The sensitivity of MR angiography (MRA) for aneurysms smaller than 3 mm in diameter is limited. Diagnostic pitfalls may arise from primary T1 hyperintense lesions on time-of-flight (TOF) imaging adjacent to a vessel. Independently, three patients were referred from outside facilities for diagnostic workup of suspected aneurysms of the vertebrobasilar system on TOF images. The lesions were identified as small lipomas, which prompted us to systematically analyze characteristics of intracranial lipomas on TOF images.
