1
|
Ramasubbu R, Brown EC, Mouches P, Moore JA, Clark DL, Molnar CP, Kiss ZHT, Forkert ND. Multimodal imaging measures in the prediction of clinical response to deep brain stimulation for refractory depression: A machine learning approach. World J Biol Psychiatry 2024; 25:175-187. [PMID: 38185882 DOI: 10.1080/15622975.2023.2300795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 12/27/2023] [Indexed: 01/09/2024]
Abstract
OBJECTIVES This study compared machine learning models using unimodal imaging measures and combined multi-modal imaging measures for deep brain stimulation (DBS) outcome prediction in treatment resistant depression (TRD). METHODS Regional brain glucose metabolism (CMRGlu), cerebral blood flow (CBF), and grey matter volume (GMV) were measured at baseline using 18F-fluorodeoxy glucose (18F-FDG) positron emission tomography (PET), arterial spin labelling (ASL) magnetic resonance imaging (MRI), and T1-weighted MRI, respectively, in 19 patients with TRD receiving subcallosal cingulate (SCC)-DBS. Responders (n = 9) were defined by a 50% reduction in HAMD-17 at 6 months from the baseline. Using an atlas-based approach, values of each measure were determined for pre-selected brain regions. OneR feature selection algorithm and the naïve Bayes model was used for classification. Leave-out-one cross validation was used for classifier evaluation. RESULTS The performance accuracy of the CMRGlu classification model (84%) was greater than CBF (74%) or GMV (74%) models. The classification model using the three image modalities together led to a similar accuracy (84%0 compared to the CMRGlu classification model. CONCLUSIONS CMRGlu imaging measures may be useful for the development of multivariate prediction models for SCC-DBS studies for TRD. The future of multivariate methods for multimodal imaging may rest on the selection of complementing features and the developing better models.Clinical Trial Registration: ClinicalTrials.gov (#NCT01983904).
Collapse
Affiliation(s)
- Rajamannar Ramasubbu
- Department of Psychiatry, Clinical Neurosciences, Mathison Centre for Mental Health Research & Education, Calgary, Alberta, Canada
- Hotchkiss Brain Institute Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elliot C Brown
- School of Health and Care Management, Arden University, Berlin, Germany
| | - Pauline Mouches
- Department of Radiology, Clinical Neurosciences, Hotchkiss Brain Institute, Cumming school of medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jasmine A Moore
- Department of Radiology, Clinical Neurosciences, Hotchkiss Brain Institute, Cumming school of medicine, University of Calgary, Calgary, Alberta, Canada
| | - Darren L Clark
- Department of Psychiatry, Clinical Neurosciences, Mathison Centre for Mental Health Research & Education, Calgary, Alberta, Canada
- Hotchkiss Brain Institute Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Christine P Molnar
- Department of Radiology, Cumming school of medicine, University of Calgary, Calgary, Alberta, Canada
| | - Zelma H T Kiss
- Department of Psychiatry, Clinical Neurosciences, Mathison Centre for Mental Health Research & Education, Calgary, Alberta, Canada
- Hotchkiss Brain Institute Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nils D Forkert
- Department of Radiology, Clinical Neurosciences, Hotchkiss Brain Institute, Cumming school of medicine, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
2
|
Zhang Y, Wang Y, Li Z, Wang Z, Cheng J, Bai X, Hsu YC, Sun Y, Li S, Shi J, Sui B, Bai R. Vascular-water-exchange MRI (VEXI) enables the detection of subtle AXR alterations in Alzheimer's disease without MRI contrast agent, which may relate to BBB integrity. Neuroimage 2023; 270:119951. [PMID: 36805091 DOI: 10.1016/j.neuroimage.2023.119951] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/21/2023] Open
Abstract
Blood-brain barrier (BBB) impairment is an important pathophysiological process in Alzheimer's disease (AD) and a potential biomarker for early diagnosis of AD. However, most current neuroimaging methods assessing BBB function need the injection of exogenous contrast agents (or tracers), which limits the application of these methods in a large population. In this study, we aim to explore the feasibility of vascular water exchange MRI (VEXI), a diffusion-MRI-based method proposed to assess the BBB permeability to water molecules without using a contrast agent, in the detection of the BBB breakdown in AD. We tested VEXI on a 3T MRI scanner on three groups: AD patients (AD group), mild cognitive impairment (MCI) patients due to AD (MCI group), and the age-matched normal cognition subjects (NC group). Interestingly, we find that the apparent water exchange across the BBB (AXRBBB) measured by VEXI shows higher values in MCI compared with NC, and this higher AXRBBB happens specifically in the hippocampus. This increase in AXRBBB value gets larger and extends to more brain regions (medial orbital frontal cortex and thalamus) from MCI group to the AD group. Furthermore, we find that the AXRBBB values of these three regions is correlated significantly with the impairment of respective cognitive domains independent of age, sex and education. These results suggest VEXI is a promising method to assess the BBB breakdown in AD.
