51
|
Zhu H, Zhang J, Wang Z. Arterial spin labeling perfusion MRI signal denoising using robust principal component analysis. J Neurosci Methods 2018; 295:10-19. [DOI: 10.1016/j.jneumeth.2017.11.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 10/18/2022]
|
52
|
Yan L, Liu CY, Wong KP, Huang SC, Mack WJ, Jann K, Coppola G, Ringman JM, Wang DJJ. Regional association of pCASL-MRI with FDG-PET and PiB-PET in people at risk for autosomal dominant Alzheimer's disease. NEUROIMAGE-CLINICAL 2017. [PMID: 29527482 PMCID: PMC5842754 DOI: 10.1016/j.nicl.2017.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Autosomal dominant Alzheimer's disease (ADAD) is a small subset of Alzheimer's disease that is genetically determined with 100% penetrance. It provides a valuable window into studying the course of pathologic processes that leads to dementia. Arterial spin labeling (ASL) MRI is a potential AD imaging marker that non-invasively measures cerebral perfusion. In this study, we investigated the relationship of cerebral blood flow measured by pseudo-continuous ASL (pCASL) MRI with measures of cerebral metabolism (FDG PET) and amyloid deposition (Pittsburgh Compound B (PiB) PET). Thirty-one participants at risk for ADAD (age 39 ± 13 years, 19 females) were recruited into this study, and 21 of them received both MRI and FDG and PiB PET scans. Considerable variability was observed in regional correlations between ASL-CBF and FDG across subjects. Both regional hypo-perfusion and hypo-metabolism were associated with amyloid deposition. Cross-sectional analyses of each biomarker as a function of the estimated years to expected dementia diagnosis indicated an inverse relationship of both perfusion and glucose metabolism with amyloid deposition during AD development. These findings indicate that neurovascular dysfunction is associated with amyloid pathology, and also indicate that ASL CBF may serve as a sensitive early biomarker for AD. The direct comparison among the three biomarkers provides complementary information for understanding the pathophysiological process of AD. Regional associations of three imaging biomarkers (pCASL-MRI, FDG-PET and PiB-PET) are studied in persons at risk for ADAD. PiB-PET shows different spatial pattern compared to pCASL-MRI and FDG-PET. There is considerable variability among regional correlations between pCASL and FDG. Both regional hypo-perfusion and hypo-metabolism are associated with amyloid deposition.
Collapse
Affiliation(s)
- Lirong Yan
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Neurology, University of Southern California, Los Angeles, CA, USA.
| | - Collin Y Liu
- Department of Neurology, University of Southern California, Los Angeles, CA, USA; Alzheimer's Disease Research Center, University of Southern California, Los Angeles, CA, USA
| | - Koon-Pong Wong
- Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Sung-Cheng Huang
- Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Wendy J Mack
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Kay Jann
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Neurology, University of Southern California, Los Angeles, CA, USA
| | - Giovanni Coppola
- Semel Institute of Psychiatry and Biobehavioral Sciences UCLA, USA
| | - John M Ringman
- Department of Neurology, University of Southern California, Los Angeles, CA, USA; Alzheimer's Disease Research Center, University of Southern California, Los Angeles, CA, USA
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Neurology, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
53
|
Wang Z, Suh J, Duan D, Darnley S, Jing Y, Zhang J, O'Brien C, Childress AR. A hypo-status in drug-dependent brain revealed by multi-modal MRI. Addict Biol 2017; 22:1622-1631. [PMID: 27654848 DOI: 10.1111/adb.12459] [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] [Received: 03/21/2016] [Revised: 08/15/2016] [Accepted: 08/30/2016] [Indexed: 11/30/2022]
Abstract
Drug addiction is a chronic brain disorder with no proven effective cure. Assessing both structural and functional brain alterations by using multi-modal, rather than purely unimodal imaging techniques, may provide a more comprehensive understanding of the brain mechanisms underlying addiction, which in turn may facilitate future treatment strategies. However, this type of research remains scarce in the literature. We acquired multi-modal magnetic resonance imaging from 20 cocaine-addicted individuals and 19 age-matched controls. Compared with controls, cocaine addicts showed a multi-modal hypo-status with (1) decreased brain tissue volume in the medial and lateral orbitofrontal cortex (OFC); (2) hypo-perfusion in the prefrontal cortex, anterior cingulate cortex, insula, right temporal cortex and dorsolateral prefrontal cortex and (3) reduced irregularity of resting state activity in the OFC and limbic areas, as well as the cingulate, visual and parietal cortices. In the cocaine-addicted brain, larger tissue volume in the medial OFC, anterior cingulate cortex and ventral striatum and smaller insular tissue volume were associated with higher cocaine dependence levels. Decreased perfusion in the amygdala and insula was also correlated with higher cocaine dependence levels. Tissue volume, perfusion, and brain entropy in the insula and prefrontal cortex, all showed a trend of negative correlation with drug craving scores. The three modalities showed voxel-wise correlation in various brain regions, and combining them improved patient versus control brain classification accuracy. These results, for the first time, demonstrate a comprehensive cocaine-dependence and craving-related hypo-status regarding the tissue volume, perfusion and resting brain irregularity in the cocaine-addicted brain.
