The Modified Fisher CT rating scale: Grade 1 (minimal or diffuse thing SAH without IVH); Grade 2 (minimal or thin SAH with IVH), Grade 3 (thick cisternal clot without IVH), Grade 4 (thick cisternal clot with IVH) [From: Claassen J et al. Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke 2001;32:2012-2020.]