Preoperative imaging of the aortoiliac anatomy in endovascular aneurysm surgery.

Endovascular aneurysm repair (EAR) requires precise measurement of aortoiliac lengths and diameters to select the most suitable endograft. A combination of computed tomography (CT) scanning and contrast arteriography is usually applied for this purpose. We have investigated whether spiral CT angiography with specialized data processing (CTA) may replace these imaging methods as a sole technique for sizing of endografts for EAR and present these data as a background for discussion of preoperative imaging before EAR. Typical measurements for EAR were performed using CTA, conventional CT scanning, and arteriography. The resulting measurements were compared, and their consequences on graft selection were studied. Graft diameters based on arteriography were too small in 62% of the patients, as compared with CTA. The difference in length sizing between CTA and arteriography never exceeded 1 cm. A similar graft diameter was selected by conventional CT scan and CTA in 81% of the patients, whereas minor graft oversizing by conventional CT scan was found in 14% of the patients. Length sizing by conventional CT scanning resulted in underestimation of graft length in 91% of the patients. Neither conventional CT scanning nor arteriography is adequate as a sole preoperative radiological investigation for endograft sizing in EAR. Spiral CTA with special processing combines the specific advantages of both imaging techniques and should be regarded as the method of first choice for this purpose.