Evaluation of abdominal aortic aneurysm for endovascular stent-grafting with volume-rendered CT images of vessel lumen and thrombus.

PURPOSE To evaluate the accuracy of CT images of abdominal aortic aneurysm (AAA) with volume-rendered (VR) display of vessel lumen and thrombus and to evaluate its usefulness in the planning of stent-grafting. MATERIALS AND METHODS Helical CT was performed in 11 patients with AAA. Volume data of the vessel lumen and thrombus were separately extracted, and the VR images were reconstructed. Vessel measurements were made by five radiologists and compared with the axial and multiplanar reconstruction (MPR) images. Angiography and intravascular ultrasonography were used as standard references. The relations of aneurysmal sac to the major arterial branches and the subjective overall diagnostic value were evaluated by using a continuous rating scale. RESULTS Accuracy of measurements was higher on VR images than on axial/MPR in 7 of 13 regions. Interobserver variance of VR images was smaller in 7 of 14 regions. Detection of renal and internal iliac artery involvements was better on VR images (p<0.05). Overall diagnostic value was also higher on VR images (p<0.05). CONCLUSION VR CT images of vessel lumen and thrombus are supportive of and supplementary to conventional axial/MPR images in planning stent-grafting for AAA.