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Le TT, Im GH, Lee CH, Choi SH, Kim SG. Mapping cerebral perfusion in mice under various anesthesia levels using highly sensitive BOLD MRI with transient hypoxia. SCIENCE ADVANCES 2024; 10:eadm7605. [PMID: 38416820 PMCID: PMC10901365 DOI: 10.1126/sciadv.adm7605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/24/2024] [Indexed: 03/01/2024]
Abstract
Cerebral perfusion is critical for the early detection of neurological diseases and for effectively monitoring disease progression and treatment responses. Mouse models are widely used in brain research, often under anesthesia, which can affect vascular physiology. However, the impact of anesthesia on regional cerebral blood volume and flow in mice has not been thoroughly investigated. In this study, we have developed a whole-brain perfusion MRI approach by using a 5-second nitrogen gas stimulus under inhalational anesthetics to induce transient BOLD dynamic susceptibility contrast (DSC). This method proved to be highly sensitive, repeatable within each imaging session, and across four weekly sessions. Relative cerebral blood volumes measured by BOLD DSC agree well with those by contrast agents. Quantitative cerebral blood volume and flow metrics were successfully measured in mice under dexmedetomidine and various isoflurane doses using both total vasculature-sensitive gradient-echo and microvasculature-sensitive spin-echo BOLD MRI. Dexmedetomidine reduces cerebral perfusion, while isoflurane increases cerebral perfusion in a dose-dependent manner.
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Affiliation(s)
- Thuy Thi Le
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
| | - Geun Ho Im
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Chan Hee Lee
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Sang Han Choi
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
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2
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Kwiatkowski G, Kozerke S. Quantitative myocardial first-pass perfusion imaging of CO 2 -induced vasodilation in rats. NMR IN BIOMEDICINE 2021; 34:e4593. [PMID: 34337796 DOI: 10.1002/nbm.4593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Inducible hypercapnia is an alternative for increasing the coronary blood flow necessary to facilitate the quantification of myocardial blood flow during hyperemia. The current study aimed to quantify the pharmacokinetic effect of a CO2 gas challenge on myocardial perfusion in rats using high-resolution, first-pass perfusion CMR and compared it with pharmacologically induced hyperemia using regadenoson. A dual-contrast, saturation-recovery, gradient-echo sequence with a Cartesian readout was used on a small-animal 9.4-T scanner; additional cine images during hyperemia/rest were recorded with an ultrashort echo time sequence. The mean myocardial blood flow value at rest was 6.1 ± 1.4 versus 13.9 ± 3.7 and 14.3 ± 4 mL/g/min during vasodilation with hypercapnia and regadenoson, respectively. Accordingly, the myocardial flow reserve value was 2.6 ± 1.1 for the gas challenge and 2.5 ± 1.4 for regadenoson. During hyperemia with both protocols, a significantly increased cardiac output was found. It was concluded that hypercapnia leads to significantly increased coronary flow and yields similar myocardial flow reserves in healthy rats as compared with pharmacological stimulation. Accordingly, inducible hypercapnia can be selected as an alternative stressor in CMR studies of myocardial blood flow in small animals.
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Affiliation(s)
- Grzegorz Kwiatkowski
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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3
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Celestine M, Nadkarni NA, Garin CM, Bougacha S, Dhenain M. Sammba-MRI: A Library for Processing SmAll-MaMmal BrAin MRI Data in Python. Front Neuroinform 2020; 14:24. [PMID: 32547380 PMCID: PMC7270712 DOI: 10.3389/fninf.2020.00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 04/23/2020] [Indexed: 11/23/2022] Open
Abstract
Small-mammal neuroimaging offers incredible opportunities to investigate structural and functional aspects of the brain. Many tools have been developed in the last decade to analyse small animal data, but current softwares are less mature than the available tools that process human brain data. The Python package Sammba-MRI (SmAll-MaMmal BrAin MRI in Python; http://sammba-mri.github.io) allows flexible and efficient use of existing methods and enables fluent scriptable analysis workflows, from raw data conversion to multimodal processing.
