Intravenous contrast medium impairs CT-based muscle quality but not quantity assessment: a translational study.

Objectives: CT-based body composition analysis (BCA) provides imaging biomarkers, including muscle volume and surrogates of muscle quality. Concerns over the comparability of Non-contrast and contrast-enhanced CT scans have limited their clinical application. This study aims to assess the influence of various contrast phases on a volumetric CT-based BCA. Materials and methods: 20 Göttingen minipigs were subjected to a Non-contrast (NC) and five contrast-enhanced [Early Arterial, Late Arterial, Vascular Portal Venous, Parenchymal Portal Venous (PPV), Late] CT scans. 114 tri-phasic (Non-Contrast, Arterial, Venous) CT scans were analyzed for human validation. A volumetric BCA network [Body and Organ Analysis (BOA)] extracted muscle radiodensity and the following features as volumes: Muscle, Subcutaneous Adipose Tissue (SAT), Inter- and Intramuscular Adipose Tissue (IMAT), Visceral Adipose Tissue (VAT), and Total Adipose Tissue (TAT). Significance was assessed by a one-way ANOVA with Tukey's multiple comparisons test. Results: In the animal model, there was a tendency toward reduced IMAT volumes after CM injection [NC = 245 ml (±105 ml), e.g., PPV = 241 ml (±105 ml)]. Muscle radiodensity was significantly higher following CM administration [Non-contrast: 51.1 HU (±1.9 HU), e.g., Late: 56.6 HU (±2.4 HU), Conclusion: Myosteatosis surrogates, such as muscle radiodensity or IMAT, are susceptible to interference by CM, while quantification of muscle tissue and extramuscular fat remains robust.