Computed tomography (CT) of abdominal aortic aneurysms: determination of longitudinal extent.

The aim of this study was to evaluate computed tomography (CT) in the assessment of abdominal aortic aneurysms with particular reference to their longitudinal extent. Twenty-nine patients were examined by CT, 21 of whom came to surgery. Sixteen of these 21 patients were also examined by ultrasound. At CT the relation of the aneurysm to the renal arteries proximally and the bifurcation distally was noted, along with the definition of the aortic outline. At subsequent surgery the longitudinal relations of the aneurysm and evidence of localized stretching of or leakage from the sac were assessed by an observer without knowledge of the CT scan report. Correct extent of the aneurysm in relation to the renal arteries was predicted by CT in 20 out of 21 patients who underwent surgery. CT assessment with respect to the bifurcation was correct in 16. The CT findings proved correct in one patient with localized stretching of one part of the aneurysm and in one patient where leakage was occurring. CT scanning was found to be superior to ultrasound in our preoperative assessment of the superior extent of abdominal aortic aneurysms. CT is considered to be the investigation of first choice when evaluation an abdominal aortic aneurysm.