Perivascular Spaces and Diffusion Tensor Imaging Analysis Along the Perivascular Space Show Distinct Associations with Aging and Alzheimer's Disease.
Abstract
Background
AND
Purpose
MRI-visible perivascular spaces (PVS) are structural findings on T2-weighted MRI, whereas diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) measures directional water diffusivity in deep white matter. We compared PVS burden and ALPS across young controls, elderly controls, and patients with Alzheimer's disease (AD).
Materials And Methods
This retrospective, institutional review board-approved study included an acquisition-harmonized cohort of 16 young controls, 22 elderly controls, and 32 patients with biomarker-confirmed AD, all with DTI acquired on the same 3T Siemens MAGNETOM Vida platform. Two blinded readers graded basal ganglia (BG) and centrum semiovale (CSO) PVS on 2D axial T2-weighted images. PVS and ALPS were compared across the 3 groups; age- and sex-adjusted regression evaluated the elderly-control versus AD difference.
Results
Interrater reliability was excellent (quadratic-weighted kappa = 0.873-0.929). Median combined PVS scores (range, 0-8) were 2.75, 5.00, and 4.75 in young, elderly controls, and AD, respectively (P < .001), with no elderly-control versus AD difference (P = .89). Median ALPS indices were 1.365, 1.235, and 1.102 (P < .001). In pairwise testing unadjusted for age or sex, the elderly-control versus AD ALPS difference did not reach statistical significance (P = .05). In age- and sex-adjusted regression, AD was associated with lower ALPS (beta = -0.080; 95% CI, -0.158 to -0.003; P = .04), and the association persisted after additional adjustment for combined PVS (beta = -0.082; P = .04).
Conclusions
In a single-scanner, acquisition-harmonized cohort, MRI-visible PVS burden was predominantly associated with older age, whereas a modest AD-associated reduction in ALPS emerged after covariate adjustment. PVS grading and ALPS characterize different structural and diffusion features and should not be considered interchangeable. Longitudinal validation with higher-resolution diffusion imaging is needed to determine whether ALPS provides additional clinical value.