To evaluate feasibility, image quality and radiation dose of CCTA in obese patients using new generation 256-MDCT.

Thirty consecutive obese patients (Body Mass Index (BMI)>30) undergoing CCTA on a 256-MDCT (Revolution CT, General Electric) were retrospectively included. Prevalence and impact on diagnosis of motion and step artifacts were independently evaluated by two experienced readers using a 3-point scale (0: no artifact; 1: artifacts without interference on diagnosis; 2: artifacts interfere with diagnosis) and percentage of assessable coronary segments was calculated. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were measured for quantitative assessment. Radiation dose was evaluated by calculating the mean effective dose (ED).

Mean BMI was 36.0±5.9kg/m ² with a mean HR of 91.4.0±48.9 bpm. Mean injected contrast volume (Iohexol 350) was 73.0±11.2mL. On a per-patient analysis, all the coronary segments were assessable in 29 (97%) patients. Only 2 coronary segments were not assessable in 1 patient due to motion arte-facts resulted in a coronary segments assessability of 99.6% (455/457 segments) in the overall population. No step artifact was observed whereas motion arte-facts (3-point scale score of 0.27±0.9) were infrequent and do not interfere with diagnosis. The mean CNR and mean SNR were respectively 10.0±2.6 and 11.1±2.0. ED remains low with an average of 2.71±1.6 mSv.

CCTA is feasible in obese patients using a new generation 256-MDCT providing good image quality and low radiation dose in this challenging population.