Figure 2 - available via license: Creative Commons Attribution-NonCommercial 4.0 International
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Illustration of reference sites of dWMH. The degrees of the dilatation and number of PVS within a spherical area with a radius of 1 cm around dWMH and the anatomically corresponding reference area in the contralateral hemisphere were evaluated in axil plane (A), coronal plane (B) and sagittal plane (C and D). dWMH, deep white matter hyperintensity; PVS, perivascular space. on September 29, 2022 by guest. Protected by copyright.
Source publication
Background
The association between perivascular space (PVS) and white matter hyperintensity (WMH) has been unclear. Normal-appearing white matter (NAWM) around WMH is also found correlated with the development of focal WMH. This study aims to investigate the topological connections among PVS, deep WMH (dWMH) and NAWM around WMH using 7 Tesla (7T) M...
Context in source publication
Context 1
... images were registered to the T2-weighted images with an affine transformation based on the statistical parametric mapping 12 registration packages (www.fil.ion.ucl.ac.uk/spm). We assessed the PVS dilatation in a sphere with a radius of 1 cm surrounding dWMH and the symmetrical reference region in the contralateral hemisphere ( figure 2). A radius of 1 cm was chosen in this study because microstructural changes were usually reported to extend 2-9 mm from the WMHs. ...
Citations
BACKGROUND
Recent studies, using diffusion tensor image analysis along the perivascular space (DTI-ALPS), suggest impaired perivascular space (PVS) function in cerebral small vessel disease, but they were cross-sectional, making inferences on causality difficult. We determined associations between impaired PVS, measured using DTI-ALPS and PVS volume, and cognition and incident dementia.
METHODS
In patients with lacunar stroke and confluent white matter hyperintensities, without dementia at baseline, recruited prospectively in a single center, magnetic resonance imaging was performed annually for 3 years, and cognitive assessments, including global, memory, executive function, and processing speed, were performed annually for 5 years. We determined associations between DTI-ALPS and PVS volume with cerebral small vessel disease imaging markers (white matter hyperintensity volume, lacunes, and microbleeds) at baseline and with changes in imaging markers. We determined whether DTI-ALPS and PVS volume at baseline and change over 3 years predicted incident dementia. Analyses were controlled for conventional diffusion tensor image metrics using 2 markers (median mean diffusivity [MD] and peak width of skeletonized MD) and adjusted for age, sex, and vascular risk factors.
RESULTS
A total of 120 patients, mean age 70.0 years and 65.0% male, were included. DTI-ALPS declined over 3 years, while no change in PVS volume was found. Neither DTI-ALPS nor PVS volume was associated with cerebral small vessel disease imaging marker progression. Baseline DTI-ALPS was associated with changes in global cognition (β=0.142, P =0.032), executive function (β=0.287, P =0.027), and long-term memory (β=0.228, P =0.027). Higher DTI-ALPS at baseline predicted a lower risk of dementia (hazard ratio, 0.328 [0.183–0.588]; P <0.001), and this remained significant after including median MD as a covariate (hazard ratio, 0.290 [0.139–0.602]; P <0.001). Change in DTI-ALPS predicted dementia conversion (hazard ratio, 0.630 [0.428–0.964]; P =0.048), but when peak width of skeletonized MD and median MD were entered as covariates, the association was not significant. There was no association between baseline PVS volume, or PVS change over 3 years, and conversion to dementia.
CONCLUSIONS
DTI-ALPS predicts future dementia risk in patients with lacunar strokes and confluent white matter hyperintensities. However, the weakening of the association between change in DTI-ALPS and incident dementia after controlling for peak width of skeletonized MD and median MD suggests part of the signal may represent conventional diffusion tensor image metrics. PVS volume is not a predictor of future dementia risk.
