Specific Imaging Findings

Cerebral cavernous malformations (CCM, cavernous angiomas/hemangiomas, cavernomas) show characteristically mild-to-moderate increased density on unenhanced CT reflecting the presence of calcium and blood at various stages of degradation with some cavernomas disclosing clear internal calcifications. MR imaging of CCM demonstrates typical popcorn-like multilobulated lesion with smooth margins and multiple internal septations. There is characteristically high T2 signal centrally, frequently with associated T1 hyperintensities, and a T2 dark peripheral hemosiderin ring. Smaller cavernomas may appear as foci of just low T2 signal. On T2* imaging the characteristic signal loss from hemosiderin due to susceptibility effects reveals cavernomas missed on other sequences. T2* images are very helpful in patients with CCM, as they frequently show multiple lesions, especially in familial cases. Surrounding edema and mass effect may be seen in acute hemorrhage. T1 hyperintensity in the perilesional edema appears to be a characteristic feature of CCMs with a recent bleed. Contrast enhancement is usually absent, while peripheral enhancement may surround an acute hematoma. There is a commonly observed association with a developmental venous anomaly (DVA), which does enhance. CCM are otherwise occult at DSA, CTA, and MRA.

Pertinent Clinical Information

CCM are common vascular malformations of the CNS that may present with seizures, headache, or focal neurological deficits, usually from hemorrhage. They may also be asymptomatic and incidentally discovered. CCM can occur everywhere in the brain, including the extra-axial locations. Compared with adults, pediatric patients with brainstem cavernomas tend to have larger lesions and higher recurrence rate.