Collapse
Affiliation(s)
- Yifan Zhang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Yue Wang
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhaoqing Li
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Zejun Wang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Juange Cheng
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoyan Bai
- Tiantan Neuroimaging Center of Excellence, China National Clinical Research Center for Neurological Diseases, Beijing, China; Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing Neurosurgical Institute, Beijing, China
| | - Yi-Cheng Hsu
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Yi Sun
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Shiping Li
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Jiong Shi
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.
| | - Binbin Sui
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Ruiliang Bai
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University.
| |
Collapse
|
3
|
Role of Transmembrane Water Exchange in Glioma Invasion/Migration: In Vivo Preclinical Study by Relaxometry at Very Low Magnetic Field. Cancers (Basel) 2022; 14:cancers14174180. [PMID: 36077717 PMCID: PMC9454706 DOI: 10.3390/cancers14174180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
This work shows that the longitudinal relaxation differences observed at very low magnetic fields between invasion/migration and proliferation processes on glioma mouse models in vivo are related to differences in the transmembrane water exchange basically linked to the aquaporin expression changes. Three glioma mouse models were used: Glio6 and Glio96 as invasion/migration models and U87 as cell proliferation model. In vivo proton longitudinal relaxation-rate constants (R1) at very low fields were measured by fast field cycling NMR (FFC-NMR). The tumor contribution to the observed proton relaxation rate, R1tum (U87: 12.26 ± 0.64 s−1; Glio6: 3.76 ± 0.88 s−1; Glio96: 6.90 ± 0.64 s−1 at 0.01 MHz), and the intracellular water lifetime, τin (U87: 826 ± 19 ms; Glio6: 516 ± 8 ms; Glio96: 596 ± 15 ms), were found to be good diagnostic hallmarks to distinguish invasion/migration from proliferation (p < 0.01 and 0.001). Overexpression of AQP4 and AQP1 were assessed in invasion/migration models, highlighting the pathophysiological role of these two aquaporins in water exchange that, in turn, determine the lower values in the observed R1 relaxation rate constant in glioma invasion/migration. Overall, our findings demonstrate that τin and R1 (measured at very low fields) are relevant biomarkers, discriminating invasion/migration from proliferation in vivo. These results highlight the use of FFC-NMR and FFC-imaging to assess the efficiency of drugs that could modulate aquaporin functions.
Collapse
|
4
|
Mahroo A, Buck MA, Huber J, Breutigam NJ, Mutsaerts HJMM, Craig M, Chappell M, Günther M. Robust Multi-TE ASL-Based Blood-Brain Barrier Integrity Measurements. Front Neurosci 2021; 15:719676. [PMID: 34924924 PMCID: PMC8678075 DOI: 10.3389/fnins.2021.719676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/25/2021] [Indexed: 12/30/2022] Open
Abstract
Multiple echo-time arterial spin labelling (multi-TE ASL) offers estimation of blood–tissue exchange dynamics by probing the T2 relaxation of the labelled spins. In this study, we provide a recipe for robust assessment of exchange time (Texch) as a proxy measure of blood–brain barrier (BBB) integrity based on a test-retest analysis. This includes a novel scan protocol and an extension of the two-compartment model with an “intra-voxel transit time” (ITT) to address tissue transit effects. With the extended model, we intend to separate the underlying two distinct mechanisms of tissue transit and exchange. The performance of the extended model in comparison with the two-compartment model was evaluated in simulations. Multi-TE ASL sequence with two different bolus durations was used to acquire in vivo data (n = 10). Cerebral blood flow (CBF), arterial transit time (ATT) and Texch were fitted with the two models, and mean grey matter values were compared. Additionally, the extended model also extracted ITT parameter. The test-retest reliability of Texch was assessed for intra-session, inter-session and inter-visit pairs of measurements. Intra-class correlation coefficient (ICC) and within-subject coefficient of variance (CoV) for grey matter were computed to assess the precision of the method. Mean grey matter Texch and ITT values were found to be 227.9 ± 37.9 ms and 310.3 ± 52.9 ms, respectively. Texch estimated by the extended model was 32.6 ± 5.9% lower than the two-compartment model. A significant ICC was observed for all three measures of Texch reliability (P < 0.05). Texch intra-session CoV, inter-session CoV and inter-visit CoV were found to be 6.6%, 7.9%, and 8.4%, respectively. With the described improvements addressing intra-voxel transit effects, multi-TE ASL shows good reproducibility as a non-invasive measure of BBB permeability. These findings offer an encouraging step forward to apply this potential BBB permeability biomarker in clinical research.
