scholarly journals Disconnectome Associated with Progressive Ischemic Periventricular White Matter Lesions

2019 ◽  
Author(s):  
Zhengjun Li ◽  
Sudipto Dolui ◽  
Mohamad Habes ◽  
Danielle S. Bassett ◽  
David Wolk ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Diffusion Tensor ◽  
Normal Aging ◽  
Elderly Subjects ◽  
Periventricular White Matter ◽  
Structural Connectome ◽  
Virtual Lesion ◽  
The Brain

AbstractPeriventricular white matter (PVWM) hyperintensities on T2-weighted MRI are ubiquitous in older adults and associated with dementia. Efforts to determine how PVWM lesions impact structural connectivity to impinge on brain function remain challenging in part because white matter tractography algorithms for diffusion tensor imaging (DTI) may lose fidelity in the presence of lesions. We used a “virtual lesion” approach to characterize the “disconnectome” associated with periventricular white matter (PVWM) lesions. We simulated progressive ischemic PVWM lesions using sub-threshold cerebral blood flow (CBF) masks derived from a previously published group-averaged map acquired from N=436 middle aged subjects in which the lowest CBF values were seen in PVWM and morphologically recapitulated the spatial pattern of PVWM hyperintensities seen in typical aging. We mimicked the age-dependent evolution of PVWM lesion burden by varying the threshold applied to the CBF map. We found that the optic radiations, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, corpus callosum, temporopontine tract and fornix were affected in early simulated PVWM lesion burdens, and that the connectivity of subcortical, cerebellar, and visual regions were significantly disrupted with increasing simulated PVWM lesion burdens. We also validated the use of virtual lesions to simulate the disconnectome due to WM hyperintensities in a cognitively normal elderly cohort (N=46) by evaluating correlations between structural and functional connectomes. The virtual lesion approach provides new insights into the spatial-temporal changes of the brain structural connectome under progressive PVWM burdens during normal aging.Significance StatementWe determined the disconnectomes caused by periventricular white matter (PVWM) lesions using the “virtual lesion” approach. We validated the approach using lesions, DTI and resting-state fMRI data from elderly subjects. We simulated disconnectome of progressive PVWM lesions using cerebral blood flow (CBF) masks in PVWM region with normative DTI data, which provides specificity for an ischemic mechanism and begins to address the possibility that connectivity may be affected by reduced CBF prior to the development of overt lesions on T2-weighted FLAIR MRI. The current study presented new insights into the spatial-temporal evolutions of the brain structural connectome under progressive PVWM burdens under normal aging.

scholarly journals Trial of remote ischaemic preconditioning in vascular cognitive impairment (TRIC-VCI): protocol

BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e040466
Author(s):  
Aravind Ganesh ◽  
Philip Barber ◽  
Sandra E Black ◽  
Dale Corbett ◽  
Thalia S Field ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Vascular Cognitive Impairment ◽  
White Matter Injury ◽  
White Matter Hyperintensity ◽  
Limb Ischaemia ◽  
Ischaemic Brain

