NEGATIVE MRI VERSUS REAL DISEASE - DISCUSSION

A 76-year-old diabetic woman presented with progressive binocular vert ical diplopia and right eye pain. Examination revealed a pupil-involvi ng partial right third cranial nerve palsy with development of anisoco ria over the course of several hours. MRI of the brain showed no mass lesion. MRA, even with retrospective review of the images, failed to c learly identify a 1 cm right posterior communicating artery aneurysm d etected by subsequent conventional cerebral angiography While MRA has been reported to be highly sensitive in cerebral aneurysm detection at some centers, other investigators have indicated less favorable data. Standardized protocols for data acquisition and meticulous attention to proper post-processing and image interpretation are essential if MR A is to supplant invasive arteriography. Currently conventional (x-ray ) angiography remains the gold standard for aneurysm detection, while MRA possesses excellent potential in this regard.