Collapse
Affiliation(s)
- Amnah Mahroo
- MR Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
| | - Mareike Alicja Buck
- MR Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany.,MR-Imaging and Spectroscopy, University of Bremen, Bremen, Germany
| | - Jörn Huber
- MR Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
| | | | - Henk J M M Mutsaerts
- Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Martin Craig
- Mental Health and Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Michael Chappell
- Mental Health and Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Nottingham Biomedical Research Centre, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Matthias Günther
- MR Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany.,MR-Imaging and Spectroscopy, University of Bremen, Bremen, Germany.,mediri GmbH, Heidelberg, Germany
| |
Collapse
|
5
|
Bai R, Li Z, Sun C, Hsu YC, Liang H, Basser P. Feasibility of filter-exchange imaging (FEXI) in measuring different exchange processes in human brain. Neuroimage 2020; 219:117039. [DOI: 10.1016/j.neuroimage.2020.117039] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/18/2020] [Accepted: 06/05/2020] [Indexed: 12/15/2022] Open
|
6
|
Schidlowski M, Boland M, Rüber T, Stöcker T. Blood-brain barrier permeability measurement by biexponentially modeling whole-brain arterial spin labeling data with multiple T 2 -weightings. NMR IN BIOMEDICINE 2020; 33:e4374. [PMID: 32715563 DOI: 10.1002/nbm.4374] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/24/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Blood-brain barrier (BBB) permeability assessment remains of ongoing interest in clinical practice and research. Transitions between intravascular (IV) and extravascular (EV) gray matter (GM) compartments may provide information regarding the microstructural status of the BBB. Due to different transverse relaxation times (T2 ) of water protons in vessels and GM, it is possible to determine the compartment in which these protons are located. This work presents and investigates the feasibility of a simplified analytical approach for compartmentalizing the proportions of magnetically marked water protons into IV and EV GM components by biexponentially modeling T2 -weighted arterial spin labeling (ASL) data. Numerous model assumptions were used to stabilize the fit and achieve in vivo applicability. Particularly, transverse relaxation times of IV and EV water protons were determined from the analysis of two supporting T2 -weighted ASL measurements, utilizing a monoexponential signal model. This stabilized a two-parameter biexponential fit of ASL data with T2 preparation (PLD = 0.9/1.2/1.5/1.8 s, TET2Prep = 0/30/40/60/80/120/160 ms), which thereby robustly provided estimates of the IV and EV compartment fractions. Experiments were conducted with three healthy volunteers in a 3 T scanner. Averaged over all subjects, the labeled water protons inherit T2,IV = 200 ± 18 ms initially and adapt T2,EV = 91 ± 2 ms with a longer retention time in cerebral structures. Accordingly, the EVlocated ASL signal fraction rises with increasing PLD from 0.31 ± 0.11 at the shortest PLD of 0.9 s to 0.73 ± 0.02 at the longest PLD of 1.8s. These results indicate a transition of the water protons from IV to EV space. The findings support the potential of biexponential modeling for compartmentalizing ASL spin fractions between IV and EV space. The novel integration of monoexponential parameter estimates stabilizes the two-compartment model fit, suggesting that this technique is suitable for robustly estimating the BBB permeability in vivo.
