Total effective radiation dose attributable to medical imaging in patients with acute chest pain: A single-center comparison study between dual-source coronary CT angiography and usual care

Introduction: Coronary CT angiography (CCTA) can safely disposition low to intermediate risk chest pain (CP); however, there is conflicting data with respect to cumulative radiation exposure when compared with usual care over short follow-up intervals. Objectives: We report the effective radiation dose from index and downstream testing in low to intermediate risk symptomatic patients evaluated for chest pain in the ED with either CCTA or usual care to define various sources of patient radiation dose and quantify effective dose over a year and a half of follow-up. Patients and Methods: We evaluated radiation exposure from initial and downstream testing in a prospectively collected, matched cohort evaluated for CP in the emergency department (ED) with either CCTA compared with usual care over a median follow-up of 19.6 months. Effective radiation dose was calculated using published conversion factors. Results: Prospective, ECG-triggered acquisition using a 128-slice dual-source multidetector computed tomography (DSCT) scanner was performed in 92.9% of scans with a median effective dose from CCTA of 6.8 mSv (IQR 5.2, 9.1 mSv). CCTA cohort patients were more likely to undergo cardiac testing with exposure to radiation (P < 0.001); however, the median effective dose in patients exposed to radiation from cardiac testing was significantly lower in the CCTA cohort (7.1 mSv vs. 11.8 mSv, P < 0.001). Fewer patients in the CCTA cohort had additional non-cardiac thoracic imaging radiation exposure (40.8%) compared with usual care (92.8%). Total radiation exposure from any source was similar between the CCTA and usual care groups (100% vs 98.4%, P = 0.087), as was median total effective radiation dose (P = 0.105). Upfront CCTA was not associated with higher rates of incidental non-cardiac findings. Conclusions: Initial evaluation of acute chest pain in the ED with CCTA was not associated with an increase in total radiation exposure over a follow-up period of 19 months. CCTA offers a more comprehensive evaluation of multiple thoracic organ systems leading to reduced radiation exposure from non-cardiac thoracic testing and no increase in incidental imaging findings. This may represent an added benefit in this population of patients presenting acutely.