Preoperative evaluation of intracranial aneurysms: usefulness of intraarterial 3D CT angiography and conventional angiography with a combined unit--initial experience

PURPOSE: To assess the usefulness of intraarterial computed tomographic (CT) angiography in conjunction with digital subtraction angiography (DSA) by using a combined CT and angiographic unit in the preoperative evaluation of intracranial aneurysms. MATERIALS AND METHODS: Prospectively, 22 patients with or without subarachnoid hemorrhage underwent CT angiography in conjunction with DSA. Two radiologists independently evaluated DSA and CT angiographic images. Referring neurosurgeons were questioned as to how the additional information provided by CT angiography changed patient treatment. RESULTS: Intraarterial CT angiography was superior to DSA for use in aneurysm detection in three (12%) of 26 aneurysms and for delineation of aneurysm shape, neck, and location in more than half. In 14 (64%) of 22 patients, CT angiography demonstrated 18 additional findings: a very small aneurysm (n = 2), aneurysm shape and neck (n = 6), relationship of the aneurysm to adjacent arteries or bone structure (n = 8), and branches deriving from the aneurysm (n = 2). In four (27%) of 15 patients who underwent surgery or embolization, additional information obtained at CT angiography affected the treatment. CT angiography failed to clearly demonstrate an aneurysm adjacent to bone structures and small perforators, which were derived from the parent artery. CONCLUSION: Intraarterial CT angiography is useful for preoperative evaluation of intracranial aneurysms as a supplement to DSA.