Collapse
Affiliation(s)
- Martin Schidlowski
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Markus Boland
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Theodor Rüber
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
- Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Tony Stöcker
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
- Department for Physics and Astronomy, University of Bonn, Bonn, Germany
| |
Collapse
|
7
|
Wengler K, Ha J, Syritsyna O, Bangiyev L, Coyle PK, Duong TQ, Schweitzer ME, He X. Abnormal blood-brain barrier water exchange in chronic multiple sclerosis lesions: A preliminary study. Magn Reson Imaging 2020; 70:126-133. [DOI: 10.1016/j.mri.2020.04.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 12/17/2022]
|
8
|
Wengler K, Bangiyev L, Canli T, Duong TQ, Schweitzer ME, He X. 3D MRI of whole-brain water permeability with intrinsic diffusivity encoding of arterial labeled spin (IDEALS). Neuroimage 2019; 189:401-414. [DOI: 10.1016/j.neuroimage.2019.01.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 12/11/2022] Open
|
9
|
Shao X, Ma SJ, Casey M, D'Orazio L, Ringman JM, Wang DJJ. Mapping water exchange across the blood-brain barrier using 3D diffusion-prepared arterial spin labeled perfusion MRI. Magn Reson Med 2018; 81:3065-3079. [PMID: 30561821 DOI: 10.1002/mrm.27632] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/19/2018] [Accepted: 11/17/2018] [Indexed: 01/22/2023]
Abstract
PURPOSE To present a novel MR pulse sequence and modeling algorithm to quantify the water exchange rate (kw ) across the blood-brain barrier (BBB) without contrast, and to evaluate its clinical utility in a cohort of elderly subjects at risk of cerebral small vessel disease (SVD). METHODS A diffusion preparation module with spoiling of non-Carr-Purcell-Meiboom-Gill signals was integrated with pseudo-continuous arterial spin labeling (pCASL) and 3D gradient and spin echo (GRASE) readout. The tissue/capillary fraction of the arterial spin labeling (ASL) signal was separated by appropriate diffusion weighting (b = 50 s/mm2 ). kw was quantified using a single-pass approximation (SPA) model with total generalized variation (TGV) regularization. Nineteen elderly subjects were recruited and underwent 2 MRIs to evaluate the reproducibility of the proposed technique. Correlation analysis was performed between kw and vascular risk factors, Clinical Dementia Rating (CDR) scale, neurocognitive assessments, and white matter hyperintensity (WMH). RESULTS The capillary/tissue fraction of ASL signal can be reliably differentiated with the diffusion weighting of b = 50 s/mm2 , given ~100-fold difference between the (pseudo-)diffusion coefficients of the 2 compartments. Good reproducibility of kw measurements (intraclass correlation coefficient = 0.75) was achieved. Average kw was 105.0 ± 20.6, 109.6 ± 18.9, and 94.1 ± 19.6 min-1 for whole brain, gray and white matter. kw was increased by 28.2%/19.5% in subjects with diabetes/hypercholesterolemia. Significant correlations between kw and vascular risk factors, CDR, executive/memory function, and the Fazekas scale of WMH were observed. CONCLUSION A diffusion prepared 3D GRASE pCASL sequence with TGV regularized SPA modeling was proposed to measure BBB water permeability noninvasively with good reproducibility. kw may serve as an imaging marker of cerebral SVD and associated cognitive impairment.
Collapse
Affiliation(s)
- Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Samantha J Ma
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Marlene Casey
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lina D'Orazio
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - John M Ringman
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| |
Collapse
|
10
|
He X, Wengler K, Schweitzer ME. Diffusion sensitivity of 3D-GRASE in arterial spin labeling perfusion. Magn Reson Med 2018; 80:736-747. [DOI: 10.1002/mrm.27058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/02/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Xiang He
- Department of Radiology; Stony Brook University; Stony Brook New York USA
| | - Kenneth Wengler
- Department of Biomedical Engineering; Stony Brook University; Stony Brook New York USA
| | - Mark E. Schweitzer
- Department of Radiology; Stony Brook University; Stony Brook New York USA
| |
Collapse
|
11
|
Kaczkurkin AN, Moore TM, Ruparel K, Ciric R, Calkins ME, Shinohara RT, Elliott MA, Hopson R, Roalf DR, Vandekar SN, Gennatas ED, Wolf DH, Scott JC, Pine DS, Leibenluft E, Detre JA, Foa EB, Gur RE, Gur RC, Satterthwaite TD. Elevated Amygdala Perfusion Mediates Developmental Sex Differences in Trait Anxiety. Biol Psychiatry 2016; 80:775-785. [PMID: 27395327 PMCID: PMC5074881 DOI: 10.1016/j.biopsych.2016.04.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/15/2016] [Accepted: 04/18/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND Adolescence is a critical period for emotional maturation and is a time when clinically significant symptoms of anxiety and depression increase, particularly in females. However, few studies relate developmental differences in symptoms of anxiety and depression to brain development. Cerebral blood flow is one brain phenotype that is known to have marked developmental sex differences. METHODS We investigated whether developmental sex differences in cerebral blood flow mediated sex differences in anxiety and depression symptoms by capitalizing on a large sample of 875 youths who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. Perfusion was quantified on a voxelwise basis using arterial spin-labeled magnetic resonance imaging at 3T. Perfusion images were related to trait and state anxiety using general additive models with penalized splines, while controlling for gray matter density on a voxelwise basis. Clusters found to be related to anxiety were evaluated for interactions with age, sex, and puberty. RESULTS Trait anxiety was associated with elevated perfusion in a network of regions including the amygdala, anterior insula, and fusiform cortex, even after accounting for prescan state anxiety. Notably, these relationships strengthened with age and the transition through puberty. Moreover, higher trait anxiety in postpubertal females was mediated by elevated perfusion of the left amygdala. CONCLUSIONS Taken together, these results demonstrate that differences in the evolution of cerebral perfusion during adolescence may be a critical element of the affective neurobiological characteristics underlying sex differences in anxiety and mood symptoms.
