3 T and 7 T ASL techniques for concurrent functional perfusion and BOLD studies. Neuroimage 2017; 156:363-376. [DOI: 10.1016/j.neuroimage.2017.05.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 02/04/2023] Open
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16
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Zhang J, Cho J, Zhou D, Nguyen TD, Spincemaille P, Gupta A, Wang Y. Quantitative susceptibility mapping-based cerebral metabolic rate of oxygen mapping with minimum local variance. Magn Reson Med 2017; 79:172-179. [PMID: 28295523 DOI: 10.1002/mrm.26657] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 01/05/2017] [Accepted: 02/03/2017] [Indexed: 12/14/2022]
Abstract
PURPOSE The objective of this study was to demonstrate the feasibility of a cerebral metabolic rate of oxygen (CMRO2 ) mapping method based on its minimum local variance (MLV) without vascular challenge using quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF). METHODS Three-dimensional multi-echo gradient echo imaging and arterial spin labeling were performed in 11 healthy subjects to calculate QSM and CBF. Minimum local variance was used to compute whole-brain CMRO2 map from QSM and CBF. The MLV method was compared with a reference method using the caffeine challenge. Their agreement within the cortical gray matter (CGM) was assessed on CMRO2 and oxygen extraction fraction (OEF) maps at both baseline and challenge states. RESULTS Mean CMRO2 (in µmol/100 g/min) obtained in CGM using the caffeine challenge and MLV were 142 ± 16.5 and 139 ± 14.8 µmol/100 g/min, respectively; the corresponding baseline OEF were 33.0 ± 4.0% and 31.8 ± 3.2%, respectively. The MLV and caffeine challenge methods showed no statistically significant differences across subjects with small ( < 4%) biases in CMRO2 and OEF values. CONCLUSIONS Minimum local variance-based CMRO2 mapping without vascular challenge using QSM and arterial spin labeling is feasible in healthy subjects. Magn Reson Med 79:172-179, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jingwei Zhang
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Junghun Cho
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Dong Zhou
- 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
| | - Pascal Spincemaille
- 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 Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Department of Radiology, Weill Cornell Medical College, New York, New York, USA
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Setsompop K, Feinberg DA, Polimeni JR. Rapid brain MRI acquisition techniques at ultra-high fields. NMR IN BIOMEDICINE 2016; 29:1198-221. [PMID: 26835884 PMCID: PMC5245168 DOI: 10.1002/nbm.3478] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 11/28/2015] [Accepted: 12/02/2015] [Indexed: 05/04/2023]
Abstract
Ultra-high-field MRI provides large increases in signal-to-noise ratio (SNR) as well as enhancement of several contrast mechanisms in both structural and functional imaging. Combined, these gains result in a substantial boost in contrast-to-noise ratio that can be exploited for higher-spatial-resolution imaging to extract finer-scale information about the brain. With increased spatial resolution, however, there is a concurrent increased image-encoding burden that can cause unacceptably long scan times for structural imaging and slow temporal sampling of the hemodynamic response in functional MRI - particularly when whole-brain imaging is desired. To address this issue, new directions of imaging technology development - such as the move from conventional 2D slice-by-slice imaging to more efficient simultaneous multislice (SMS) or multiband imaging (which can be viewed as "pseudo-3D" encoding) as well as full 3D imaging - have provided dramatic improvements in acquisition speed. Such imaging paradigms provide higher SNR efficiency as well as improved encoding efficiency. Moreover, SMS and 3D imaging can make better use of coil sensitivity information in multichannel receiver arrays used for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher in these imaging acquisition schemes, with low image artifact levels and high SNR. Here we review the latest developments of SMS and 3D imaging methods and related technologies at ultra-high field for rapid high-resolution functional and structural imaging of the brain. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Kawin Setsompop
