Abstract：
OBJECTIVE: Significant variability exists in the contrast phases applied during computed tomography (CT) studies when assessing morphometric measurements of muscle area (CT-assessed sarcopenia) and density (CT-assessed myosteatosis) and visceral adipose tissue area (CT-assessed visceral obesity). This study explored the impact of contrast phase timing on changes in morphometric measurements of body composition.
METHODS: This single-center retrospective cohort study included 459 patients undergoing a multiphase CT scan. Morphometric measurements were obtained at the third lumbar vertebra level. Patients were classified as sarcopenic, myosteatotic, or visceral obese using predefined cutoff values. The intraclass correlation coefficient was used to assess correlations across different enhancement phases, and Cohen\'s κ measured the inter-enhancement agreement for sarcopenia, myosteatosis, and visceral obesity.
RESULTS: Significant differences were observed in mean visceral adipose tissue area, muscle density, and muscle area (P < 0.001). The intraclass correlation coefficient between unenhanced and arterial phases was 0.987 (95% confidence interval [CI], 0.759-0.996) for adipose tissue, 0.995 (95% CI, 0.989-0.997) for muscle area, and 0.850 (95% CI, 0.000-0.956) for muscle density. However, when morphometric measurements were categorized using predefined cutoffs, the κ agreement was considerably lower, particularly for CT-assessed myosteatosis, ranging from 0.635 (unenhanced to arterial) to 0.331 (unenhanced to late venous phase).
CONCLUSIONS: Different CT contrast phases induce small but clinically significant alterations in the measurements of muscle area and density and visceral fat. Such minor changes can result in misclassification issues when fixed cutoff values are used to diagnose myosteatosis with CT. This underscores the importance of reporting absolute values and the specific contrast phase used in future studies.
METHODS: This single-center retrospective cohort study included 459 patients undergoing a multiphase CT scan. Morphometric measurements were obtained at the third lumbar vertebra level. Patients were classified as sarcopenic, myosteatotic, or visceral obese using predefined cutoff values. The intraclass correlation coefficient was used to assess correlations across different enhancement phases, and Cohen\'s κ measured the inter-enhancement agreement for sarcopenia, myosteatosis, and visceral obesity.
RESULTS: Significant differences were observed in mean visceral adipose tissue area, muscle density, and muscle area (P < 0.001). The intraclass correlation coefficient between unenhanced and arterial phases was 0.987 (95% confidence interval [CI], 0.759-0.996) for adipose tissue, 0.995 (95% CI, 0.989-0.997) for muscle area, and 0.850 (95% CI, 0.000-0.956) for muscle density. However, when morphometric measurements were categorized using predefined cutoffs, the κ agreement was considerably lower, particularly for CT-assessed myosteatosis, ranging from 0.635 (unenhanced to arterial) to 0.331 (unenhanced to late venous phase).
CONCLUSIONS: Different CT contrast phases induce small but clinically significant alterations in the measurements of muscle area and density and visceral fat. Such minor changes can result in misclassification issues when fixed cutoff values are used to diagnose myosteatosis with CT. This underscores the importance of reporting absolute values and the specific contrast phase used in future studies.
摘要：
目的：在评估肌肉面积（CT评估的肌肉减少症）和密度（CT评估的肌肉骨化）和内脏脂肪组织面积（CT评估的内脏肥胖）的形态测量时，在计算机断层扫描（CT）研究中应用的对比阶段存在显着差异。这项研究探讨了对比相位定时对身体成分形态测量变化的影响。
方法：这项单中心回顾性队列研究包括459例接受多期CT扫描的患者。在第三腰椎水平获得形态测量。患者被归类为肌少症，肌肉骨质疏松,或使用预定义的临界值的内脏肥胖。组内相关系数用于评估不同增强阶段的相关性，和科恩κ测量了肌肉减少症的增强间一致性，肌肉骨化病,和内脏肥胖。
结果：在平均内脏脂肪组织面积上观察到显著差异，肌肉密度,肌肉面积(P<0.001)。未增强期和动脉期之间的组内相关系数为0.987(95%置信区间[CI]，0.759-0.996）用于脂肪组织，肌肉面积为0.995（95%CI，0.989-0.997），肌肉密度为0.850（95%CI，0.000-0.956）。然而,当使用预定义的截止值对形态测量进行分类时，κ协议相当低，特别是CT评估的肌骨沉着，范围从0.635（未增强到动脉）到0.331（未增强到晚期静脉期）。
结论：不同的CT对比期会引起肌肉面积和密度以及内脏脂肪测量值的微小但具有临床意义的改变。当固定的截止值用于CT诊断肌萎缩时，这种微小的变化可能会导致错误分类问题。这强调了报告绝对值和未来研究中使用的特定对比相位的重要性。
方法：这项单中心回顾性队列研究包括459例接受多期CT扫描的患者。在第三腰椎水平获得形态测量。患者被归类为肌少症，肌肉骨质疏松,或使用预定义的临界值的内脏肥胖。组内相关系数用于评估不同增强阶段的相关性，和科恩κ测量了肌肉减少症的增强间一致性，肌肉骨化病,和内脏肥胖。
结果：在平均内脏脂肪组织面积上观察到显著差异，肌肉密度,肌肉面积(P<0.001)。未增强期和动脉期之间的组内相关系数为0.987(95%置信区间[CI]，0.759-0.996）用于脂肪组织，肌肉面积为0.995（95%CI，0.989-0.997），肌肉密度为0.850（95%CI，0.000-0.956）。然而,当使用预定义的截止值对形态测量进行分类时，κ协议相当低，特别是CT评估的肌骨沉着，范围从0.635（未增强到动脉）到0.331（未增强到晚期静脉期）。
结论：不同的CT对比期会引起肌肉面积和密度以及内脏脂肪测量值的微小但具有临床意义的改变。当固定的截止值用于CT诊断肌萎缩时，这种微小的变化可能会导致错误分类问题。这强调了报告绝对值和未来研究中使用的特定对比相位的重要性。
