摘要目的:分析腓肠肌内侧头的厚度(MT)、回声强度(EI)与肌肉质量、力量及功能参数的相关性，评估MT、EI对于肌量减少的诊断效能。方法:收集2021年3－12月于福建医科大学附属第二医院超声医学科就诊的52例受检者，采用二维超声测量腓肠肌内侧头MT，使用Image J软件分析感兴趣区EI值。选择其中20例采用组内相关系数(ICC)评估观察者内及观察者间对于MT、EI值测量的一致性并作Altman-Bland分析。按照2019年亚洲肌少症工作组(AWGS)诊断标准分为健康对照组(30例)与肌量减少组(22例)，比较两组间MT、EI值的差异，采用Pearson相关分析法分析MT、EI值与肌肉质量、力量和功能之间的相关性。使用ROC曲线获得MT、EI值对于肌量减少的诊断截值，评估诊断效能。结果:①相同医师和不同医师检测腓肠肌内侧头MT、EI的ICC均大于0.97，重测信度较好；②与健康对照组比较，肌量减少组腓肠肌内侧头MT值减小，EI值增大( t＝4.759、－3.789，均 P<0.001)；③腓肠肌内侧头MT值与四肢骨骼肌质量(ASM)、四肢骨骼肌质量指数(ASMI)、下肢骨骼肌质量(LLSM)、握力、步速呈正相关( r＝0.579、0.568、0.585、0.495、0.415，均 P<0.001)，其中与LLSM的相关性最好；④腓肠肌内侧头EI与ASM、ASMI、LLSM、握力、步速呈负相关( r＝－0.583、－0.591、－0.590、－0.537、－0.455，均 P<0.001)，其中与ASMI的相关性最好；⑤腓肠肌内侧头MT与EI对于预测肌量减少截值分别为14.33 mm、58.85，且两者对于肌量减少的诊断效能差异无统计学意义( Z＝0.734 3， P>0.05)。 结论:腓肠肌内侧头MT、EI值可以准确评估肌肉质量并用于肌量减少患者的评估。

abstractsObjective:To analyze the correlation between the muscle thickness (MT) and echo intensity (EI) of the medial head of gastrocnemius and muscle mass, strength and functional parameters, and to evaluate the diagnostic efficacy of MT and EI for decreased muscle mass.Methods:Fifty-two subjects who visited the Department of Ultrasound Medicine of the Second Affiliated Hospital of Fujian Medical University from March to December 2021 were collected.MT of the medial head of gastrocnemius was measured by two-dimensional ultrasound, and EI values in the region of interest were analyzed using Image J software. Twenty of the subjects were selected to assess the intra-observer and inter-observer agreements in measuring MT and EI values using the intraclass correlation coefficient (ICC) and Altman-Bland analysis was performed. The subjects were divided into healthy control group (30 cases) and decreased muscle mass group (22 cases) according to 2019 Asian Sarcopenia Working Group (AWGS) diagnostic criteria, the differences in MT and EI values between the two groups were compared, and the correlation between MT, EI values and muscle mass, strength, function were analyzed using Pearson correlation analysis. The diagnostic cutoff values of MT and EI values for decreased muscle mass were obtained using ROC curves, and the diagnostic efficacy was compared.Results:①The ICC of MT and EI in medial head of gastrocnemius detected by the same physician and different physicians were greater than 0.97, and the retest reliability was good. ②Compared with the healthy control group, the MT value in medial head of gastrocnemius decreased and the EI value increased in the decreased muscle mass group ( t=4.759, -3.789; all P<0.001). ③The MT value in medial head of gastrocnemius was positively correlated with appendicular skeletal muscle mass (ASM), appendicular skeletal muscle mass index (ASMI), lower limb skeletal muscle mass (LLSM), grip strength, and gait speed ( r=0.579, 0.568, 0.585, 0.495, 0.415; all P<0.001), of which, the correlation with LLSM was the best; ④EI in medial head of gastrocnemius was negatively correlated with ASM and ASMI, LLSM, grip strength, and gait speed, ( r=-0.583, -0.591, -0.590, -0.537, -0.455; all P<0.001), and among which the correlation with ASMI was the best. ⑤The medial head of gastrocnemius MT and EI were 14.33 mm and 58.85 for predicting decreased muscle mass, respectively, and there was no significant difference in the diagnostic performance of the two for decreased muscle mass ( Z=0.734 3, P>0.05). Conclusions:The MT and EI values of the medial head of gastrocnemius can accurately assess muscle mass and can be used in the evaluation of patients with decreased muscle mass.