Collapse
Affiliation(s)
- Ze Wang
- Center for Cognition and Brain Disorders, Institutes of Psychological Science; Hangzhou Normal University; China
- Affiliated Hospital of Hangzhou Normal University; China
- Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments; China
| | - Jesse Suh
- Department of Psychiatry, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- VISN-4 Mental Illness Research, Education and Clinical Center; VA Medical Center; Philadelphia PA USA
| | - Dingna Duan
- School of Biomedical Engineering; Zhejiang University; China
| | - Stefanie Darnley
- Department of Psychiatry, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Ying Jing
- Center for Cognition and Brain Disorders, Institutes of Psychological Science; Hangzhou Normal University; China
- Affiliated Hospital of Hangzhou Normal University; China
- Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments; China
| | - Jian Zhang
- Center for Cognition and Brain Disorders, Institutes of Psychological Science; Hangzhou Normal University; China
- Affiliated Hospital of Hangzhou Normal University; China
- Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments; China
| | - Charles O'Brien
- Department of Psychiatry, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- VISN-4 Mental Illness Research, Education and Clinical Center; VA Medical Center; Philadelphia PA USA
| | - Anna Rose Childress
- Department of Psychiatry, Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- VISN-4 Mental Illness Research, Education and Clinical Center; VA Medical Center; Philadelphia PA USA
| |
Collapse
|
54
|
Dolui S, Vidorreta M, Wang Z, Nasrallah IM, Alavi A, Wolk DA, Detre JA. Comparison of PASL, PCASL, and background-suppressed 3D PCASL in mild cognitive impairment. Hum Brain Mapp 2017; 38:5260-5273. [PMID: 28737289 DOI: 10.1002/hbm.23732] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/30/2017] [Accepted: 07/09/2017] [Indexed: 12/21/2022] Open
Abstract
We compared three implementations of single-shot arterial spin labeled (ASL) perfusion magnetic resonance imaging: two-dimensional (2D) pulsed ASL (PASL), 2D pseudocontinuous ASL (PCASL), and background-suppressed (BS) 3D PCASL obtained in a cohort of patients with mild cognitive impairment (MCI) and elderly controls. Study subjects also underwent 18 F-fluorodeoxyglucose positron emission tomography (18 F-FDG PET). While BS 3D PCASL showed the lowest (P < 0.001) gray matter-white matter cerebral blood flow (CBF) contrast ratio, it provided the highest (P < 0.001) temporal signal-to-noise ratio. Mean relative CBF estimated using the PCASL methods in posterior cingulate cortex (PCC), precuneus, and hippocampus showed hypoperfusion in the MCI cohort compared to the controls consistent with hypometabolism measured by 18 F-FDG PET. BS 3D PCASL demonstrated the highest discrimination between controls and patients with effect size comparable to that seen with 18 F-FDG PET. 2D PASL did not demonstrate group differentiation with relative CBF in any ROI, whereas 2D PCASL demonstrated significant differences only in PCC and hippocampus. Mean global CBF values did not differ across methods and were highly correlated; however, the correlations were significantly higher (P < 0.001) when either the same labeling (PCASL) or the same acquisition strategy (2D) was used as compared to when both the labeling and readout methods differed. In addition, there were differences in regional distribution of CBF between the three modalities, which can be attributed to differences in sequence parameters. These results demonstrate the superiority of ASL with PCASL and BS 3D readout as a biomarker for regional brain function changes in MCI. Hum Brain Mapp 38:5260-5273, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marta Vidorreta
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ze Wang
- Department of Radiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Ilya M Nasrallah
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Abass Alavi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David A Wolk
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, Pennsylvania
| |
Collapse
|
55
|
Shirzadi Z, Stefanovic B, Chappell MA, Ramirez J, Schwindt G, Masellis M, Black SE, MacIntosh BJ. Enhancement of automated blood flow estimates (ENABLE) from arterial spin-labeled MRI. J Magn Reson Imaging 2017; 47:647-655. [DOI: 10.1002/jmri.25807] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/20/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Zahra Shirzadi
- Department of Medical Biophysics; University of Toronto; Toronto ON Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
| | - Bojana Stefanovic
- Department of Medical Biophysics; University of Toronto; Toronto ON Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
| | - Michael A. Chappell
- Institute of Biomedical Engineering, Department of Engineering Science; University of Oxford; Oxford UK
- Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
| | - Joel Ramirez
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
| | - Graeme Schwindt
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Department of Family and Community Medicine; University of Toronto; Toronto ON Canada
| | - Mario Masellis
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Department of Medicine (Neurology), Sunnybrook Health Sciences Centre; University of Toronto; Toronto ON Canada
| | - Sandra E. Black
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Department of Medicine (Neurology), Sunnybrook Health Sciences Centre; University of Toronto; Toronto ON Canada
| | - Bradley J. MacIntosh
- Department of Medical Biophysics; University of Toronto; Toronto ON Canada
- Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
- Hurvitz Brain Sciences, Sunnybrook Research Institute; University of Toronto; Toronto ON Canada
| |
Collapse
|
56
|
Dolui S, Wang Z, Shinohara RT, Wolk DA, Detre JA. Structural Correlation-based Outlier Rejection (SCORE) algorithm for arterial spin labeling time series. J Magn Reson Imaging 2017; 45:1786-1797. [PMID: 27570967 PMCID: PMC5332532 DOI: 10.1002/jmri.25436] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 08/05/2016] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To propose and validate Structural Correlation-based Outlier REjection (SCORE), a novel algorithm for removal of artifacts arising from outlier control-label pairs in 2D arterial spin labeling (ASL) data. MATERIALS AND METHODS The proposed method was assessed with respect to other state-of-the-art ASL signal processing approaches using 2D pulsed ASL data obtained with a 3T Siemens scanner from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Longitudinal data from control participants acquired 3 months apart were used to assess within-subject coefficient of variation (wsCV) based on the assumption that the optimal signal processing strategy will minimize control subject retest variability in Cerebral Blood Flow (CBF). SCORE was further evaluated by determining its sensitivity for distinguishing patients with Alzheimer's disease (AD) from controls based on hypoperfusion in predefined regions of interest (ROIs) that are known to be sensitive to AD-related changes. RESULTS SCORE coupled with a preprocessing step to discard a few extreme outliers (combined algorithm referred to as SCORE+) reduced wsCV up to 21% in gray matter and 39% in smaller ROIs compared to the reference algorithms. It also provided an average increase in effect size for patient-control differences of 50% compared to other algorithms in a priori ROIs sensitive to AD-related changes. This increase was statistically significant (P < 0.05) for the majority of the ROIs and methods as evaluated by permutation tests. CONCLUSION CBF maps generated with SCORE or SCORE + provide improved retest reliability in control subjects while simultaneously increasing sensitivity to pathological CBF effects between controls and patients. J. Magn. Reson. Imaging 2016 Level of Evidence: 2 J. MAGN. RESON. IMAGING 2017;45:1786-1797.
Collapse
Affiliation(s)
- Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ze Wang
- Center for Cognition and Brain Disorders and the Affiliated Hospital, Hangzhou Normal University, Hangzhou, China
- Departments of Psychiatry and Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Russell T Shinohara
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David A Wolk
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|
57
|
Hoscheidt SM, Kellawan JM, Berman SE, Rivera-Rivera LA, Krause RA, Oh JM, Beeri MS, Rowley HA, Wieben O, Carlsson CM, Asthana S, Johnson SC, Schrage WG, Bendlin BB. Insulin resistance is associated with lower arterial blood flow and reduced cortical perfusion in cognitively asymptomatic middle-aged adults. J Cereb Blood Flow Metab 2017; 37:2249-2261. [PMID: 27488909 PMCID: PMC5464714 DOI: 10.1177/0271678x16663214] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals. We hypothesized that higher HOMA-IR would be associated with reduced flow in macrovessels and lower cortical perfusion. One hundred and twenty cognitively asymptomatic middle-aged adults (57 ± 5 yrs) underwent fasting blood draw, phase contrast-vastly undersampled isotropic projection reconstruction (PC VIPR) MRI, and arterial spin labeling (ASL) perfusion. Higher HOMA-IR was associated with lower arterial blood flow, particularly within the internal carotid arteries (ICAs), and lower cerebral perfusion in several brain regions including frontal and temporal lobe regions. Higher blood flow in bilateral ICAs predicted greater cortical perfusion in individuals with lower HOMA-IR, a relationship not observed among those with higher HOMA-IR. Findings provide novel evidence for an uncoupling of macrovascular blood flow and microvascular perfusion among individuals with higher IR in midlife.
