Presentation and management of patients with initial negative 4-vessel cerebral angiography in subarachnoid hemorrhage.

The importance of repeat-angiography in patients with acute subarachnoid hemorrhage (SAH) and initial negative angiography has been reviewed in the light of our patient population (19 patients with initial negative angiography/168 patients with SAH). The type of SAH i.e., nontraumatic perimesencephalic SAH versus focal or generalized non perimesencephalic SAH, as well as the amount and distribution of blood on the initial CT examination are important factors in decision making. 3D-Angio-CT, in 3/5 patients, and MR-angiography (MRA) in 1/5 patients were complementary non-invasive methods to diagnose aneurysms on repeated examinations. Repeat-cerebral angiography confirmed the source of hemorrhage in 3 patients.