The use of three-dimensional computed tomographic angiography in the accurate diagnosis of internal carotid artery aneurysms: degree for expression of posterior communicating and anterior choroidal arteries.

We have improved the scan protocol of three-dimensional computed tomographic angiography (3D-CTA) to maximize the accuracy of examining unruptured cerebral aneurysms. Sixty-seven cases of suspected internal carotid-posterior communicating (Pcom) and internal carotid-anterior choroidal (Ant Cho) artery aneurysms were evaluated as to the opacification of arteries. In the 46 cases of suspected fetal-type Pcom and Ant Cho aneurysms, the arteries were opacified from its origin to the periphery in all cases. A final diagnosis of the presence of an aneurysm was made possible by complete opacification. A definite diagnosis was impossible to make in only ten cases having adult-type Pcom. In conclusion, 3D-CTA, using our own scan protocol, was proven to be quite useful for making a more accurate diagnosis.