Enlarged Centrum Semiovale Perivascular Spaces as a Noninvasive Imaging Marker of Vascular Amyloid Deposition in Amyloid-Positive Individuals without Cerebral Amyloid Angiopathy-Related Hemorrhages.

Introduction: Anti-amyloid therapy has increased the need for noninvasive methods to assess vascular amyloid. Reductions in cerebrospinal fluid (CSF) Aβ40 and Aβ42 are characteristic of cerebral amyloid angiopathy (CAA), but lumbar puncture limits their use in routine practice. Magnetic resonance imaging-visible perivascular spaces in the centrum semiovale (CSO-PVS) have emerged as a potential imaging marker, although their relevance in amyloid-positive individuals without CAA-related hemorrhages remains uncertain. Methods: We retrospectively analyzed 30 patients with mild cognitive impairment due to Alzheimer's disease (AD) or mild AD who exhibited reduced CSF Aβ42/40 ratio and no CAA-related hemorrhagic findings. CSO-PVS were visually quantified and dichotomized into high- and low-degree groups using the median raw count. CSF Aβ40, Aβ42, and p-tau181 levels were compared between groups. Results: Patients with high-degree CSO-PVS demonstrated significantly lower CSF Aβ40 levels than those with low-degree CSO-PVS ( Conclusion: A higher CSO-PVS burden was associated with lower CSF Aβ40 and Aβ42 levels, suggesting that CSO-PVS dilation may serve as a noninvasive surrogate marker of vascular amyloid deposition in amyloid-positive patients undergoing anti-amyloid therapy.