IntroductionCerebral small vessel disease (cSVD) accounts for 20%–25% of strokes and is the most common cause of vascular cognitive impairment (VCI). In an animal VCI model, inducing brief periods of limb ischaemia-reperfusion reduces subsequent ischaemic brain injury with remote and local protective effects, with hindlimb remote ischaemic conditioning (RIC) improving cerebral blood flow, decreasing white-matter injury and improving cognition. Small human trials suggest RIC is safe and may prevent recurrent strokes. It remains unclear what doses of chronic daily RIC are tolerable and safe, whether effects persist after treatment cessation, and what parameters are optimal for treatment response.Methods and analysisThis prospective, open-label, randomised controlled trial (RCT) with blinded end point assessment and run-in period, will recruit 24 participants, randomised to one of two RIC intensity groups: one arm treated once daily or one arm twice daily for 30 consecutive days. RIC will consistent of 4 cycles of blood pressure cuff inflation to 200 mm Hg for 5 min followed by 5 min deflation (total 35 min). Selection criteria include: age 60–85 years, evidence of cSVD on brain CT/MRI, Montreal Cognitive Assessment (MoCA) score 13–24 and preserved basic activities of living. Outcomes will be assessed at 30 days and 90 days (60 days after ceasing treatment). The primary outcome is adherence (completing ≥80% of sessions). Secondary safety/tolerability outcomes include the per cent of sessions completed and pain/discomfort scores from patient diaries. Efficacy outcomes include changes in cerebral blood flow (per arterial spin-label MRI), white-matter hyperintensity volume, diffusion tensor imaging, MoCA and Trail-Making tests.Ethics and disseminationResearch Ethics Board approval has been obtained. The results will provide information on feasibility, dose, adherence, tolerability and outcome measures that will help design a phase IIb RCT of RIC, with the potential to prevent VCI. Results will be disseminated through peer-reviewed publications, organisations and meetings.Trial registration numberNCT04109963.

scholarly journals Cerebral Blood Flow Heterogeneity in Preterm Sheep: Lack of Physiologic Support for Vascular Boundary Zones in Fetal Cerebral White Matter

2007 ◽  
Vol 28 (5) ◽  
pp. 995-1008 ◽  
Author(s):  
Melissa M McClure ◽  
Art Riddle ◽  
Mario Manese ◽  
Ning Ling Luo ◽  
Dawn A Rorvik ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Ischemia Reperfusion ◽  
Three Dimensional ◽  
Cerebral White Matter ◽  
Periventricular White Matter ◽  
Fetal Sheep ◽  
Border Zones ◽  
Neurologic Disability

Periventricular white matter (PVWM) injury is the leading cause of neurologic disability in survivors of prematurity. To address the role of ischemia in PVWM and cerebral cortical injury, we hypothesized that immaturity of spatially distal vascular ‘end zones’ or ‘border zones’ predisposes PVWM to greater decreases in cerebral blood flow (CBF) than more proximal structures. We quantified regional CBF with fluorescently labeled microspheres in 0.65 gestation fetal sheep in histopathologically defined three-dimensional regions by post hoc digital dissection and coregistration algorithms. Basal flow in PVWM was significantly lower than in gyral white matter and cortex, but was equivalent in superficial, middle, and deep PVWM. Absolute and relative CBF (expressed as percentage of basal) did not differ significantly during ischemia or reperfusion between PVWM, gyral white matter, or cortex. Moreover, CBF during ischemia-reperfusion was equivalent in three adjacent PVWM levels and was not consistent with the magnitude of severity of PVWM injury, defined by TUNEL (terminal deoxynucleotidyltransferase-mediated dUPT nick end labeling) staining. However, the magnitude of ischemia was predicted by the severity of discrete cortical lesions. Hence, unlike cerebral cortex, unique CBF disturbances did not account for the distribution of PVWM injury. Previously defined cellular maturational factors, thus, appear to have a greater influence on PVWM vulnerability to ischemic injury than the presence of immature vascular boundary zones.

scholarly journals White Matter Hyperintensity Associations with Cerebral Blood Flow in Elderly Subjects Stratified by Cerebrovascular Risk

2017 ◽  
Vol 26 (4) ◽  
pp. 779-786 ◽  
Author(s):  
Ahmed A. Bahrani ◽  
David K. Powell ◽  
Guoqiang Yu ◽  
Eleanor S. Johnson ◽  
Gregory A. Jicha ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
White Matter Hyperintensity ◽  
Elderly Subjects ◽  
Cerebrovascular Risk

Beagle pup model of brain injury: regional cerebral blood flow and cerebral prostaglandins

1987 ◽  
Vol 67 (2) ◽  
pp. 278-283 ◽  
Author(s):  
Laura R. Ment ◽  
William B. Stewart ◽  
Charles C. Duncan ◽  
Bruce R. Pitt ◽  
Judith Cole
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
White Matter ◽  
Regional Cerebral Blood Flow ◽  
Ventilatory Support ◽  
Periventricular White Matter ◽  
Regional Cerebral Blood ◽  
Content Type ◽  
Carbon 14