Collapse
Affiliation(s)
- Antonia N Kaczkurkin
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Tyler M Moore
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Kosha Ruparel
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Rastko Ciric
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Monica E Calkins
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Russell T Shinohara
- Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Mark A Elliott
- Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Ryan Hopson
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - David R Roalf
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Simon N Vandekar
- Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Efstathios D Gennatas
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Daniel H Wolf
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - J Cobb Scott
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Philadelphia Veterans Administration Medical Center, Philadelphia, Pennsylvania
| | - Daniel S Pine
- Emotion and Development Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
| | - Ellen Leibenluft
- Emotion and Development Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
| | - John A Detre
- Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Neurology,University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Edna B Foa
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Raquel E Gur
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Ruben C Gur
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Emotion and Development Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
| | - Theodore D Satterthwaite
- Departments of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
| |
Collapse
|
12
|
Springer CS, Li X, Tudorica LA, Oh KY, Roy N, Chui SYC, Naik AM, Holtorf ML, Afzal A, Rooney WD, Huang W. Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? NMR IN BIOMEDICINE 2014; 27:760-73. [PMID: 24798066 PMCID: PMC4174415 DOI: 10.1002/nbm.3111] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 05/10/2023]
Abstract
Shutter-speed pharmacokinetic analysis of dynamic-contrast-enhanced (DCE)-MRI data allows evaluation of equilibrium inter-compartmental water interchange kinetics. The process measured here - transcytolemmal water exchange - is characterized by the mean intracellular water molecule lifetime (τi). The τi biomarker is a true intensive property not accessible by any formulation of the tracer pharmacokinetic paradigm, which inherently assumes it is effectively zero when applied to DCE-MRI. We present population-averaged in vivo human breast whole tumor τi changes induced by therapy, along with those of other pharmacokinetic parameters. In responding patients, the DCE parameters change significantly after only one neoadjuvant chemotherapy cycle: while K(trans) (measuring mostly contrast agent (CA) extravasation) and kep (CA intravasation rate constant) decrease, τi increases. However, high-resolution, (1 mm)(2), parametric maps exhibit significant intratumor heterogeneity, which is lost by averaging. A typical 400 ms τi value means a trans-membrane water cycling flux of 10(13) H2O molecules s(-1)/cell for a 12 µm diameter cell. Analyses of intratumor variations (and therapy-induced changes) of τi in combination with concomitant changes of ve (extracellular volume fraction) indicate that the former are dominated by alterations of the equilibrium cell membrane water permeability coefficient, PW, not of cell size. These can be interpreted in light of literature results showing that τi changes are dominated by a PW (active) component that reciprocally reflects the membrane driving P-type ATPase ion pump turnover. For mammalian cells, this is the Na(+), K(+)-ATPase pump. These results promise the potential to discriminate metabolic and microenvironmental states of regions within tumors in vivo, and their changes with therapy.
Collapse
Affiliation(s)
- Charles S Springer
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- *Correspondence to: C. S. Springer, Jr, Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, USA. E-mail:
| | - Xin Li
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
| | - Luminita A Tudorica
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Department of Diagnostic Radiology, Oregon Health and Science UniversityPortland, OR, USA
| | - Karen Y Oh
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Department of Diagnostic Radiology, Oregon Health and Science UniversityPortland, OR, USA
| | - Nicole Roy
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Department of Diagnostic Radiology, Oregon Health and Science UniversityPortland, OR, USA
| | - Stephen Y-C Chui
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Department of Hematology/Oncology, Oregon Health and Science UniversityPortland, OR, USA
| | - Arpana M Naik
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Department of Surgical Oncology, Oregon Health and Science UniversityPortland, OR, USA
| | - Megan L Holtorf
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
- Clinical Trials Office, Oregon Health and Science UniversityPortland, OR, USA
| | - Aneela Afzal
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
| | - William D Rooney
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
| | - Wei Huang
- Advanced Imaging Research Center, Oregon Health and Science UniversityPortland, OR, USA
- Knight Cancer Institute, Oregon Health and Science UniversityPortland, OR, USA
| |
Collapse
|
13
|
Jespersen SN, Lundell H, Sønderby CK, Dyrby TB. Orientationally invariant metrics of apparent compartment eccentricity from double pulsed field gradient diffusion experiments. NMR IN BIOMEDICINE 2013; 26:1647-1662. [PMID: 24038641 DOI: 10.1002/nbm.2999] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 06/02/2023]
Abstract
