The Experts below are selected from a list of 8628 Experts worldwide ranked by ideXlab platform
Farshid Sepehrband - One of the best experts on this subject based on the ideXlab platform.
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volumetric distribution of Perivascular Space in relation to mild cognitive impairment
Neurobiology of Aging, 2021Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikhbahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (asMTL) (1.29 times lower PVS volume fraction in cognitively impaired individuals, p
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global and regional changes in Perivascular Space in idiopathic and familial parkinson s disease
Movement Disorders, 2021Co-Authors: Erin K Donahue, Arthur W. Toga, Amjad Murdos, Michael W Jakowec, Nasim Sheikhbahaei, Giselle M Petzinger, Farshid SepehrbandAbstract:Background The glymphatic system, including the Perivascular Space (PVS), plays a critical role in brain homeostasis. Although mounting evidence from Alzheimer's disease has supported the potential role of PVS in neurodegenerative disorders, its contribution in Parkinson's disease (PD) has not been fully elucidated. Although idiopathic (IPD) and familial PD (FPD) share similar pathophysiology in terms of protein aggregation, the differential impact of PVS on PD subtypes remains unknown. Our objective was to examine the differences in PVS volume fraction in IPD and FPD compared to healthy controls (HCs) and nonmanifest carriers (NMCs). Methods A total of 470 individuals were analyzed from the Parkinson's Progression Markers Initiative database, including (1) IPD (n = 179), (2) FPD (LRRK2 [leucine-rich repeat kinase 2], glucocerebrosidase, or α-synuclein) (n = 67), (3) NMC (n = 101), and (4) HCs (n = 84). Total PVS volume fraction (%) was compared using parcellation and quantitation within greater white matter volume at global and regional levels in all cortical and subcortical white matter. Results There was a significant increase in global and regional PVS volume fraction in PD versus non-PD, particularly in FPD versus NMC and LRRK2 FPD versus NMC. Regionally, FPD and NMC differed in the medial orbitofrontal region, as did LRRK2 FPD versus NMC. Non-PD and PD differed in the medial orbitofrontal region and the banks of the superior temporal regions. IPD and FPD differed in the cuneus and lateral occipital regions. Conclusions Our findings support the role of PVS in PD and highlight a potentially significant contribution of PVS to the pathophysiology of FPD, particularly LRRK2. © 2021 International Parkinson and Movement Disorder Society.
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Volumetric Distribution of Perivascular Space in Relation to Mild Cognitive Impairment
Neurobiology of aging, 2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (1.29 times lower PVS volume fraction in cognitively impaired individuals compared with those unimpaired, p
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Perivascular Space Imaging at Ultrahigh Field MR Imaging.
Magnetic resonance imaging clinics of North America, 2020Co-Authors: Giuseppe Barisano, Meng Law, Arthur W. Toga, Rachel M Custer, Farshid SepehrbandAbstract:The recent Food and Drug Administration approval of 7 T MR imaging scanners for clinical use has introduced the possibility to study the brain not only in physiologic but also in pathologic conditions at ultrahigh field (UHF). Because UHF MR imaging offers higher signal-to-noise ratio and spatial resolution compared with lower field clinical scanners, the benefits of UHF MR imaging are particularly evident for imaging small anatomic structures, such as the cerebral Perivascular Spaces (PVS). In this article, the authors describe the application of UHF MR imaging for the investigation of PVS.
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Alteration of Perivascular Spaces in early cognitive decline
2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Helena C. Chui, John M. Ringman, Arthur W. TogaAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Space. Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered Perivascular Space presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted decreased Perivascular Space presence in the anterosuperior medial temporal lobe, which was associated with neurofibrillary tau tangle deposition in the entorhinal cortex, one of the hallmarks of early Alzheimer’s disease pathology. Our results suggest that anatomically-specific alteration of the Perivascular Spaces may provide an early biomarker of cognitive impairment in aging adults.
Arthur W. Toga - One of the best experts on this subject based on the ideXlab platform.
