MR imaging of cerebral venous angiomas

Five patients with cerebral venous angioma studied by CT scan and angiography were imaged with magnetic resonance (MR). Three patients had supratentorial lesions and two had cerebellar ones. Their ages ranged from 46 to 59 (mean 53) years. Two patients presented intracerebral hemorrhage, and in two other cases the cerebral venous angioma was asymptomatic and discovered during angiography to evaluate other lesions. In all cases, angiogram revealed a typical caput medusae appearance with dilated radiating veins converging to a large draining vein during the late venous phase. Noncontrast CT scan showed subtle or slight linear high density areas in four of five cases, and after contrast medium administration, linear or curvilinear enhancement was demonstrated in all cases. The all-venous angiomas were clearly recognized on MRI. Particularly on T2-weighted images, an enlarged draining vein was visible as a linear or curvilinear low signal intensity in all five cases, and a linear high signal intensity in three cases. The high signal intensity on T2-weighted images indicated relatively slow flow in the vessels comprising venous angioma. T1-weighted images detected the lesions as linear low intensity in four of five patients. T2-weighted images were helpful in manifesting venous angioma clearly as compared with T1-weighted images. By use of T2-weighted and multiple echo techniques, the venous nature of venous angiomas can be recognized. Comparing MR images and CT scan, MR images proved to be more accurate in detection of the lesions. In our series, the distinction between the venous angioma body and the draining vein was difficult on MRI. We suggest that further investigation of MRI techniques such as pulse sequences and section thickness would be helpful in detecting a caput medusae appearance on MR images. (author)