Tracking the Changes in Longitudinal MRI-detected Perivascular Spaces following Ischaemic Stroke

Stroke is a leading cause of mortality and morbidity worldwide. MRI-visible perivascular spaces (PVS) are an emerging marker of cerebral small vessel disease and may have prognostic value in stroke. We investigated longitudinal changes in PVS volume and cluster count following ischaemic stroke. PVS volumes and cluster counts were compared between stroke survivors (n=124; 39 women; median [Q1, Q3] age=70 [62, 76] years) and healthy controls (n=39; 15 women; median age=69 [66, 72.5] years). MRI scans were acquired at 3 months, 12 months, and 36 months post-stroke. PVS were automatically segmented from T1-weighted MRI using a validated deep learning algorithm (nnU-Net). Generalised linear mixed-effects models were used to assess group differences and longitudinal changes in PVS, adjusting for baseline age, sex, total intracranial volume, and BMI. At the 12-month timepoint, no significant differences in PVS metrics were observed between stroke and control groups. However, at the 36-month timepoint we observed a significant brain-wide reduction in PVS volume (exp({beta})=0.93, 95%CI [0.87, 1], p=0.035) and cluster count (exp({beta})=0.92, 95%CI [0.85, 0.99], p=0.003) in the stroke group compared to control. Regionally, by 36 months, stroke patients demonstrated significant PVS reductions relative to controls in the frontal (PVS volume: exp({beta})=0.93, 95%CI [0.82, 0.99], p=0.032; PVS cluster counts: exp({beta})=0.91, 95%CI [0.83, 1], p=0.037) and parietal lobes (PVS volume: exp({beta})=0.93, 95%CI [0.85, 1.01], p=0.10; PVS cluster counts: exp({beta})=0.84, 95%CI [0.68, 1.08], p<0.001). These findings suggest that ischaemic stroke is associated with dynamic and regional changes in PVS volume and counts.