Helical CT angiography replaces conventional aortography in the preoperative evaluation of abdominal aortic aneurysm

Conventional aortography accurately defines arterial anatomy for the preoperative assessment of abdominal aortic aneurysms (AAA). Helical computed tomography angiography (CTA) allows enhanced visualization of the aneurysm using less invasive, conventional, computed tomography (CT) methods. Also, three-dimensional (3-D) images may be reconstructed which provide perspective not possible with biplanar arteriograms. The authors tested the hypothesis that helical CTA matches the utility of conventional aortography in the preoperative evaluation of infrarenal AAA. Thirty-one patients with a suspected AAA were evaluated by helical CTA, which included 3-D reconstructions using the maximum intensity projection (MIP) technique. Seven of these patients also received conventional aortography after CTA. Three radiologists and 1 surgeon evaluated all the radiographs for the location and size of the aneurysm or thrombus, for patency of the renal and mesenteric vessels, and for iliac artery patency. In the 7 patients for whom both CTA and aortography were performed, the mesenteric and renal arteries were visualized in both tests. The inferior mesenteric artery (IMA) was recorded in 4 of 7 patients by aortography and in 2 of 7 patients by CTA. In addition, CTA provided detail regarding aneurysm size, presence of aneurysm thrombus, and vessel wall calcification that was not provided by conventional angiography. Of the 31 patients who had CTA, 16 received conventional surgical aneurysm repair after their imaging procedure with no significant intraoperative findings that were not present on CTA. These results suggest that helical CTA is a useful technique in the preoperative evaluation of AAAs. The arteriogram should be reserved for patients with peripheral occlusive disease or for further evaluation of and possible percutaneous transluminal angioplasty of renal or visceral arterial disease.