USEFULNESS OF A PROTOTYPE INTRAVASCULAR ULTRASOUND IMAGING IN EVALUATION OF AORTIC DISSECTION AND COMPARISON WITH ANGIOGRAPHIC STUDY, TRANSESOPHAGEAL ECHOCARDIOGRAPHY, COMPUTED-TOMOGRAPHY, AND MAGNETIC-RESONANCE-IMAGING

The aim of this study was to evaluate the accuracy of information obta ined with a prototype intravascular ultrasound (IVUS) system in chroni c aortic dissection by comparing results with angiography, transesopha geal echocardiography (TEE), computed tomography, or magnetic resonanc e imaging. We assigned 15 patients to IVUS imaging after they underwen t angiography. The detection rate of the intimal flap was 100% in all segments of the aorta, and the detection rate of the intimal tear was 0%, 50%, 50%, and 77.8% in the ascending, arch, descending, and abdomi nal aorta, respectively. IVUS demonstrated 100% of the celiac and rena l arteries, and 80% of the superior mesenteric arteries as well as the ir relation to dissection. It clarified the origin of 12 of 60 main ab dominal branches (20%) which were not clear on the angiogram. It also determined the distal extent of the dissection in all cases. With rega rd to the size of the vessel, there was a good correlation between IVU S and computed tomographic values (r = 0.98, p < 0.01). No complicatio ns occurred in any patient. IVUS accurately demonstrated thrombus or s pontaneous echo contrast in the false lumen that was confirmed with co mputed tomography or TEE, or both. It was especially useful in evaluat ing the abdominal aorta with regard to determining the size of the ves sel, the extent of dissection, the relation of the branches to the fal se lumen, and the detection of intimal tears-important information for follow-up of patients and for planning surgery. IVUS proved to be an accurate, useful, and safe method for confirming, clarifying, or even adding new information to the other diagnostic tools in the evaluation of aortic dissection.