Abdominal virtual non-contrast images derived from energy spectrum CT to evaluate chemotherapy-related fatty liver disease

BACKGROUND: Chemotherapy-related fatty liver disease (CRFLD) is an important evaluation in patients undergoing computed tomography (CT) for cancer follow-up. This study set out to explore the feasibility of using abdominal virtual non-contrast (VNC) images derived from energy spectrum CT to evaluate CRFLD and reduce the radiation dose. METHODS: A total of 160 eligible consecutive patients who underwent energy spectrum CT at Lanzhou University Second Hospital between June 2020 and July 2021 were retrospectively enrolled. The average CT attenuation values of the liver and spleen and the liver-to-spleen ratio (LSR) were measured by two independent blinded radiologists on true non-contrast (TNC) images and three types of VNC image. The diagnostic performance of the LSR for CRFLD, image quality, and diagnostic confidence were compared between the two types of imaging. RESULTS: The average CT attenuation values of the liver and spleen were significantly lower on VNC images than on TNC images (P<0.05), whereas the LSR showed good agreement between the two (P>0.05). The average CT attenuation values of the liver and the LSR measured on the TNC and three types of VNC image were significantly lower in patients with CRFLD than in those without CRFLD (P<0.001). The area under the curve (AUC) values of the LSR for the diagnosis of CRFLD calculated on TNC and three types of VNC image were 0.870 (95% CI: 0.808–0.918), 0.852 (95% CI: 0.787–0.903), 0.819 (95% CI: 0.750–0.875), and 0.851 (95% CI: 0.786–0.902), respectively. The DeLong test confirmed the consistency of TNC and VNC images of diagnostic efficacy (P>0.05). There were no significant differences in image quality or diagnostic confidence between the TNC and three types of VNC image (P>0.05). When VNC imaging was applied, the radiation dose was reduced by approximately 25.0%. CONCLUSIONS: VNC imaging could become a reliable alternative to TNC imaging for the clinical evaluation of patients with CRFLD and could reduce the radiation dose by up to 25%.