多参数MRI对子宫平滑肌肉瘤及不典型子宫肌瘤的鉴别诊断

Using multiparametric MRI to differentiate uterine leiomyosarcoma from atypical leiomyoma

目的探索磁共振成像(magnetic resonance imaging,MRI)定性及定量参数对子宫平滑肌肉瘤(leiomyosarcoma,LMS)及不典型子宫肌瘤(atypical leiomyoma,ALM)的鉴别价值。材料与方法在2011年6月至2016年12月间,收集到由我院病理证实的19例LMS和88例ALM患者的临床资料,术前曾行MRI扫描并符合条件的有12例LMS和79例ALM。分析并比较两组患者肿瘤在MRI定性图像特点、扩散加权成像(diffusion weighted imaging,DWI)及增强定量参数方面的差异性。结果 MRI定性指标中,LMS主要位于宫腔,边界不清,实质T2WI多为混杂信号,实质DWI多为高信号,增强无强化区多位于中央,以上指标与ALM比较差异具有统计学意义(P<0.05)。MRI定量指标中,肿瘤实质的平均表观扩散系数值(mean apparent diffusion coefficient,m ADC)、早期强化率(early enhancement ratio,EER)、最大对比增强率(maximum contrast enhancement ratio,MCER)均能辅助区分LMS与ALM(P<0.05),根据受试者工作特征(receiver operating characteristic,ROC)曲线,当mADC以1.09×10^(-3) mm^2/s作为阈值时,诊断LMS的敏感性及特异性分别为97.5%和75.0%。结论多参数MRI在LMS与ALM的鉴别诊断中具有重要价值。

Objective： To explore the diagnostic value of clinical parameters and qualitative and quantitative magnetic resonance imaging （MRI） features in distinguishing uterine leiomyosarcoma （LMS） from atypical leiomyoma （ALM）. Materials and Methods： From June 2011 to December 2016, clinical data of 19 LMSs and 88 ALMs confrmed by pathology was collected in our hospital. Twelve LMSs and 79 ALMs underwent MRI scan before surgery and met the conditions. Analyzing and comparing the differences in MRI qualitative features, diffusion weighted imaging （DWI）, and dynamic contrast-enhanced parameters between LMS and ALM. Results： There were signifcant differences between LMS and ALM in the following qualitative MRI parameters： LMS was mainly located in the uterine cavity with an ill-defned margin, showed heterogeneous signal on T2WI and hyperintensity on DWI, no enhancement region was in the center of the tumor on contrast-enhanced MRI （P〈0.05）. For quantitative MRI parameters, mean apparent diffusion coeffcient （mADC） values, early enhancement ratio （EER）, maximum contrast enhancement ratio （MCER） of the solid component of LMS could help to distinguish from ALM （P〈0.05）. According to receiver operating characteristic （ROC） curves, when the cut-off values of mADC was 1.09×10-3 mm2/s, the sensitivity and specifcity were 97.5% and 75.0%. Conclusions： It was valuable to use multiparametric MRI to differentiate LMS from ALM.