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Affiliation(s)
- Marina Celestine
- UMR9199 Laboratory of Neurodegenerative Diseases, Centre National de la Recherche Scientifique (CNRS), Fontenay-aux-Roses, France.,MIRCen, Institut de Biologie François Jacob, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses, France
| | - Nachiket A Nadkarni
- UMR9199 Laboratory of Neurodegenerative Diseases, Centre National de la Recherche Scientifique (CNRS), Fontenay-aux-Roses, France.,MIRCen, Institut de Biologie François Jacob, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses, France
| | - Clément M Garin
- UMR9199 Laboratory of Neurodegenerative Diseases, Centre National de la Recherche Scientifique (CNRS), Fontenay-aux-Roses, France.,MIRCen, Institut de Biologie François Jacob, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses, France
| | - Salma Bougacha
- UMR9199 Laboratory of Neurodegenerative Diseases, Centre National de la Recherche Scientifique (CNRS), Fontenay-aux-Roses, France.,MIRCen, Institut de Biologie François Jacob, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses, France.,UMR-S U1237 Physiopathologie et imagerie des troubles Neurologiques (PhIND), INSERM, Université de Caen-Normandie, GIP Cyceron, Caen, France.,Normandie Université, UNICAEN, PSL Research University, EPHE, Inserm, U1077, CHU de Caen, Neuropsychologie et Imagerie de la Mémoire Humaine, Caen, France
| | - Marc Dhenain
- UMR9199 Laboratory of Neurodegenerative Diseases, Centre National de la Recherche Scientifique (CNRS), Fontenay-aux-Roses, France.,MIRCen, Institut de Biologie François Jacob, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses, France
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4
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Gottschalk M. Look-Locker FAIR TrueFISP for arterial spin labelling on mouse at 9.4 T. NMR IN BIOMEDICINE 2020; 33:e4191. [PMID: 31829485 DOI: 10.1002/nbm.4191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/21/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Pulsed arterial spin labelling remains a non-invasive and highly used method for the study of rodent cerebral blood flow (CBF). Flow-sensitive alternating inversion recovery (FAIR) is one of the most commonly used MR-sequences for this purpose and exists with many different strategies to record the images. This study investigates Look-Locker (LL) TrueFISP readout for FAIR as an alternative to the standard EPI readout, which is provided by the manufacturer. The aim was to show the improved image quality using TrueFISP and to verify the reproducibility of the determination of the cerebral blood flow values. The measurement of many inversion points also allowed to investigate the influence of the correct blood relaxation rate on the fit of the CBF data. For the LL-FAIR TrueFISP an in-house written method was created. The method was tested on a group of C57BL/6 mice at the field strength of 9.4 T. The results show CBF maps with less distortion than for EPI and the values found are in good agreement with the literature. A comparison of the CBF values found with EPI and LL-TrueFISP shows very small differences, most being not significant. In conclusion, the method presented gives equivalent CBF maps in comparison to standard FAIR-EPI. Both methods have the same measurement time. TrueFISP has the advantage to EPI of producing undistorted images over larger areas of the mouse brain. It is advisable to check the value of the blood relaxation rate by measurement or to estimate it as a fitting parameter.
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5
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Buck J, Larkin JR, Simard MA, Khrapitchev AA, Chappell MA, Sibson NR. Sensitivity of Multiphase Pseudocontinuous Arterial Spin Labelling (MP pCASL) Magnetic Resonance Imaging for Measuring Brain and Tumour Blood Flow in Mice. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:4580919. [PMID: 30532663 PMCID: PMC6247770 DOI: 10.1155/2018/4580919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/28/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022]
Abstract
Brain and tumour blood flow can be measured noninvasively using arterial spin labelling (ASL) magnetic resonance imaging (MRI), but reliable quantification in mouse models remains difficult. Pseudocontinuous ASL (pCASL) is recommended as the clinical standard for ASL and can be improved using multiphase labelling (MP pCASL). The aim of this study was to optimise and validate MP pCASL MRI for cerebral blood flow (CBF) measurement in mice and to assess its sensitivity to tumour perfusion. Following optimization of the MP pCASL sequence, CBF data were compared with gold-standard autoradiography, showing close agreement. Subsequently, MP pCASL data were acquired at weekly intervals in models of primary and secondary brain tumours, and tumour microvessel density was determined histologically. MP pCASL measurements in a secondary brain tumour model revealed a significant reduction in blood flow at day 35 after induction, despite a higher density of blood vessels. Tumour core regions also showed reduced blood flow compared with the tumour rim. Similarly, significant reductions in CBF were found in a model of glioma 28 days after tumour induction, together with an increased density of blood vessels. These findings indicate that MP pCASL MRI provides accurate and robust measurements of cerebral blood flow in naïve mice and is sensitive to changes in tumour perfusion.
