MRI对于乳腺X线摄影BI-RADS 4~5类微钙化病变的诊断价值

The Value of breast MRI in evaluation of BI-RADS 4-5 mammographic microcalcifications

目的探讨MRI对于X线摄影乳腺影像报告和数据系统(BI-RADS)4~5类微钙化病变的诊断价值。方法回顾性分析经活检或手术病理证实、乳腺X线摄影发现BI-RADS 4~5类微钙化病变且行乳腺MRI检查的118例女性病人(共119个病灶),年龄27~66岁,平均(46.6±9.3)岁。参照BI-RADS标准,对乳腺X线摄影和MR影像进行BI-RADS分类。在MR DWI的ADC图上测量病灶的ADC值,X线摄影、MRI与病理分别测量病灶大小。采用卡方检验和t检验分别比较良恶性病变微钙化形态、分布及ADC值的差异。采用Wilcoxon符号秩和检验比较X线摄影、MRI与病理测量病灶大小的差异。以病理结果为金标准,计算X线摄影和MRI诊断的敏感度、特异度、准确度、阳性预测值(PPV)、阴性预测价值(NPV)。采用受试者操作特征(ROC)曲线评价诊断效能。采用Z检验比较X线摄影和MRI诊断微钙化病变的ROC曲线下面积(AUC)。采用Spearman相关分析和Bland-Altman法评价X线摄影、MRI与病理测量乳腺癌肿瘤大小的相关性和一致性。结果 119个病灶中,良性病灶46个,恶性病灶73个。良恶性病变微钙化形态、分布及ADC值差异均有统计学意义(均P<0.05)。乳腺X线摄影和MRI诊断的敏感度、特异度、准确度、PPV、NPV分别为84.93%、32.61%、64.71%、66.67%、57.59%和95.89%、71.74%、86.55%、84.34%、91.67%,MRI的AUC大于X线摄影(P<0.05)。X线摄影、MRI测得的肿瘤大小均大于病理测量结果(均P<0.05)。X线摄影、MRI与病理测量肿瘤大小均具有中度相关性(rs分别为0.602、0.603,均P<0.05)。Bland-Altman分析显示,与病理结果比较,X线摄影、MRI均高估肿瘤大小,一致性欠佳。结论乳腺MRI对X线摄影BI-RADS 4~5类微钙化的敏感度和阴性预测值较高。与病理学结果比较,MRI与X线摄影均高估肿瘤大小。

Objective To retrospectively investigate the value of breast MRI in evaluation of breast imaging reporting and data system(BI-RADS) 4-5 mammographic microcalcifications. Methods The clinicopathologic and radiological data of 118 patients(mean age, 46.6±9.3 years;range 27-66 years) who were confirmed by biopsy or surgical pathology were retrospectively analyzed. All mammography and MR images were reviewed with BI-RADS. The apparent diffusion coefficients(ADCs) of the lesions were measured on the ADC maps of diffusion-weighted imaging, and the tumor sizes were measured on mammography, MRI, and pathology, respectively. The comparison between the two groups was performed with chi-square test or t-test. The tumor sizes measured on mammography, MRI and pathology were compared using Wilcoxon signed ranks test. Using histopathological diagnosis as the golden standard, the sensitivity, specificity,accuracy, positive predictive value(PPV), and negative predictive value(NPV) were calculated on the basis of BI-RADS category. The diagnostic efficacy was evaluated with ROC curve. Z test was used to compare the areas under the ROC curves(AUC) of mammography and MRI in the diagnosis of microcalcification. The association and consistency of lesion sizes acquired by mammography, MRI, and pathology were assessed by Spearman rank correlation and Bland-Altman analysis.Results Of the 119 lesions, 46 were benign and 73 were malignant. There were significant differences in the morphology,distribution of microcalcifications, and ADC between benign and malignant lesions(P <0.05). The sensitivity, specificity,accuracy, PPV and NPV of mammography and MRI were 84.93%, 32.61%, 64.71%, 66.67% and 57.59%, and 95.89%,71.74%, 86.55%, 84.34%, and 91.67%, respectively. The AUC of MRI assessment was larger than that of mammography(P<0.05). The tumor sizes measured on mammography and MRI were larger than that on pathology(P<0.05). The sizes of tumors measured on mammography and MRI showed moderate correlation with the measurements obtained on pathology(rs=0.602,rs=0.603, P <0.05). Bland-Altman analysis showed that compared with pathological results, mammography and MRI overestimated the tumor sizes, and the consistencies were not good enough. Conclusions In the evaluation of BI-RADS 4-5 mammographic microcalcifications, breast MR imaging provides additional information with high sensitivity and NPV. Both MRI and mammography overestimate tumor sizes.