Comparison of CT Angiography Using Prospectively ECG-Gated Wide-Volume 320-Row CT and Conventional Helical CT Angiography in the Evaluation of Suspected Aortic Dissection, and the Potential Utility for “Triple Rule-Out” Examinations

Purpose: To compare triple rule-out (TRO) computed tomography (CT) examination and conventional aortic CT angiography (CTA) for imaging aortic dissection (AD), in terms of image quality and radiation exposure. Methods: Patients with suspected AD underwent TRO examination (52 patients) or conventional aortic CTA (50 patients) with a 320-row multidetector CT system operated in the wide-volume or spiral mode, respectively. Image quality and radiation dose were compared between the systems. Results: No differences were found between the groups in their baseline characteristics, except heart rate. For aortic image quality, 100% and 0% of images were rated as "excellent" and "good," respectively, in the TRO group, compared to 50% and 40%, respectively, in the control group. In the TRO group, 80.8% and 19.2% of coronary artery images and 100% and 0% of pulmonary artery images were rated as "excellent" and "good," respectively. Radiation exposures were 1.04 +/- 0.23 versus 1.32 +/- 0.27 mSv in the TRO versus control group. Conclusions: TRO examination using the prospective wide-volume mode of a 320-row multidetector CT can reduce radiation exposure compared to conventional aortic CTA, while achieving the same image quality for the aorta. In addition, TRO examination can exclude other causes of acute chest pain, such as acute coronary syndrome and pulmonary embolism, while identifying AD.