Abstract P144: The Adoption of Prospective ECG Gating in Cardiac Computed Tomography Angiography Reduces Radiation Exposure

Abstract

INTRODUCTION The mean effective radiation dose values of a conventional cardiac computed tomography angiography (CCTA) can reach 41 millisieverts (mSv). Radiation doses above 10 mSv can cause 1 additional cancer in 1000 patients. Prospective gating reduces radiation exposure during CCTA since the radiation exposure occurs only during a portion of diastole as compared to whole cardiac cycle in conventional CCTA. Effective radiation dose value is a quality measure used across the CCTA centers to determine radiation dose exposure. This aim of this analysis evaluates the impact of this method in reducing radiation dose in real life setting. METHODS This is a non randomized, controlled, prospective study which included 663 consecutive patients that underwent CCTA during 2.5 years at a single center. Prospective ECG gating was employed after June 2008. The main outcome measure was the total effective radiation dose. Image quality was assessed as excellent, good, adequate and non-diagnostic. RESULTS For maintaining homogeniety and comparison of data, patients were divided into 5 cohorts based on 6-month periods in which they were exposed to radiation. The patients did not differ regarding sex, age, BMI, race, Framingham score, diabetes, hyperlipidemia or hypertension (p>0.1) across the cohorts. The image quality did not differ before and afer June 2008 (p>0.3). Radiation dose reduced by 55% after June 2008 with 36% (90 of 251) patients having <8 mSv exposure (Figure). CONCLUSION The study demonstrated that the quality improvement initiative of employing prospective ECG gating in CCTA reduced the radiation dose exposure without compromising the image quality.