髌骨与髌韧带长度比值的MR测量

目的:通过MR成像确定髌骨与髌韧带长度比值的正常范围,诊断髌骨位置异常。方法:无髌骨及髌韧带损伤患者311名,行单膝关节MRI检查。在MRI矢状面图像上测量髌骨长度(PL)和髌韧带长度(TL),并计算TL/PL的比值。比值分布范围的两个极端2.5%认为是髌骨高位和髌骨低位。结果:TL/PL值范围为0.617～1.88(平均1.067)。MRI上髌骨高位的TL/PL值>1.433,髌骨低位的TL/PL值<0.775。女性的TL/PL值(平均1.083)和男性(平均1.054)差异有显著性意义(P<0.05)。本研究人群与以色列学者Shabshin等所研究人群之间的TL/PL比值分布没有统计学差异(t=1.865,P=0.063>0.05)。结论:MRI上TL/PL值的正常范围为0.775～1.433(平均1.067)。>1.433可认为髌骨高位;<0.775可认为髌骨低位。通过MRI诊断髌骨高位和髌骨低位准确可行。

Length Ratio of Patellar Tendon and Patella Measured on MR Images

Objective:By measuring the length of patellar tendon and patella,and calculating their ratio on sagittal imaging of MRI to establish MRI criteria of patella alta and baja for making diagnoses of abnormal patellar position on MRI.Methods:Three hundred and eleven patients without patellar tendon or patellar trauma were subjected to MRI studies of single knee.Patellar tendon length(TL) and patellar length(PL) were measured on center sagittal images of MRI and TL/PL ratio was subsequently calculated.The extreme 2.5% at each end of the distribution of ratios was defined as patella alta and baja.Results:The TL/PL ratio ranged between 0.617 and 1.88(mean 1.067).The MRI definition of patella alta and baja was a ratio of TL/PL of more than 1.433 and less than 0.775 respectively.Females had significantly higher TL/PL ratio than males(P<0.05)(mean 1.083 and 1.054 respectively).Conclusion:The TL/PL ratio ranged between 0.775 and 1.433(mean 1.067) on MRI;Patella alta and baja are determined as TL/PL of more than 1.433 and less than 0.775 respectively;It's an accurate and feasible technique to determine patella alta and baja on MRI.