Collapse
Affiliation(s)
- Siobhan M Hoscheidt
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | | | - Sara E Berman
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Leonardo A Rivera-Rivera
- 3 Department of Medical Physics, University of Wisconsin, Madison, WI, USA.,4 Department of Radiology, University of Wisconsin, Madison, WI, USA
| | - Rachel A Krause
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jennifer M Oh
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Michal S Beeri
- 5 The Joseph Sagol Neuroscience Center, Sheba Medical Center, Israel.,6 The Icahn School of Medicine, Mount Sinai, NY, USA
| | - Howard A Rowley
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,4 Department of Radiology, University of Wisconsin, Madison, WI, USA
| | - Oliver Wieben
- 3 Department of Medical Physics, University of Wisconsin, Madison, WI, USA.,4 Department of Radiology, University of Wisconsin, Madison, WI, USA
| | - Cynthia M Carlsson
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,7 Geriatric Research Education and Clinical Center, Wm. S. Middleton Veterans Hospital, Madison, WI, USA.,8 Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sanjay Asthana
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,7 Geriatric Research Education and Clinical Center, Wm. S. Middleton Veterans Hospital, Madison, WI, USA.,8 Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sterling C Johnson
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,7 Geriatric Research Education and Clinical Center, Wm. S. Middleton Veterans Hospital, Madison, WI, USA.,8 Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - William G Schrage
- 2 Department of Kinesiology, University of Wisconsin, Madison, WI, USA
| | - Barbara B Bendlin
- 1 Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,8 Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| |
Collapse
|
58
|
Spann SM, Kazimierski KS, Aigner CS, Kraiger M, Bredies K, Stollberger R. Spatio-temporal TGV denoising for ASL perfusion imaging. Neuroimage 2017; 157:81-96. [PMID: 28559192 DOI: 10.1016/j.neuroimage.2017.05.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 12/21/2022] Open
Abstract
In arterial spin labeling (ASL) a perfusion weighted image is achieved by subtracting a label image from a control image. This perfusion weighted image has an intrinsically low signal to noise ratio and numerous measurements are required to achieve reliable image quality, especially at higher spatial resolutions. To overcome this limitation various denoising approaches have been published using the perfusion weighted image as input for denoising. In this study we propose a new spatio-temporal filtering approach based on total generalized variation (TGV) regularization which exploits the inherent information of control and label pairs simultaneously. In this way, the temporal and spatial similarities of all images are used to jointly denoise the control and label images. To assess the effect of denoising, virtual ground truth data were produced at different SNR levels. Furthermore, high-resolution in-vivo pulsed ASL data sets were acquired and processed. The results show improved image quality, quantitative accuracy and robustness against outliers compared to seven state of the art denoising approaches.
Collapse
Affiliation(s)
- Stefan M Spann
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
| | - Kamil S Kazimierski
- Institute for Mathematics and Scientific Computing, University of Graz, NAWI Graz, Heinrichstrasse 36, 8010 Graz, Austria
| | - Christoph S Aigner
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Markus Kraiger
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria
| | - Kristian Bredies
- Institute for Mathematics and Scientific Computing, University of Graz, NAWI Graz, Heinrichstrasse 36, 8010 Graz, Austria
| | - Rudolf Stollberger
- Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010 Graz, Austria; BioTechMed-Graz, Graz, Austria.
| |
Collapse
|
59
|
van Erp S, Ercan E, Breedveld P, Brakenhoff L, Ghariq E, Schmid S, Osch MV, van Buchem M, Emmer B, van der Grond J, Wolterbeek R, Hommes D, Fidder H, van der Wee N, Huizinga T, van der Heijde D, Middelkoop H, Ronen I, van der Meulen-de Jong A. Cerebral magnetic resonance imaging in quiescent Crohn’s disease patients with fatigue. World J Gastroenterol 2017; 23:1018-1029. [PMID: 28246475 PMCID: PMC5311090 DOI: 10.3748/wjg.v23.i6.1018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/14/2016] [Accepted: 12/08/2016] [Indexed: 02/06/2023] Open
Abstract
AIM
To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).
METHODS
Multiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study groups.
RESULTS
Reduced glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P < 0.001). Cognitive functioning scores related to memory (P = 0.007) and executive functioning (P = 0.02) were lower in CD patients and both scores showed correlation with depression and anxiety. No correlation was found subcortical volumes between CD patients and controls in the T1-weighted analysis. In addition, no correlation was found between mental status and MRI findings.
CONCLUSION
This work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls.
Collapse
|
60
|
Kile S, Au W, Parise C, Rose K, Donnel T, Hankins A, Chan M, Ghassemi A. IVIG treatment of mild cognitive impairment due to Alzheimer's disease: a randomised double-blinded exploratory study of the effect on brain atrophy, cognition and conversion to dementia. J Neurol Neurosurg Psychiatry 2017; 88:106-112. [PMID: 26420886 DOI: 10.1136/jnnp-2015-311486] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/27/2015] [Accepted: 09/01/2015] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To determine the effect of intravenous immunoglobulin (IVIG) on brain atrophy and cognitive function in mild cognitive impairment (MCI) due to Alzheimer's disease (AD). METHODS 50 participant 50-84 years of age with amnestic MCI were administered 0.4 g/kg 10% IVIG or 0.9% saline every 2 weeks for a total of 5 infusions (2 g/kg total dose) in a randomised double-blinded design. MRI brain was completed at baseline, 12 and 24 months. Cognitive testing was completed at baseline and every 4 months. Participants were stratified into early and late (LMCI) MCI stages. Average annualised per cent change in ventricular volume was computed as a measure of brain atrophy. RESULTS There was significantly less brain atrophy (p=0.037, adjusted for MCI status) in the IVIG group (5.87%) when compared with placebo (8.14%) at 12 months; at 24 months, the reduction in brain atrophy no longer reached statistical significance. The LMCI participants who received IVIG performed better on Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog; p=0.011) and Mini-Mental State Examination (MMSE; p=0.004) at 1 year; these differences were not present after 2 years. There was no difference in conversion to AD dementia between the treatment and control groups after 2 years; however, at 1 year, there were fewer conversions from LMCI to AD dementia in the IVIG group (33.3%) when compared with control group (58.3%). CONCLUSIONS This exploratory study provides limited evidence that a short course of IVIG administered in the MCI stage of AD reduces brain atrophy, prevents cognitive decline in LMCI and delays conversion to AD dementia for at least 1 year; however, this effect of IVIG appears to wane by 2 years. TRIAL REGISTRATION NUMBER ClinicalTrials.gov, NCT01300728.
