Aortic aneurysm morphology for planning endovascular aortic grafts: limitations of conventional imaging methods

To test whether conventional computed tomography scanning (CT) and contrast aortography (CA) provide adequate data for planning endovascular aortic grafting by measuring 33 parameters in patients having both imaging examinations for evaluation of abdominal aortic aneurysms (AAA).

Fifty consecutive patients with AAA (41 men, 9 women; average age 65 years) had CT and CA (mean 26 days between exams). The data collected and analyzed included: 8 sites of diameter, 4 lengths, 6 angles, and 15 other dimensional measurements.

Conflicts between CA and CT data were common. Eighteen patients appeared to have a distal cuff by CA but not by CT. Proximal neck length could not be assessed by CT in 5 and had a difference between CA and CT > 1 cm in 25 patients. CA overestimated neck length in 11 patients. Common iliac artery angulation > 60 degrees unilaterally in 27 patients and bilaterally in 5. Seven patients had both iliac aneurysm and > 60 degree iliac angulation. Thirteen patients had one or more iliac aneurysms (> 2 cm) shown by CT but not by CA.

For endovascular graft planning: (1) more detailed measurement is required than for traditional surgery; and (2) conventional CT and CA are complementary imaging studies, but each has important limitations.