目的: 通过观测髌骨上缘不同水平位置股四头肌横截面积(cross-sectional area,CSA)与体积(quadriceps muscle volume,QMV)的相关性,探讨评估股四头肌肌肉参数的最佳测量位置。方法: 对22例单侧前交叉韧带(anterior cruciate ligament,ACL)断裂男性患者行双侧大腿磁共振成像检查,患者平均年龄(29±6)岁,分别选取髌骨上缘18、15和12 cm处,利用半自动分割和医学影像处理软件确定QMV和各水平位置CSA。通过拟合回归方程建立模型估计QMV,采用Bland-Altman分析评价两者之间的一致性。结果: 受试者健侧QMV平均为(1 944.45±323.77) cm³。髌骨上缘18、15和12 cm处的股四头肌CSA分别为(80.80±12.16) cm²、(77.53±12.03) cm²和(72.68±10.51) cm²,拟合方程R²分别为0.819、0.755、0.684(P均<0.001),QMV估计值的标准误(standard error of the estimate,SEE)分别为7.4%、8.7%、9.8%(以体积的百分比表示)。三个水平位置的拟合方程均较好,但以髌骨上缘18 cm处的拟合度最高。Bland-Altman散点图结果显示,髌骨上缘18、15和12 cm处的QMV差值平均值分别为0.8 cm³、-1.1 cm³、0.9 cm³,95%一致性界限分别为(-268.8, 270.5)、(-315.2, 313.1)、(-355.7, 357.5),髌骨上缘18 cm处QMV的估计值与实测值一致性最好,患侧与健侧结果一致。结论: 以髌骨上缘作为基线探讨青年男性QMV与CSA的相关性具有可靠性和一致性,其中以髌骨上缘18 cm处的股四头肌CSA与QMV的相关性最好,但对于股四头肌的不同损伤部位,可选择不同观测位置。

Objective: To investigate the correlation between the quadriceps cross-sectional area (CSA) and quadriceps muscle volume (QMV) at different horizontal levels from the upper edge of the patella, and to determine the best observation position. Methods: Thigh magnetic resonance imaging (MRI) images of 22 Chinese young men [age: (29±6) years] with anterior cruciate ligament (ACL) rupture were examined. The CSA was measured at 18, 15, and 12 cm above the upper edge of the pate-lla (denoted by CSA-18, CSA-15 and CSA-12 respectively), and the QMV and CSA were determined by semiautomatic segmentation. A curve model was established to estimate QMV. Bland-Altman analysis was performed to determine the confidence limits of the volumes. Results: On the unaffected side, the mean QMV was (1 944.45±323.77) cm³. The quadriceps CSA at the upper edge of the patella at 18, 15, and 12 cm was (80.80±12.16) cm², (77.53±12.03) cm², and (72.68±10.51) cm², respectively. The coefficients of determination (R²), ascertained using curve estimation models, for the 3 positions were 0.819, 0.755, and 0.684 (P<0.001), and the standard deviations of the volume estimated value (SEE) were 7.4%, 8.7%, and 9.8%. The fitting equations of the three horizontal positions were all good, but the fitting degree of CSA-18 was the highest. The Bland-Altman scatter plot showed that the arithmetic means of the QMV at 18, 15 and 12 cm from the upper edge of the patella 0.8 cm³, -1.1 cm³, and 0.9 cm³ and 95% limits of agreement (LoA) were (-268.8, 270.5), (-315.2, 313.1), and (-355.7, 357.5), respectively. The estimated QMV was in good agreement with the measured value. The difference between the estimated CSA-18 and measured values was the smallest. The results on the affected side were consistent. Conclusion: The correlation between QMV and CSA in the young men with the upper edge of patella as baseline was reliable and consistent. Among them, CSA-18 had the highest correlation with the QMV. However, different observation sites could be selected for different injuries of the quadriceps.