目的研究磁共振成像(magnetic resonance imaging,MRI)平扫结合扩散加权成像(diffusion weighted imaging,DWI)在大鼠诱发性乳腺良恶性病变中的诊断价值。方法 Wistar雌性大鼠50只,7,12-二甲基苯蒽(DMBA)灌胃诱发大鼠乳腺肿块,MRI常规T1WI、T2WI和压脂序列扫描,以及DWI成像,测量乳腺肿块的T1WI信号强度(SIT1)、T2WI信号强度(SIT2)和最大横截面积(Amax),DWI图像后处理得到乳腺肿块的表观扩散系数(apparent diffusion coefficient,ADC)和指数化表观扩散系数(exponential apparent diffusion coefficient,eADC)。取感兴趣区组织行HE染色,观察乳腺肿块的病理表现,将其分为乳腺良性增生和乳腺癌2组。采用判别分析法,得出MRI各参数值联合应用的线性判别公式。应用受试者工作特性(ROC)曲线确定各指标鉴别乳腺良恶性病变的最佳切点值。结果 43只大鼠诱发出乳腺肿块,其中乳腺良性增生18只,乳腺癌25只。除SIT1外(P>0.05),乳腺良性病变与乳腺癌的SIT2、Amax、DWI ADC值和eADC值均有显著性差异(P<0.01)。MR平扫结合DWI成像对乳腺良恶性病变诊断的线性判别得分值(Score)=-0.007×SIT1+0.008×SIT2+0.302×Amax-2.042×ADC-1.639。Score值的ROC曲线下面积为0.951,大于任一单个参数的ROC曲线下面积,其联合诊断作用大于单个参数的诊断作用。结论大鼠诱发性乳腺肿瘤是MR成像研究的适合模型,MRI平扫结合DWI成像有助于提高对乳腺良恶性病变的诊断价值。 Objective To study the diagnostic value of magnetic resonance imaging (MRI) combined with diffusion weighted imaging (DWI) in benign and malignant lesions induced by rats. Methods Fifty male Wistar rats and 7,12-dimethylbenzyl anthracene (DMBA) were intragastrically induced by mammary gland in rats. MRI was performed on T1WI, T2WI and liposuction sequence scan, and DWI imaging. The intensity of T1WI signal in breast tumor (ADC) and exponential apparent diffusion coefficient (ADC) of breast tumor were obtained by SIT1, SIT2 and Amax. , eADC). Take the tissue of interest area HE staining, observe the pathological manifestations of breast lesions, will be divided into benign breast hyperplasia and breast cancer 2 groups. Discriminant analysis was used to get the linear discriminant formula of the combination of MRI parameters. The receiver operating characteristic (ROC) curve was used to determine the optimal cut-point value for the differential diagnosis of benign and malignant breast lesions. Results 43 rats induced breast mass, including 18 benign breast hyperplasia and 25 breast cancer. In addition to SIT1 (P> 0.05), benign breast lesions and breast cancer SIT2, Amax, DWI ADC value and eADC values ​​were significantly different (P <0.01). Linear discriminant score of MR plain scan combined with DWI imaging in the diagnosis of benign and malignant breast lesions Score = - 0.007 × SIT1 + 0.008 × SIT2 + 0.302 × Amax - 2.042 × ADC - 1.639. The area under the ROC curve of Score was 0.951, which was greater than the area under the ROC curve of any single parameter, and its combined diagnostic effect was greater than the diagnostic value of a single parameter. Conclusion Induced breast tumor in rats is a suitable model for MR imaging studies. MRI combined with DWI imaging can help to improve the diagnostic value of benign and malignant breast lesions.