Applied Radiology

Diagnosis

CADASIL

Findings

CT images demonstrate ill-defined periventricular white matter hypodensity as well as hypodensity involving the external capsules and subcortical white matter of the anterior temporal lobes. A focal hypodensity is present in the left thalamus.

T2 weighted and FLAIR MRI images demonstrate abnormal hyperintensity within the subcortical and periventricular matter with involvement of the anterior temporal lobes, external capsules, and thalami. An old infarct is noted in the left thalamus and there are chronic ischemic changes in the brainstem. Contrast enhanced T1 weighted images demonstrate no abnormal enhancement. DWI images demonstrate no signal abnormalities.

Discussion

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is an inherited disorder which involves a mutation on chromosome 19q12, affecting the Notch 3 gene. The mutation results in an angiopathy of the small and medium sized arteries resulting in luminal narrowing and decreased cerebral blood flow. Patients generally present between the ages of 30 and 50, most often with recurrent transient ischemic attacks and strokes involving multiple vascular territories. Approximately 20 to 40% of patients will present with migraines, often with auras. Migraines also tend to involve a younger population with CADASIL. Almost all patients eventually progress to dementia characterized by executive dysfunction as well as changes in memory and attention. Most patients will also develop behavioral disturbances, commonly including depression, sleep disturbances, apathy, and irritability.

CT is often the initial examination performed due to ease and availability. CT will demonstrate nonspecific hypodense lesions within the subcortical white matter and basal ganglia. MRI is required for further evaluation and classically demonstrates hyperintense lesions within the white matter which may be small and discrete or large and confluent. Involvement of the anterior temporal lobes is highly sensitive and specific for CADASIL. Other commonly involved locations include the frontal and parietal lobes as well as the external capsule. Lacunar infarcts of varying ages are also often seen, most commonly involving the basal ganglia.

No specific therapy is available for treatment of CADASIL.

1. Liem MK et al: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: progression of MR abnormalities in prospective 7-year follow-up study. Radiology. 249(3):964-71, 2008.
2. Chabriat H et al: Cadasil. Lancet Neurol. 8(7):643-53, 2009.
3. Auer DP et al: Differential lesion patterns in CADASIL and sporadic subcortical arteriosclerotic encephalopathy: MR imaging study with statistical parametric group comparison. Radiology. 218(2):443-51, 2001.