Fisher grade
The Fisher Grade classifies the appearance of subarachnoid hemorrhage on CT scan:
- Grade 1= No hemorrhage evident
- Grade 2= Subarachnoid hemorrhage less than 1 mm thick
- Grade 3= Subarachnoid hemorrhage more than 1 mm thick
- Grade 4= Subarachnoid hemorrhage of any thickness with intra-ventricular hemorrhage (IVH) or parenchymal extension

