结合MRI和X线分类对乳腺X线筛查为BI-RADS 4类肿块的处理体会

目的:评价结合MRI和X线分类对乳腺X线筛查为BI-RADS 4类肿块的良恶性评估价值,探讨BI-RADS 4类肿块新的处理建议.方法:X线筛查为BI-RADS 4a类(105个)、4b类(42个)和4c类(19个)的151例共166个乳腺肿块,在活检前行MRI.动态增强结合扩散加权成像(DWI)进行MRI BI-RADS分类.结合X线与MRI分类提出新的良恶性评估法.统计X线与MRI诊断乳腺癌的敏感度、特异度及诊断符合率;绘制两者的ROC曲线,Z检验比较曲线下面积;统计结合MRI和X线的新的良恶性评估法发现乳腺癌的敏感性、诊断符合率和对良性病变检出率.结果:2名X线诊断医师和2名MRI诊断医师的BI-RADS分类的Kappa值分别为0.70和0.76,一致性较好.166个肿块,恶性41个,占24.7％.X线BI-RADS 4a类105个:恶性12个,MRI分类为4、5类12个;良性93个,MRI为2、3类81个.X线BI-RADS 4b类42个:恶性16个,MRI分类为4、5类15个;良性26个,MRI为2、3类16个.X线BI-RADS 4c类19个:恶性13个,MRI分类为4、5类12个;良性6个,MRI为3类2个.X线诊断敏感度、特异度为70.7％、74.4％,诊断符合率为73.5％.MRI诊断敏感度、特异性及诊断符合率为95.1％、79.2％和83.1％.X线及MRI诊断乳腺癌的ROC曲线下面积分别为0.749及0.927,两者差异有统计学意义(Z=2.282,P＜0.05).新的良恶性评估法发现乳腺癌的敏感度为100％,诊断符合率为77.7％,良性病变检出率为53.0％.结论:MRI对乳腺X线筛查为BI-RADS 4类肿块有较高的诊断价值.结合X线及MRI分类进行新的良恶性评估,能减少良性肿块不必要的活检.

Experience of using MRI BI-RADs category in combination with mammography for the evaluation of BI-RADS category 4 mass detected by mammography screening

Objective:To evaluate the value of using MRI BI-RADs category in combination with mammography in the assessment of malignancy and benignity for patients with BI-RADS 4 mass detected by mammography screening,in order to provide a new approach for the treatment of BI-RADs Category 4 lesion.Methods:151 female patients with 166 breast mas ses which were classified as BI-RADS category 4a,4b and 4c (n=105,42,19 respectively) on mammography.All had MRI with dynamic contrast-enhancement and DWI before biopsy.MRI BI-RADs category was performed,which in combination with the BI-RADs category of mammography and a new approach for the differentiation of malignancy and benignity was put forward of BI-RADS-MRI.The sensitivity,specificity,and accuracy for the diagnosis of breast cancer by mammography and MRI were calculated,the ROC curves of the two were drawn,the areas under ROC were compared with Z test.The sensitivity and accuracy for the diagnosis of malignancy and the detection rate of benign lesion using the new approach with MRI in combination with mammography were also studied.Results:The Kappa value of the BI-RADS category by two radi ology specialists for mammography and two MRI specialists was 0.70 and 0.76 respectively,with favorable consistency.Of the 166 breast masses,malignant lesions were found in 41 cases (24.7％).Among the 105 masses classified as BI-RADS category 4a on mammography,there were 12 diagnosed as malignant,with 12 cases were assessed as BI-RADs category 4,5 by MRI.93 lesions were benign,with 81 lesions classified as BI-RADs category 2,3 by MRI.Of the 42 lesions classified as BI-RADS category 4b on mammography,there were malignant lesion (n=16),with 15 lesions were assessed as BI-RADs category 4,5 on MRI.26 masses were benign,with 16 lesions classified as BI-RADs category 2,3 on MRI.Among the 19 masses classified as BI-RADS category 4c on mammography:13 cases were malignant,with 12 cases were assessed as BI-RADs category 4,5 on MRI;6 masses were benign,with 2 lesions were classified as BI-RADs category 3 by MRI.The sensitivity,specificity and accuracy of mammography for diagnosing malignancy was 70.7％,74.4％ and 73.5％ respectively.The sensitivity,specificity and accuracy for diagnosing malignancy of MRI was 95.1％ 、79.2 ％ and 83.1％ respectively.The area under ROC curve of mammography was 0.749 and that of MRI was 0.927,with significant difference (Z=2.282,P＜0.05).According to the new approach for differentiating malignant and benign lesions,the sensitivity for the diagnosis of malignancy was 100 ％,the accuracy was 77.7 ％,and the detection rate of benign lesions was 53.0％ (88 cases).Conclusion:MRI showed high diagnostic value in BI-RADS category 4 masses detected by mammography screening.Mammography in combination with MRI is useful in the differentiation of benignity and malignancy,and unnecessary biopsy could be avoided.