[Magnetic resonance imaging of occult intracranial malformations].

11 patients with angiographically occult intracranial vascular malformations proved by surgery and pathology were studied by magnetic resonance imaging (MRI). The chief MRI findings were: On T1-weighted imaging, there was a homogeneous or heterogeneous hyperintensity or isointensity signal at the centre of the lesion with a surrounding rim of hypointensity signal; On T2-weighted imaging, there was a hyperintensity signal at the centre and hypointensity signal at the peripheral region. Differential diagnosis between hemorrhagic tumor and occult vascular malformation lies in that the latter has no edema and is often single. comparing with CT, the size of occult vascular malformation on MRI was equal to that on CT.