Use of automatic exposure control in multislice computed tomography of the coronaries: comparison of 16-slice and 64-slice scanner data with conventional coronary angiography

Abstract

Objective: To evaluate the radiation-dose-reduction potential of automatic exposure control (AEC) in 16-slice and 64-slice multislice computed tomography (MSCT) of the coronary arteries (computed tomography angiography, CTA) in patients. The rapid growth in MSCT CTA emphasises the necessity of adjusting technique factors to reduce radiation dose exposure. Design: A retrospective data analysis was performed for 154 patients who had undergone MSCT CTA. Group 1 (n = 56) had undergone 16-slice MSCT without AEC, and group 2 (n = 51), with AEC. In group 1, invasive coronary angiography (ICA) had been performed in addition. Group 3 (n = 47) had been examined using a 64-slice scanner (with AEC, without ECG-triggered tube current modulation). Results: In group 1, the mean (SD) effective dose (ED) for MSCT CTA was 9.76 (1.84) mSv and for ICA it was 2.6 (1.27) mSv. In group 2, the mean ED for MSCT CTA was 5.83 (1.73) mSv, which signifies a 42.8% dose reduction for CTA by the use of AEC. In comparison to ICA, MSCT CTA without AEC shows a 3.8-fold increase in radiation dose, and the radiation dose of CTA with AEC was increased by a factor of 1.9. In group 3, the mean ED for MSCT CTA was 13.58 (2.80) mSV. Conclusions: This is the first study to show the significant dose-reduction potential (42.8%) of AEC in MSCT CTA in patients. This relatively new technique can be used to optimise the radiation dose levels in MSCT CTA. R apid advances in multislice computed tomography (MSCT) imaging technology have substantially improved the diagnostic accuracy of non-invasive coronary artery imaging, leading to increasing numbers of MSCT computed tomography angiography (CTA) investigations. The increasing relevance of this investigation in clinical routine emphasises the necessity of looking into radiation dose exposure. To attain a radiation dose as low as reasonably achievable a new technique providing an automatic exposure control (AEC) and tube current modulation has recently been introduced to most stateof-the-art MSCT equipment. The aim of this study is to evaluate the dose-reduction potential of this new technique for MSCT CTA.

Low kilovoltage cardiac dual-source CT: attenuation, noise, and radiation dose

“…The CNR (mean CNR of the LMA and RCA) was significantly higher for the 100-kV protocols (100 kV, 330mAs: 25 Fig. 2c).…”

“…Another approach to tube current modulation was introduced into CTCA studies that accounts for the differences in body shape and density by automatically adjusting the tube current to the size and attenuation of the body region (i.e., CareDose 4D) [25]. The authors reported RCA Right coronary artery, LMA left main artery, CNR contrast-to-noise ratio a radiation dose reduction potential of 42.8% in a dedicated CTCA protocol.…”

Detection of Relevant Coronary Artery Disease Using Dual-Source Computed Tomography in a High Probability Patient Series Comparison With Invasive Angiography

“…Tube current was 360 mA, and tube voltage was 120 kV for both tubes. In accordance with previously published studies for dose reduction algorithms, [15][16][17] ECG-gated tube current modulation and automatic radiation exposure control were both used in all patients, and the pulsing window was fixed from 65% to 70% of the RRcycle with heart rates <70 bpm, or from 40% to 70% of the RR-cycle with heart rates >70 bpm.…”

Role of Cardiac Multidetector Computed Tomography in Acute Ischemic Stroke: A Preliminary Report

“…Reported data show that the radiation dose of 64-slice cardiac MDCT with 120 kVp could be as much as 14–15 mSv [27,28]. The delivered radiation dose of our study was estimated to be 7–11 mSv for early, ECG-gated imaging and 1.5–2.6 mSv for delayed, nongated imaging.…”