Heterogeneity of cerebral cavernous hemangiomas diagnosed by MR imaging.

The cavernous hemangioma (cavernoma) is increasingly recognized as a vascular malformation of the brain that may present with seizures, hemorrhage, or progressive neurological deficit. Since 1985 we have identified 13 cases of presumed cavernoma of the brain based on the findings on CT, selective angiography, and magnetic resonance (MR) imaging. In each case CT showed a high density lesion that was "occult" or "cryptic" on angiography. However, within all lesions MR revealed a complex internal structure consisting of reticulated patches of high and low intensity signal surrounded by a hypointense rim on T1- and T2-weighted pulse sequences. Of the nine operated cases, five resected specimens were compatible with pure arteriovenous malformations (AVMs), and the other four were mixtures of cavernoma with either AVM or venous angioma. Our experience strongly suggests that the above complex of radiographic findings is not at all specific for the cavernoma. We propose that the major common factor shared by such "cavernomatoid" malformations is low blood flow. We believe low flow lesions follow a relatively benign clinical course, and they readily lend themselves to surgical resection.