Collapse
Affiliation(s)
- Shawn Kile
- Sutter Neuroscience Institute, Sacramento, California, USA
| | - William Au
- Sutter Neuroscience Institute, Sacramento, California, USA
| | - Carol Parise
- Sutter Institute for Medical Research (SIMR), Sacramento, California, USA
| | - Kimberley Rose
- Sutter Neuroscience Institute, Sacramento, California, USA
| | - Tammy Donnel
- Sutter Institute for Medical Research (SIMR), Sacramento, California, USA
| | - Andrea Hankins
- Sutter Institute for Medical Research (SIMR), Sacramento, California, USA
| | - Matthew Chan
- Sutter Imaging, Neuroradiology, Sacramento, California, USA
| | - Azad Ghassemi
- Sutter Imaging, Neuroradiology, Sacramento, California, USA
| |
Collapse
|
61
|
Tani K, Mio M, Toyofuku T, Kato S, Masumoto T, Ijichi T, Matsushima M, Morimoto S, Hirata T. [Comparison of Arterial Spin-labeling Perfusion Images at Different Spatial Normalization Methods Based on Voxel-based Statistical Analysis]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2017; 73:737-746. [PMID: 28931770 DOI: 10.6009/jjrt.2017_jsrt_73.9.737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
PURPOSE Spatial normalization is a significant image pre-processing operation in statistical parametric mapping (SPM) analysis. The purpose of this study was to clarify the optimal method of spatial normalization for improving diagnostic accuracy in SPM analysis of arterial spin-labeling (ASL) perfusion images. METHODS We evaluated the SPM results of five spatial normalization methods obtained by comparing patients with Alzheimer's disease or normal pressure hydrocephalus complicated with dementia and cognitively healthy subjects. We used the following methods: 3DT1-conventional based on spatial normalization using anatomical images; 3DT1-DARTEL based on spatial normalization with DARTEL using anatomical images; 3DT1-conventional template and 3DT1-DARTEL template, created by averaging cognitively healthy subjects spatially normalized using the above methods; and ASL-DARTEL template created by averaging cognitively healthy subjects spatially normalized with DARTEL using ASL images only. RESULTS Our results showed that ASL-DARTEL template was small compared with the other two templates. Our SPM results obtained with ASL-DARTEL template method were inaccurate. Also, there were no significant differences between 3DT1-conventional and 3DT1-DARTEL template methods. In contrast, the 3DT1-DARTEL method showed higher detection sensitivity, and precise anatomical location. CONCLUSIONS Our SPM results suggest that we should perform spatial normalization with DARTEL using anatomical images.
Collapse
Affiliation(s)
- Kazuki Tani
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Motohira Mio
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Tatsuo Toyofuku
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Shinichi Kato
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Tomoya Masumoto
- Department of Radiology, Fukuoka University Chikushi Hospital
| | - Tetsuya Ijichi
- Department of Radiology, Fukuoka University Chikushi Hospital
| | | | | | - Takumi Hirata
- Department of Radiology, Fukuoka University Chikushi Hospital
| |
Collapse
|
62
|
Zhang N, Gordon ML, Goldberg TE. Cerebral blood flow measured by arterial spin labeling MRI at resting state in normal aging and Alzheimer’s disease. Neurosci Biobehav Rev 2017; 72:168-175. [DOI: 10.1016/j.neubiorev.2016.11.023] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 11/12/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
|
63
|
Iyalomhe O, Swierczek S, Enwerem N, Chen Y, Adedeji MO, Allard J, Ntekim O, Johnson S, Hughes K, Kurian P, Obisesan TO. The Role of Hypoxia-Inducible Factor 1 in Mild Cognitive Impairment. Cell Mol Neurobiol 2016; 37:969-977. [PMID: 27858285 DOI: 10.1007/s10571-016-0440-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/26/2016] [Indexed: 01/16/2023]
Abstract
Neuroinflammation and reactive oxygen species are thought to mediate the pathogenesis of Alzheimer's disease (AD), suggesting that mild cognitive impairment (MCI), a prodromal stage of AD, may be driven by similar insults. Several studies document that hypoxia-inducible factor 1 (HIF-1) is neuroprotective in the setting of neuronal insults, since this transcription factor drives the expression of critical genes that diminish neuronal cell death. HIF-1 facilitates glycolysis and glucose metabolism, thus helping to generate reductive equivalents of NADH/NADPH that counter oxidative stress. HIF-1 also improves cerebral blood flow which opposes the toxicity of hypoxia. Increased HIF-1 activity and/or expression of HIF-1 target genes, such as those involved in glycolysis or vascular flow, may be an early adaptation to the oxidative stressors that characterize MCI pathology. The molecular events that constitute this early adaptation are likely neuroprotective, and might mitigate cognitive decline or the onset of full-blown AD. On the other hand, prolonged or overwhelming stressors can convert HIF-1 into an activator of cell death through agents such as Bnip3, an event that is more likely to occur in late MCI or advanced Alzheimer's dementia.
