![Modified Fisher CT rating scale

Grade 1 (minimal or diffuse thin SAH without IVH), indicating low risk for symptomatic vasospasm;

Grade 2 (minimal or thin SAH with IVH) and

Grade 3 (thick cisternal clot without IVH), indicating intermediate risk for symptomatic vasospasm; and

Grade 4 (cisternal clot with IVH), indicating high risk for symptomatic vasospasm.

Claassen J, Bernardini GL, Kreiter K, Bates J, Du YE, Copeland D, Connolly ES Jr, Mayer SA: Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke 32:2012-2020, 2001. From: Frontera: Neurosurgery, Volume 59(1).July 2006.21-27

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Modified Fisher CT rating scale

Grade 1 (minimal or diffuse thin SAH without IVH), indicating low risk for symptomatic vasospasm;

Grade 2 (minimal or thin SAH with IVH) and

Grade 3 (thick cisternal clot without IVH), indicating intermediate risk for symptomatic vasospasm; and

Grade 4 (cisternal clot with IVH), indicating high risk for symptomatic vasospasm.

Claassen J, Bernardini GL, Kreiter K, Bates J, Du YE, Copeland D, Connolly ES Jr, Mayer SA: Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke 32:2012-2020, 2001. From: Frontera: Neurosurgery, Volume 59(1).July 2006.21-27