MRI-visible perivascular spaces: relationship to cognition and small vessel disease MRI markers in ischaemic stroke and TIA

Background MRI-visible perivascular spaces (PVS) are potential neuroimaging markers of cerebral small vessel disease, but their functional significance and mechanisms remain uncertain. We investigated the association between PVS and cognitive impairment, and other MRI markers of small vessel disease, in a patient cohort of ischaemic stroke/transient ischaemic attack (TIA) referrals. Methods Data were collected from a prospective observational database. Standardised detailed neuropsychological testing was performed. A validated visual rating scale on T-2-weighted MRI was used to categorise PVS severity; validated scales were used to assess white matter hyperintensities (WMH), cerebral microbleeds (CMB) and lacunes. Results We included 246 patients (45.1% female, mean age 62 years). No significant association between PVS severity grade in any brain region and impairment in any cognitive domain was identified. In multivariable analysis, WMH and hypertension (but not age) were independently associated with basal ganglia PVS severity (OR: 1.27; p< 0.0001 and OR: 4.89; p= 0.013, respectively). Increasing PVS severity in the basal ganglia was associated with lacunar stroke subtype (p< 0.0001). Age and hypertension (but not WMH or lacunar stroke subtype) were independently associated with centrum semiovale PVS severity (OR: 1.19; p= 0.013 and OR: 3.71; p= 0.007, respectively). Conclusions PVS do not have an independent association with cognitive impairment in patients with ischaemic stroke or TIA. The associations with clinical-radiological factors are consistent with the hypothesis that PVS reflect cerebral small vessel disease; the different associations for basal ganglia and centrum semiovale PVS might indicate different underlying small vessel arteriopathies according to PVS anatomical distribution, but this requires further study.