Collapse
Affiliation(s)
- Osigbemhe Iyalomhe
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Sabina Swierczek
- Department of Hematology/BMT, University of Utah School of Medicine, 30 N Medical Dr, Salt Lake City, UT, 84132, USA
| | - Ngozi Enwerem
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Yuanxiu Chen
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Monica O Adedeji
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Joanne Allard
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Oyonumo Ntekim
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Sheree Johnson
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Kakra Hughes
- Division of Endovascular Surgery, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Philip Kurian
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA.,Human Genome Center, Howard University, 2041 Georgia Ave NW, Washington, DC, 20060, USA
| | - Thomas O Obisesan
- Geriatrics Division, Department of Medicine, Howard University Hospital, 2041 Georgia Ave NW, Washington, DC, 20060, USA. .,Howard University Clinical Research Unit (GHUCCTS CTSA), 2041 Georgia Ave, NW, Washington, DC, 20060, USA.
| |
Collapse
|
64
|
Huang W, Zeng S, Wan M, Chen G. Medical media analytics via ranking and big learning: A multi-modality image-based disease severity prediction study. Neurocomputing 2016. [DOI: 10.1016/j.neucom.2015.07.148] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
65
|
Steketee RME, Meijboom R, de Groot M, Bron EE, Niessen WJ, van der Lugt A, van Swieten JC, Smits M. Concurrent white and gray matter degeneration of disease-specific networks in early-stage Alzheimer's disease and behavioral variant frontotemporal dementia. Neurobiol Aging 2016; 43:119-28. [PMID: 27255821 DOI: 10.1016/j.neurobiolaging.2016.03.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/22/2016] [Accepted: 03/30/2016] [Indexed: 01/08/2023]
Abstract
This study investigates regional coherence between white matter (WM) microstructure and gray matter (GM) volume and perfusion measures in Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) using a correlational approach. WM-GM coherence, compared with controls, was stronger between cingulum WM and frontotemporal GM in AD, and temporoparietal GM in bvFTD. In addition, in AD compared with controls, coherence was stronger between inferior fronto-occipital fasciculus WM microstructure and occipital GM perfusion. In this first study assessing regional WM-GM coherence in AD and bvFTD, we show that WM microstructure and GM volume and perfusion measures are coherent, particularly in regions implicated in AD and bvFTD pathology. This indicates concurrent degeneration in disease-specific networks. Our methodology allows for the detection of incipient abnormalities that go undetected in conventional between-group analyses.
Collapse
Affiliation(s)
- Rebecca M E Steketee
- Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Rozanna Meijboom
- Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Marius de Groot
- Department of Epidemiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands; Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands; Biomedical Imaging Group Rotterdam, Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Esther E Bron
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands; Biomedical Imaging Group Rotterdam, Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Wiro J Niessen
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands; Biomedical Imaging Group Rotterdam, Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands; Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Aad van der Lugt
- Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - John C van Swieten
- Department of Neurology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Marion Smits
- Department of Radiology, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands.
| |
Collapse
|
66
|
A Dietary Treatment Improves Cerebral Blood Flow and Brain Connectivity in Aging apoE4 Mice. Neural Plast 2016; 2016:6846721. [PMID: 27034849 PMCID: PMC4806294 DOI: 10.1155/2016/6846721] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/22/2016] [Indexed: 11/17/2022] Open
Abstract
APOE ε4 (apoE4) polymorphism is the main genetic determinant of sporadic Alzheimer's disease (AD). A dietary approach (Fortasyn) including docosahexaenoic acid, eicosapentaenoic acid, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium has been proposed for dietary management of AD. We hypothesize that the diet could inhibit AD-like pathologies in apoE4 mice, specifically cerebrovascular and connectivity impairment. Moreover, we evaluated the diet effect on cerebral blood flow (CBF), functional connectivity (FC), gray/white matter integrity, and postsynaptic density in aging apoE4 mice. At 10–12 months, apoE4 mice did not display prominent pathological differences compared to wild-type (WT) mice. However, 16–18-month-old apoE4 mice revealed reduced CBF and accelerated synaptic loss. The diet increased cortical CBF and amount of synapses and improved white matter integrity and FC in both aging apoE4 and WT mice. We demonstrated that protective mechanisms on vascular and synapse health are enhanced by Fortasyn, independent of apoE genotype. We further showed the efficacy of a multimodal translational approach, including advanced MR neuroimaging, to study dietary intervention on brain structure and function in aging.
Collapse
|
67
|
Xie L, Dolui S, Das SR, Stockbower GE, Daffner M, Rao H, Yushkevich PA, Detre JA, Wolk DA. A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment. Neuroimage Clin 2016; 11:388-397. [PMID: 27222794 PMCID: PMC4821452 DOI: 10.1016/j.nicl.2016.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/16/2016] [Accepted: 03/01/2016] [Indexed: 11/24/2022]
Abstract
Arterial spin labeled perfusion magnetic resonance imaging (ASL MRI) provides non-invasive quantification of cerebral blood flow, which can be used as a biomarker of brain function due to the tight coupling between cerebral blood flow (CBF) and brain metabolism. A growing body of literature suggests that regional CBF is altered in neurodegenerative diseases. Here we examined ASL MRI CBF in subjects with amnestic mild cognitive impairment (n = 65) and cognitively normal healthy controls (n = 62), both at rest and during performance of a memory-encoding task. As compared to rest, task-enhanced ASL MRI improved group discrimination, which supports the notion that physiologic measures during a cognitive challenge, or "stress test", may increase the ability to detect subtle functional changes in early disease stages. Further, logistic regression analysis demonstrated that ASL MRI and concomitantly acquired structural MRI provide complementary information of disease status. The current findings support the potential utility of task-enhanced ASL MRI as a biomarker in early Alzheimer's disease.
Collapse
Key Words
- AAL, Anatomical Automatic Labeling
- ASL, arterial spin labeled
- Alzheimer's disease
- Arterial spin labeling
- BOLD, blood oxygen level dependent
- Biomarker
- CBF, cerebral blood flow
- CSF, cerebrospinal fluid
- FDG PET, flourodeoyglucose positron emission tomography
- FWER, familywise error rate
- HC, health control
- MCI, mild cognitive impairment
- MMSE, mini-mental status exam
- MNI, Montreal Neurological Institute
- MTL, medial temporal lobe
- Medial temporal lobe
- PASL, pulsed ASL
- PCC, posterior cingulate cortex
- ROI, region of interest
- SCORE, structural correlation based outlier rejection
- Scene-encoding memory task
- a-MCI, amnestic mild cognitive impairment
- aCBF, absolute cerebral blood flow
- pCASL, pseudo-continuous ASL
- rCBF, relative cerebral blood flow
Collapse
Affiliation(s)
- Long Xie
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Sudipto Dolui
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sandhitsu R Das
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Grace E Stockbower
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Molly Daffner
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hengyi Rao
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Yushkevich
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - David A Wolk
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
68
|
Michels L, Warnock G, Buck A, Macauda G, Leh SE, Kaelin AM, Riese F, Meyer R, O'Gorman R, Hock C, Kollias S, Gietl AF. Arterial spin labeling imaging reveals widespread and Aβ-independent reductions in cerebral blood flow in elderly apolipoprotein epsilon-4 carriers. J Cereb Blood Flow Metab 2016; 36:581-95. [PMID: 26661143 PMCID: PMC4794091 DOI: 10.1177/0271678x15605847] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/07/2015] [Indexed: 12/11/2022]
Abstract
Changes in cerebral blood flow are an essential feature of Alzheimer's disease and have been linked to apolipoprotein E-genotype and cerebral amyloid-deposition. These factors could be interdependent or influence cerebral blood flow via different mechanisms. We examined apolipoprotein E-genotype, amyloid beta-deposition, and cerebral blood flow in amnestic mild cognitive impairment using pseudo-continuous arterial spin labeling MRI in 27 cognitively normal elderly and 16 amnestic mild cognitive impairment participants. Subjects underwent Pittsburgh Compound B (PiB) positron emission tomography and apolipoprotein E-genotyping. Global cerebral blood flow was lower in apolipoprotein E ɛ4-allele carriers (apolipoprotein E4+) than in apolipoprotein E4- across all subjects (including cognitively normal participants) and within the group of cognitively normal elderly. Global cerebral blood flow was lower in subjects with mild cognitive impairment compared with cognitively normal. Subjects with elevated cerebral amyloid-deposition (PiB+) showed a trend for lower global cerebral blood flow. Apolipoprotein E-status exerted the strongest effect on global cerebral blood flow. Regional analysis indicated that local cerebral blood flow reductions were more widespread for the contrasts apolipoprotein E4+ versus apolipoprotein E4- compared with the contrasts PiB+ versus PiB- or mild cognitive impairment versus cognitively normal. These findings suggest that apolipoprotein E-genotype exerts its impact on cerebral blood flow at least partly independently from amyloid beta-deposition, suggesting that apolipoprotein E also contributes to cerebral blood flow changes outside the context of Alzheimer's disease.
