Maximilian Russe MD, Presenter: Nothing to Disclose

Fabian A. Kari, Abstract Co-Author: Nothing to Disclose

Nadja Maria Kocher, Abstract Co-Author: Nothing to Disclose

Benjamin Fritz MD, Abstract Co-Author: Nothing to Disclose

Gregor Pache MD, Abstract Co-Author: Nothing to Disclose

Mathias F. J. Langer MD, PhD, Abstract Co-Author: Nothing to Disclose

Evaluation of 4D flow MRI to detect alterations in flow parameters in a postoperative setting after ascending aortic aneurysm and/or aortic root repair.

4D flow MRI was performed at 3T MR systems for a prospective study of 12 patients (age 56±13 years) before surgery and of 5 patients within 10 days after surgery. Flow quantification was performed using ECG gated three-directional velocity encoding with full 3D coverage of the thoracic aorta. 4D flow MRI was acquired in a sagittal oblique 3D volume using flip angle of 8°, VENC: 150 cm/s, spatial resolution = (2.0-2,4)³mm³, and temporal resolution: 20-40 ms. Data analysis included 3D blood flow visualization (EnSight, CEI, USA) based on 3D particle traces and 3D streamlines. Time-resolved 2D data was extracted on a plane based queries in the ascending thoracic aorta (TAA) in the aneurysm and the postoperative aortic graft for each dataset. The diameter, net flow, velocity, time to peak (TTP) and percentage of retrograde flow were derived.  

Following changes were shown between the preoperative ascending aorta and the postoperative graft. Slight increase in net flow (TAA: 65.2 (±31.9) ml; graft: 76.5 (±14.7) ml; +17%; p-value=0.5). Increase in mean velocity (TAA: 4.43 (±1.73) cm/s; graft: 19.4 (±2.25) cm/s; +339%; p-value<0.05). Decrease in percentage of retrograde flow (TAA: 19.1 (±13.3)%; graft: 3.6 (±2.2)%; -81% p-value<0.05). Slight decrease in TTP (TAA: 155 (±65) ms; graft: 111 (±14) ms; -28%; p-value=0.18). The mean internal diameter was measured in the TAA with 48.1 (±4.7) mm and in the graft with 29.7 (±2.8) mm (-38%, p<0.05).  

These preliminary results revealed quantifiable hemodynamic changes after surgery for ascending thoracic aortic aneurysms. Significant changes of velocity and retrograde were observed. Only small changes on net flow and TTP could be demonstrated. Further studies are warranted to investigate the influence of the aortic repair on the whole thoracic aorta and evaluate these parameters as a method for early prediction of long time outcome after aortic repair.  

These findings in flow parameters after surgery for ascending thoracic aortic aneurysms are additional quantifiable parameters for the evaluation of the postoperative result.

Russe, M, Kari, F, Kocher, N, Fritz, B, Pache, G, Langer, M, Hemodynamic Changes in the Thoracic Aorta Due to Surgery on Ascending Thoracic Aortic Aneurysms using 4D Flow MRI.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010066.html