Comparison of Muscle and Fat Measurements Between True Noncontrast and Virtual Noncontrast Images From Three Phases of Dual-Energy Dynamic Liver CT

초록

Rationale and Objectives: To determine whether virtual noncontrast (VNC) images derived from three-phase dynamic dual-energy CT (DECT) imaging can reliably substitute true noncontrast (TNC) images in assessing muscle and fat with automatic segmentation software. Materials and methods: The data from 476 dynamic liver DECT examinations performed between April 2019 and December 2020 were retrospectively analyzed. VNC images were generated from arterial (VNCa), portal-venous (VNCp), and delayed (VNCd) phase images. Automated software measured muscle, visceral fat (VF), and subcutaneous fat (SF) areas. Sarcopenia was defined using muscle-related indices. Differences in muscle and fat measurements, as well as sarcopenia prevalence, between TNC and VNC images were assessed using paired t tests and McNemar tests, respectively. Results: The average age of the 476 patients (307 men) was 58.4 ± 12.5 years. Muscle density and area differed significantly between the TNC and VNC images; TNC images showed higher mean muscle density and smaller skeletal muscle area (SMA) than all VNC images (P<0.001). VF and SF attenuations were significantly lower on TNC images than on all VNC images (P<0.001). The proportions of sarcopenic patients did not differ significantly between TNC and VNCp or VNCd, regardless of the muscle index used. Conclusion: Despite significant differences in muscle and fat attenuations between TNC and VNC images, VNCp and VNCd may be acceptable alternatives for measuring muscle and fat areas. However, TNC and VNC images should not be used interchangeably for assessing tissue attenuation or specific muscle components such as LAMA or NAMA. © 2025 The Association of University Radiologists

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