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Affiliation(s)
- Jessica Buck
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - James R. Larkin
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Manon A. Simard
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Alexandre A. Khrapitchev
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Michael A. Chappell
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, Oxford, UK
| | - Nicola R. Sibson
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
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6
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Gagnon L, Sakadžić S, Lesage F, Pouliot P, Dale AM, Devor A, Buxton RB, Boas DA. Validation and optimization of hypercapnic-calibrated fMRI from oxygen-sensitive two-photon microscopy. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0359. [PMID: 27574311 DOI: 10.1098/rstb.2015.0359] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2016] [Indexed: 01/30/2023] Open
Abstract
Hypercapnic-calibrated fMRI allows the estimation of the relative changes in the cerebral metabolic rate of oxygen (rCMRO2) from combined BOLD and arterial spin labelling measurements during a functional task, and promises to permit more quantitative analyses of brain activity patterns. The estimation relies on a macroscopic model of the BOLD effect that balances oxygen delivery and consumption to predict haemoglobin oxygenation and the BOLD signal. The accuracy of calibrated fMRI approaches has not been firmly established, which is limiting their broader adoption. We use our recently developed microscopic vascular anatomical network model in mice as a ground truth simulator to test the accuracy of macroscopic, lumped-parameter BOLD models. In particular, we investigate the original Davis model and a more recent heuristic simplification. We find that these macroscopic models are inaccurate using the originally defined parameters, but that the accuracy can be significantly improved by redefining the model parameters to take on new values. In particular, we find that the parameter α that relates cerebral blood-volume changes to cerebral blood-flow changes is significantly smaller than typically assumed and that the optimal value changes with magnetic field strength. The results are encouraging in that they support the use of simple BOLD models to quantify BOLD signals, but further work is needed to understand the physiological interpretation of the redefined model parameters.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- Louis Gagnon
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA Department of Medicine, Laval University, Quebec City, Quebec, Canada Deparment of Electrical Engineering, École Polytechnique Montreal, Montreal, Quebec, Canada
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Frédéric Lesage
- Deparment of Electrical Engineering, École Polytechnique Montreal, Montreal, Quebec, Canada
| | - Philippe Pouliot
- Deparment of Electrical Engineering, École Polytechnique Montreal, Montreal, Quebec, Canada
| | - Anders M Dale
- Department of Neurosciences and Radiology, UCSD, La Jolla, CA, USA
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA Department of Neurosciences and Radiology, UCSD, La Jolla, CA, USA
| | | | - David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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7
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Crescenzi R, DeBrosse C, Nanga RP, Byrne MD, Krishnamoorthy G, D’Aquilla K, Nath H, Morales KH, Iba M, Hariharan H, Lee VM, Detre JA, Reddy R. Longitudinal imaging reveals subhippocampal dynamics in glutamate levels associated with histopathologic events in a mouse model of tauopathy and healthy mice. Hippocampus 2017; 27:285-302. [PMID: 27997993 PMCID: PMC5396955 DOI: 10.1002/hipo.22693] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 11/08/2022]
Abstract
