The Study Of Intravoxel Incoherent Motion MR Imaging In The Assessment Of The Value Of The Diagnosis And Prognosis Of Breast Lesions

Purpose: To compare the value of the intravoxel incoherent motion(IVIM)imaging(Bi-exponential model and Stretched-exponential model)and Diffusion-weighted imaging(mono-exponential model)in the differential diagnosis of benign and malignant breast lesions.And further analysis for evaluate the associations between IVIM derived parameters and histopathological features and subtypes of breast cancer.Methods: Two hundreds and fifty-seven patients with 276 breast lesions(including 197 malignant lesions and 79 benign lesions)confirmed by pathology were retrospectively analyzed.The normal breast tissue was used as contral group.All of the patients underwent routine MRI sequences and multiple b-value DWI sequences to obtain the bi-exponential model,Stretched-exponential model parameters of the IVIM and the mono-exponential model parameters of the traditional DWI(ADC,slow ADC,fast ADC,f,DDC and ? values).The parameters were compared in different groups(normal control group,breast benign lesions and malignant lesions)by K independent samples test,P < 0.05 were considered statistically significant;Mann–Whitney U test was used for further comparisons between specific group pairs(Malignant vs.Benign,Malignant vs.Normal,Benign vs.Normal),P < 0.02 were considered statistically significant.These parameters were compared among the normal breast tissues,benign lesions and malignant lesions.The sensitivity,specificity and best thresholds of these parameters for differential diagnosing of malignant and benign lesions were calculated by the receiver operating characteristic(ROC)curve.Analysis the pathologic and immunohistochemical index of the 187 malignant lesions,10 cases of ductal carcinoma in situ and 151 cases of invasive ductal carcinoma in the second part of the study,For analysis of histopathological features and subtypes,Mann Whitney U-tests and Kruskall-Wallis tests were used.P<0.05 were considered statistically significant.Results: The ADC,slow ADC,fast ADC,f,DDC and ? values were significantly different among the malignant lesions,benign lesions and normal breast tissue(P<0.001).Mann–Whitney U test further comparisons,The ADC,slow ADC,fast ADC,f,DDC and ? values were significantly different between the malignant lesions and benign lesions/ malignant lesions and normal breast tissue(P<0.001).and The ADC,slow ADC,f,DDC and ? values were gradually reduced in normal breast tissue,breast benign lesions and malignant lesions,fast ADC values were gradually increased in normal breast tissue,breast benign lesions and malignant lesions;The ADC,slow ADC,DDC and ? values were significantly different between the benign lesions and normal breast tissue(P<0.001).The areas under the ROC curve(AUC)of ADC,slow ADC,f,DDC and ? values were 0.865,0.861,0.742,0.85 and 0.735,respectively;The optimal diagnostic threshold of ADC,slow ADC,DDC and ? values were 1.105×10-3mm2/s,0.883×10-3mm2/s,1.025×10-3mm2/s and 0.842 respectively.The sensitivity is highest for slow ADC(90.3%),the specificity is highest for DDC(79.5%)?the AUC of combining slow ADC with fast ADC were 0.882.the AUC of combining DDC and ? values were 0.853.The slow ADC value were higher in low Ki-67 cancer than in high Ki-67 cancer(P =0.045).Her-2 positive breast cancer showed higher slow ADC(P =0.014)than other types.Slow ADC?f?DDC and ADC was lower in IDC than in DCIS(P =0.013,0.028,0.01,0.003).Conclusion: The traditional DWI and IVIM-MRI are all help to differential diagnosis of benign and malignant breast lesions.Combining slow ADC and fast ADC derived from the bi-exponential mode can provide a higher diagnostic accuracy.Some parameters derived from IVIM has a certain correlation between Ki-67 index,molecular classification and histological,who has the potential value for predicting the prognosis of breast cancer.