Development and validation of a rating scale for perivascular spaces on 3T MRI

To develop and validate a novel perivascular space rating scale, based on single axial slices in the basal ganglia and the centrum semiovale on T1-weighted and FLAIR images obtained on a 3T MRI scanner.

414 community dwelling older adults age 70-90 were assessed. The number of perivascular spaces in the slices 2 mm (basal ganglia) and 37 mm (centrum semiovale) above the anterior commissure were counted. The construct validity of the scale was tested by examining associations with age, sex, vascular risk factors and neuroimaging markers of small vessel disease; white matter hyperintensities, lacunes and cerebral microbleeds. Associations with cross sectional global and domain specific cognition were also examined.

The rating scale had excellent inter-rater reliability (intraclass correlation coefficient in basal ganglia 0.82 and centrum semiovale 0.96), good intra-rater reliability (ICC in basal ganglia 0.72 and centrum semiovale 0.87) and reasonable concurrent validity with an existing perivascular spaces scale (Spearman rho = 0.49, p < .001). There was a median of four basal ganglia and zero centrum semiovale perivascular spaces. Basal ganglia perivascular spaces were more common in men and associated with the other neuroimaging markers. Perivascular spaces in either location were not independently associated with global or domain specific cognitive impairment.

The new rating scale is easy to use, quick, has good psychometric properties and performs better than existing scales in a community dwelling older cohort. Further studies are needed to validate the scale in more diverse cohorts with greater cerebrovascular burden.