Prediction of Parent Artery of Anterior Communicating Artery Aneurysm on CT Angiography

Purpose : To determine whether CT angiography can predict the parent artery of an anterior communicating aneurysm on the basis of characteristics of the aneurysm and precommunicating anterior cerebral artery. Materials and Methods : Eighteen patients with anterior communicating aneurysm were studied prospectively using CT angiography and conventional angiography. The parent artery of an aneurysm was predicted by e-valuating aneurysm neck location, direction of aneurysm projection, and size of the precommunicating anteri-or cerebral artery, as seen on CT angiography. A somatom Plus-4 spiral CT scanner was used and shaded-sur-face display three-dimensional images were constructed. Results : Aneurysm neck was located near the parent artery in 12 cases(66.7%), and aneurysm projection was against the parent artery in 11 cases(61.1 %). The parent artery of the anterior cerebral artery was larger in 15 cases (8 3 .3 %), including ten cases of hypoplasia or agenesis of the contralateral anterior cerebral artery. In 17 of 18 aneurysms(94.4%) the parent artery seen on DSA was correctly predicted by CT angiography. Conclusion : Teh parent artery of an anterior communicating aneurysm can be predicted by evaluating a-neurysm neck location, direction of aneurysm projection, and precommunicating anterior cerebral artery, as seen on CT angiography.