Nonaneurysmal Subarachnoid Hemorrhage
Findings:
SAH in prepontine cistern- normal 4 vessel angio (only
vertebrals shown)
Differential Diagnosis:
aneurysm, trauma, nonaneurysmal SAH
Discussion:
criteria- no intraventricular blood, should not extend
into anterior interhemispheric fissure, not beyond medial third of sylvian
fissure, confined to posterior portion of suprasellar cistern/ambient cistern.
etiology thought to be spontaneous hemorrhage from small veins in pontine
or perimesencephalic regions.