This case illustrates radiological findings most consistent with a diagnosis of CADASIL in a patient with a positive family history. 

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common form of hereditary cerebral angiopathy¹ . It is a non-amyloid type of small vessel arterial disease caused by mutation NOTCH3 gene on chromosome 19q12². The NOTCH3 gene encodes a transmembrane protein expressed in vascular smooth muscle ^1,3. This protein dictates maturation of smooth muscle cells and is thereby required for maintenance of the structural and functional integrity of small arteries. Mutations of the NOTCH3 gene result in mural fibrosis and subsequent loss of vasomotor reactivity in small blood vessel walls.  There is resultant dysfunctional arterial autoregulation, cerebral hypoperfusion and ischemic infarction ³.

Clinical hallmarks of CADASIL include migraine with aura, stroke, mood disturbances and cognitive impairment ⁴. The first clinical manifestations of the disease often start in patients during the 3rd decade, and death often occurs in patients during the 6th decade ².

The main neuroimaging findings of CADASIL are ^1-4:

• White matter regions of high signal intensities on T2 weighted images and FLAIR sequences. These white matter hyperintensities are usually found in the periventricular region and deep white matter. There is a predelication for the frontal, parietal, and anterior temporal, followed by external capsule areas of the brain.
• Lacunar infarcts, most commonly of the in the semioval center, thalamus, basal ganglia, and pons.
• Cerebral microbleeds most sensitive on Gradient echo planar T2* MRI and common to the cortical/subcortical areas, white matter, thalamus and brainstem. 

Case courtesy of Associate Professor Pramit Phal.