Value of routine computed tomography in the preoperative assessment of abdominal aneurysm replacement

This study compares the findings of conventional computed tomography (CT) and ultrasound (US) imaging in the preoperative evaluation of patients with abdominal aortic aneurysm (AAA). It also assesses the impact of preoperative CT-derived information on operative strategy. A prospective study was conducted of 96 patients who were considered for aortic aneurysm surgery, and the operative notes and US and CT reports were analyzed to assess correlation of findings and influence of CT on operative tactics. Agreement between CT and US in sizing the aneurysm was generally good. CT was more accurate than US for defining the upper and lower extent of the aneurysm (75% and 83%, respectively, with CT, compared to 47% and 41% with US), although it had a high false positive rate (48%) for juxtarenal disease. Its advantage over US in regard to showing other intraabdominal pathology was only marginal, and it predicted an inflammatory reaction in only two of the five cases. Its influence on operative strategy was minimal: Of the 25 cases where a juxtarenal aneurysm was predicted by CT, only 2 patients did not have surgery as a result. CT is a relatively expensive and time-consuming procedure, and its ionizing radiation, however small, and potential side effects from contrast material hypersensitivity cannot be ignored. In light of the above findings, we suggest that CT scanning need not be routinely employed in the preoperative workup of elective aortic aneurysm repair but should be used only in selected cases.