Daniela Muenzel, Presenter: Nothing to Disclose

Peter B. Noel MS, Abstract Co-Author: Nothing to Disclose

Franziska Dorn, Abstract Co-Author: Nothing to Disclose

Martin Dobritz MD, Abstract Co-Author: Nothing to Disclose

Ernst J. Rummeny MD, Abstract Co-Author: Nothing to Disclose

Armin Michael Huber MD, Abstract Co-Author: Nothing to Disclose

To evaluate the effect of heart rate and heart rate variability on stairstep and motion artifacts in coronary CT angiography (CCTA) with prospective ECG-gating at a 256- slice CT scanner.

60 patients underwent CTCA using a step-and-shoot mode with prospectively ECG-gating at a 256-slice CT scanner (Brilliance iCT, Philips). Heart rate during CT scan was registered. Variability of heart rate was defined by the difference of maximum and minimum heart rate during the scan. Motion artifacts were quantified using a 5-point scale with 1 point indicating no motion artifacts whereas coronary segments rated with 5 points were considered nondiagnostic. Stairstep artifacts between single CT scans were defined as misalignment of continuous cardiac structures (e.g. myocardium, coronary arteries), quantified by measurement of lateral off-set in coronal CT slices of raw data. Regression analysis was performed.

Mean heart rate during the CT scans varied between 45 and 125 beats per minute (mean 66 bpm, SD 16.7). Mean variability of heart rate was 10.7 bpm (SD 17.5). An increase of heart rate correlated with an increase of stairstep artifacts (r=0.43, p<0.001) and motion artifacts (r=0.40, p<0.05). An excellent image quality with a small lateral off-sets (mean value 0.4 mm) on uncorrected images was achieved using a threshold of 65/min (n=32). A pulse rate higher than 65/min (n=28) caused significantly increased step artifacts with a mean lateral off-set of 1.4 mm (p<0.01). Motion artifacts were significantly higher in patients with high heart rates (>65 bpm) compared to patients with low heart rates (mean image quality score: 1.3 vs. 1.7) , p<0.0001. There was no significant effect of heart rate variability on stairstep or motion artifacts (p > 0.05).

Stairstep and motion artifacts caused by heart motion during single CT scan steps gain in importance with increase of heart rate. Heart rate variability during the scan has no significant effect on motion and stairstep artifacts at CCTA using a 256-slice CT scanner.

Stairstep and motion artifacts depend on heart rate but not on heart rate variability during CCTA examination on a 256-slice CT scanner.

Muenzel, D, Noel, P, Dorn, F, Dobritz, M, Rummeny, E, Huber, A, CT Coronary Angiography at a 256-Slice CT Scanner: Effect of Heart Rate and Heart Rate Variability on Image Quality.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008671.html