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global and regional changes in Perivascular Space in idiopathic and familial parkinson s disease
Movement Disorders, 2021Co-Authors: Erin K Donahue, Arthur W. Toga, Amjad Murdos, Michael W Jakowec, Nasim Sheikhbahaei, Giselle M Petzinger, Farshid SepehrbandAbstract:Background The glymphatic system, including the Perivascular Space (PVS), plays a critical role in brain homeostasis. Although mounting evidence from Alzheimer's disease has supported the potential role of PVS in neurodegenerative disorders, its contribution in Parkinson's disease (PD) has not been fully elucidated. Although idiopathic (IPD) and familial PD (FPD) share similar pathophysiology in terms of protein aggregation, the differential impact of PVS on PD subtypes remains unknown. Our objective was to examine the differences in PVS volume fraction in IPD and FPD compared to healthy controls (HCs) and nonmanifest carriers (NMCs). Methods A total of 470 individuals were analyzed from the Parkinson's Progression Markers Initiative database, including (1) IPD (n = 179), (2) FPD (LRRK2 [leucine-rich repeat kinase 2], glucocerebrosidase, or α-synuclein) (n = 67), (3) NMC (n = 101), and (4) HCs (n = 84). Total PVS volume fraction (%) was compared using parcellation and quantitation within greater white matter volume at global and regional levels in all cortical and subcortical white matter. Results There was a significant increase in global and regional PVS volume fraction in PD versus non-PD, particularly in FPD versus NMC and LRRK2 FPD versus NMC. Regionally, FPD and NMC differed in the medial orbitofrontal region, as did LRRK2 FPD versus NMC. Non-PD and PD differed in the medial orbitofrontal region and the banks of the superior temporal regions. IPD and FPD differed in the cuneus and lateral occipital regions. Conclusions Our findings support the role of PVS in PD and highlight a potentially significant contribution of PVS to the pathophysiology of FPD, particularly LRRK2. © 2021 International Parkinson and Movement Disorder Society.
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Perivascular Space Imaging at Ultrahigh Field MR Imaging.
Magnetic resonance imaging clinics of North America, 2020Co-Authors: Giuseppe Barisano, Meng Law, Arthur W. Toga, Rachel M Custer, Farshid SepehrbandAbstract:The recent Food and Drug Administration approval of 7 T MR imaging scanners for clinical use has introduced the possibility to study the brain not only in physiologic but also in pathologic conditions at ultrahigh field (UHF). Because UHF MR imaging offers higher signal-to-noise ratio and spatial resolution compared with lower field clinical scanners, the benefits of UHF MR imaging are particularly evident for imaging small anatomic structures, such as the cerebral Perivascular Spaces (PVS). In this article, the authors describe the application of UHF MR imaging for the investigation of PVS.
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Alteration of Perivascular Spaces in early cognitive decline
2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Helena C. Chui, John M. Ringman, Arthur W. TogaAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Space. Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered Perivascular Space presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted decreased Perivascular Space presence in the anterosuperior medial temporal lobe, which was associated with neurofibrillary tau tangle deposition in the entorhinal cortex, one of the hallmarks of early Alzheimer’s disease pathology. Our results suggest that anatomically-specific alteration of the Perivascular Spaces may provide an early biomarker of cognitive impairment in aging adults.
