Die Bedeutung der 64-Zeilen-Dual-Energy-CT-Angiographie in der Diagnostik von pAVK-Patienten mit kritischer Extremitätenischämie und/oder schweren Claudicatio Beschwerden: Ein Vergleich der Maximum-Intensity-Projektionen mit dem Goldstandard der Digitalen Subtraktionsangiographie

The purpose of this study was to evaluate the diagnostic accuracy of dual-energy 64-row computed tomography angiography (CTA) in patients with symptomatic lower extremity peripheral arterial occlusive disease or critical limb ischemia, compared with conventional digital subtraction angiography (DSA) serving as the reference standard. DSA and CTA were consecutively performed in 94 patients (representing 99 examinations and 198 cases). Classification of stenosis (normal, mild, moderate, severe, occluded), extent of calcification, image quality und artifacts were visually observed in maximum intensity projections (MIPs) and cross-sectional images by two radiologists and in DSA images by a third radiologist. For this dissertation only the MIP scores were used and compared to the DSA scores. Accuracy, sensitivity and specificity were calculated per extremity, per region and for all arteries. Agreement between CTA scorers was evaluated by a Cohen kappa statistic. Of 198 cases 111 were assessable on both DSA and CTA. Sensitivity and specificity of CTA were 100 % / 95 % (two scorers) and 58 % / 42 % detecting significant stenosis per leg. The agreement between both CTA readers was good. Calcification levels and the localisation of the stenosis showed a significant effect on detecting the correct grade of stenosis. In the pelvic region, the high degree of calcifications lead to difficulties in the evaluation. In the crural and pedal region, the proximity between calcified vessels and bony structures caused suboptimal results for the specificity. In conclusion the MIPs oft he 64-row dual-energy CTA are reliable for classification of significant stenosis in patients with suspected peripheral arterial occlusive disease. Considering the good results of this study, future developments, such as high-pitch-acquisition-modus and dynamic-CTA, promise excellent results.