Pulsed field gradient diffusion sequences (PFG) with multiple diffusion encoding blocks have been indicated to offer new microstructural tissue information, such as the ability to detect nonspherical compartment shapes in macroscopically isotropic samples, i.e. samples with negligible directional signal dependence on diffusion gradients in standard diffusion experiments. However, current acquisition schemes are not rotationally invariant in the sense that the derived metrics depend on the orientation of the sample, and are affected by the interplay of sampling directions and compartment orientation dispersion when applied to macroscopically anisotropic systems. Here we propose a new framework, the d-PFG 5-design, to enable rotationally invariant estimation of double wave vector diffusion metrics (d-PFG). The method is based on the idea that an appropriate orientational average of the signal emulates the signal from a powder preparation of the same sample, where macroscopic anisotropy is absent by construction. Our approach exploits the theory of exact numerical integration (quadrature) of polynomials on the rotation group, and we exemplify the general procedure with a set consisting of 60 pairs of diffusion wave vectors (the d-PFG 5-design) facilitating a theoretically exact determination of the fourth order Taylor or cumulant expansion of the orientationally averaged signal. The d-PFG 5-design is evaluated with numerical simulations and ex vivo high field diffusion MRI experiments in a nonhuman primate brain. Specifically, we demonstrate rotational invariance when estimating compartment eccentricity, which we show offers new microstructural information, complementary to that of fractional anisotropy (FA) from diffusion tensor imaging (DTI). The imaging observations are supported by a new theoretical result, directly relating compartment eccentricity to FA of individual pores.
Collapse
Affiliation(s)
- Sune Nørhøj Jespersen
- Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Clinical Institute, Aarhus University, Aarhus, Denmark; Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | | | | |
Collapse
|
14
|
Cha YHK, Jog MA, Kim YC, Chakrapani S, Kraman SM, Wang DJJ. Regional correlation between resting state FDG PET and pCASL perfusion MRI. J Cereb Blood Flow Metab 2013; 33:1909-14. [PMID: 23963370 PMCID: PMC3851899 DOI: 10.1038/jcbfm.2013.147] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 06/05/2013] [Accepted: 07/15/2013] [Indexed: 11/08/2022]
Abstract
To determine how arterial spin labeling (ASL) measured perfusion relates to baseline metabolism, we compared resting state cerebral perfusion using pseudo-continuous ASL and cerebral glucose metabolism using (18)F-FDG PET in 20 normal volunteers. Greater regional metabolism relative to perfusion was observed in the putamen, orbitofrontal and temporal lobes, whereas perfusion was relatively higher in the hippocampus and insula. In a region of interest analysis limited to gray matter, the overall mean correlation between perfusion and metabolism across voxels was r=0.43 with considerable regional variability. Cross-voxel correlations between relative perfusion and metabolism in mean ASL and PET images of all 20 subjects were the highest in the striatum (caudate: r=0.78; putamen: r=0.81), and the lowest in medial temporal structures (amygdala: r=0.087; hippocampus: r=-0.26). Correlations between mean relative perfusion and metabolism across 20 subjects were the highest in the striatum (caudate: r=0.76; putamen: r=0.58), temporal lobe (r=0.59), and frontal lobe (r=0.52), but very poor in all other structures (r<0.3), particularly in caudal structures such as the hippocampus (r=-0.0026), amygdala (r=0.18), and insula (r=0.14). Although there was good overall correlation between perfusion and glucose metabolism, regional variability should be considered when using either ASL or (18)F-FDG PET as surrogate markers for neural activity.
Collapse
Affiliation(s)
- Yoon-Hee K Cha
- Department of Neurology, University of California Los Angeles, Los Angeles, California, USA
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA
| | - Mayank A Jog
- Department of Neurology, University of California Los Angeles, Los Angeles, California, USA
- Laboratory of Functional MRI Technology, Ahmanson-Lovelace Brain Mapping Center, University of California Los Angeles, Los Angeles, California, USA
| | - Yoon-Chung Kim
- Department of Neurology, University of California Los Angeles, Los Angeles, California, USA
- Laboratory of Functional MRI Technology, Ahmanson-Lovelace Brain Mapping Center, University of California Los Angeles, Los Angeles, California, USA
| | - Shruthi Chakrapani
- Semel/Resnick Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Stephen M Kraman
- University of California Los Angeles (Undergraduate Economics), Los Angeles, California, USA
| | - Danny JJ Wang
- Department of Neurology, University of California Los Angeles, Los Angeles, California, USA
- Laboratory of Functional MRI Technology, Ahmanson-Lovelace Brain Mapping Center, University of California Los Angeles, Los Angeles, California, USA
| |
Collapse
|
15
|
Updated physiology and pathophysiology of CSF circulation--the pulsatile vector theory. Childs Nerv Syst 2013; 29:1811-25. [PMID: 23832074 DOI: 10.1007/s00381-013-2219-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 06/19/2013] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Hydrocephalus is still a not well-understood diagnostic and a therapeutic dilemma because of the lack of sufficient and comprehensive model of cerebrospinal fluid circulation and pathological alterations. CONCLUSIONS Based on current studies, reviews, and knowledge of cerebrospinal fluid dynamics, brain water dynamics, intracranial pressure, and cerebral perfusion physiology, a new concept is deducted that can describe normal and pathological changes of cerebrospinal fluid circulation and pathophysiology of idiopathic intracranial hypertension.