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - David A. Feinberg
- Helen Wills Institute for Neuroscience, University of California, Berkeley, CA, USA
- Advanced MRI Technologies, Sebastopol, CA, USA
| | - Jonathan R. Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
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18
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Ivanov D, Poser BA, Huber L, Pfeuffer J, Uludağ K. Optimization of simultaneous multislice EPI for concurrent functional perfusion and BOLD signal measurements at 7T. Magn Reson Med 2016; 78:121-129. [PMID: 27465273 PMCID: PMC5484334 DOI: 10.1002/mrm.26351] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 11/17/2022]
Abstract
Purpose To overcome limitations of previous ultra‐high‐field arterial spin labeling (ASL) techniques concerning temporal resolution and brain coverage by utilizing the simultaneous multi‐slice (SMS) approach. Methods An optimized, flow‐alternating inversion recovery quantitative imaging of perfusion using a single subtraction II scheme was developed that tackles the challenges of 7 tesla (T) ASL. The implementation of tailored labeling radiofrequency pulses reduced the effect of transmit field (
B1+) inhomogeneities. The proposed approach utilizes an SMS echo‐planar imaging (EPI) readout to efficiently achieve large brain coverage. Results A pulsed ASL (PASL) technique with large brain coverage is described and optimized that can be applied at temporal resolutions below 2.5 s, similar to those achievable at 1.5 and 3T magnetic field strength. The influences of within‐ and through‐slice acceleration factors and reconstruction parameters on perfusion and blood‐oxygenation‐level‐dependent (BOLD)‐signal image and temporal signal‐to‐noise ratio (SNR) are presented. The proposed approach yielded twice the brain coverage as compared to conventional PASL at 7T, without notable loss in image quality. Conclusion The presented SMS EPI PASL at 7T overcomes current limitations in SNR, temporal resolution, and spatial coverage for functional perfusion and BOLD signal as well as baseline perfusion measurements. Magn Reson Med 78:121–129, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
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Affiliation(s)
- Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Benedikt A Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Laurentius Huber
- SFIM at the National Institute of Mental Health, Bethesda, Maryland, USA
| | - Josef Pfeuffer
- Siemens Healthcare, MR Application Development, Erlangen, Germany
| | - Kâmil Uludağ
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
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19
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Stafford RB, Woo MK, Oh SH, Dolui S, Zhao T, Kim YB, Detre JA, Cho ZH, Lee J. An Actively Decoupled Dual Transceiver Coil System for Continuous ASL at 7 T. INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY 2016; 26:106-115. [PMID: 27695192 PMCID: PMC5042328 DOI: 10.1002/ima.22165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
7 T arterial spin labeling (ASL) faces major challenges including the increased specific absorption rate (SAR) and increased B0 and B1 inhomogeneity. This work describes the design and implementation of a dual-coil system that allows for continuous ASL (CASL) at 7 T. This system consisted of an actively detunable eight-channel transceiver head coil, and a three-channel transceiver labeling coil. Four experiments were performed in 5 healthy subjects: (i) to demonstrate that active detuning during ASL labeling reduces magnetization transfer; (ii) to measure the B1 profile at the labeling plane; (iii) to quantify B0 off-resonance at the labeling plane; and (iv) to collect in vivo CASL data. The magnetization transfer ratio in the head coil was reduced to 0.0 ± 0.2% by active detuning during labeling. The measured B1 profiles in all 5 subjects were sufficient to satisfy the flow-driven adiabatic inversion necessary for CASL, however the actual labeling efficiency was significantly impacted by B0 off-resonance at the labeling plane. The measured CASL percent signal change in gray matter (0.94% ± 0.10%) corresponds with the low labeling efficiency predicted by the B0 off-resonance. This work demonstrates progress in the technical implementation of 7 T CASL, and reinforces the need for improved B0 homogeneity at the labeling plane.
