The Value Of Intravoxel Incoherent Motion Of Diffusion Weighted Imaging In Differentiating Benign From Malignant Breast Lesions

Objective:To study the differentiation of breast lesions malignantlesions from benign lesions and normal breast tissue using apparent diffusion coefficient(ADC) value of conventional single b-value monoexponential model diffusion weighted imaging(DWI) and pure diffusion coefficient(D) perfusion related diffusion coefficient(D*) and perfusion fraction(F) of the intravoxel incoherent motion(IVIM) DWI. To evaluate the diagnostic value of these parameters and to determine if additional information provided by DWI improves the diagnostic value of breast dynamic contrast-enhanced(DCE). Methods:Patients with suspected breast lesions were examined on MR scanner including single b-value monoexponential model DWI, IVIM DWI and dynaic contrast-enhanced MRI. 58 cases(31 cases of benign lesions, 27 cases of malignant lesions) of breast disease were confirmed by pathological result or follow- up. DWI data were analyzed by monoexponential and biexponential models. ADC parametric maps were calculated by a monoexponential fit. The derived parameters of D, D*and f were calculated by biexponential IVIM analysis. Paraeters derived by conventional monoexponential model and IVIM DWI of malignant, benign lesions and normal breast tissue were compared by the independent-samples t test. Receiver operating characteristic(ROC) curve was used to analysis and compare the ability of the parameters in differential diagnosis benign and malignant lesions. Results:ADC and D values of malignant lesions were significantly smaller than those of benign legions(P<0.001). f values of malignant lesions were significantly larger than those of benign legions and normal breast tissues(P<0.001). There were no significant differences of D* value among malignant, benign lesions(P=0.294). AUC of D value was 0.897 which was the highest one.The optimal threshold D value for the differential diagnosis of benign and malignant lesions were 1.06×10-3 mm2/s. The sensitivity D value was 90% and the specificity were 78.8%. The combinations of D with DC E-MRI provided higher area under the curve(AUC) for discrimination between malignant and benign lesions. AUC value can be increased to 0.946 by combining D with TIC, corresponding specificity increased to 96.9%. Conclusion:The D and f value from the IVIM model can be used to distinguish benign from malignant breast lesions. Associated with D and TIC can obtain better diagnostic performance.