Tauopathies are neurodegenerative disorders characterized by abnormal intracellular aggregates of tau protein, and include Alzheimer's disease, corticobasal degeneration, frontotemporal dementia, and traumatic brain injury. Glutamate metabolism is altered in neurodegenerative disorders manifesting in higher or lower concentrations of glutamate, its transporters or receptors. Previously, glutamate chemical exchange saturation transfer (GluCEST) magnetic resonance imaging (MRI) demonstrated that glutamate levels are reduced in regions of synapse loss in the hippocampus of a mouse model of late-stage tauopathy. We performed a longitudinal GluCEST imaging experiment paired with a cross-sectional study of histologic markers of tauopathy to determine whether (1) early GluCEST changes are associated with synapse loss before volume loss occurs in the hippocampus, and whether (2) subhippocampal dynamics in GluCEST are associated with histopathologic events related to glutamate alterations in tauopathy. Live imaging of the hippocampus in three serial slices was performed without exogenous contrast agents, and subregions were segmented based on a k-means cluster model. Subregions of the hippocampus were analyzed (cornu ammonis CA1, CA3, dentate gyrus DG, and ventricle) in order to associate local MRI-observable changes in glutamate with histological measures of glial cell proliferation (GFAP), synapse density (synaptophysin, VGlut1) and glutamate receptor (NMDA-NR1) levels. Early differences in GluCEST between healthy and tauopathy mice were measured in the CA1 and DG subregions (30% reduction, P ≤ 0.001). Synapse density was also significantly reduced in every subregion of the hippocampus in tauopathy mice by 6 months. Volume was not significantly reduced in any subregion until 13 months. Further, a gradient in glutamate levels was observed in vivo along hippocampal axes that became polarized as tauopathy progressed. Dynamics in hippocampal glutamate levels throughout lifetime were most closely correlated with combined changes in synaptophysin and GFAP, indicating that GluCEST imaging may be a surrogate marker of glutamate concentration in glial cells and at the synaptic level. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Rachelle Crescenzi
- Department of Biochemistry & Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Catherine DeBrosse
- Department of Biochemistry & Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi P.R. Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew D. Byrne
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - Guruprasad Krishnamoorthy
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Kevin D’Aquilla
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Nath
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Knashawn H. Morales
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michiyo Iba
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Virginia M.Y Lee
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - John A. Detre
- Center for Functional Neuroimaging (CfN), University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
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8
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A novel anesthesia regime enables neurofunctional studies and imaging genetics across mouse strains. Sci Rep 2016; 6:24523. [PMID: 27080031 PMCID: PMC4832200 DOI: 10.1038/srep24523] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 03/30/2016] [Indexed: 12/18/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) has revolutionized neuroscience by opening a unique window that allows neurocircuitry function and pathological alterations to be probed non-invasively across brain disorders. Here we report a novel sustainable anesthesia procedure for small animal neuroimaging that overcomes shortcomings of anesthetics commonly used in rodent fMRI. The significantly improved preservation of cerebrovascular dynamics enhances sensitivity to neural activity changes for which it serves as a proxy in fMRI readouts. Excellent cross-species/strain applicability provides coherence among preclinical findings and is expected to improve translation to clinical fMRI investigations. The novel anesthesia procedure based on the GABAergic anesthetic etomidate was extensively validated in fMRI studies conducted in a range of genetically engineered rodent models of autism and strains commonly used for transgenic manipulations. Etomidate proved effective, yielded long-term stable physiology with basal cerebral blood flow of ~0.5 ml/g/min and full recovery. Cerebrovascular responsiveness of up to 180% was maintained as demonstrated with perfusion- and BOLD-based fMRI upon hypercapnic, pharmacological and sensory stimulation. Hence, etomidate lends itself as an anesthetic-of-choice for translational neuroimaging studies across rodent models of brain disorders.
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9
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Quantifying the microvascular origin of BOLD-fMRI from first principles with two-photon microscopy and an oxygen-sensitive nanoprobe. J Neurosci 2015; 35:3663-75. [PMID: 25716864 DOI: 10.1523/jneurosci.3555-14.2015] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences.
