Evaluation of an adaptive detector collimation for prospectively ECG-triggered coronary CT angiography with third-generation dual-source CT
To investigate the impact of an adaptive detector collimation on the dose parameters and accurateness of scan length adaption at prospectively ECG-triggered sequential cardiac CT with a wide-detector third-generation dual-source CT.
Ideal scan lengths for human hearts were retrospectively derived from 103 triple-rule-out examinations. These measures were entered into the new scanner operated in prospectively ECG-triggered sequential cardiac scan mode with three different detector settings: (1) adaptive collimation, (2) fixed 64 × 0.6-mm collimation, and (3) fixed 96 × 0.6-mm collimation. Differences in effective scan length and deviation from the ideal scan length and dose parameters (CTDIvol, DLP) were documented.
The ideal cardiac scan length could be matched by the adaptive collimation in every case while the mean scanned length was longer by 15.4% with the 64 × 0.6 mm and by 27.2% with the fixed 96 × 0.6-mm collimation. While the DLP was almost identical between the adaptive and the 64 × 0.6-mm collimation (83 vs. 89 mGycm at 120 kV), it was 62.7% higher with the 96 × 0.6-mm collimation (135 mGycm), p < 0.001.
The adaptive detector collimation for prospectively ECG-triggered sequential acquisition allows for adjusting the scan length as accurate as this can only be achieved with a spiral acquisition. This technique allows keeping patient exposure low where patient dose would significantly increase with the traditional step-and-shoot mode.
• Adaptive detector collimation allows keeping patient exposure low in cardiac CT.
• With novel detectors the desired scan length can be accurately matched.
• Differences in detector settings may cause 62.7% of excessive dose.
KeywordsMulti-detector CT Adaptive detector collimation Dual-source CT Coronary CT angiography Over-ranging
coronary CT angiography
computed tomography dose index volume
The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Ralf W. Bauer.
Conflict of interest
The authors of this manuscript declare relationships with the following companies: Ralf W. Bauer is on the speakers’ bureau of Siemens Healthcare, Bayer Healthcare and GE Healthcare. The other authors state no conflicts of interest.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Institutional Review Board approval was not required because of phantom study.
Written informed consent was not required for this study because no patient data were handled for this manuscript.
retrospective, experimental, performed at one institution.
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