A CT scan showed a hypodense lesion (-48 Hounsfield units) with arc like calcification in left half of quadrigeminal plate cistern.
The findings were consistent with fat and a diagnosis of quadrigeminal plate cistern lipoma was made.
Characteristic imaging appearances of asymmetric narrowing of the internal carotid arteries (especially the supraclinoid portion) with numerous collateral vessels around the brainstem, especially within the ambient and quadrigeminal plate cisterns, are demonstrated with progression.
MR images (Figs 1a - c) demonstrated numerous collateral vessels around the brainstem, especially within the ambient and quadrigeminal plate cisterns.
Because patients are usually scanned in the supine position, particularly important locations include the interpeduncular cistern, the occipital horns of the lateral ventricles, the quadrigeminal plate
cistern, and the dependent portions of the Sylvian fissures (Figure 1).