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image processing approaches to enhance Perivascular Space visibility and quantification using mri
Scientific Reports, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Nasim Sheikhbahaei, Arthur W. TogaAbstract:Imaging the Perivascular Spaces (PVS), also known as Virchow-Robin Space, has significant clinical value, but there remains a need for neuroimaging techniques to improve mapping and quantification of the PVS. Current technique for PVS evaluation is a scoring system based on visual reading of visible PVS in regions of interest, and often limited to large caliber PVS. Enhancing the visibility of the PVS could support medical diagnosis and enable novel neuroscientific investigations. Increasing the MRI resolution is one approach to enhance the visibility of PVS but is limited by acquisition time and physical constraints. Alternatively, image processing approaches can be utilized to improve the contrast ratio between PVS and surrounding tissue. Here we combine T1- and T2-weighted images to enhance PVS contrast, intensifying the visibility of PVS. The Enhanced PVS Contrast (EPC) was achieved by combining T1- and T2-weighted images that were adaptively filtered to remove non-structured high-frequency spatial noise. EPC was evaluated on healthy young adults by presenting them to two expert readers and also through automated quantification. We found that EPC improves the conspicuity of the PVS and aid resolving a larger number of PVS. We also present a highly reliable automated PVS quantification approach, which was optimized using expert readings.
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Perivascular Space fluid contributes to diffusion tensor imaging changes in white matter
NeuroImage, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Arthur W. TogaAbstract:Diffusion tensor imaging (DTI) has been extensively used to map changes in brain tissue related to neurological disorders. Among the most widespread DTI findings are increased mean diffusivity and decreased fractional anisotropy of white matter tissue in neurodegenerative diseases. Here we utilize multi-shell diffusion imaging to separate diffusion signal of the brain parenchyma from non-parenchymal fluid within the white matter. We show that unincorporated anisotropic water in Perivascular Space (PVS) significantly, and systematically, biases DTI measures, casting new light on the biological validity of many previously reported findings. Despite the challenge this poses for interpreting these past findings, our results suggest that multi-shell diffusion MRI provides a new opportunity for incorporating the PVS contribution, ultimately strengthening the clinical and scientific value of diffusion MRI.
Giuseppe Barisano - One of the best experts on this subject based on the ideXlab platform.
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volumetric distribution of Perivascular Space in relation to mild cognitive impairment
Neurobiology of Aging, 2021Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikhbahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (asMTL) (1.29 times lower PVS volume fraction in cognitively impaired individuals, p
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Volumetric Distribution of Perivascular Space in Relation to Mild Cognitive Impairment
Neurobiology of aging, 2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (1.29 times lower PVS volume fraction in cognitively impaired individuals compared with those unimpaired, p
-
Perivascular Space Imaging at Ultrahigh Field MR Imaging.
Magnetic resonance imaging clinics of North America, 2020Co-Authors: Giuseppe Barisano, Meng Law, Arthur W. Toga, Rachel M Custer, Farshid SepehrbandAbstract:The recent Food and Drug Administration approval of 7 T MR imaging scanners for clinical use has introduced the possibility to study the brain not only in physiologic but also in pathologic conditions at ultrahigh field (UHF). Because UHF MR imaging offers higher signal-to-noise ratio and spatial resolution compared with lower field clinical scanners, the benefits of UHF MR imaging are particularly evident for imaging small anatomic structures, such as the cerebral Perivascular Spaces (PVS). In this article, the authors describe the application of UHF MR imaging for the investigation of PVS.
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Alteration of Perivascular Spaces in early cognitive decline
2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Helena C. Chui, John M. Ringman, Arthur W. TogaAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Space. Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered Perivascular Space presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted decreased Perivascular Space presence in the anterosuperior medial temporal lobe, which was associated with neurofibrillary tau tangle deposition in the entorhinal cortex, one of the hallmarks of early Alzheimer’s disease pathology. Our results suggest that anatomically-specific alteration of the Perivascular Spaces may provide an early biomarker of cognitive impairment in aging adults.
