Volume subtraction three-dimensional CT angiography for cerebrovascular disease: report of two cases.

We report two cases in which volume subtraction three-dimensional CT angiography (VS-3DCTA) was used for cerebral aneurysm and vascular stenosis with intramural calcification. Case 1: VS-3DCTA with volume rendering clearly showed carotid cave aneurysm of the internal carotid artery. The location and size of the aneurysm was confirmed by digital subtraction angiography (DSA). In evaluation of the aneurysm, VS-3DCTA was equal to DSA and endovascular findings. Case 2: VS-3DCTA with volume rendering clearly showed stenosis of the middle cerebral artery, and intramural calcification with the cause of the stenosis was subtracted. On the other hand, it was difficult for DSA to reveal the stenosis because of the limitation of the imaging angle. In evaluation of the stenosis, VS-3DCTA was superior to DSA. VS-3DCTA was an important diagnostic tool that enabled visualization of the aneurysm in the area of the skull base and stenosis of the intracerebral artery.