A left-sided craniotomy is noted, with post surgical change extending through the temporal lobe to the site of previous cavernous malformation, which now appears resected with no convincing residual cavernoma evident, and only a small amount of residual haemosiderin staining. A 17mm deep subdural collection extends over the left cerebral convexity exerting significant local mass effect and 5 mm midline shift. The remainder of the brain is unremarkable.