| Objective:To research and analysis the imaging features of full-field digital mammography(FFDM)and dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)for all BI-RADS 4-5 non-mass microcalcification lesions on FFDM,and the pathological results were taken as the gold standard to compare the diagnostic efficiency of the two methods,in order to improve the diagnostic rate of non-mass microcalcification of the breast,as well as assist clinicians in making a reasonable diagnosis and treatment plan.Methods:Retrospective analysis of 148 patients including 152 lesions for BI-RADS 4-5 non-mass microcalcification lesions on FFDM from January 2017 to August 2019 in the Imaging Center of Chengde Central Hospital,all patients underwent bilateral breast DCE-MRI scans before and before operation and puncture,and all lesions had pathological results.Two diagnostic doctors of subtropical high and above with experience in breast diagnosis,without knowing the pathological results,analyzed,evaluated and classified FFDM and DCE-MRI images respectively and reach a consensus when there is a difference of opinion,according to the fifth edition of Breast Imaging and Reporting Data System(BI-RADS)designed by the American Society of Radiology(ACR)in 2013.The classification of FFDM images is mainly based on the shape and distribution of microcalcification and whether it is accompanied by structural distortion and asymmetric dense shadow of the local focus.The classification of DCE-MRI images is mainly based on the morphological manifestations,internal enhancement characteristics and time to signal intensity curve(TIC)type of the lesions.Do statistical analysis with SPSS25.0 and Medcalc15.2.2 software:(1)The relationship between the imaging features of FFDM and DCE-MRI and benign and malignant tumors was analyzed;(2)Draw the receiver operator characteristic curves(ROC)the two diagnostic methods,threshold was found according to the most approximate Youden index,which is used to judge the benign and malignant boundary of the two diagnostic methods for BI-RADS classification of breast lesions.(3)With histopathological results as the golden standard,the sensitivity,specificity and positive predictive value(PPV),negative predictive value(NPV)and accuracy of the two methods for different BI-RADS classification were calculated and compared with χ2 test or Fisher exact test.(4)The area under the ROC curve(AUC)of the two diagnostic methods were compared with Z test for different BI-RADS classification,the confidence interval(CI)was 95%;To P<0.05 for the difference was statistically significant.Results:1 Comparison of FFDM imaging features between pathological benign and malignantThe imaging features of FFDM,such as the shape and distribution of microcalcification,whether accompanied by structural distortion and asymmetric dense shadow of local focus,were significantly different between benign and malignant lesions(χ2=40.232,36.047,13.761,respectively,all P=0.000<0.05).2 Comparison of DCE-MRI imaging features between pathological benign and malignant(1)The PPV of non-enhancement,focus enhancement,mass enhancement and non-mass enhancement are 0,22.2%,86.7% and 28.6%,respectively.The enhancement type of lesions between benign and malignant was significant difference(P< 0.05);(2)A total of 152 lesions,4 lesions were no enhancement,148 lesions were enhancement,90 malignant lesions and 58 benign lesions of 148 enhancement lesions.Draw time-signal strength curve(TIC),the PPV of persistent type,plateau type and washout type were 16.7%,71.4% and 95.0%,respectively,and TIC type between benign and malignant lesions was significant difference(χ2=74.608,P=0.000<0.05).3 Draw the ROC curve of the two diagnostic methods to obtain the best diagnostic thresholdTaking the pathological results as the gold standard,the sensitivity,specificity and Youden index of FFDM and DCE-MRI in the diagnosis of benign and malignant breast BI-RADS were calculated respectively.Taking the sensitivity as the ordinate and the 1-specificity as the abscissa,the BI-RADS classification ROC curves of the two diagnostic methods were drawn for the diagnosis of breast lesions.The diagnostic cutoff point closest to the upper left corner of the ROC curve(when the Youden index was the highest)was the best diagnostic threshold,the best diagnostic thresholds of both methods were 4b.4 For breast BI-RADS 4-5 non-mass microcalcification lesions on FFDM,comparison of the diagnostic efficacy of the two methods.(1)The sensitivity,specificity,PPV,NPV and accuracy of FFDM were 86.7%,53.2%,72.9%,73.3%,73.0%,DCE-MRI were 93.3%,83.9%,89.4%,89.7%,89.5%,respectively.The sensitivity,specificity,PPV,NPV and accuracy of DCE-MRI were higher than FFDM,the sensitivity of the two methods was not significant difference(χ2=2.222,P=0.136>0.05),the specificity,PPV,NPV and accuracy of the two methods were statistically significant difference(χ2=13.503,8.674,4.681,13.495,respectively,all P<0.05).(2)The area under the ROC curve(AUC)of FFDM and DCE-MRI diagnostic methods were 0.752 and 0.907,respectively,the difference between the two AUC was statistically significant.(Z=4.068,P<0.0001,95% CI was 0.0804～0.230).5 For breast BI-RADS 4 non-mass microcalcification lesions on FFDM,comparison of the diagnostic efficacy of the two methods.(1)The sensitivity,specificity,PPV,NPV and accuracy of FFDM were 82.4%,57.9%,70.0%,73.3%,71.2%,DCE-MRI were 92.6%,86.0%,88.7%,90.7%,89.6%,respectively.The sensitivity,specificity,PPV,NPV and accuracy of DCE-MRI were higher than FFDM,the sensitivity of the two methods was not significant difference(χ2=3.294,P=0.070>0.05),the specificity,PPV,NPV and accuracy of the two methods were statistically significant difference(χ2=11.122,7.903,5.299,13.428,respectively,all P<0.05).(2)The area under the ROC curve(AUC)of FFDM and DCE-MRI diagnostic methods were 0.745 and 0.899,respectively,the difference between the two AUC was statistically significant.(Z=3.796,P=0.0001<0.05,95% CI was 0.0745～0.234).6 For breast BI-RADS 5 non-mass microcalcification lesions on FFDM,comparison of the diagnostic efficacy of the two methodsThe sensitivity,specificity,PPV,NPV and accuracy of FFDM were 100.0%,0,81.5%,0,81.5%,DCE-MRI were 95.5%,60.0%,91.3%,75.0%,88.9%,respectively.Although the specificity,PPV,NPV and accuracy of DCE-MRI were higher than FFDM,but the sensitivity specificity,PPV and accuracy of the two methods was not significant difference(all P>0.05).Conclusion:1 The imaging features of FFDM(such as the shape and distribution of microcalcification,whether accompanied by structural distortion and asymmetric dense shadow of local focus)and the imaging features of DCE-MRI(such as morphology,internal enhancement,TIC curve)have a certain value in the differential diagnosis of benign and malignant lesions.2 The best diagnostic threshold of FFDM and DCE-MRI was 4b,so the BI-RADS 4b or above was malignant and the BI-RADS below 4b was benign.3 For breast BI-RADS 4-5 and breast BI-RADS 4 non-mass microcalcification lesions on FFDM,the sensitivity of DCE-MRI was not significantly improved,but the specificity,PPV,NPV and accuracy were significantly improved.While for breast BI-RADS 5 non-mass microcalcification lesions on FFDM,DCE-MRI has no obvious advantage over FFDM in the qualitative diagnosis of breast lesions. |
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