Chinese Journal of Geriatrics · Oct 14, 2026
Diagnostic value of CT-related skeletal muscle parameters at the third lumbar vertebra level for sarcopenia in elderly patients with gastrointestinal tumors
By 齐竟竟, 向群艳, 伍特明 et al.
Objective To investigate the diagnostic value of computed tomography (CT)-derived skeletal muscle mass index (CT-SMI) and skeletal muscle density (CT-SMD) at the third lumbar vertebra (L3) level for sarcopenia in elderly patients with gastrointestinal tumors, and to determine sex-specific optimal diagnostic cutoff values.Methods This was a single-center retrospective cross-sectional study.Elderly hospitalized patients with gastrointestinal tumors at the Second Xiangya Hospital of Central South University from June 2022 to January 2024 were enrolled.Demographic data, appendicular skeletal muscle mass index (ASMI), handgrip strength, and the 5-times chair stand test were collected.L3-level CT images were analyzed using Slice-O-Matic 5.0 software, with muscle attenuation thresholds set at-29 to+ 150 Hounsfield units (Hu).CT-SMI was defined as L3 skeletal muscle area divided by height squared.According to the Asian Working Group for Sarcopenia 2019 (AWGS2019) criteria (reduced muscle mass along with either decreased handgrip strength or impaired physical performance), the diagnostic performance of each individual indicator was evaluated using receiver operating characteristic (ROC) curves, and a combined CT-SMI+ CT-SMD model was constructed using multivariate logistic regression.Results A total of 216 patients were enrolled, of whom 35 (16.2%) were diagnosed with sarcopenia.The prevalence increased with age: 8.8% in the 60-69 years group, 24.3% in the 70-79 years group, and 66.7% in the ≥80 years group.The cutoff values for CT-SMI and CT-SMD were 44.32 cm /m and 36.70 Hu for males, and 39.14 cm /m and 35.15 Hu for females, respectively.The area under the curve (AUC) for CT-SMI and CT-SMD were 0.654 and 0.701 in males, and 0.730 and 0.705 in females, respectively.The combined model achieved higher specificity (males: 80.0%; females: 95.7%) but lower sensitivity (males: 60.0%; females: 53.3%), with AUCs of 0.712 for males and 0.766 for females. Conclusions Both CT-SMI and CT-SMD have moderate diagnostic value for sarcopenia in elderly patients with gastrointestinal tumors.The sex-specific cutoff values derived from this study can be used for clinical screening.Single indicator screening provides higher sensitivity, while the combined model offers improved specificity, allowing for flexible clinical application based on screening needs.