BACKGROUND AND PURPOSE: CADASIL is the most frequent hereditary small-vessel 
disease of the brain. The clinical impact of various MR imaging markers has been 
repeatedly studied in this disorder, but alterations of contrast between gray 
matter and normal-appearing white matter remain unknown. The aim of this study 
was to evaluate the contrast alterations between gray matter and 
normal-appearing white matter on T1-weighted images in patients with CADASIL 
compared with healthy subjects.
MATERIALS AND METHODS: Contrast between gray matter and normal-appearing white 
matter was assessed by using histogram analyses of 3D T1 high-resolution MR 
imaging in 23 patients with CADASIL at the initial stage of the disease 
(Mini-Mental State Examination score > 24 and modified Rankin scale score ≤ 1; 
mean age, 53.5 ± 11.1 years) and 30 age- and sex-matched controls.
RESULTS: T1 contrast between gray matter and normal-appearing white matter was 
significantly reduced in patients compared with age- and sex-matched controls 
(patients: 1.35 ± 0.08 versus controls: 1.43 ± 0.04, P < 10(-5)). This reduction 
was mainly driven by a signal decrease in normal-appearing white matter. 
Contrast loss was strongly related to the volume of white matter 
hyperintensities.
CONCLUSIONS: Conventional 3D T1 imaging shows significant loss of contrast 
between gray matter and normal-appearing white matter in CADASIL. This probably 
reflects tissue changes in normal-appearing white matter outside signal 
abnormalities on T2 or FLAIR sequences. These contrast alterations should be 
taken into account for image interpretation and postprocessing.