合成MRI定量技术在半月板损伤中的应用价值

Application of synthetic MRI quantification in knee meniscal injury

目的探讨合成MRI定量技术在膝关节半月板损伤中的应用价值。方法收集临床拟诊半月板损伤患者50例,均行常规MRI及MR集合序列(MAGIC)检查。由2位资深放射科医师评估半月板形态和信号改变,将半月板分为正常组(0级)、变性组(Ⅰ、Ⅱ级)及撕裂组(Ⅲ级),将正常组分为内侧前角组、外侧前角组、内侧后角组和外侧后角组。在合成MRI定量图内侧前角、外侧前角、内侧后角、外侧后角最大层面测量所有半月板的纵向弛豫时间(T_(1))、横向弛豫时间(T_(2))和质子密度(PD)。采用Kruskal-Wallis H检验比较正常半月板4组间及正常、损伤半月板间定量参数值的差异。采用ROC曲线分析T_(1)、T_(2)诊断半月板损伤的效能。结果正常半月板4组间T_(2)值差异有统计学意义(P<0.05),内侧后角组T_(2)小于外侧前角组和外侧后角组(均P<0.05)。变性组、撕裂组T_(1)、T_(2)值均高于正常组(均P<0.05),撕裂组T_(1)、T_(2)值与变性组比较差异无统计学意义(P>0.05)。各组间PD值比较差异均无统计学意义(均P>0.05)。当T_(1)和T_(2)的阈值分别为920和39 ms时,鉴别半月板损伤的AUC分别为0.718、0.987,灵敏度分别为73.8%、100.0%,特异度分别为68.9%、95.1%,T_(2)诊断半月板损伤的效能优于T_(1)。结论合成MRI技术可以对损伤半月板进行定量分析,其中T_(2)是诊断效能较高的定量指标。

Objective To explore the application value of synthetic MRI quantification in knee meniscus injury.Methods Fifty patients with suspected knee meniscus injury underwent routine MRI and magnetic resonance image compilation(MAGIC)scanning,the meniscus shape and signal change were assessed by two senior radiologists indipendently.The meniscus were divided into normal group(0),modified(Ⅰ,Ⅱ)and tear group(Ⅲ).The longitudinal relaxation time(T_(1)),transverse relaxation time(T_(2))and proton density(PD)values of normal and injured meniscus were measured at maximum levels of anterior and posterior angles of medial and lateral meniscus in synthetic MRI quantitative images.Kruskal-wallis H test was used to analyze the difference of quantitative parameter values of anterior and posterior angle of medial and lateral meniscus of knee joint and the difference of quantitative parameter values of normal and injured meniscus.ROC curve was applied to analyze the diagnostic efficacy of T_(1)and T_(2)values in meniscus injury.Results The T_(2)values between the anterior and posterior corners of medial and lateral meniscus groups were significantly different(P<0.05),and T_(2)values in the medial posterior corner group were lower than those in the lateral anterior and posterior corners groups(both P<0.05).T_(1)and T_(2)values in denaturation group and tear group were higher than those in normal group(both P<0.05),while there was no significant difference in T_(1)and T_(2)values between tear group and denaturation(P>0.05).There were no significant differences in PD values among all groups.When the threshold values of T_(1)and T_(2)were 920 and 39 ms,respectively,the AUC for meniscus injury was 0.718 and 0.987,with a sensitivity of 73.8%,100%,and specificity of 68.9%,95.1%,respectively.The diagnostic efficiency of T_(2)value in meniscus injury was better than T_(1)value.Conclusion Synthetic MRI technology can be used for quantitative analysis of injured meniscus,and T_(2)value is a quantitative index with high diagnostic efficiency.