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Affiliation(s)
- Randall B Stafford
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Myung-Kyun Woo
- Neuroscience Research Institute, Gachon University, Incheon, Korea; Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea; Department of Electrical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Se-Hong Oh
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Imaging Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tiejun Zhao
- Siemens Medical Solutions USA, Inc., Siemens Healthcare, New York, NY, USA
| | - Young-Bo Kim
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Zang-Hee Cho
- Neuroscience Research Institute, Gachon University, Incheon, Korea; Advanced Institutes of Convergence Technology, Seoul National University, Seoul, Korea
| | - Jongho Lee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
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Skurdal MJ, Bjørnerud A, van Osch MJP, Nordhøy W, Lagopoulos J, Groote IR. Voxel-Wise Perfusion Assessment in Cerebral White Matter with PCASL at 3T; Is It Possible and How Long Does It Take? PLoS One 2015; 10:e0135596. [PMID: 26267661 PMCID: PMC4534420 DOI: 10.1371/journal.pone.0135596] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 07/23/2015] [Indexed: 11/18/2022] Open
Abstract
Purpose To establish whether reliable voxel-wise assessment of perfusion in cerebral white matter (WM) is possible using arterial spin labeling (ASL) at 3T in a cohort of healthy subjects. Materials and Methods Pseudo-continuous ASL (PCASL) with background suppression (BS) optimized for WM measurements was performed at 3T in eight healthy male volunteers aged 25–41. Four different labeling schemes were evaluated by varying the labeling duration (LD) and post-labeling delay (PLD). Eight slices with voxel dimension 3.75x3.75x5 mm3 were acquired from the anterosuperior aspect of the brain, and 400 image/control pairs were collected for each run. Rigid head immobilization was applied using individually fitted thermoplastic masks. For each voxel in the resulting ASL time series, the time needed to reach a 95% significance level for the ASL signal to be higher than zero (paired t-test), was estimated. Results The four protocols detected between 88% and 95% (after Bonferroni correction: 75% and 88%) of WM voxels at 95% significance level. In the most efficient sequence, 80% was reached after 5 min and 95% after 53 min (after Bonferroni correction 40% and 88% respectively). For all protocols, the fraction of significant WM voxels increased in an asymptotic fashion with increasing scan time. A small subgroup of voxels was shown to not benefit at all from prolonged measurement. Conclusion Acquisition of a significant ASL signal from a majority of WM voxels is possible within clinically acceptable scan times, whereas full coverage needs prohibitively long scan times, as a result of the asymptotic trajectory.
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Affiliation(s)
- Mikjel Johannes Skurdal
- Department of Neurology, Faculty Division, Akershus University Hospital, University of Oslo, Lørenskog, Norway
| | - Atle Bjørnerud
- The Intervention Center, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Department of Physics, University of Oslo, Oslo, Norway
| | - Matthias J. P. van Osch
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
- C.J. Gorter Center for High Field MRI, Leiden, The Netherlands
| | - Wibeke Nordhøy
- The Intervention Center, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Jim Lagopoulos
- Brain and Mind Research Institute, Sydney Medical School, Sydney, Australia
| | - Inge Rasmus Groote
- The Intervention Center, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Department of Psychology, Institute of Social Sciences, University of Oslo, Oslo, Norway
- * E-mail:
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Gawryluk JR, Mazerolle EL, D'Arcy RCN. Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions. Front Neurosci 2014; 8:239. [PMID: 25152709 PMCID: PMC4125856 DOI: 10.3389/fnins.2014.00239] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 07/21/2014] [Indexed: 12/13/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI.
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Affiliation(s)
- Jodie R Gawryluk
- Division of Medical Sciences, Department of Psychology, University of Victoria Victoria, BC, Canada
| | - Erin L Mazerolle
- Department of Radiology, Faculty of Medicine, University of Calgary Calgary, AB, Canada
| | - Ryan C N D'Arcy
- Applied Sciences, Simon Fraser University Burnaby, BC, Canada ; Fraser Health Authority, Surrey Memorial Hospital Surrey, BC, Canada
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