3.0 T MRI水-脂分离Dixon技术鉴别良恶性椎体压缩性骨折的价值

Value of 3.0 T MRI fat-water separation Dixon technique in the differential diagnosis of benign and malignant verte-bral compression fracture

目的:探讨MRI水-脂分离Dixon技术对良恶性椎体压缩性骨折的鉴别诊断价值。方法 :收集因椎体压缩性骨折接受CT扫描且难以诊断的患者76例。均应用Siemens skyra 3.0 T MRI行常规矢状位T1WI、T2WI、STIR;T1WI Dixon序列获得同相位、反相位、纯水相、纯脂相。根据临床随访或病理结果,76例中良性压缩性骨折43例(良性组),其中35例骨质疏松性骨折,5例创伤性骨折,3例感染性骨折;恶性压缩性骨折33例(恶性组),其中28例转移性骨折,3例非霍奇金淋巴瘤,2例多发性骨髓瘤。计算病变椎体信号强度指数(SIR)及脂肪分数(FF)。结果:良性组的FF值显著高于恶性组(P<0.01);良性组的SIR显著低于恶性组(P<0.01)。绘制FF及SIR对良恶性椎体压缩性骨折的诊断效能ROC曲线,FF和SIR鉴别良恶性椎体压缩性骨折的曲线下面积分别为0.79和0.88,最佳鉴别阈值分别为12.75%和0.86。结论:3.0 T MRI水-脂分离Dixon技术可定量测定椎体SIR和脂肪含量的变化,对椎体骨折性质的诊断和鉴别诊断具有重要的临床价值。

Objective:To explore the value of MRI fat-water separation Dixon technique in differential diagnosis of benign and malignant vertebral compression fractures.Methods:We retrospectively analyzed 76 patients with vertebral lesions who scanned at a CT scanner and were difficult to diagnose.Then all patients underwent conventional sagittal T1WI,T2WI,STIR and fat-water separation Dixon T1WI sequence on MRI.The patients were identified as either benign compression fractures(a total of 43 cases,including 35 cases with osteoporotic fractures,5 with traumatic fractures,3 with infective fractures)or malignant compression fractures(a total of 33 cases,including 28 cases with metastatic fractures,3 with non-Hodgkin lymphoma,2 with multiple myeloma)based on clinical follow-up or pathologically results.Four series of images(in/opposed phases,fat/water only)generated by the system were used for fat fraction(FF)analysis.The signal intensity ratio(SIR)was defined as SIR=SIopp-phase/SIin-phase and the FF was defined as FF=SIfat/SIin-phase×100%.Results:The value of FF in the benign group was significantly higher than that in the malignant group(P<0.01).The SIR in the benign group was significantly lower than that in the malignant group(P<0.01).Through drawing ROC curve used the FF and SIR of benign and malignant vertebral compression fractures,the diagnostic critical value of benign and malignant vertebral compression fractures was 12.75%and 0.86.The AUC of FF and SIR were 0.79 and 0.88.Conclusion:The vertebral SIR and FF through 3.0 T MRI fat-water separation Dixon technique can reflect the change of the vertebral body fat content in patients,and is helpful in differentiation between benign and malignant vertebral compression fractures.