Collapse
|
16
|
Yablonskiy DA, Sukstanskii AL, He X. Blood oxygenation level-dependent (BOLD)-based techniques for the quantification of brain hemodynamic and metabolic properties - theoretical models and experimental approaches. NMR IN BIOMEDICINE 2013; 26:963-86. [PMID: 22927123 PMCID: PMC3510357 DOI: 10.1002/nbm.2839] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/19/2012] [Accepted: 06/22/2012] [Indexed: 05/06/2023]
Abstract
The quantitative evaluation of brain hemodynamics and metabolism, particularly the relationship between brain function and oxygen utilization, is important for the understanding of normal human brain operation, as well as the pathophysiology of neurological disorders. It can also be of great importance for the evaluation of hypoxia within tumors of the brain and other organs. A fundamental discovery by Ogawa and coworkers of the blood oxygenation level-dependent (BOLD) contrast opened up the possibility to use this effect to study brain hemodynamic and metabolic properties by means of MRI measurements. Such measurements require the development of theoretical models connecting the MRI signal to brain structure and function, and the design of experimental techniques allowing MR measurements to be made of the salient features of theoretical models. In this review, we discuss several such theoretical models and experimental methods for the quantification of brain hemodynamic and metabolic properties. The review's main focus is on methods for the evaluation of the oxygen extraction fraction (OEF) based on the measurement of the blood oxygenation level. A combination of the measurement of OEF and the cerebral blood flow (CBF) allows an evaluation to be made of the cerebral metabolic rate of oxygen consumption (CMRO2 ). We first consider in detail the magnetic properties of blood - magnetic susceptibility, MR relaxation and theoretical models of the intravascular contribution to the MR signal under different experimental conditions. We then describe a 'through-space' effect - the influence of inhomogeneous magnetic fields, created in the extravascular space by intravascular deoxygenated blood, on the formation of the MR signal. Further, we describe several experimental techniques taking advantage of these theoretical models. Some of these techniques - MR susceptometry and T2 -based quantification of OEF - utilize the intravascular MR signal. Another technique - quantitative BOLD - evaluates OEF by making use of through-space effects. In this review, we target both scientists just entering the MR field and more experienced MR researchers interested in the application of advanced BOLD-based techniques to the study of the brain in health and disease.
Collapse
|
17
|
Hansen MB, Jespersen SN, Leigland LA, Kroenke CD. Using diffusion anisotropy to characterize neuronal morphology in gray matter: the orientation distribution of axons and dendrites in the NeuroMorpho.org database. Front Integr Neurosci 2013; 7:31. [PMID: 23675327 PMCID: PMC3653140 DOI: 10.3389/fnint.2013.00031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 04/16/2013] [Indexed: 01/07/2023] Open
Abstract
Accurate mathematical modeling is integral to the ability to interpret diffusion magnetic resonance (MR) imaging data in terms of cellular structure in brain gray matter (GM). In previous work, we derived expressions to facilitate the determination of the orientation distribution of axonal and dendritic processes from diffusion MR data. Here we utilize neuron reconstructions available in the NeuroMorpho database (www.neuromorpho.org) to assess the validity of the model we proposed by comparing morphological properties of the neurons to predictions based on diffusion MR simulations using the reconstructed neuron models. Initially, the method for directly determining neurite orientation distributions is shown to not depend on the line length used to quantify cylindrical elements. Further variability in neuron morphology is characterized relative to neuron type, species, and laboratory of origin. Subsequently, diffusion MR signals are simulated based on human neocortical neuron reconstructions. This reveals a bias in which diffusion MR data predict neuron orientation distributions to have artificially low anisotropy. This bias is shown to arise from shortcomings (already at relatively low diffusion weighting) in the Gaussian approximation of diffusion, in the presence of restrictive barriers, and data analysis methods involving higher moments of the cumulant expansion are shown to be capable of reducing the magnitude of the observed bias.
