体素内不相干运动DWI对肝脏良恶性病变的诊断价值

目的：探讨体素内不相干运动（IVIM）扩散加权成像对肝脏良恶性病变的诊断价值。方法：搜集2014年12月－2015年7月临床怀疑为肝脏肿瘤、且经手术病理、穿刺活检、临床或随访明确诊断的92例患者（共93个病灶）的病例资料，其中恶性组69例、良性组23例（24个病灶）。所有患者均行常规 MRI平扫、多期动态增强扫描及IVIM（b＝0、20、50、100、200、400、600、800和1200s／mm2）。将ROI 放置于肿瘤最大实性区域，采用单指数及双指数模型获得以下参数值：表观扩散系数（ADC）、慢速表观扩散系数（D）、快速表观扩散系数（D*）及快速扩散成分所占比例（f）。采用独立样本t检验比较良恶性组间各参数的差异，并采用受试者工作特征曲线（ROC ）计算各参数的诊断效能。结果：良性病变的ADC、D、D*和f值分别为（1．67±0．59）×10－3、（1．23±0．34）×10－3、（36．13±17．84）×10－3mm2／s 和（29．96％±15．67％），恶性组者分别为（1．20±0．36）×10－3、（0．88±0．21）×10－3、（34．84±19．75）×10－3mm2／s 和（21．77％±10．07％）。除D*值外，ADC值、D值及f值在两组间的差异有统计学意义（P值分别为0．001、0．000及0．023），相应ROC下面积分别为0．764、0．804及0．665。以D值＜1．13×10－3mm2／s为阈值，诊断肝脏恶性肿瘤的敏感度及特异度分别为85．5％和62．5％。结论：体素内不相干运动扩散加权成像有助于肝脏良恶性病变的鉴别，其中使用双指数模型计算的慢速表观扩散系数值诊断效能最高。

Intravoxel incoherent motion diffusion weighted imaging in differentiation between benign and malignant lesions of liver

Objective:To determine the value of intravoxel incoherent motion (IVIM)diffusion weighted imaging (DWI)in differentiation between benign and malignant lesions of liver.Methods:From December 2014 to July 2015,92 pa-tients with 93 liver lesions proved by postsurgical pathology,aspiration biopsy,clinical data or follow-up results were en-rolled in our study,and were divided into two groups:malignant group (69 lesions in 69 patients)and benign group (24 le-sions in 23 patients).All patients underwent conventional non-enhanced and contrast-enhanced MRI and IVIM-DWI (b= 0, 20,50,100,200,400,600,800 and 1200s/mm2 ).ROIs were placed on the largest solid part of the lesions and parameters (ADC,D,D* and f)were measured with monoexponential model and biexponential model respectively.The values of these parameters in the two groups were analyzed and compared using independent samplest-test,and receiver operating charac-teristic curve (ROC)was used to determine the diagnostic efficacy of these parameters in diagnosis of malignant liver le-sions.Results:The values of ADC,D,D* and f in benign group were (1.67±0.59)×10-3 ,(1.23±0.34)×10-3 ,(36.13± 17.84)×10-3mm2/s and (29.96%±15.67%),and those in malignant group were (1.20±0.36)×10-3 ,(0.88±0.21)× 10-3 ,(34.84±19.75)×10-3mm2/s and (21.77%±10.07%)respectively.Significant inter-group difference was observed in ADC,D and f (P= 0.001,0.000 and 0.023,respectively),the correlated areas under the ROC curve of ADC,D and f were 0.764,0.804 and 0.665.With the cut-off of 1.13×10-3mm2/s,the sensitivity and specificity of D in diagnosis of ma-lignant lesions of liver were 85.5% and 62.5% respectively.Conclusion:IVIM-DWI is useful to distinguish benign and ma-lignant lesions of liver,and the D value in biexponential model has the best diagnostic efficacy for differentiation.