CAROTID-ARTERY STENOSIS - OPTIMIZATION OF CT ANGIOGRAPHY WITH A COMBINATION OF SHADED SURFACE DISPLAY AND SOURCE IMAGES

PURPOSE: To evaluate the accuracy of CT angiography of occlusive disea se of the carotid arteries using three-dimensional surface-rendered im ages alone and in conjunction with display of axial source images. MET HODS: Forty-eight symptomatic patients had conventional angiography fo llowed by CT angiography within 24 hours. Images of 96 carotid arterie s were acquired using contrast-enhanced spiral CT. Image postprocessin g was performed on a free-standing workstation to produce 3-D shaded s urface display (SSD) images. Two readers independently evaluated the C T angiographic (SSD) images and then reevaluated each case while simul taneously reviewing the SSD and axial source images. Digital subtracti on angiograms were evaluated in a separate session and eventually comp ared with CT angiograms. All evaluations were performed under blinded conditions to control for reader bias. RESULTS SSD images alone undere stimated stenosis relative to angiograms whereas combined SSD and axia l images did not. CONCLUSION: SSD angiograms in conjunction with the s ource images are better than SSD images alone in estimating the degree of stenosis in carotid artery disease.