Purpose: Body composition measurements from routine abdominal CT can yield personalized risk assessments for asymptomatic and diseased patients. In particular, attenuation and volume measures of muscle and fat are associated with important clinical outcomes, such as cardiovascular events, fractures, and death. This study evaluates the reliability of an Internal tool for the segmentation of muscle and fat (subcutaneous and visceral) as compared to the well-established public TotalSegmentator tool. Methods: We assessed the tools across 900 CT series from the publicly available SAROS dataset, focusing on muscle, subcutaneous fat, and visceral fat. The Dice score was employed to assess accuracy in subcutaneous fat and muscle segmentation. Due to the lack of ground truth segmentations for visceral fat, Cohen's Kappa was utilized to assess segmentation agreement between the tools. Results: Our Internal tool achieved a 3% higher Dice (83.8 vs. 80.8) for subcutaneous fat and a 5% improvement (87.6 vs. 83.2) for muscle segmentation respectively. A Wilcoxon signed-rank test revealed that our results were statistically different with p<0.01. For visceral fat, the Cohen's kappa score of 0.856 indicated near-perfect agreement between the two tools. Our internal tool also showed very strong correlations for muscle volume (R^2=0.99), muscle attenuation (R^2=0.93), and subcutaneous fat volume (R^2=0.99) with a moderate correlation for subcutaneous fat attenuation (R^2=0.45). Conclusion: Our findings indicated that our Internal tool outperformed TotalSegmentator in measuring subcutaneous fat and muscle. The high Cohen's Kappa score for visceral fat suggests a reliable level of agreement between the two tools. These results demonstrate the potential of our tool in advancing the accuracy of body composition analysis.

翻译：目的：通过常规腹部CT测量身体成分，可为无症状及患病患者提供个性化风险评估。其中，肌肉与脂肪的衰减值及体积测量与心血管事件、骨折、死亡等重要临床结局密切相关。本研究评估了自主开发工具（Internal tool）与权威公开工具TotalSegmentator在肌肉及脂肪（皮下脂肪与内脏脂肪）分割任务中的可靠性差异。方法：基于公开SAROS数据集的900个CT序列，我们重点评估了肌肉、皮下脂肪及内脏脂肪的分割性能。采用Dice系数评估皮下脂肪与肌肉分割的准确性；由于缺乏内脏脂肪的真实标注数据，采用Cohen's Kappa系数评估两种工具在分割结果上的一致性。结果：与TotalSegmentator相比，本工具在皮下脂肪分割上Dice系数提升3%（83.8 vs. 80.8），肌肉分割提升5%（87.6 vs. 83.2）。Wilcoxon符号秩检验表明差异具有统计学显著性（p<0.01）。内脏脂肪的Cohen's Kappa系数达0.856，显示两种工具间具有近乎完美的一致性。本工具与参考标准呈强相关性：肌肉体积（R²=0.99）、肌肉衰减值（R²=0.93）、皮下脂肪体积（R²=0.99），而皮下脂肪衰减值呈中等相关性（R²=0.45）。结论：本工具在皮下脂肪与肌肉测量方面优于TotalSegmentator。内脏脂肪的高Kappa系数表明两种工具间具有可靠的一致性。上述结果展示了本工具在提升身体成分分析准确性方面的潜力。