VARIABLE AGREEMENT BETWEEN VISUAL RATING-SCALES FOR WHITE-MATTER HYPERINTENSITIES ON MRI - COMPARISON OF 13 RATING-SCALES IN A POSTSTROKE COHORT

Background and Purpose Previous reports on the frequency, extent. and clinical correlates of white matter hyperintensities (WMHIs) have been contradictory. The purpose of this study was to test whether part of this variation could be explained by the different properties of the v isual WMHI rating scales used. Methods The periventricular (PVHIs) and deep white matter (DWMHIs) hyperintensities of 395 poststroke patient s were systematically analyzed and transformed to correspond to 13 dif ferent rating scales. The scales were compared with the use of Goodman -Kruskal measures of association. The relative frequencies, means, and medians of PVHI and DWMHI grades as well as Spearman rank correlation s between WMHI grade and hypertension were calculated. Results At best more than 80% of the patients received an equivalent WMHI grade by di fferent scales, but at worst the corresponding values were only 0.4% f or PVHI and 18% for DWMHI. At best different scales categorized patien ts similarly in regard to WMHI grade, but at worst the corresponding v alues were 8% for PVHI and 57% for DWMHI ratings. The distribution of WMHI grades also varied, and when the effect of age on WMHI was assess ed, some of the scales had a ceiling effect and some had a Boor effect . Only 1 of the 7 PVHI, 5 of the 9 DWMHI, and 1 of the 3 combined rati ng scales showed a significant correlation with arterial hypertension, a putative risk factor for WMHIs. Conclusions Some of the inconsisten cies in previous studies of WMHIs are due to differences in visual rat ing scales. Our findings may warrant international debate regarding ha rmonization of WMHI ratings.