Hans-Christoph Richard F. Becker MD, Presenter: Nothing to Disclose

Udo Hoffmann MD, Abstract Co-Author: Nothing to Disclose

Suhny Abbara MD, Abstract Co-Author: Research Grant, Bracco Group Pending research funded, Becton, Dickinson and Company Consultant, Partners Imaging Consultant, Perceptive Informatics, Inc Consultant, Magellan Health Services, Inc

Mohamed Marwan MD, Abstract Co-Author: Nothing to Disclose

Katharina Anders MD, Abstract Co-Author: Nothing to Disclose

Peter Aulbach, Abstract Co-Author: Employee, Siemens AG

Daniel S. Berman MD, Abstract Co-Author: Research grant, Lantheus Medical Imaging, Inc Research grant, Astellas Group Research grant, Siemens AG Speaker, Bristol-Myers Squibb Company Speaker, Covidien AG Speaker, Astellas Group Stockholder, Spectrum Dynamics Ltd Consultant, Bracco Group Consultant, FlouroPharma, Inc

Michael Marcus Lell MD, Abstract Co-Author: Research grant, Siemens AG Speakers Bureau, Siemens AG Research grant, Bayer AG Speakers Bureau, Bayer AG Research Consultant, Bracco Group

Michael Uder MD, Abstract Co-Author: Nothing to Disclose

Jörg Hausleiter MD, Abstract Co-Author: Nothing to Disclose

Stephan Achenbach MD, Abstract Co-Author: Speakers Bureau, Siemens AG Consultant, SERVIER Research grant, Siemens AG Research grant, Bayer AG

To determine image quality and radiation dose of Dual Source CT (DSCT) coronary angiography without beta blocker medication in a multicenter trial of 415 patients with suspected coronary artery disease (CAD).

At 6 international sites, after exclusion of patients with renal failure, arrhythmias, or an Agatston score >800, 415 patients (61±12 years, 51% male) scheduled for invasive coronary angiography due to suspected CAD were studied with DSCT coronary angiography (Definition or Definition FLASH, Siemens Healthcare). Coronary CT angiography was performed in spiral mode with ECG-based tube current modulation and,100 kV tube voltage for patients < 90kg. No beta blockers were administered to lower heart rate. Contrast agent (iopromide, Ultravist 370, Bayer Healthcare) was injected at a rate of 6 ml/s (mean: 66 ml). CT data were evaluated concerning image quality in a central core laboratory (0 = unevaluable, 1= severe doubts, 2= artefacts, confident evaluation; 3 = slight artefact, fully evaluable; 4 = no artefact). As a further measure of image quality, the ability of DSCT to identify patients requiring revascularization was assessed.

Mean and maximum heart rate during DSCT was 67±20 and 72±20 bpm. Mean DLP was 424±237 mGy*cm (5.9 mSv). Mean image quality score of all 5777 segments was 3.7±0.7 with 0.3% of segments rated “unevaluable” (score 0), 0.4% score 1; 7.3% score 2; 19% score 3, and 74% score 4. Mean image quality (3.8±0.6 vs. 3.5±0.7; p = 0.5), and number of patients with at least one unevaluable segment (1.8% vs. 1.0%, p = 0.1) were not different for 212 patients with a heart rate ≤65 bpm and 213 patients >65bpm, but more segments had score “4” for heart rates ≤65bpm (83% vs. 63%, p<0.001). Sensitivity and specificity for identifying 83 patients who subsequently underwent revascularization were 95 % and 91%,

In the largest multicenter trial to date, DSCT coronary angiography without the use of beta blockers to lower heart rate provided high image quality and high accuracy to identify individuals requiring revascularization. Radiation dose was reasonably low even though no specific low-dose protocols were used.

DSCT coronary angiography without beta blockers provides high image quality with resonable low radiation exposure

Becker, H, Hoffmann, U, Abbara, S, Marwan, M, Anders, K, Aulbach, P, Berman, D, Lell, M, Uder, M, Hausleiter, J, Achenbach, S, Image Quality and Radiation Exposure of Dual-Source CT Coronary Angiography in Spiral Mode without Heart Rate Lowering in Patients with Suspected Coronary Artery Disease: Results of the International Multicenter MEDIC Trial.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014424.html