CT ANGIOGRAPHY IN CAROTID STENOSIS

Purpose: Prospective evaluation of the accuracy of CT angiography (CTA ) with different postprocessing for extracranial carotid artery in com parison with DSA. Method: one hundred patients were studied with stand arized CTA. For postprocessing, MPR, MIP, and 3D reconstruction based on segmentation with upper and lower threshold were used. Intravascula r density profiles were considered. All CTA studies were correlated wi th intra-arterial angiography. The degree and classification of stenos es was determined using the guidelines established by the NASCET colla borators. Results: Measurement of stenosis was possible by MPR in 82.5 %, by MIP in 85 %, and 3D in 100 %. Correct classification was found i n 65.5 % for MPR, 66 % for MIP and 88.5 % for 3D. The sensitivity for severe stenoses was 74% for MPR, 82 % for MIP, and 93 % for 3D. The sp ecificity of these methods was 98 %, 96 %, and 97 %, respectively. All carotid occlusions were correctly identified, no carotid artery was w rongly classified as occluded. Conclusions: CT angiography allows reli able examinations in carotid artery stenoses and occlusions. 3D recons truction based on threshold segmentation is superior to MPR and MIP. I n some circumstances, e.g., carotid occlusion, further investigation b y invasive procedures is not necessary.