Intravoxel Incoherent Motion MR Imaging Differentiates Benign And Malignant Breast Lesions: Comparison With Quantitative Dynamic Contrast-enhanced MR Imaging

Objective:To compare diagnostic performance for breast lesions by quantitative parameters derived from intravoxel incoherent motion（IVIM）and dynamic contrast-enhanced（DCE）magnetic resonance imaging（MRI）and to explore whether correlations exist between these perfusion parameters.Material and Methods:Retrospective analysis was performed on 88 cases of breast tumor diagnosed by pathology in our hospital from October 2019 to July 2020,including 93 lesions.According to the pathological results,the patients were divided into benign tumor group and malignant tumor group,of which 44 were benign tumors and 49were malignant tumors.All the patients underwent routine breast MRI examination,IVIM and DCE-MRI examination within 2 weeks before needle biopsy or surgery.The IVIM parameters true diffusion coefficient（D）,perfusion-related diffusion coefficient（D*）,perfusion fraction（f）and DCE-MRI parameters volume transfer coefficient(K^trans),reverse reflux rate constant(K_ep),volume fraction of extravascular space（V_e）were measured by GE post-processing workstation AW 4.6.Two independent samples t-test or Mann-Whitney U test were used to compare the statistical differences of each parameter in benign and malignant breast tumors.The ROC curve was drawn to determine the threshold of each parameter in the diagnosis of malignant breast tumors,as well as the area under the curve（AUC）for diagnostic sensitivity and specificity.Correlation between IVIM prefusion-related and DCE-MRI parameters was assessed Using Pearson’s rank correlation.Result:The D and f values of malignant breast tumors were lower than those of benign breast tumors（P<0.001,respectively）,the D value（10-3mm²/s）of the benign tumor group and the f value（%）of the malignant tumor group were 1.002±0.193 and0.732±0.132,respectively,and 34.1±8.9 and 24.1±6.5.There was no statistical difference in the D*value between the two groups（P=0.078）,and the D*value(10^-3mm²/s)of the two groups were 3.916±1.485 and 4.464±1.523,respectively.The K^trans and K_ep value of breast cancer was higher than that of benign group（P<0.001,respectively）,K^tarns value(min^-1)of benign tumor group and K_ep value(min^-1)of malignant tumor group were 0.310±0.108 and 0.777±0.270,and K_epvalue(min^-1)of malignant tumor group were 0.390（0.244）and 0.971（0.502）,respectively.There was no statistical difference in Ve value between the two groups（P=0.081）,and Ve value of benign tumor group and malignant tumor group were 0.962（0.339）and0.730（0.368）,respectively.The AUC of IVIM parameter D and f value in diagnosis of breast cancer was 0.891 and 0.827,respectively,The combined AUC of IVIM parameters was 0.876.The AUC of DCE-MRI(K^trans and K_ep)in the diagnosis of breast cancer was 0.933 and 0.948,respectively.The combined AUC of DCE-MRI parameters was 0.955.There was no statistically significant difference in the diagnostic efficacy between D value between K^trans and K_ep,and was no significant difference between the AUCs of DCE-MRI and IVIM with parameters combined（P=0.568）.Correlation analysis demonstrated that D was moderly negatively correlated with ktransand kep（r=-0.469,r=-0.510,P<0.001 for all）,f was weak negatively correlated with Ktrans,K_ep（r=-0.397,r=-0.328,P<0.001 for all）.Conclusion:Both Ktrans,Kep D and f can effectively differentiate benign and malignant breast tumors,IVIM and DCE-MRI have similar diagnostic efficacy,and perfusion parameters of IVIM and DCE-MRI are correlated to some extent.