Prospective comparison of CT angiography of the legs with intraarterial digital subtraction angiography

The aim of this study was to determine the accuracy of CT angiography (CTA) with a single spiral acquisition for the diagnosis of arterial stenoses and occlusion in patients with peripheral vascular occlusive disease. In a prospective study, intraarterial digital subtraction angiography and i.v. CTA from the groin to the lower calves were performed on 50 patients with vascular occlusive disease. Maximum-intensity-projection images in multiple views were produced. The accuracy of CTA with and without analysis of the axial scans was determined with digital subtraction angiography as the standard. The sensitivities of CTA were 100% for the diagnosis of femoral artery occlusion, 100% for the detection of popliteal artery (including tibial-peroneal arterial trunk) occlusion, and 94% for the detection of tibial artery occlusion. The specificities were 100%, 99%, and 98%, respectively. When maximum-intensity-projection images were interpreted without axial scans, sensitivities were 98%, 85%, and 92% and specificities were 100%, 99%, and 97%, respectively. For the accurate grading of high-grade (75-99%) stenoses of the superficial femoral artery and the popliteal artery (including tibial-peroneal arterial trunk), the sensitivities of CTA were 88% and 73% and the specificities were 94% and 100%, respectively. When maximum-intensity-projection images alone were used, the sensitivities for the correct grading of high-grade stenoses were 58% and 36% and the specificities were 99% and 100%, respectively. CTA from the groin to the lower calves is feasible, and the short examination time is a significantly advantage over the time required for other noninvasive techniques. CTA is particularly accurate in the depiction of femoral artery occlusions. Maximum-intensity-projection images are useful, but analysis of axial scans is more accurate for the grading of arterial stenoses. The results of CTA are encouraging enough to warrant further studies. A CTA protocol covering the pelvic and pedal vessels remains to be established and evaluated.