Collapse
Affiliation(s)
- Lars Michels
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland Center of MR-Research, University Children's Hospital Zurich, Zurich, Switzerland
| | - Geoffrey Warnock
- Clinic of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Alfred Buck
- Clinic of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Gianluca Macauda
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Sandra E Leh
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Andrea M Kaelin
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Florian Riese
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Rafael Meyer
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Ruth O'Gorman
- Center of MR-Research, University Children's Hospital Zurich, Zurich, Switzerland
| | - Christoph Hock
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Spyros Kollias
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
| | - Anton F Gietl
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| |
Collapse
|
69
|
Hess DC, Khan MB, Hoda N, Morgan JC. Remote ischemic conditioning: a treatment for vascular cognitive impairment. Brain Circ 2015; 1:133-139. [PMID: 30221201 DOI: 10.4103/2394-8108.172885] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
There is a strong link between hypoperfusion and white matter (WM) damage in patients with leukoaraiosis and vascular cognitive impairment (VCI). Other than management of vascular risk factors, there is no treatment for WM damage and VCI that delays progression of the disease process to dementia. Observational studies suggest that exercise may prevent or slow down the progression of Alzheimer's disease (AD) and VCI. However, getting patients to exercise is challenging especially with advancing age and disability. Remote ischemic conditioning, an "exercise equivalent", allows exercise to be given with a "device" in the home for long periods of time. Since RIC increases CBF in pre-clinical studies and in humans, RIC may be an ideal therapy to treat VCI and WM disease and perhaps even sporadic AD. By using MRI imaging of WM progression, a sample size in the range of about 100 subjects per group could determine if RIC has activity in WM disease and VCI.
Collapse
Affiliation(s)
- David C Hess
- Department of Neurology Medical College of Georgia, Georgia Regent's University, Augusta, GA USA
| | - Mohammad B Khan
- Department of Neurology Medical College of Georgia, Georgia Regent's University, Augusta, GA USA
| | - Nasrul Hoda
- Department of Medical Laboratory, Imaging, and Radiologic Sciences, College of Allied Health Sciences, Georgia Regent's University, Augusta, GA USA
| | - John C Morgan
- Department of Neurology Medical College of Georgia, Georgia Regent's University, Augusta, GA USA
| |
Collapse
|
70
|
A neuroradiologist's guide to arterial spin labeling MRI in clinical practice. Neuroradiology 2015; 57:1181-202. [PMID: 26351201 PMCID: PMC4648972 DOI: 10.1007/s00234-015-1571-z] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/05/2015] [Indexed: 01/01/2023]
Abstract
Arterial spin labeling (ASL) is a non-invasive MRI technique to measure cerebral blood flow (CBF). This review provides a practical guide and overview of the clinical applications of ASL of the brain, as well its potential pitfalls. The technical and physiological background is also addressed. At present, main areas of interest are cerebrovascular disease, dementia and neuro-oncology. In cerebrovascular disease, ASL is of particular interest owing to its quantitative nature and its capability to determine cerebral arterial territories. In acute stroke, the source of the collateral blood supply in the penumbra may be visualised. In chronic cerebrovascular disease, the extent and severity of compromised cerebral perfusion can be visualised, which may be used to guide therapeutic or preventative intervention. ASL has potential for the detection and follow-up of arteriovenous malformations. In the workup of dementia patients, ASL is proposed as a diagnostic alternative to PET. It can easily be added to the routinely performed structural MRI examination. In patients with established Alzheimer’s disease and frontotemporal dementia, hypoperfusion patterns are seen that are similar to hypometabolism patterns seen with PET. Studies on ASL in brain tumour imaging indicate a high correlation between areas of increased CBF as measured with ASL and increased cerebral blood volume as measured with dynamic susceptibility contrast-enhanced perfusion imaging. Major advantages of ASL for brain tumour imaging are the fact that CBF measurements are not influenced by breakdown of the blood–brain barrier, as well as its quantitative nature, facilitating multicentre and longitudinal studies.
