Patterns of MRI lesions in CADASIL

Abstract

Objective: To investigate the location and severity of MRI signal abnormalities in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).Background: One hallmark of this arteriopathy due to mutations of Notch 3 gene is the presence of MRI signal abnormalities in both symptomatic and asymptomatic patients.Methods: MRIs of 75 patients (43 with symptoms) were reviewed by a neuroradiologist masked to their clinical status. After assessing the presence of MRI lesions on T1- and T2-weighted images (T1-WI, T2-WI) in different subcortical regions, the severity of hyperintensities on T2-WI was scored using a global rating scale and a regional semiquantitative scale in the periventricular white matter (PV), deep white matter (WM), basal ganglia (BG), and infratentorial areas (IT).Results: Sixty-eight patients (90%) had hyperintensities on T2-WI located in the white matter, more frequent in PV (96%) and WM (85%) than in the superficial white matter (25%). Hyperintensities also occurred in BG (60%) and brainstem(45%). Forty-seven patients (62%) presented with hypointensities on T1-WI. In one-third of the affected inviduals, white matter hyperintensities occurred in the absence of small deep infarcts on T1-WI. The frequency and severity scores calculated for PV, WM, BG, or IT hyperintensities increase dramatically with age. These scores were higher in symptomatic compared with asymptomatic gene carriers. Dementia, Rankin score >1, or both occurred only in the presence of diffuse white matter signal abnormalities.Conclusion: Our results suggest that different subcortical areas have different vulnerabilities to ischemia in CADASIL. The age effect we observed may show an accumulation of lesions with aging during the course of the disease. A prospective study is needed to investigate if the rating of MRI lesions is of prognostic value in CADASIL.