Felix G. Meinel MD, Presenter: Nothing to Disclose

Konstantin Nikolaou MD, Abstract Co-Author: Speakers Bureau, Siemens AG Speakers Bureau, Bracco Group Speakers Bureau, Bayer AG

Rolf Weidenhagen, Abstract Co-Author: Nothing to Disclose

Katharina Hellbach, Abstract Co-Author: Nothing to Disclose

Andreas Dietrich Helck MD, Abstract Co-Author: Nothing to Disclose

Fabian Bamberg MD, MPH, Abstract Co-Author: Speakers Bureau, Bayer AG Speakers Bureau, Siemens AG Research Grant, Bayer AG Research Grant, Siemens AG

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Wieland H. Sommer MD, Abstract Co-Author: Nothing to Disclose

We performed this study to assess feasibility and additional diagnostic value of time-resolved CT angiography of the entire aorta in patients with aortic dissection.

14 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 48cm, time resolution 6s, 6 phases, 100kV, 110mAs/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.

Mean 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.

Multiphasic, 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.

Important complications of aortic dissection such as dynamic occlusion of aortic branches or true lumen collapse are not adequately visualized with standard CTA protocols.

Meinel, F, Nikolaou, K, Weidenhagen, R, Hellbach, K, Helck, A, Bamberg, F, Reiser, M, Sommer, W, Time-resolved CT Angiography in Aortic Dissection.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12031112.html