Collapse
Affiliation(s)
- Mikkel B Hansen
- Center for Functionally Integrative Neuroscience and MINDLab, NeuroCampus Aarhus, Aarhus University Aarhus, Denmark
| | | | | | | |
Collapse
|
18
|
He X, Aghayev A, Gumus S, Ty Bae K. Estimation of single-kidney glomerular filtration rate without exogenous contrast agent. Magn Reson Med 2013; 71:257-66. [PMID: 23468406 DOI: 10.1002/mrm.24668] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/07/2013] [Accepted: 01/10/2013] [Indexed: 11/06/2022]
Abstract
PURPOSE Measurement of single-kidney filtration fraction and glomerular filtration rate (GFR) without exogenous contrast is clinically important to assess renal function and pathophysiology, especially for patients with comprised renal function. The objective of this study is to develop a novel MR-based tool for noninvasive quantification of renal function using conventional MR arterial spin labeling water as endogenous tracer. THEORY AND METHODS The regional differentiation of the arterial spin labeling water between the glomerular capsular space and the renal parenchyma was characterized and measured according to their MR relaxation properties (T1ρ or T2 ), and applied to the estimation of filtration fraction and single-kidney GFR. The proposed approach was tested to quantify GFR in healthy volunteers at baseline and after a protein-loading challenge. RESULTS Biexponential decay of the cortical arterial spin labeling water MR signal was observed. The major component decays the same as parenchyma water; the minor component decays much slower as expected from glomerular ultra-filtrates. The mean single-kidney GFR was estimated to be 49 ± 9 mL/min at baseline and increased by 28% after a protein-loading challenge. CONCLUSION We developed an arterial spin labeling-based MR imaging method that allows us to estimate renal filtration fraction and singe-kidney GFR without use of exogenous contrast.
Collapse
Affiliation(s)
- Xiang He
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | | | | |
Collapse
|
19
|
Wells JA, Siow B, Lythgoe MF, Thomas DL. Measuring biexponential transverse relaxation of the ASL signal at 9.4 T to estimate arterial oxygen saturation and the time of exchange of labeled blood water into cortical brain tissue. J Cereb Blood Flow Metab 2013; 33:215-24. [PMID: 23168531 PMCID: PMC3564190 DOI: 10.1038/jcbfm.2012.156] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The transverse decay of the arterial spin labeling (ASL) signal was measured at four inflow times in the rat brain cortex at 9.4 T. Biexponential T2 decay was observed that appears to derive from different T2 values associated with labeled water in the intravasculature (IV) and extravascular (EV) compartments. A two compartment biexponential model was used to assess the relative contribution of the IV and EV compartments to the ASL signal, without assuming a value for T2 of labeled blood water in the vessels. This novel methodology was applied to estimate the exchange time of blood water into EV tissue space and the oxygen saturation of blood on the arterial side of the vasculature. The mean exchange time of labeled blood water was estimated to be 370±40 ms. The oxygen saturation of the arterial side of the vasculature was significantly less than 100% (∼85%), which may have implications for quantitative functional magnetic resonance imaging studies where the arterial oxygen saturation is frequently assumed to be 100%.
Collapse
Affiliation(s)
- Jack A Wells
- Division of Medicine and Institute of Child Health, UCL Centre for Advanced Biomedical Imaging, University College London, London, UK
| | | | | | | |
Collapse
|
20
|
Goense J, Merkle H, Logothetis NK. High-resolution fMRI reveals laminar differences in neurovascular coupling between positive and negative BOLD responses. Neuron 2013; 76:629-39. [PMID: 23141073 DOI: 10.1016/j.neuron.2012.09.019] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2012] [Indexed: 11/29/2022]
Abstract
The six cortical layers have distinct anatomical and physiological properties, like different energy use and different feedforward and feedback connectivity. It is not known if and how layer-specific neural processes are reflected in the fMRI signal. To address this question we used high-resolution fMRI to measure BOLD, CBV, and CBF responses to stimuli that elicit positive and negative BOLD signals in macaque primary visual cortex. We found that regions with positive BOLD responses had parallel increases in CBV and CBF, whereas areas with negative BOLD responses showed a decrease in CBF but an increase in CBV. For positive BOLD responses, CBF and CBV increased in the center of the cortex, but for negative BOLD responses, CBF decreased superficially while CBV increased in the center. Our findings suggest different mechanisms for neurovascular coupling for BOLD increases and decreases, as well as laminar differences in neurovascular coupling.
Collapse
Affiliation(s)
- Jozien Goense
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany.
| | | | | |
Collapse
|
21
|
He X. Functional MR imaging of kidney--novel approaches to monitoring renal physiology. Am J Physiol Renal Physiol 2012; 303:F639-40. [PMID: 22573377 DOI: 10.1152/ajprenal.00224.2012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|