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image processing approaches to enhance Perivascular Space visibility and quantification using mri
Scientific Reports, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Nasim Sheikhbahaei, Arthur W. TogaAbstract:Imaging the Perivascular Spaces (PVS), also known as Virchow-Robin Space, has significant clinical value, but there remains a need for neuroimaging techniques to improve mapping and quantification of the PVS. Current technique for PVS evaluation is a scoring system based on visual reading of visible PVS in regions of interest, and often limited to large caliber PVS. Enhancing the visibility of the PVS could support medical diagnosis and enable novel neuroscientific investigations. Increasing the MRI resolution is one approach to enhance the visibility of PVS but is limited by acquisition time and physical constraints. Alternatively, image processing approaches can be utilized to improve the contrast ratio between PVS and surrounding tissue. Here we combine T1- and T2-weighted images to enhance PVS contrast, intensifying the visibility of PVS. The Enhanced PVS Contrast (EPC) was achieved by combining T1- and T2-weighted images that were adaptively filtered to remove non-structured high-frequency spatial noise. EPC was evaluated on healthy young adults by presenting them to two expert readers and also through automated quantification. We found that EPC improves the conspicuity of the PVS and aid resolving a larger number of PVS. We also present a highly reliable automated PVS quantification approach, which was optimized using expert readings.
Ryan P. Cabeen - One of the best experts on this subject based on the ideXlab platform.
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volumetric distribution of Perivascular Space in relation to mild cognitive impairment
Neurobiology of Aging, 2021Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikhbahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (asMTL) (1.29 times lower PVS volume fraction in cognitively impaired individuals, p
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Volumetric Distribution of Perivascular Space in Relation to Mild Cognitive Impairment
Neurobiology of aging, 2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (1.29 times lower PVS volume fraction in cognitively impaired individuals compared with those unimpaired, p
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Alteration of Perivascular Spaces in early cognitive decline
2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Helena C. Chui, John M. Ringman, Arthur W. TogaAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Space. Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered Perivascular Space presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted decreased Perivascular Space presence in the anterosuperior medial temporal lobe, which was associated with neurofibrillary tau tangle deposition in the entorhinal cortex, one of the hallmarks of early Alzheimer’s disease pathology. Our results suggest that anatomically-specific alteration of the Perivascular Spaces may provide an early biomarker of cognitive impairment in aging adults.
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image processing approaches to enhance Perivascular Space visibility and quantification using mri
Scientific Reports, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Nasim Sheikhbahaei, Arthur W. TogaAbstract:Imaging the Perivascular Spaces (PVS), also known as Virchow-Robin Space, has significant clinical value, but there remains a need for neuroimaging techniques to improve mapping and quantification of the PVS. Current technique for PVS evaluation is a scoring system based on visual reading of visible PVS in regions of interest, and often limited to large caliber PVS. Enhancing the visibility of the PVS could support medical diagnosis and enable novel neuroscientific investigations. Increasing the MRI resolution is one approach to enhance the visibility of PVS but is limited by acquisition time and physical constraints. Alternatively, image processing approaches can be utilized to improve the contrast ratio between PVS and surrounding tissue. Here we combine T1- and T2-weighted images to enhance PVS contrast, intensifying the visibility of PVS. The Enhanced PVS Contrast (EPC) was achieved by combining T1- and T2-weighted images that were adaptively filtered to remove non-structured high-frequency spatial noise. EPC was evaluated on healthy young adults by presenting them to two expert readers and also through automated quantification. We found that EPC improves the conspicuity of the PVS and aid resolving a larger number of PVS. We also present a highly reliable automated PVS quantification approach, which was optimized using expert readings.
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Perivascular Space fluid contributes to diffusion tensor imaging changes in white matter
NeuroImage, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Arthur W. TogaAbstract:Diffusion tensor imaging (DTI) has been extensively used to map changes in brain tissue related to neurological disorders. Among the most widespread DTI findings are increased mean diffusivity and decreased fractional anisotropy of white matter tissue in neurodegenerative diseases. Here we utilize multi-shell diffusion imaging to separate diffusion signal of the brain parenchyma from non-parenchymal fluid within the white matter. We show that unincorporated anisotropic water in Perivascular Space (PVS) significantly, and systematically, biases DTI measures, casting new light on the biological validity of many previously reported findings. Despite the challenge this poses for interpreting these past findings, our results suggest that multi-shell diffusion MRI provides a new opportunity for incorporating the PVS contribution, ultimately strengthening the clinical and scientific value of diffusion MRI.
