SPIRAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF THE RENAL-ARTERIES - A PROSPECTIVE COMPARISON WITH INTRAVENOUS AND INTRAARTERIAL DIGITAL SUBTRACTION ANGIOGRAPHY

Purpose: To assess the accuracy of computed tomographic angiography (C TA) in the evaluation of the renal arteries in comparison with intrave nous (IVDSA) and intraarterial digital subtraction angiography (IADSA) . Methods: In 18 patients, 35 CTAs and DSAs (27 IADSA, 8 IVDSA) of the renal arteries were performed. CTA was done with 2-3 mm collimation, 2-4 mm/sec table speed, after intravenous injection of 80 mi of contra st medium at 4 ml/sec with a scanning delay time of 14-21 sec. No prev ious circulation time curve was performed. CTA data were reconstructed with maximum intensity projection (MIP) and shaded surface display (S SD). The presence of stenosis was assessed on a three-point rating sca le (grade 1-3). The quality of the examinations; visualization of the ostium, the main artery, and its branches; vessel sharpness, linearity , and intraluminal contrast filling were evaluated. We compared CTA wi th DSA. Results: CTA had 96% sensitivity, 77% specificity, and 89% acc uracy in the detection of stenoses > 50%. Due to technical errors two stenoses were erroneously diagnosed as positive but there were no fals e negative diagnoses. The quality of CTA was good in 56% and moderate in 34% of cases. Visualization of the ostium and main artery was grade d as 1.74 (out of 2) points and of the renal branches as 1.02 (out of 2) points. The quality of CTA images was worse than that of IADSA in 5 2%, equal in 41%, and better in 7% of cases. CTA was equal to IVDSA in 25% and better in 75% of the cases. Conclusion: CTA is an accurate no ninvasive method for the evaluation of renal arteries. Examination qua lity is essential for the diagnosis. CTA is limited in its ability to visualize the branches of the renal artery and accessory arteries. CTA seems to be superior to IVDSA.