• Felix G Meinel, Konstantin Nikolaou, Rolf Weidenhagen, Katharina Hellbach, Andreas Helck, Fabian Bamberg, Maximilian F Reiser, and Wieland H Sommer.
• Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany. felix.meinel@med.uni-muenchen.de
• Eur J Radiol. 2012 Nov 1; 81 (11): 3254-61.

ObjectivesWe performed this study to assess feasibility and additional diagnostic value of time-resolved CT angiography of the entire aorta in patients with aortic dissection.Materials And Methods14 consecutive patients with known or suspected aortic dissection (aged 60±9 years) referred for aortic CT angiography were scanned on a dual-source CT scanner (Somatom Definition Flash; Siemens, Forchheim, Germany) using a shuttle mode for multiphasic image acquisition (range 48 cm, time resolution 6s, 6 phases, 100 kV, 110 mAs/rot). Effective radiation doses were calculated from recorded dose length products. For all phases, CT densities were measured in the aortic lumen and renal parenchyma. From the multiphasic data, 3 phases corresponding to a triphasic standard CT protocol, served as a reference and were compared against findings from the time-resolved datasets.ResultsMean effective radiation dose was 27.7±3.5 mSv. CT density of the true lumen peaked at 355±53 HU. Compared to the simulated triphasic protocol, time-resolved CT angiography added diagnostic information regarding a number of important findings: the enhancement delay between true and false lumen (n=14); the degree of membrane oscillation (n=14); the perfusion delay in arteries originating from the false lumen (n=9). Other additional information included true lumen collapse (n=4), quantitative assessment of renal perfusion asymmetry (n=2), and dynamic occlusion of aortic branches (n=2). In 3/14 patients (21%), these additional findings of the multiphasic protocol altered patient management.ConclusionsMultiphasic, time-resolved CT angiography covering the entire aorta is feasible at a reasonable effective radiation dose and adds significant diagnostic information with therapeutic consequences in patients with aortic dissection.Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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