MR扩散加权成像体素内不相干运动模型对于乳腺良恶性病变诊断价值的研究

目的探讨扩散加权成像体素内不相干运动(IVIM)模型对于乳腺良恶性病变的诊断价值,并与传统的单指数模型及多期动态增强扫描进行比较。材料与方法搜集70例(23例良性,共24个病灶;47例恶性,共48个病灶)乳腺病变并行乳腺MRI检查的患者,所有患者均行乳腺单b值、多b值扩散加权成像及多期动态增强(DCE-MRI)扫描。利用GE AW4.4工作站对于图像进行后处理,生成单b值、多b值DWI图像相应参数值ADC、ADCstandard、D、D*、f值,同时生成DCE-MRI的时间-信号强度曲线(TIC)。良恶性乳腺肿瘤之间各参数值利用Mann-Whitney U检验进行比较,并利用受试者特性曲线(ROC曲线)评价各参数的诊断效能。结果恶性病灶的ADC、ADCstandard、D、f值分别为(1.01±0.18)×10-3 mm2/s、(1.10±0.18)×10-3 mm2/s、(0.86±0.16)×10-3 mm2/s、(25.50±9.23)%,良性病灶分别为(1.42±0.29)×10-3 mm2/s、(1.53±0.27)×10-3 mm2/s、(1.28±0.26)×10-3 mm2/s、(15.98±3.68)%,两者间差异均存在统计学意义(P值均0.001),良恶性病灶之间D*值差异不存在统计学意义(P=0.223)。良性病灶I型TIC曲线更多见,恶性病灶III型TIC曲线更多见。各参数行ROC曲线分析得到D值的曲线下面积(AUC)最大为0.932,当取最佳诊断阈值1.03×10-3 mm2/s,相应的诊断敏感性和特异性分别为89.6%,91.7%,而联合IVIM模型参数D和f值所得AUC可提高到0.974,相应的诊断敏感性和特异性分别为85.4%和100%。结论扩散加权成像IVIM模型参数中ADCstandard、D、f值能够用来协助诊断乳腺的良恶性病变,联合D和f值能够得到比传统的ADC值、多期动态增强TIC更好的诊断效能。

The value of intravoxel incoherent motion model of diffusion weighted imaging in differentiating benign from malignant breast lesions

Objective: To investigate the diagnostic value of parameters derived from diffusion-weighted imaging intravoxel incoherent motion (IVIM) model for benign and malignant breast lesions, and compare these parameters with that of monoexponential model and dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI). Materials and Methods: Seventy cases (23 cases of benign lesions in total 24, 47 cases of malignant lesions in total 48) of breast disease with breast MRI examination in our hospital were collected. All of them were examined with multiple-b-value diffusion-weighted imaging (DWI) and DCE-MRI scans. GE AW4.4 workstation was used to calculate the value of ADC, ADCstandard, D, D*, f, and to generate time-signal intensity curve (TIC). All parameters between benign and malignant breast lesions were compared byMann-Whitney U test. The diagnostic performance of different parameters was evaluated by receiver operating characteristic curve (ROC curve) analysis.Results:The ADC, ADCstandard, D, f value of malignant lesions were (1.01±0.18)×10-3 mm2/s, (1.10±0.18)×10-3 mm2/s, (0.86±0.16)×10-3 mm2/s, (25.50±9.23) % respectively, benignlesions were (1.42±0.29)×10-3 mm2/s, (1.53±0.27)×10-3 mm2/s, (1.28±0.26)×10-3 mm2/s, (15.98±3.68) %. There were statistically signiifcant differences between these parameters (P<0.001). With ROC curve analysis for each parameter value, the area under the curve (AUC) of D value was 0.932 which was the highest one, and corresponding diagnostic sensitivity and speciifcity were 89.6%and 91.7% while taking the optimal threshold of 1.03×10-3 mm2/s. AUC value can be increased to 0.974 by combining D with f value, and the corresponding diagnostic sensitivity and speciifcity were 85.4% and 100% respectively.Conclusions:The ADCstandard, D and f value from the IVIM model can be used to distinguish benign from malignant breast lesions. Associated with D and f value can obtain better diagnostic performance than the ADC value and the TIC.