Automatic 3D camera positioning in cardiac computed tomography: A phantom study.

作者信息

Hadi Y H, Legoff A, Moore N, Murphy M-J, Sweetman L, Precht H, England A, McEntee M

机构信息

Discipline of Medical Imaging and Radiation Therapy, School of Medicine and Health, University College Cork, Ireland; Department of Medical Imaging and Intervention, King Abdullah Medical City (KAMC), Makkah, Saudi Arabia.

Discipline of Health Engineering, Faculty of Science and Engineering, University Toulouse III - Paul Sabatier, France.

出版信息

Radiography (Lond). 2025 Jul;31(4):102981. doi: 10.1016/j.radi.2025.102981. Epub 2025 May 15.

DOI:10.1016/j.radi.2025.102981

PMID:40378647

Abstract

INTRODUCTION

Cardiac computed tomography angiography (CCTA) is essential for diagnosing coronary artery disease, with accurate positioning critical for optimising image quality (IQ) and radiation exposure. Vertical misalignment can degrade IQ and increase radiation dose. Automatic 3D camera positioning systems claim to improve accuracy and reduce errors, though research on their effectiveness in CCTA remains limited. This study evaluates positioning accuracy, radiation dose, and IQ when using automatic 3D camera positioning in CCTA across scenarios.

METHODS

This prospective phantom study utilised the Multipurpose Chest N1 Phantom (Kyoto Kagaku, Japan) across three body sizes. Positioning variations included supine versus prone, head-first versus feet-first orientations, and various body surface coverings. CT scans were undertaken on a GE Revolution Apex Elite (GE Healthcare, USA) scanner. Vertical offsets from the isocentre were measured using DoseWatch software (GE Healthcare), while radiation dose was quantified through dose-length product (DLP) and Computed Tomography Dose Index (CTDI). IQ was assessed by calculating the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and conspicuity index.

RESULTS

Automatic 3D camera positioning achieved a mean (standard deviation) vertical offset of -1.0 (1.5) mm. Larger phantom sizes were significantly associated with increased off-centring, as indicated by Fisher's exact test (p = 0.004), and greater offsets correlated with higher radiation doses (r = 0.45, p < 0.05). IQ metrics, including SNR and CNR, decreased with increased offsets; SNR dropped from 71. to 50.9, and CNR from 0.2 to -0.6.

CONCLUSION

This study demonstrates that automated 3D camera positioning in CCTA supports radiographers by enhancing positioning accuracy, lowering radiation exposure and improving IQ. Further work should examine the impact of automatic 3D camera positioning within clinical practice.