There is evidence of acute subarachnoid blood in a location consistent with possible aneurysm hemorrhage.

There is evidence of concurrent intra ventricular bleeding.

There is evidence of concurrent parenchymal and  SAH suggesting sentinel aneurysm bleed.

There is evidence of either non localizing diffuse SAH or only trace amount of blood in occipital horns, posterior intrasylvian sulci, or the interpeduncular fossa.

There is evidence of intercurrent hydrocephalus related to the SAH.

There is evidence of SAH in relationship to cortical veins or dural sinuses consistent with venous thrombosis.

There is evidence of SAH near falx (possibly post traumatic in origin).

There is evidence of vertex sulcal blood (possibly reversible vasoconstrictive vasc disorders or vasculitis or coagulopathy source).

There is evidence of concurrent focal blood and cytogenic edema consistent with a intercurrent hemorrhagic stroke source.

There is evidence of thrombosed pial artery/vein simulating acute SAH.

There is evidence of thrombosed vascular malformation simulating acute CNS bleed.

There is evidence of pial calcification simulating SAH.

There is evidence of hemorrhagic met or other tumor as the source for SAH.

There is evidence of multicentric bleeding sites consistent with coagulopathy as cause for bleeding.

There is evidence of mass effected (and possible herniation) produced by hemorrhage, tissue edema, or hydrocephalus.

There is evidence of a giant aneurysm or sacculo-fusiform atherosclerotic aneurysm or arteriosclerotic dolichoectasia possibly with calcification in its wall.

Other abnormalities