Prospectively gated axial CT coronary angiography: preliminary experiences with a novel low-dose technique

Abstract

To assess image quality and radiation exposure with prospectively gated axial CT coronary angiography (PGA) compared to retrospectively gated helical techniques (RGH). Forty patients with suspected coronary artery disease (CAD) and a stable heart rate below 65 bpm underwent CT coronary angiography (CTCA) using a 64-channel CT system. The patient cohort consisted of 20 consecutive patients examined using a PGA technique and 20 patients examined using a standard RGH technique. Both groups were matched demographically according to age, gender, body mass index, and heart rate. For both groups, two independent observers assessed image quality for all coronary segments on an ordinal scale from 1 (nonassessable) to 5 (excellent quality). Image quality and radiation exposure were compared between patient groups. There were no significant differences in vessel-based image quality between the two groups (P > 0.05). Mean (+/- SD) effective radiation exposure in the PGA group was 3.7 +/- 0.8 mSv compared to 18.9 +/- 3.8 mSv in the RGH group without ECG-based tube current modulation (P < 0.001). Preliminary experience shows PGA technique to be a promising approach for CTCA resulting in a substantial reduction in radiation exposure with image quality comparable to that of standard RGH technique.

Impact of Increasing Levels of Advanced Iterative Reconstruction on Image Quality in Low-Dose Cardiac CT Angiography

“…In this study, a CCTA protocol with optimized dose-related parameters was employed. The estimated mean effective dose (according to ICRP 60) of 1.7 ± 0.7 mSv was in the same range as in previous studies [11]. Using the high-pitch mode on a dualsource CT unit, the mean effective dose for small and averagesized can even be reduced below 1 mSv [23,24].…”

Dose levels at coronary CT angiography—a comparison of Dual Energy-, Dual Source- and 16-slice CT

“…Other studies using low radiation protocols for DSCT coronary angiography found similar results [28][29][30] and on the basis of theoretical considerations a dose reduction of approximately 40% can be expected [31]. However, one disadvantage of CT with lower tube voltage is the parallel increase in image noise [32,33] shows an increase in image noise in cCTA studies obtained at 100 kV in comparison to the standard 120 kV protocol [28,34,35]. Most recently a promising new technique of high pitch spiral acquisition in coronary CT angiography was introduced and showed dose levels around 0,97-2.1 mSv in the initial experience [36,37].…”

Prospectively gated axial CT coronary angiography: comparison of image quality and effective radiation dose between 64- and 256-slice CT

“…Prospectively gated axial CT coronary angiography (CTCA) performed on 64-slice CT provides equivalent or improved image quality compared with helically acquired CTCA while substantially reducing radiation exposure [1][2][3][4]. With temporal resolution limited by single-cycle reconstruction and dependence on predictive gating algorithms, prospectively gated acquisitions require appropriate patient selection with aggressive heart rate control and are typically only indicated for patients with stable heart rates below 65 bpm on 64-slice CT [4,5].…”

“…With temporal resolution limited by single-cycle reconstruction and dependence on predictive gating algorithms, prospectively gated acquisitions require appropriate patient selection with aggressive heart rate control and are typically only indicated for patients with stable heart rates below 65 bpm on 64-slice CT [4,5]. To overcome these limitations, new-generation CT systems with wider detector coverage and faster gantry rotation speeds have recently been introduced.…”