Tim Weber MD, Presenter: Nothing to Disclose

Hendrik von Tengg-Kobligk MD, Abstract Co-Author: Nothing to Disclose

Marika Ganten MD, Abstract Co-Author: Nothing to Disclose

Philipp Geisbüsch MD, Abstract Co-Author: Nothing to Disclose

Dittmar Böckler, Abstract Co-Author: Nothing to Disclose

Hans-Ulrich Kauczor MD, Abstract Co-Author: Research grant, Siemens AG Research grant, Toshiba Corporation

Endovascular repair of the thoracic aorta is continuously gaining in importance for different aortic pathologies. For adequate selection regarding size and type of endovascular grafts detailed information about dynamic vessel behaviour is required. Aim of this study was to assess time-resolved conformational data of the thoracic aorta in patients with chronic type-B dissection using CTA.

ECG-gated CTA was performed in 10 patients with chronic type-B dissection: collimation 16x1mm, pitch 0.2, slice thickness 1mm, reconstruction increment 0.8mm, inspiratory breath-hold. Aortic cross-sections perpendicular to the centerline were reformatted at relevant surgical levels: ascending aorta (A), proximal (B), distal (C) and 10 cm distal (D) of the left subclavian artery for 20 temporal intervals. Changes in mean diameter, area and eccentricity (a parameter for vessel unrounding) of the proximal aorta (A to C) and the true lumen at D, were examined.

Alterations of mean diameter were as follows: at A 6.4%±1.9% (range from -8.8% to 6.5%), at B 7.3%±3.0% (-5.1% to 5.1%), at C 7.7%±2.0% (-6.3% to 5.5%), and at D 7.9%±5.8% (-11.6% to 11.5%). Mean area changes were: at A by 12.9%±5.3%, at B by 13.5%±5.3%, at C by 13.2%±4.4%, and at D by 18.7%±10.4%. Changes in mean eccentricity ranged from 0.18±0.07 to 0.39±0.07 at A, from 0.24±0.14 to 0.44±0.1 at B, from 0.33±0.17 to 0.49±0.13 at C and from 0.79±0.16 to 0.83±0.16 at D.

Cardiac volume ejection leads to pulsatile alterations of aortic diameter and area that are evenly distributed over the aortic arch. The numerically greater area changes of true lumina in dissected segments are primarily due to excursions rather of the detached intima than of the maximum vessel diameter. Temporally variations of luminal eccentricity indicate a minor unrounding of the vessel contour during the heart cycle.

In patients with thoracic aortic disease considerations of dynamic conformational alterations of the thoracic aorta may be integrated in preoperative selection of endograft design and size.

Weber, T, von Tengg-Kobligk, H, Ganten, M, Geisbüsch, P, Böckler, D, Kauczor, H, Assessment of Thoracic Aortic Conformational Changes by 4D-CTA in Patients with Chronic Type-B Dissection.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5012787.html