This patient had a known diagnosis of Moyamoya disease, an idiopathic vascular occlusive disease, which causes progressive stenosis of the terminal internal carotid artery bifurcation including the proximal anterior and middle cerebral arteries in association with the development of dilated perforating arteries that function as collateral pathways. 

In adults, hemorrhage from the abnormal vessels can occur resulting in intracerebral or intraventricular hematoma as seen in this case. The common site of hemorrhage is intraventricular and in the paraventricular area of the posterior lateral ventricle which is the blood supply area of the lateral posterior choroidal artery ¹.

It is worth learning to recognize it on non-vascular imaging, and T2 is best for this.