Observational Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Oct 28, 2018; 10(10): 135-142
Published online Oct 28, 2018. doi: 10.4329/wjr.v10.i10.135
Low-radiation and high image quality coronary computed tomography angiography in “real-world” unselected patients
Caryl Elizabeth Richards, Stephen Dorman, Patricia John, Anthony Davies, Sharon Evans, Tishi Ninan, David Martin, Sriranj Kannoly, Gail Roberts-Davies, Mark Ramsey, Daniel Rhys Obaid
Caryl Elizabeth Richards, Daniel Rhys Obaid, Swansea University Medical School, Swansea University, Grove Building, Singleton Park, Sketty, Swansea SA2 8PP, United Kingdom
Stephen Dorman, Mark Ramsey, Daniel Rhys Obaid, Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
Patricia John, Anthony Davies, Sharon Evans, Tishi Ninan, Department of Radiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom
David Martin, Gail Roberts-Davies, Department of Radiology, Singleton Hospital, Sketty Ln, Sketty, Swansea SA2 8QA, United Kingdom
Sriranj Kannoly, Department of Cardiology, Singleton Hospital, Sketty Ln, Sketty, Swansea SA2 8QA, United Kingdom
Author contributions: Obaid DR designed the study; all authors performed the research; Richards CE analyzed the data and wrote the paper; Obaid DR revised the manuscript for final submission.
Institutional review board statement: As the study involved no deviation from standard treatment protocols and no randomization it was not considered “research requires ethical approval” by the NHS Research authority tool.
Informed consent statement: As this study does not involve patient randomization or any deviation from standard treatment protocols and as it was deemed “non - research” by the NHS Health Research Authority tool no informed consent forms were used
Conflict-of-interest statement: None of the authors have any conflicts of interest or financial disclosure related to this study.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Daniel Rhys Obaid, PhD, Associate Professor, Department of Cardiology, Morriston Hospital, Heol Maes Eglwys, Morriston, Cwmrhydyceirw, Swansea SA6 6NL, United Kingdom. daniel.obaid@wales.nhs.uk
Telephone: +44-1792-704123 Fax: +44-1792-704149
Received: April 30, 2018
Peer-review started: April 30, 2018
First decision: June 6, 2018
Revised: August 14, 2018
Accepted: October 8, 2018
Article in press: October 8, 2018
Published online: October 28, 2018
Abstract
AIM

To determine the radiation dose and image quality in coronary computed tomography angiography (CCTA) using state-of-the-art dose reduction methods in unselected “real world” patients.

METHODS

In this single-centre study, consecutive patients in sinus rhythm underwent CCTA for suspected coronary artery disease (CAD) using a 320-row detector CT scanner. All patients underwent the standard CT acquisition protocol at our institute (Morriston Hospital) a combination of dose saving advances including prospective electrocardiogram-gating, automated tube current modulation, tube voltage reduction, heart rate reduction, and the most recent novel adaptive iterative dose reconstruction 3D (AIDR3D) algorithm. The cohort comprised real-world patients for routine CCTA who were not selected on age, body mass index, or heart rate. Subjective image quality was graded on a 4-point scale (4 = excellent, 1 = non-diagnostic).

RESULTS

A total of 543 patients were included in the study with a mean body weight of 81 ± 18 kg and a pre-scan mean heart rate of 70 ± 11 beats per minute (bpm). When indicated, patients received rate-limiting medication with an oral beta-blocker followed by additional intravenous beta-blocker to achieve a heart rate below 65 bpm. The median effective radiation dose was 0.88 mSv (IQR, 0.6-1.4 mSv) derived from a Dose Length Product of 61.45 mGy.cm (IQR, 42.86-100.00 mGy.cm). This also includes what we believe to be the lowest ever-reported radiation dose for a routine clinical CCTA (0.18 mSv). The mean image quality (± SD) was 3.65 ± 0.61, with a subjective image quality score of 3 (“good”) or above for 93% of patient CCTAs.

CONCLUSION

Combining a low-dose scan protocol and AIDR3D with a 320-detector row CT scanner can provide high quality images at exceptionally low radiation dose in unselected patients being investigated for CAD.

Keywords: Effective radiation dose, Tube voltage, Tube current, Iterative reconstruction, Coronary computed tomography angiography, Image quality, Prospectively electrocardiogram gating

Core tip: Coronary computed tomography angiography (CCTA) is now widely used in the diagnosis of coronary artery disease since it is a rapid, minimally invasive test with high diagnostic accuracy. To meet the demands for increasing spatial and temporal resolution of CT images, a number of dose saving algorithms have been implemented to CCTA to minimise radiation exposure to “as low as reasonably achievable” without compromising diagnostic image quality. This study demonstrates that advances in CT scanner hardware and reconstruction software allow ultra-low dose of radiation with high image quality in routine clinical examination of real-world patients.