Breast Lesions Presented As Nonmass Enhancement On MRI:Multimodal Imaging Analysis

Part ⅠComparative Studyof MRI,Mammography and Ultrasonography in the Diagnosis of Nonmass Enhancement Breast LesionsObjective:To compare the diagnostic values of MRI,digital mammography and ultrasonography for breast lesions categorized as non-mass enhancement(NME).Materials and Methods:Patients with NME breast lesions who underwent preoperative MRI,digital mammography and ultrasonography from July 1st 2015 to December 30 th 2016 were recruited in this study.The imaging features of MRI,digital mammography and ultrasonography were retrospectively analyzedand their diagnostic performanceswere compared.Histopathological outcomes were used as the reference.Results: Seventy-six patients with 81 NME lesions were analyzed.Among the 81 lesions,32 lesions were benign and 49 lesions were malignant according to the pathological results.The diagnostic sensitivities of ultrasonography,digital mammography and MRI were 57.14%,61.22% and 97.96%,respectively.The specificities were 93.75%,68.75% and 59.38%,respectively.The accuracies were 71.60%,64.20% and 62.50%,respectively.The positive predictive values(PPV)were 93.33%,75.00% and 80.00%,respectively.The negative predictive values(NPV)were 58.82%,52.50% and 95.24%,respectively.After combination of MRI,digital mammography and ultrasonography,the diagnostic sensitivity,specificity,accuracy,PPV and NPV were 97.96%,68.75%,86.42%,82.76% and 95.65%,respectively.The micro-calcification on mammography,calcification and blood flow echo on ultrasonography were the key indexes for malignant NME lesions.Significant differences(P<0.05)were observed in distribution and TIC type between benign and malignant NME lesions.Conclusion:The diagnosticsensitivity of MRI in NME lesions was higher than those of mammography and ultrasonography.The specificity of the combination was higher than MRI alone.It is helpful for the diagnosis of NME breast lesions by MRI withcombinaion of mammography and ultrasonography.PartⅡ Diagnostic Value of Incoherent Motion Model Diffusion-weighted MRI for Non-mass Enhancement Breast LesionsObjective:To evaluate the value of intravoxel incoherent motion diffusion weighted imaging(IVIM-DWI)in the diagnosis of breast lesions categorized as non-mass enhancement(NME).Materials and Methods:Forty-seven patients with 78 NME breast lesions who underwent preoperative conventional MRI and IVIM-DWI from December 1st 2015 to December 30 th 2016 were recruited in this prospective study.Seventy-eight NME lesions(32 benign and 46 malignant lesions)were analyzed with histopathological outcomes.The ADC values and the IVIM-derived parameters pure diffusion coefficient(D),pseudodiffusion coefficient(D*),and perfusion fraction(f)were calculated separately and compared for the two groups.The diagnostic performance of different parameters was compared by using the receiver operating characteristic curve(ROC curve).Results: The mean ADC and D values in malignant lesions were(1.06±0.23×10-3 mm2/s)and(0.88±0.22×10-3 mm2/s),respectively,which were significantly lower than those of(1.30±0.26)×10-3 mm2/s and(1.24±0.24)×10-3 mm2/s in benign lesions.The mean f value in malignant lesions was significantly higher than that in benign lesions [16.15(9.10,28.13)% vs 14.24(6.90,11.95)%,P=0.003]。However,there was no significant difference in D* between the benign and malignant groups.The area under the ROCs(AUCs)for D,ADC,and f in distinguishing malignant from benign lesions were 0.890,0.769 and 0.695,respectively.The AUC of D value was the highest and the corresponding diagnostic sensitivity and specificity were 78.3% and 75.0%,respectively,with the threshold of 1.07×10-3 mm2/s.The corresponding diagnostic sensitivity and specificity of ADC value were 73.9% and 68.8% while taking the optimal threshold of 1.14×10-3 mm2/s.The corresponding diagnostic sensitivity and specificity of f value were 60.9% and 78.1% while taking the optimal threshold of 12.00%.The diagnostic sensitivity,specificity,accuracy,PPV and NPV of conventional MRI were 97.83%,68.75%,85.90%,81.82% and 95.65%,respectively.After combination of D and f value,the diagnostic sensitivity,specificity,accuracy,PPV and NPV of MRI were 97.83%,84.38%,90.00%,92.31% and 96.43%,respectively.Conclusion:The D and f values derived from the IVIM-DWI model are able to distinguish malignant from benign NME breast lesions.D value can provide the most valuable information.