✓ Asphyxia is the most common cause of severe brain injury in very young children, and frequently results in lesions of the periventricular white matter in addition to other neuropathological changes. This study examines the effects of asphyxia on regional cerebral blood flow (rCBF) and the role of prostaglandins (PG's) in its control in the newborn beagle pup. Pups were anesthetized, tracheotomized, paralyzed, artificially ventilated, and randomly assigned to two groups: asphyxial insult produced by discontinuing ventilatory support, and no insult. Experiments for carbon-14-iodoantipyrine autoradiographic determination of rCBF and regional cerebral PG determination were performed on separate groups of pups. These studies demonstrated a significant increase in cortical gray PGE2 levels at a time when rCBF was significantly impaired in response to severe asphyxial insult. No such increase was noted in the periventricular white matter zones.

scholarly journals Periventricular white matter lucency and cerebral blood flow autoregulation in hypertensive patients.

Hypertension ◽  
1994 ◽  
Vol 23 (5) ◽  
pp. 565-568 ◽  
Author(s):  
K Matsushita ◽  
Y Kuriyama ◽  
K Nagatsuka ◽  
M Nakamura ◽  
T Sawada ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Periventricular White Matter ◽  
Hypertensive Patients ◽  
Cerebral Blood Flow Autoregulation

Changes in Brain White Matter Assessed Via Textural Features Using a Neural Network

2010 ◽  
Vol 5 (2) ◽  
pp. 37-48
Author(s):  
R. Kalpana ◽  
S. Muttan ◽  
B. Agrawala
Keyword(s):  
Neural Network ◽  
White Matter ◽  
Diffusion Tensor ◽  
Age Groups ◽  
Elderly Subjects ◽  
Textural Features ◽  
Statistical Parameters ◽  
Brain White Matter ◽  
Age Related ◽  
The Brain

Diffusion Tensor Magnetic Resonance Imaging (DTMRI) has proved useful for microstructure characterization of the brain. This technique also helps determining complex connectivity of fiber tracts. The brain white matter (BMW) changes with respect to age and corresponding appearance of white-matter lesions among the brain’s message-carrying axons affects cognitive functions in old age. In this paper, the observed morphology in BWM on ageing is analyzed using statistical parameters extracted from DTMR images of different age groups. The gray level co-occurrence matrix (GLCM) obtained from the segmented images gives 14 textural features, subsets of which are adopted as the input sets in a backpropagation neural network classifier. The network is trained to predict the age based on BMW details used as the inputs. The proposed method helps in understanding the age-related changes in white matter. This is useful for the physician in understanding miscorrelation in motor activities and relevant causes in elderly subjects.

Age-Related Decline in the Topological Efficiency of the Brain Structural Connectome and Cognitive Aging

2020 ◽  
Vol 30 (8) ◽  
pp. 4651-4661 ◽  
Author(s):  
Xin Li ◽  
Yezhou Wang ◽  
Wenxiao Wang ◽  
Weijie Huang ◽  
Kewei Chen ◽  
...  
Keyword(s):  
Executive Function ◽  
Cognitive Functions ◽  
Cognitive Aging ◽  
Normal Aging ◽  
Elderly Subjects ◽  
Elderly Individuals ◽  
Structural Connectome ◽  
Age Related ◽  
Topological Efficiency ◽  
The Brain

