Anne-Lise Hachulla MD, Presenter: Nothing to Disclose

Jean-Paul Marcel Vallee MD, Abstract Co-Author: Nothing to Disclose

Xavier Montet, Abstract Co-Author: Nothing to Disclose

Stephane Noble, Abstract Co-Author: Nothing to Disclose

Dominique Didier MD, Abstract Co-Author: Nothing to Disclose

To study dose length-products (DLP), image quality and contrast-to-noise ratio (CNR) of thoracic and abdominal gated aortic CT obtained with a high-pitch CT imaging protocol using sinogram-affirmed iterative reconstruction (SAFIRE®) or filtered back projection (FBP) algorithms.

Eighty-four patients underwent gated aortic CT without β-blockers on a Somatom Definition Flash CT scanner for aortic disease with Flash protocol using a pitch of 3.2 with both SAFIRE® and FBP reconstruction algorithms. CNR between vessels and myocardium were calculated on the aorta and the coronary arteries. Two blinded readers graded subjective image quality of the aorta and the coronary arteries on a 3-point scale. Coronary artery stenoses were recorded and compared with coronarography in 24 patients. Kappa values were also calculated.

High-pitch acquisition protocol resulted in a DLP of 234 ±93 mGy.cm(4.2 mSv) for an acquisition of the entire aorta, with a mean heartbeat of 73 ±16 beats per minute. CNR (ascending aorta vs myocardium) was 7.3 ±2.8 and 10.6 ±4 for FBP and SAFIRE® algorithms respectively (p<0.0001). CNR (right coronary vs myocardium) was 6.5 ±3.0 and 9.4 ±4.3 for FBP and SAFIRE® algorithms respectively (p<0.0001). The image quality was graded excellent in 79/84 patients (94%) without motion artifact. Despite relatively high heart rate, the diagnostic quality of proximal and mid-segments of the coronary arteries was graded as excellent in all patients except for the vertical segment of the right coronary artery (non diagnostic in 8/84 patients). 1087/1127 segments of coronary arteries were graded as excellent or moderate but diagnostic. 74 significant stenosis were observed in these segments and 38/40 significant stenosis were confirmed by coronarography (Kappa:0.91, Se:0.97, Sp:0.98).

ECG-gated aortic CT with high-pitch acquisition reconstructed with SAFIRE® allows better CNR than with FBP alone. Despite the lack of β-blockers, proximal and mid-segments of the coronary arteries could be evaluated in the same acquisition.

ECG-gated aortic CT with high-pitch acquisition has the potential to reduce radiation exposure as well as to analyze the whole aorta and the coronary arteries in a single acquisition.

Hachulla, A, Vallee, J, Montet, X, Noble, S, Didier, D, ECG-gated aortic CT using High-pitch and Iterative Reconstruction: Dose and Image Quality—Can Coronary Arteries be Simultaneously Assessed?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045579.html