 SAH was confirmed on computed tomography CT or lumbar puncture. Only patients with a non-traumatic SAH were included. In our hospital algorithm all patients with SAH underwent angiography including 3D digital subtraction angiography DSA since 2002 to rule out intracranial sources for SAH. In case of a negative initial angiography, DSA was repeated after 14 days. Additionally, magnetic resonance imaging MRI of headspine was performed to rule out any spinal bleeding sources. In patients with blood distribution exceeding the typical perimesencephalic pattern, a third DSA was performed 3 months after SAH. The first short-term follow-up FU was performed six months after ictus. Outcome was measured according to the modified Rankin Scale mRS and stratified into favorable mRS 0-2 and unfavorable mRS 3-6 after six months. Patients with non-aSAH were divided into perimesencephalic SAH PM-SAH, non-perimesencephalic SAH NPM-SAH and excellent Outcome group mRS 0. Also the NPM-SAH group was further stratified into Fisher 3 blood pattern and NPM-SAH without Fisher 3 blood pattern. 