Collapse
|
71
|
Weiner MW, Veitch DP, Aisen PS, Beckett LA, Cairns NJ, Cedarbaum J, Green RC, Harvey D, Jack CR, Jagust W, Luthman J, Morris JC, Petersen RC, Saykin AJ, Shaw L, Shen L, Schwarz A, Toga AW, Trojanowski JQ. 2014 Update of the Alzheimer's Disease Neuroimaging Initiative: A review of papers published since its inception. Alzheimers Dement 2015; 11:e1-120. [PMID: 26073027 PMCID: PMC5469297 DOI: 10.1016/j.jalz.2014.11.001] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/18/2013] [Indexed: 01/18/2023]
Abstract
The Alzheimer's Disease Neuroimaging Initiative (ADNI) is an ongoing, longitudinal, multicenter study designed to develop clinical, imaging, genetic, and biochemical biomarkers for the early detection and tracking of Alzheimer's disease (AD). The initial study, ADNI-1, enrolled 400 subjects with early mild cognitive impairment (MCI), 200 with early AD, and 200 cognitively normal elderly controls. ADNI-1 was extended by a 2-year Grand Opportunities grant in 2009 and by a competitive renewal, ADNI-2, which enrolled an additional 550 participants and will run until 2015. This article reviews all papers published since the inception of the initiative and summarizes the results to the end of 2013. The major accomplishments of ADNI have been as follows: (1) the development of standardized methods for clinical tests, magnetic resonance imaging (MRI), positron emission tomography (PET), and cerebrospinal fluid (CSF) biomarkers in a multicenter setting; (2) elucidation of the patterns and rates of change of imaging and CSF biomarker measurements in control subjects, MCI patients, and AD patients. CSF biomarkers are largely consistent with disease trajectories predicted by β-amyloid cascade (Hardy, J Alzheimer's Dis 2006;9(Suppl 3):151-3) and tau-mediated neurodegeneration hypotheses for AD, whereas brain atrophy and hypometabolism levels show predicted patterns but exhibit differing rates of change depending on region and disease severity; (3) the assessment of alternative methods of diagnostic categorization. Currently, the best classifiers select and combine optimum features from multiple modalities, including MRI, [(18)F]-fluorodeoxyglucose-PET, amyloid PET, CSF biomarkers, and clinical tests; (4) the development of blood biomarkers for AD as potentially noninvasive and low-cost alternatives to CSF biomarkers for AD diagnosis and the assessment of α-syn as an additional biomarker; (5) the development of methods for the early detection of AD. CSF biomarkers, β-amyloid 42 and tau, as well as amyloid PET may reflect the earliest steps in AD pathology in mildly symptomatic or even nonsymptomatic subjects and are leading candidates for the detection of AD in its preclinical stages; (6) the improvement of clinical trial efficiency through the identification of subjects most likely to undergo imminent future clinical decline and the use of more sensitive outcome measures to reduce sample sizes. Multimodal methods incorporating APOE status and longitudinal MRI proved most highly predictive of future decline. Refinements of clinical tests used as outcome measures such as clinical dementia rating-sum of boxes further reduced sample sizes; (7) the pioneering of genome-wide association studies that leverage quantitative imaging and biomarker phenotypes, including longitudinal data, to confirm recently identified loci, CR1, CLU, and PICALM and to identify novel AD risk loci; (8) worldwide impact through the establishment of ADNI-like programs in Japan, Australia, Argentina, Taiwan, China, Korea, Europe, and Italy; (9) understanding the biology and pathobiology of normal aging, MCI, and AD through integration of ADNI biomarker and clinical data to stimulate research that will resolve controversies about competing hypotheses on the etiopathogenesis of AD, thereby advancing efforts to find disease-modifying drugs for AD; and (10) the establishment of infrastructure to allow sharing of all raw and processed data without embargo to interested scientific investigators throughout the world.
Collapse
Affiliation(s)
- Michael W Weiner
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, CA, USA; Department of Radiology, University of California, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, CA, USA.
| | - Dallas P Veitch
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, CA, USA
| | - Paul S Aisen
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Laurel A Beckett
- Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA, USA
| | - Nigel J Cairns
- Knight Alzheimer's Disease Research Center, Washington University School of Medicine, Saint Louis, MO, USA; Department of Neurology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Jesse Cedarbaum
- Neurology Early Clinical Development, Biogen Idec, Cambridge, MA, USA
| | - Robert C Green
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Danielle Harvey
- Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA, USA
| | | | - William Jagust
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Johan Luthman
- Neuroscience Clinical Development, Neuroscience & General Medicine Product Creation Unit, Eisai Inc., Philadelphia, PA, USA
| | - John C Morris
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | | | - Andrew J Saykin
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Leslie Shaw
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Li Shen
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Adam Schwarz
- Tailored Therapeutics, Eli Lilly and Company, Indianapolis, IN, USA
| | - Arthur W Toga
- Laboratory of Neuroimaging, Institute of Neuroimaging and Informatics, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - John Q Trojanowski
- Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Alzheimer's Disease Core Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Udall Parkinson's Research Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
72
|
Hegedűs N, Laszy J, Gyertyán I, Kocsis P, Gajári D, Dávid S, Deli L, Pozsgay Z, Tihanyi K. Scopolamine provocation-based pharmacological MRI model for testing procognitive agents. J Psychopharmacol 2015; 29:447-55. [PMID: 25586394 DOI: 10.1177/0269881114565652] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
There is a huge unmet need to understand and treat pathological cognitive impairment. The development of disease modifying cognitive enhancers is hindered by the lack of correct pathomechanism and suitable animal models. Most animal models to study cognition and pathology do not fulfil either the predictive validity, face validity or construct validity criteria, and also outcome measures greatly differ from those of human trials. Fortunately, some pharmacological agents such as scopolamine evoke similar effects on cognition and cerebral circulation in rodents and humans and functional MRI enables us to compare cognitive agents directly in different species. In this paper we report the validation of a scopolamine based rodent pharmacological MRI provocation model. The effects of deemed procognitive agents (donepezil, vinpocetine, piracetam, alpha 7 selective cholinergic compounds EVP-6124, PNU-120596) were compared on the blood-oxygen-level dependent responses and also linked to rodent cognitive models. These drugs revealed significant effect on scopolamine induced blood-oxygen-level dependent change except for piracetam. In the water labyrinth test only PNU-120596 did not show a significant effect. This provocational model is suitable for testing procognitive compounds. These functional MR imaging experiments can be paralleled with human studies, which may help reduce the number of false cognitive clinical trials.
Collapse
Affiliation(s)
- Nikolett Hegedűs
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Judit Laszy
- Department of Behavioural Pharmacology, Gedeon Richter Plc, Budapest, Hungary
| | - István Gyertyán
- Department of Behavioural Pharmacology, Gedeon Richter Plc, Budapest, Hungary
| | - Pál Kocsis
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Dávid Gajári
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Szabolcs Dávid
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Levente Deli
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Zsófia Pozsgay
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| | - Károly Tihanyi
- Preclinical Imaging Centre, Gedeon Richter Plc, Budapest, Hungary
| |
Collapse
|
73
|
FABIANI MONICA, LOW KATHYA, TAN CHINHONG, ZIMMERMAN BENJAMIN, FLETCHER MARKA, SCHNEIDER-GARCES NILS, MACLIN EDWARDL, CHIARELLI ANTONIOM, SUTTON BRADLEYP, GRATTON GABRIELE. Taking the pulse of aging: mapping pulse pressure and elasticity in cerebral arteries with optical methods. Psychophysiology 2014; 51:1072-88. [PMID: 25100639 PMCID: PMC9906973 DOI: 10.1111/psyp.12288] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 05/20/2014] [Indexed: 12/24/2022]
Abstract
Cerebrovascular support is crucial for healthy cognitive and brain aging. Arterial stiffening is a cause of reduced brain blood flow, a predictor of cognitive decline, and a risk factor for cerebrovascular accidents and Alzheimer's disease. Arterial health is influenced by lifestyle factors, such as cardiorespiratory fitness (CRF). We investigated new noninvasive optical measures of cerebrovascular health, which provide estimates of arterial pulse parameters (pulse pressure, transit time, and compliance/elasticity) within specific cerebral arteries and cortical regions, and low-resolution maps of large superficial cerebral arteries. We studied naturally occurring variability in these parameters in adults (aged 55-87), and found that these indices of cerebrovascular health are negatively correlated with age and positively with CRF and gray and white matter volumes. Further, regional pulse transit time predicts specific neuropsychological performance.