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10
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Chaumeil MM, Najac C, Ronen SM. Studies of Metabolism Using (13)C MRS of Hyperpolarized Probes. Methods Enzymol 2015; 561:1-71. [PMID: 26358901 DOI: 10.1016/bs.mie.2015.04.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
First described in 2003, the dissolution dynamic nuclear polarization (DNP) technique, combined with (13)C magnetic resonance spectroscopy (MRS), has since been used in numerous metabolic studies and has become a valuable metabolic imaging method. DNP dramatically increases the level of polarization of (13)C-labeled compounds resulting in an increase in the signal-to-noise ratio (SNR) of over 50,000 fold for the MRS spectrum of hyperpolarized compounds. The high SNR enables rapid real-time detection of metabolism in cells, tissues, and in vivo. This chapter will present a comprehensive review of the DNP approaches that have been used to monitor metabolism in living systems. First, the list of (13)C DNP probes developed to date will be presented, with a particular focus on the most commonly used probe, namely [1-(13)C] pyruvate. In the next four sections, we will then describe the different factors that need to be considered when designing (13)C DNP probes for metabolic studies, conducting in vitro or in vivo hyperpolarized experiments, as well as acquiring, analyzing, and modeling hyperpolarized (13)C data.
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Affiliation(s)
- Myriam M Chaumeil
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Chloé Najac
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Sabrina M Ronen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.
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11
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Wells JA, Holmes HE, O'Callaghan JM, Colgan N, Ismail O, Fisher EM, Siow B, Murray TK, Schwarz AJ, O'Neill MJ, Collins EC, Lythgoe MF. Increased cerebral vascular reactivity in the tau expressing rTg4510 mouse: evidence against the role of tau pathology to impair vascular health in Alzheimer's disease. J Cereb Blood Flow Metab 2015; 35:359-62. [PMID: 25515210 PMCID: PMC4348392 DOI: 10.1038/jcbfm.2014.224] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 11/12/2014] [Accepted: 11/16/2014] [Indexed: 02/03/2023]
Abstract
Vascular abnormalities are a key feature of Alzheimer's disease (AD). Imaging of cerebral vascular reactivity (CVR) is a powerful tool to investigate vascular health in clinical populations although the cause of reduced CVR in AD patients is not fully understood. We investigated the specific role of tau pathology in CVR derangement in AD using the rTg4510 mouse model. We observed an increase in CVR in cortical regions with tau pathology. These data suggest that tau pathology alone does not produce the clinically observed decreases in CVR and implicates amyloid pathology as the dominant etiology of impaired CVR in AD patients.
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Affiliation(s)
- Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Holly E Holmes
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - James M O'Callaghan
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Niall Colgan
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Ozama Ismail
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | - Elizabeth Mc Fisher
- Department of Neurodegenerative Disease, Institute of Neurology, UCL, London, UK
| | - Bernard Siow
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
| | | | - Adam J Schwarz
- Tailored Therapeutics, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA
| | | | - Emily C Collins
- Tailored Therapeutics, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, UK
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12
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Large arteriolar component of oxygen delivery implies a safe margin of oxygen supply to cerebral tissue. Nat Commun 2014; 5:5734. [PMID: 25483924 PMCID: PMC4260810 DOI: 10.1038/ncomms6734] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 11/03/2014] [Indexed: 02/07/2023] Open
Abstract
What is the organization of cerebral microvascular oxygenation and morphology
that allows adequate tissue oxygenation at different activity levels? We address this
question in the mouse cerebral cortex using microscopic imaging of intravascular O2
partial pressure and blood flow combined with numerical modeling. Here we show that
parenchymal arterioles are responsible for 50% of the extracted O2 at baseline
activity and the majority of the remaining O2 exchange takes place within the
first few capillary branches. Most capillaries release little O2 at baseline
acting as an O2 reserve that is recruited during increased neuronal activity or
decreased blood flow. Our results challenge the common perception that capillaries are the
major site of O2 delivery to cerebral tissue. The understanding of oxygenation
distribution along arterio-capillary paths may have profound implications for the
interpretation of BOLD fMRI signal and for evaluating microvascular O2 delivery
capacity to support cerebral tissue in disease.
