Application of Dual-layer Detector Spectral Computed Tomography Virtual Non-contrast Scanning in Enhanced Chest Computed Tomography for Children

Objective: This study aimed to explore the feasibility of applying dual-layer detector spectral computed tomography (DLCT) virtual non-contrast (VNC) technology in pediatric enhanced chest CT examinations. Methods: Retrospective analysis was conducted on the enhanced chest CT imaging data and clinical information of 51 children who underwent DLCT scanning at Wuhan Union Hospital. The same processing protocol was applied to each original image. VNC images were obtained using projection space spectral reconstruction from the venous phase spectral base images (SBI) and compared with true non-contrast (TNC) images regarding image quality and radiation dose. Two radiologists measured the CT and SD values of the pulmonary artery trunk, aorta trunk, erector spinae, lung tissue, and subcutaneous fat of the chest wall on image sets, calculating the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Non-contrast, arterial, and venous phase radiation doses were recorded. Subjective image quality scores were assigned using a 5-point Likert scale, and inter-observer consistency was assessed with the Kappa test. The Mann–Whitney U test compared subjective scores, while the paired t-test was used for objective image quality and radiation dose analyses. Results: Objective evaluation of image quality showed no significant statistical differences between the SNR, CNR, and subjective scores of both groups. The median subjective image scores for TNC and VNC were 4 points. The DLP and ED values of the VNC group (298.14±119.40) mGy·cm, (4.27±1.34) mSv were significantly lower than those of the TNC group (437.31±178.28) mGy·cm, (6.26±2.00) mSv. The DLP and ED of the VNC group reduced by 31.82％ and 31.79％, respectively, compared to the TNC group. Conclusion: Spectral CT virtual non-contrast (VNC) images as a substitute for conventional non-contrast (TNC) images in pediatric enhanced chest scans offers satisfactory diagnostic image quality and can significantly reduce radiation dose.