ACUTE SUBARACHNOID HEMORRHAGE - 3D TIME-OF-FLIGHT MR-ANGIOGRAPHY VERSUS INTRAARTERIAL DIGITAL ANGIOGRAPHY

To evaluate the efficacy and reliability of 3D time-of-flight MR angio graphy (TOF MRA) as a noninvasive procedure, 27 patients with acute su barachnoid haemorrhage (SAH) were studied with MRA immediately before or after intra-arterial digital subtraction angiography (DSA). 3DTOF M SR was performed with an axial slab of 60 mm centred on the circle of Willis and isotropic voxels, DSA showed 22 aneurysms and 1 dural arter iovenous fistula in 21 patients; the aneurysms ranged in size from 2 t o 8 mm. MRA failed to show 2 small aneurysms, at the origin of the pos terior and anterior communicating arteries. The 3D display of the intr acranial vessels obtained with maximum intensity projection (MIP) or t argetted MIP sometimes rendered the aneurysms better than DSA. However , due to its high spatial resolution, DSA more clearly defined the ove rall anatomy of the walls of the normal and abnormal vessels.