135 In vivo reduction of radiation exposure with a single-source coronary CT angiography: effects of optimal parameters settings in real life conditions

BackgroundCoronary computed tomographic angiography (CCTA) has become a key diagnostic exam for coronary artery disease (CAD); however, radiation exposure as a result of the exam has been deemed too high.ObjectivesThe purpose of this study was to assess the feasibility of in vivo radiation reduction using optimal parameters during a CCTA with a single source 64-slice computed tomography (CT): General Electric Healthcare VCT XT.MethodsAcquisition of 137 consecutive patients for examination of native coronary arteries with suspected CAD was performed with optimized parameters. Prospective acquisition mode, called snap shot pulse (SSP), was performed when a heart rate under 65 bpm was obtained, retrospective acquisition mode was used otherwise. Coronary artery segments were systematically analyzed. Stenosis of 50% or more were considered as obstructive.ResultsExamination of all segments was feasible. Mean dose length product (DLP) of 56+/-22.2 mGy.cm (0.7+/-0.3 mSv) with SSP (n=117) was significantly lower than mean DLP of retrospective acquisition mode: 532 +/-130.8 mGy.cm (7.4 +/- 1.8 mSv) (n=20), p<0.0001. Compared to conventional coronary angiography, SSP significantly reduced irradiation exposure with respectively 8.54 +/- 2.16 mSv versus 0.87 +/- 0.42 mSv in 13 patients, p