Characterizing Deep White Matter Hyperintensities in Patients with Symptomatic Isolated Cortical Superficial Siderosis.

Background: In patient with cerebral amyloid angiopathy (CAA) presenting with lobar hemorrhage (LH), magnetic resonance imaging (MRI) white matter hyperintensities (WMH) tend to be predominant in posterior regions with the "multiple subcortical spots" WMH pattern as the most frequent topographical WMH pattern. Our aim was to analyze WMH severity and topographical distribution in patients with cortical superficial siderosis (CSS).

Methods: We retrospectively analyzed MRIs from consecutive symptomatic isolated (i.e., without LH) CSS and LH-CAA (with or without associated CSS) patients. We analyzed baseline clinical characteristics including age, history of hypertension, diabetes, hypercholesterolemia, and pre-existing cognitive deficit. The presence of lobar microbleeds (MB) was scored on T2*. FLAIR (fluid-attenuated inversion recovery) WMH severity (using the Fazekas scale) and topographical distribution (using [slightly modified] earlier described WMH patterns) were analyzed and compared between both groups.

Results: Twenty CSS and 63 LH-CAA patients were analyzed. Baseline clinical characteristics were similar between both groups, except for hypercholesterolemia less frequently present in the CSS group (P = .026). Lobar MB were significantly less frequently present in the CSS group (P < .01), and CSS was more frequently focal in the CSS group compared with LH-CAA patients with associated CSS (P = .03). Mean Fazekas scale was significantly lower in CSS patients (P = .011). WMH patterns did not differ between both groups, with the multiple subcortical spots pattern as the most frequently observed pattern.

Conclusions: Relative severe WMH scores and similar topographical distribution in CSS patients argue for WMH as a CAA-related feature in these patients with isolated CSS, adding level of evidence that isolated CSS could correspond to early manifestations of CAA.