Correlations between clinical findings and magnetization transfer imaging metrics of tissue damage in individuals with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Background and Purpose-We obtained magnetization transfer imaging (MTI) sca ns from individuals with cerebral autosomal-dominant arteriopathy with subc ortical infarcts and leukoencephalopathy (CADASIL) (1) to investigate the p resence, extent, and nature of pathology in white and gray matter outside p roton density (PD)-visible lesions; (2) to quantify the degree of tissue da mage occurring in lesions seen on PD-weighted scans; and (3) to correlate M TI-derived measures of disease burden with age, physical disability, and co gnitive performance. Methods-Dual-echo, T1-weighted, and MTI scans of the brain were obtained fr om 33 individuals with CADASIL and 12 control subjects. Magnetization trans fer ratio (MTR) values from PD-visible lesions, normal-appearing white matt er (NAWM), and normal-appearing gray matter (NAGM) were measured. Histogram s of MTR from the whole brain and normal-appearing brain tissue were also p roduced. Results-All MTR values from NAWM and NAGM regions studied were significantl y lower for individuals with CADASIL than for control subjects, with the ex ception of those obtained from the NAWM of the infratentorial structures an d the NAGM of the occipital cortex. The average MTR from PD lesions in indi viduals with CADASIL was significantly lower than that from all the NAWM re gions. Average MTR and peak location from whole-brain and normal-appearing brain tissue histograms were significantly lower for individuals with CADAS IL than for control subjects. MTR values from NAWM were strongly correlated with the extent of macroscopic lesions and their average MTR, Apart from N AGM, average MTR from all other tissues studied significantly decreased wit h increasing age, physical disability, and cognitive impairment. Conclusions-PD lesions of individuals with CADASIL have variable degrees of tissue damage. Brain tissue outside PD abnormalities is also damaged. This study suggests that the extent and the severity of the brain tissue damage are critical factors in determining clinical status in CADASIL.