Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: decrease in regional cerebral blood volume in hyperintense subcortical lesions inversely correlates with disability and cognitive performance

Abstract

Background and purpose: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathic syndrome related to a genetic defect on chromosome 19. Characteristic changes in CADASIL can be observed onT2-weighted MR images in the subcortical white matter. The purpose of this study was to measure changes of regional cerebral blood volume (rCBV) with dynamic contrast-enhanced MR imaging and to correlate the changes to disability and cognitive performance.

Methods: We obtained rCBV measurements of 24 individuals with proven CADASIL on a 1.5-T MR imaging unit. A susceptibility-weighted MR imaging sequence was used for bolus tracking. Principles of the indicator dilution theory were applied to estimate values of absolute rCBV (mL/100 g). Disability was determined by using the Rankin scale, and overall cognitive performance was assessed by using the Mini-Mental State Examination.

Results: The mean rCBV in the subcortical white matter that was hyperintense on the T2-weighted images (2.7 +/- 0.8 mL/100 g) was significantly lower than the rCBV in the white matter that appeared normal on the T2-weighted images (4.4 +/- 1.3 mL/100 g) (P <.05). The mean rCBV in the gray matter was within the normal range (8.3 +/- 1.7 mL/100 g). Both cognitive impairment and disability negatively correlated with rCBV in the subcortical white matter that was hyperintense (P <.05) but not with rCBV in the normal appearing white matter. rCBV did not correlate with age.

Conclusion: rCBV measured in the hyperintense subcortical white matter in individuals with CADASIL was decreased and inversely correlated with disability and cognitive impairment.

fig 1.

Mean rCBV of 24 patients with CADASIL, as measured in gray matter and subcortical white matter

fig 2.

MR imaging findings of a 53-year-old man with CADASIL (MMSE score, not measurable; Rankin score, 4). A, T2-weighted image (2300/85/1). Abnormal increases in the signal intensity in the subcortical white matter are seen in the frontal and occipital white matter (arrows) and in the basal ganglia bilaterally. B, rCBV map of the same section. Decrease of rCBV in the frontal and occipital lobes is detectable (arrows)

fig 3.

MR imaging findings of a 50-year-old man with CADASIL (MMSE score, 21; Rankin score, 1). A, T2-weighted image (2300/85/1). Lacunar defects (one arrow) and subcortical white matter abnormalities were detected (two arrows). B, rCBV map of the same section. Bilateral reduction of rCBV in the frontal lobes is visible on the rCBV map (two arrows). Lacunar defect visible on the T2-weighted image was also visible (one arrow). rCBV was calculated to be zero

fig 4.

rCBV values of 24 patients with CADASIL in normal appearing white matter as a function of age (error bars denote SD; blue dot denotes mean values).fig 5. rCBV determined in the subcortical CADASIL lesions for each age group

fig 6.

Correlation between disability (Rankin score) of patients with CADASIL and rCBV in white matter that appeared abnormal on T2-weighted images. In our group, no patient had a Rankin score of 3. One patient with a Rankin score of 5 had an rCBV of 2.2 mL/100 g. (* = statistically different from Rankin = 0.)fig 7. Correlation between cognitive performance (MMSE score, 22) and the rCBV in white matter that appeared abnormal on T2-weighted images. (*See text for definition of cognitive impairment.)