Jeiran Choupan - One of the best experts on this subject based on the ideXlab platform.
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volumetric distribution of Perivascular Space in relation to mild cognitive impairment
Neurobiology of Aging, 2021Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikhbahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (asMTL) (1.29 times lower PVS volume fraction in cognitively impaired individuals, p
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Volumetric Distribution of Perivascular Space in Relation to Mild Cognitive Impairment
Neurobiology of aging, 2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Kirsten M. Lynch, Haoyu Lan, Helena C. ChuiAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Spaces (PVS). Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered PVS presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted lower PVS presence in the anterosuperior medial temporal lobe (1.29 times lower PVS volume fraction in cognitively impaired individuals compared with those unimpaired, p
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Alteration of Perivascular Spaces in early cognitive decline
2020Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Nasim Sheikh-bahaei, Malcolm S. Crawford, Wendy J. Mack, Helena C. Chui, John M. Ringman, Arthur W. TogaAbstract:Abstract Vascular contributions to early cognitive decline are increasingly recognized, prompting further investigation into the nature of related changes in Perivascular Space. Using magnetic resonance imaging, we show that, compared to a cognitively normal sample, individuals with early cognitive dysfunction have altered Perivascular Space presence and distribution, irrespective of Amyloid-β. Surprisingly, we noted decreased Perivascular Space presence in the anterosuperior medial temporal lobe, which was associated with neurofibrillary tau tangle deposition in the entorhinal cortex, one of the hallmarks of early Alzheimer’s disease pathology. Our results suggest that anatomically-specific alteration of the Perivascular Spaces may provide an early biomarker of cognitive impairment in aging adults.
-
image processing approaches to enhance Perivascular Space visibility and quantification using mri
Scientific Reports, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Nasim Sheikhbahaei, Arthur W. TogaAbstract:Imaging the Perivascular Spaces (PVS), also known as Virchow-Robin Space, has significant clinical value, but there remains a need for neuroimaging techniques to improve mapping and quantification of the PVS. Current technique for PVS evaluation is a scoring system based on visual reading of visible PVS in regions of interest, and often limited to large caliber PVS. Enhancing the visibility of the PVS could support medical diagnosis and enable novel neuroscientific investigations. Increasing the MRI resolution is one approach to enhance the visibility of PVS but is limited by acquisition time and physical constraints. Alternatively, image processing approaches can be utilized to improve the contrast ratio between PVS and surrounding tissue. Here we combine T1- and T2-weighted images to enhance PVS contrast, intensifying the visibility of PVS. The Enhanced PVS Contrast (EPC) was achieved by combining T1- and T2-weighted images that were adaptively filtered to remove non-structured high-frequency spatial noise. EPC was evaluated on healthy young adults by presenting them to two expert readers and also through automated quantification. We found that EPC improves the conspicuity of the PVS and aid resolving a larger number of PVS. We also present a highly reliable automated PVS quantification approach, which was optimized using expert readings.
-
Perivascular Space fluid contributes to diffusion tensor imaging changes in white matter
NeuroImage, 2019Co-Authors: Farshid Sepehrband, Ryan P. Cabeen, Jeiran Choupan, Giuseppe Barisano, Meng Law, Arthur W. TogaAbstract:Diffusion tensor imaging (DTI) has been extensively used to map changes in brain tissue related to neurological disorders. Among the most widespread DTI findings are increased mean diffusivity and decreased fractional anisotropy of white matter tissue in neurodegenerative diseases. Here we utilize multi-shell diffusion imaging to separate diffusion signal of the brain parenchyma from non-parenchymal fluid within the white matter. We show that unincorporated anisotropic water in Perivascular Space (PVS) significantly, and systematically, biases DTI measures, casting new light on the biological validity of many previously reported findings. Despite the challenge this poses for interpreting these past findings, our results suggest that multi-shell diffusion MRI provides a new opportunity for incorporating the PVS contribution, ultimately strengthening the clinical and scientific value of diffusion MRI.