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13
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Zerbi V, Jansen D, Wiesmann M, Fang X, Broersen LM, Veltien A, Heerschap A, Kiliaan AJ. Multinutrient diets improve cerebral perfusion and neuroprotection in a murine model of Alzheimer's disease. Neurobiol Aging 2013; 35:600-13. [PMID: 24210253 DOI: 10.1016/j.neurobiolaging.2013.09.038] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/19/2013] [Accepted: 09/30/2013] [Indexed: 01/30/2023]
Abstract
Nutritional intervention may retard the development of Alzheimer's disease (AD). In this study we tested the effects of 2 multi-nutrient diets in an AD mouse model (APPswe/PS1dE9). One diet contained membrane precursors such as omega-3 fatty acids and uridine monophosphate (DEU), whereas another diet contained cofactors for membrane synthesis as well (Fortasyn); the diets were developed to enhance synaptic membranes synthesis, and contain components that may improve vascular health. We measured cerebral blood flow (CBF) and water diffusivity with ultra-high-field magnetic resonance imaging, as alterations in these parameters correlate with clinical symptoms of the disease. APPswe/PS1dE9 mice on control diet showed decreased CBF and changes in brain water diffusion, in accordance with findings of hypoperfusion, axonal disconnection and neuronal loss in patients with AD. Both multinutrient diets were able to increase cortical CBF in APPswe/PS1dE9 mice and Fortasyn reduced water diffusivity, particularly in the dentate gyrus and in cortical regions. We suggest that a specific diet intervention has the potential to slow AD progression, by simultaneously improving cerebrovascular health and enhancing neuroprotective mechanisms.
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Affiliation(s)
- Valerio Zerbi
- Department of Anatomy, Donders Institute for Brain Cognition & Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands; Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Chugh BP, Bishop J, Zhou YQ, Wu J, Henkelman RM, Sled JG. Robust method for 3D arterial spin labeling in mice. Magn Reson Med 2011; 68:98-106. [PMID: 22102489 DOI: 10.1002/mrm.23209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 11/12/2022]
Abstract
Arterial spin labeling is a versatile perfusion quantification methodology, which has the potential to provide accurate characterization of cerebral blood flow (CBF) in mouse models. However, a paucity of physiological data needed for accurate modeling, more stringent requirements for gradient performance, and strong artifacts introduced by magnetization transfer present special challenges for accurate CBF mapping in the mouse. This article describes robust mapping of CBF over three-dimensional brain regions using amplitude-modulated continuous arterial spin labeling. To provide physiological data for CBF modeling, the carotid artery blood velocity distribution was characterized using pulsed-wave Doppler ultrasound. These blood velocity measurements were used in simulations that optimize inversion efficiency for parameters meeting MRI gradient duty cycle constraints. A rapid slice positioning algorithm was developed and evaluated to provide accurate positioning of the labeling plane. To account for enhancement of T(1) due to magnetization transfer, a binary spin bath model of magnetization transfer was used to provide a more accurate estimate of CBF. Finally, a study of CBF was conducted on 10 mice with findings of highly reproducible inversion efficiency (mean ± standard-error-of-the-mean, 0.67 ± 0.03), statistically significant variation in CBF over 12 brain regions (P < 0.0001) and a mean ± standard-error-of-the-mean whole brain CBF of 219 ± 6 mL/100 g/min.
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Affiliation(s)
- Brige Paul Chugh
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Duhamel G, Callot V, Tachrount M, Alsop DC, Cozzone PJ. Pseudo-continuous arterial spin labeling at very high magnetic field (11.75 T) for high-resolution mouse brain perfusion imaging. Magn Reson Med 2011; 67:1225-36. [DOI: 10.1002/mrm.23096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/10/2011] [Accepted: 06/21/2011] [Indexed: 12/27/2022]
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Oosterlinck WW, Dresselaers T, Geldhof V, Van Santvoort A, Robberecht W, Herijgers P, Himmelreich U. Response of mouse brain perfusion to hypo- and hyperventilation measured by arterial spin labeling. Magn Reson Med 2011; 66:802-11. [DOI: 10.1002/mrm.23060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 04/06/2011] [Accepted: 05/25/2011] [Indexed: 11/10/2022]
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