These CT and MRI studies demonstrate a subarachnoid haemorrhage (SAH) with apparent involvement of the left cavernous sinus in CT (but apparently not reflected in the MRI), parietal and frontal sulci and interhemispheric fissure.

Also visible a right A1 hypoplasia of the circle of Willis, but no other significant vascular abnormalities were found in the arterial study (Time-of-Flight (TOF)) and venous study (Phase Contrast (PC)). 

85% of non-traumatic SAH are caused by aneurismal rupture and with basal cisternae involvement. 7% are caused by non-aneurysmal cause.