The Fisher classification was published in 1980[^1] and allows for the assessment of the severity of a subarachnoid hemorrhage (SAH). The classification into four different grades is based on the CT findings.
Classification
Fisher Grade | CT Findings |
Fisher Grade 1 | No blood visible in the subarachnoid space. |
Fisher Grade 2 | Diffuse or vertical layer of blood with a thickness of less than one millimeter. |
Fisher Grade 3 | Localized blood clot or a vertical layer with a thickness of more than one millimeter. |
Fisher Grade 4 | Predominantly intracerebral or intraventricular clots with no or only thin SAH. |