A Preliminary Study Of Diffusion Basis Spectrum Imaging(DBSI)in Evaluation Of Breast Lesions

Part 1 The Application of DBSI in differential diagnosis of benign and malignant breast lesionsObjective:To explore the characteristics of DBSI parameters in normal breast gland tissues and breast lesions,and to compare the efficiency of DBSI parameters and ADC in differential diagnosis of benign and malignant breast lesions.Methods:Between September 2016 and November 2017,a total of 75 patients with81 lesions?20 benign and 61 malignant?pathologically confirmed by surgery or biopsy were enrolled.After accurate selection of regions of interest?ROI?of tumors on contrast-enhanced T₁WI image,the parameters including ADC and ADC*,HR,RF,HF,FF from DBSI were measured on the post-processing images.The parameters of normal breast tissue,breast benign and malignant lesions was compared by Nonparametric test of multiple independent samples?Kruskal-Wallis?test.Comparison of ROC curves for parameters from DBSI and ADC were done by MedCalc to analyze the differential diagnosis efficacy of breast benign and malignant lesions.Results:The values of ADC?P<0.0001?and DBSI parameters of normal breast tissues,benign and malignant lesions were significantly different?P<0.0001,P<0.0001,P<0.0001,P=0.001,P<0.0001?.HR values of benign and malignant lesions were lower than those of normal glandular tissue?P=0.0031,P<0.001?;RF values of malignant lesions,benign lesions and normal gland decreased in turn?P<0.001,P<0.001,P=0.033?;HF value of malignant lesions were lower than those of benign lesions and normal breast tissue?P<0.001,P<0.001?,and the FF value of malignant lesions was lower than that in normal glandular tissue?P=0.034?.The specificity for differentiating benign and malignant lesions was 95%when HR cutoff value was 0.08%,but the sensitivity was very low?5%??AUC=0.549?.Using a RF,HF,FF,ADC*and ADC cutoff value of 51.45%,14.51%,23.78%,0.82×10^-3mm²/s and 1.20×10^-3mm²/s,the sensitivity and specificity of differentiating benign and malignant lesions were 83.6%,70.5%,86.9%,80%,85.3%and90%,85%,35%,82%,75%?AUC=0.906,0.872,0.559,0.837,0.813?,respectively.When combined with HF and RF,the sensitivity and specificity of differential diagnosis of benign and malignant lesions was 77%and 99%?AUC=0.929?.Conclusion:The parameters of DBSI can be well correspond to pathological components of inflammatory cells,tumor cells,edema or normal mammary glands and fiber.For identifying benign and malignant breast lesions,DBSI specific parameters?HR,RF,HF,FF?have high specificity,and the combined application of RF and HF can further improve the specificity of differential diagnosis.DBSI parameters RF and HF have the same diagnostic efficiency as ADC.Part 2 The correlations between DBSI parameters and pathological prognostic factors and molecular subtypes of breast cancer Objective: To explore the correlations between DBSI parameters and histological grade of breast invasive ductal carcinoma,and the correlations between DBSI parameters and prognostic factors?ER,PR,HER-2,Ki-67?and molecular subtypes?Luminal A,Luminal B,HER-2 overexpression and TNBC?of breast cancer.Methods: Between September 2016 and November 2017,a total of 57 patients with 61 malignant lesions pathologically confirmed by surgery or biopsy were enrolled.After accurate selection of regions of interest?ROI?of tumors on contrast-enhanced T1 WI image,the parameters from DBSI?ADC*,HR,RF,HF,FF?were measured on the postprocessing images.The difference of HR,RF,HF,FF,ADC* between low and high grade invasive ductal carcinoma was compared by two independent samples Wilcoxon test.And Wilcoxon test was also used to compare the differences of DBSI parameters between ER+/-,PR+/-,HER-2+/-,high and low Ki-67 expression tumors.Spearman correlation was used to analyze the correlations between parameters of DBSI and the expression rate of Ki-67.The differences of DBSI parameters of four molecular subtypes of breast cancer were compared by using Nonparametric test of multiple independent samples followed by Nemenyi test.Results: RF value?62.33%?of low grade invasive ductal carcinoma was lower than that of high-grade cancer?73.71%??P=0.011?.And the HF?14.43%?and ADC*?0.78×10-3mm2/s?values were higher than those in high-grade group?8.40%,0.72×10-3mm2/s??P=0.004,P=0.005?.The HF?7.66%?and ADC*?0.71×10-3mm2/s?values of ER+ breast cancer were lower than those of ER-group?14.02%,0.77×10-3mm2/s??P=0.012,P=0.007?,and FF value?14.09%?was higher than that in ER-cancer?4.35%??P=0.023?.The values of HF?7.60%?and ADC*?0.71×10-3mm2/s?of PR positive group were lower than those of PR negative group?13.33%,0.75×10-3mm2/s??P=0.009,P=0.013?.The value of HF?14.28%?and ADC*?0.76×10-3mm2/s?in HER-2 positive group was higher than that in HER-2 negative group?8.40%,0.72×10-3mm2/s??P=0.048,P=0.024?.There was no statistical difference between Ki-67 low and high expression cancers?>20%?,and no significant correlations between DBSI parameters and Ki-67 expression rate were found,either.The FF value of Luminal B subtype was larger than that of TNBC?P=0.050?.There was no significant difference between DBSI parameters of residual subtypes.Conclusion: To some extent,the parameters of DBSI can predict the histological grade and prognostic factors of breast cancers,and reveal the difference of histological composition in different types of lesions,especially RF and HF.However,the correlations between these parameters and molecular subtypes remain unclear.