Collapse
Affiliation(s)
- MONICA FABIANI
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Psychology Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - KATHY A. LOW
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - CHIN-HONG TAN
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Psychology Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - BENJAMIN ZIMMERMAN
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - MARK A. FLETCHER
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - NILS SCHNEIDER-GARCES
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Psychology Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - EDWARD L. MACLIN
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - ANTONIO M. CHIARELLI
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - BRADLEY P. SUTTON
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - GABRIELE GRATTON
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Psychology Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
74
|
Bron EE, Steketee RME, Houston GC, Oliver RA, Achterberg HC, Loog M, van Swieten JC, Hammers A, Niessen WJ, Smits M, Klein S. Diagnostic classification of arterial spin labeling and structural MRI in presenile early stage dementia. Hum Brain Mapp 2014; 35:4916-31. [PMID: 24700485 PMCID: PMC6869162 DOI: 10.1002/hbm.22522] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 03/14/2014] [Accepted: 03/24/2014] [Indexed: 11/11/2022] Open
Abstract
Because hypoperfusion of brain tissue precedes atrophy in dementia, the detection of dementia may be advanced by the use of perfusion information. Such information can be obtained noninvasively with arterial spin labeling (ASL), a relatively new MR technique quantifying cerebral blood flow (CBF). Using ASL and structural MRI, we evaluated diagnostic classification in 32 prospectively included presenile early stage dementia patients and 32 healthy controls. Patients were suspected of Alzheimer's disease (AD) or frontotemporal dementia. Classification was based on CBF as perfusion marker, gray matter (GM) volume as atrophy marker, and their combination. These markers were each examined using six feature extraction methods: a voxel-wise method and a region of interest (ROI)-wise approach using five ROI-sets in the GM. These ROI-sets ranged in number from 72 brain regions to a single ROI for the entire supratentorial brain. Classification was performed with a linear support vector machine classifier. For validation of the classification method on the basis of GM features, a reference dataset from the AD Neuroimaging Initiative database was used consisting of AD patients and healthy controls. In our early stage dementia population, the voxelwise feature-extraction approach achieved more accurate results (area under the curve (AUC) range = 86 - 91%) than all other approaches (AUC = 57 - 84%). Used in isolation, CBF quantified with ASL was a good diagnostic marker for dementia. However, our findings indicated only little added diagnostic value when combining ASL with the structural MRI data (AUC = 91%), which did not significantly improve over accuracy of structural MRI atrophy marker by itself.
Collapse
Affiliation(s)
- Esther E Bron
- Departments of Medical Informatics and Radiology, Biomedical Imaging Group Rotterdam, Erasmus MC - University Medical Center Rotterdam, the Netherlands
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
75
|
Liang X, Connelly A, Tournier JD, Calamante F. A variable flip angle-based method for reducing blurring in 3D GRASE ASL. Phys Med Biol 2014; 59:5559-73. [PMID: 25170985 DOI: 10.1088/0031-9155/59/18/5559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Arterial Spin Labeling (ASL) is an MRI technique to measure cerebral blood flow directly and noninvasively, and thus provides a more direct quantitative correlate of neural activity than blood-oxygen-level-dependent fMRI. A 3D gradient and spin-echo (GRASE) sequence is capable of enhancing signal-to-noise ratio, and has been shown to be a very useful readout module for ASL sequences. Nonetheless, the introduction of significant blurring in its single-shot version, due to T2 decay along the partition dimension, compromises the achievable spatial resolution, limiting the potential of this technique for whole-brain coverage. To address this issue, a method for reducing blurring based on a variable flip angle (VFA) scheme is proposed in this study for 3D GRASE ASL perfusion. Numerical simulations show that the proposed method is capable of reducing the blurring significantly compared to the standard constant flip angle approach; this result was further confirmed using in vivo data. The proposed VFA method should therefore be of significance to 3D GRASE ASL fMRI studies, since it is able to reduce blurring without sacrificing temporal resolution.
Collapse
Affiliation(s)
- Xiaoyun Liang
- Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
| | | | | | | |
Collapse
|
76
|
Vascular action as the primary mechanism of cognitive effects of cholinergic, CNS-acting drugs, a rat phMRI BOLD study. J Cereb Blood Flow Metab 2014; 34:995-1000. [PMID: 24643080 PMCID: PMC4050244 DOI: 10.1038/jcbfm.2014.47] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 01/05/2023]
Abstract
Concordant results of functional magnetic resonance imaging (fMRI) and behavioral tests prove that some non-blood-brain barrier-penetrating drugs produce robust central nervous system (CNS) effects. The anticholinergic scopolamine interferes with learning when tested in rats, which coincides with a negative blood-oxygen-level-dependent (BOLD) change in the prefrontal cortex (PFC) as demonstrated by fMRI. The peripherally acting butylscopolamine also evokes a learning deficit in a water-labyrinth test and provokes a negative BOLD signal in the PFC. Donepezil-a highly CNS-penetrating cholinesterase inhibitor-prevents the negative BOLD and cognitive deficits regardless whether the provoking agent is scopolamine or butylscopolamine. Interestingly, the non-BBB-penetrating cholinesterase inhibitor neostigmine also prevents or substantially inhibits those cognitive and fMRI changes. Intact cerebral blood flow and optimal metabolism are crucial for the normal functioning of neurons and other cells in the brain. Drugs that are not BBB penetrating yet act on the CNS highlight the importance of unimpaired circulation, and point to the cerebral vasculature as a primary target for drug action in diseases where impaired circulation and consequently suboptimal energy metabolism are followed by upstream pathologic events.
Collapse
|