Three-dimensional display of the orifice of intracranial aneurysms: a new potential application for magnetic resonance angiography.

Our aim was to demonstrate the orifice of intracranial aneurysms by magnetic resonance angiography (MRA). The aneurysmal orifice is that part of its lumen that communicates with the parent vessel. We studied 12 patients with 17 intracranial aneurysms using three-dimensional display (3DD) MRA; 15 of the aneurysms had previously been shown by digital subtraction angiography (DSA). The overall image quality of 3DD MRA was excellent in 10 patients. The orifice was clearly demonstrated in 13 aneurysms (76%) providing unique information about its size, shape and orientation. The orifice of 2 aneurysms (12%) was not demonstrated. Two aneurysms (12%) were not detected on MRA. Although 3DD MRA has limitations, this study suggests that it can accurately define the orifice of aneurysms and could be used to provide information crucial for endovascular treatment.