Man Ching So MBBS, Presenter: Nothing to Disclose

Wai Leng Chin, Abstract Co-Author: Employee, Siemens AG, Singapore

Chi Ming Wong, Abstract Co-Author: Nothing to Disclose

The purpose of this study was to assess the feasibility and image quality of high pitch scanning on the 2nd generation dual source CT for free-breathing coronary CTA using a single versus double scan protocol.

19 consecutive patients indicated for coronary CTA examinations were evaluated. Inclusion criterion were patients with heart rate <60bpm and could not breath hold. Patients had a single injection of contrast media and were scanned twice using the high pitch prospective ECG-triggered mode with free-breathing. Based on the 18-segment model of the Society of Cardiovascular Computed Tomography the image quality of each coronary segment was assessed by two observers blinded to all clinical results and rated on a four-point scale (Score 1= Excellent, showed no motion artifacts and had clear delineation of the segment; Score 2= Good; showed minor artifacts and mild blurring of the segment; Score 3= Adequate; showed moderate artifacts and moderate blurring without structure discontinuity; Score 4= Not evaluable; showed doubling or discontinuity in the course of the segment, preventing evaluation or vessel structures not differentiable). We compared the results of a single versus double scan protocol.

19 patients with a total of 279 segments were evaluated. Using a double scan mode diagnostic image quality could be achieved in 97% of the coronary segments in the first scan, 95% of the coronary segments in second scan and 100% of the coronary segments using the double scan mode. The mean dose length product was 131mGy.cm for a double scan resulting in an estimated radiation dose of 1.8mSv.

These results showed that a high pitch, double scan protocol improved image quality of coronary CTA in free breathing patients while maintaining a very low effective radiation dose.

Coronary CTA with diagnostic image quality is feasible in patients who cannot breath hold using a dual source CT scanner with high ptich and double scan mode.

So, M, Chin, W, Wong, C, Feasibility of Free-Breathing Coronary CT Angiography with Dual-Source CT at High Pitch: A Single versus Double Scan Protocol.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9005641.html