Abstract Brain disconnection model has been proposed as a possible neural mechanism for cognitive aging. However, the relationship between structural connectivity degeneration and cognitive decline with normal aging remains unclear. In the present study, using diffusion MRI and tractography techniques, we report graph theory-based analyses of the brain structural connectome in a cross-sectional, community-based cohort of 633 cognitively healthy elderly individuals. Comprehensive neuropsychological assessment of the elderly subjects was performed. The association between age, brain structural connectome, and cognition across elderly individuals was examined. We found that the topological efficiency, modularity, and hub integration of the brain structural connectome exhibited a significant decline with normal aging, especially in the frontal, parietal, and superior temporal regions. Importantly, network efficiency was positively correlated with attention and executive function in elderly subjects and had a significant mediation effect on the age-related decline in these cognitive functions. Moreover, nodal efficiency of the brain structural connectome showed good performance for the prediction of attention and executive function in elderly individuals. Together, our findings revealed topological alterations of the brain structural connectome with normal aging, which provides possible structural substrates underlying cognitive aging and sensitive imaging markers for the individual prediction of cognitive functions in elderly subjects.

scholarly journals Acupuncture improves white matter perfusion and white matter integrity in vascular dementia rats: an MRI-based imaging study

2020 ◽  
Author(s):  
Siming Ma ◽  
Lu Wang ◽  
Xin-Tong Su ◽  
Jin Huang ◽  
Lu-Lu Lin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Impairment ◽  
White Matter ◽  
Vascular Dementia ◽  
Acupuncture Treatment ◽  
Diffusion Tensor ◽  
White Matter Lesions ◽  
Microglia Activation ◽  
White Matter Integrity

Abstract Background: White matter lesions induced by chronic cerebral hypoperfusion (CCH) are common pathological changes, and are associated with cognitive impairment in vascular dementia (VaD). It has been reported that acupuncture can improve cognitive deficits of VaD rats through increasing cortical cerebral blood flow and attenuating neuroinflammation. However, the effects of acupuncture on white matter perfusion and white matter structural integrity have been not investigated. Methods: VaD was induced by bilateral common carotid arteries occlusion (BCCAO) in Wistar rats. Morris water maze (MWM) was used to evaluated the spatial learning and memory of rats. Arterial spin labeling imaging (ASL) and diffusion tensor imaging (DTI) were performed to measure the cerebral blood flow and white matter integrity in corpus callosum, external capsule, internal capsule, optic nerve and optic tract. Pathological staining was also applied to detect the myelin loss and neuroinflammation. Results: BCCAO rats with declined cerebral blood flow exhibited significant worse MWM performance, and altered DTI parameters including decreased fractional anisotropy, elevated radial diffusivity and axial diffusivity in white matter regions. After acupuncture treatment at GV20 and ST36, cognitive dysfunction, disruption of white matter perfusion and integrity were reversed. Pathological results supported that acupuncture could attenuate the loss of myelin sheath and microglia activation. Conclusions: Our findings suggest that acupuncture treatment protects cognitive impairment of BCCAO rats through increasing subcortical white matter perfusion and improving white matter lesions. Keywords: Acupuncture; ASL; DTI; cerebral blood flow; white matter; microglia activation

scholarly journals Iodoamphetamine as a New Tracer for Local Cerebral Blood Flow in the Rat: Comparison with Isopropyliodoamphetamine

1984 ◽  
Vol 4 (2) ◽  
pp. 270-274 ◽  
Author(s):  
Jean R. Rapin ◽  
Monique Le Poncin-Lafitte ◽  
Dominique Duterte ◽  
Richard Rips ◽  
Elisabeth Morier ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Tissue Distribution ◽  
Brain Uptake ◽  
Local Cerebral Blood Flow ◽  
Brain Uptake Index ◽  
Derivatives Of ◽  
The Brain

Rats were injected with iodoamphetamine synthesized and labeled with 125I or with 125I-isopropyliodoamphetamine, a molecule of established value for the determination of local cerebral blood flow. The blood kinetics, tissue distribution, and brain uptake index for each tracer exhibited practically no differences. Autoradiographic quantification of the local cerebral blood flow, calculated according to the microsphere model, produced identical results for both molecules. However, compared with the values reported for other tracers, our values constituted an underestimation of white matter blood flow and a more real estimation of hippocampal flow. It is concluded from the brain uptake of the derivatives of both amphetamines during the first minutes following their injection that these tracers can be used as a chemical microembolus for the measurement of local cerebral blood flow.

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