Diffuse Patterns of Nonaneurysmal Subarachnoid Hemorrhage Originating from the Basal Cisterns Have Predictable Vasospasm Rates Similar to Aneurysmal Subarachnoid Hemorrhage

Nonaneurysmal SAH is associated with the potential for vasospasm, with higher rates in the diffuse versus perimesencephalic SAH patterns. The BNI grading scale for aneurysmal SAH can be used to predict the risk of vasospasm in diffuse, nonaneurysmal SAH.