Coronary CT radiation dose reduction strategies at an Australian Tertiary Care Center – improvements in radiation exposure through an evidence‐based approach

Abstract

Introduction Coronary CT Angiography (CCTA) is a rapidly increasing technique for coronary imaging; however, it exposes patients to ionising radiation. We examined the impact of dose reduction techniques using ECG‐triggering, kVp/mAs reduction and high‐pitch modes on radiation exposure in a large Australian tertiary CCTA service. Methods Data on acquisition modes and dose exposure were prospectively collected on all CCTA scans from November 2009 to March 2014 at an Australian tertiary care centre. A dose reduction algorithm was developed using published techniques and implemented with education of medical staff, radiographers and referrers. Associations of CCTA acquisition to radiation over time were analysed with multivariate regression. Specificity in positive CCTA was assessed by correlation with invasive coronary angiography. Results 3333 CCTAs were analysed. Mean radiation dose decreased from 8.4 mSv to 5.3, 4.4, 3.7, 2.9 and 2.8 mSv (P < 0.001) per year. Patient characteristics were unchanged. Dose reduction strategies using ECG‐triggering, kVp/mAs reduction accounted for 91% of the decrease. High‐pitch scanning reduced dose by an additional 9%. Lower dose was independently related to lower kVp, heart rate, tube current modulation, BMI, prospective triggering and high‐pitch mode (P < 0.01). CCTA specificity remained unchanged despite dose reduction. Conclusion Implementation of evidence‐based CCTA dose reduction algorithm and staff education programme resulted in a 67% reduction in radiation exposure, while maintaining diagnostic specificity. This approach is widely applicable to clinical practice for the performance of CCTA.

Effect of Body Mass Index in Coronary CT Angiography Performed on a 256-Slice Multi-Detector CT Scanner

“…In this study, the CTDI vol for BMI < 25 and ≥25 kg/m 2 were 20.03 and 24.83 mGy, respectively, which are consistent with previous reports [ 25 , 26 ]. Over the past decades, various dose reduction strategies have been proposed for CCTA scans [ 27 , 28 ].…”

Estimation of Effective Dose in Monte Carlo Simulation Method for CT Coronary Angiography Patients

“…Recent research using ECG-based tube current modulation and dualsource CT coronary angiography revealed radiation dose values ranging from 7 to 9 mSv 13 . In this study, when it represented the effective dose graphically for the two hospitals, it found that the effective doses for males (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) mSv were lower than females (13-29) mSv; this result was presented in Figure-3 for both the hospitals (X) and (Y). This difference in effective doses for males and females may be due to differences in tissue composition and weight.…”

Impact of an ultra-low dose unenhanced planning scan on CT coronary angiography scan length and effective radiation dose

“…Several radiation dose reduction techniques have been introduced in recent years in CTCA including prospective ECG-triggered scanning, heart rate control, reduced tube voltage and tube current modulation. 5 This has resulted in rapid improvements in the reduction of radiation dose from CTCA; the British Society of Cardiovascular Imaging and the British Society of Cardiac Computed Tomography conducted an audit of radiation dose from coronary CT angiography in 2014 and 2016. In the 2-year interval, they identified a 30% reduction in the median exam DLP for prospective ECG-gated acquisitions with tube current padding.…”

“… 4 There are several ways to reduce effective dose from CTCA investigations including prospective ECG triggered scanning, heart rate control, tube current modulation, optimised contrast monitoring, iterative reconstruction, and high pitch scanning. 5,6 …”