CT ANGIOGRAPHY FOR PERIPHERAL OCCLUSIVE V ASCULAR-DISEASE - COMPARISON OF 3 RENDERING TECHNIQUES

Purpose: To evaluate different rendering techniques of CT data for the assessment of long vessel segments in peripheral vascular occlusive d isease. Material and methods: 40 CT angiograms (aortoiliac: n=20, leg arteries: n=20) were viewed using three different rendering techniques : 1, maximum intensity projection (MIP); 2, volume rendering (VR); 3, shaded surface display (SSD). CT angiograms were obtained in 6 or 8 pr ojections. Axial cross-section images were analysed using an interacti ve cine mode. Intraarterial DSA was the standard in all cases. Results : The sensitivities for the diagnosis of occlusive disease were 100% ( cross-section images), 94% (MIP), 91% (VR) and 93% (SSD). The specific ities were 100%, 99%, 99% and 99%, respectively. For the accurate grad ing of high-grade (> 75%) stenoses, the sensitivities were 85% (cross- section images), 62% (MIP), 44% (VR) and 35% (SSD). Specificity was 99 % for all techniques. Conclusions: CTA is accurate in occlusive diseas e. Interactive viewing of cross-section images is the most accurate te chnique. Min is superior to VR in the imaging of high-grade stenoses b ecause contrast-to-noise ratio is high and thresholding is not necessa ry.