Diagnostic value of diffusion kurtosis imaging combined with quantitative dynamic contrast-enhanced MRI in breast lesions

Abstract

Objective To evaluate the diagnostic efficacy of MRI diffusion kurtosis imaging (DKI) and quantitative dynamic contrast enhancement MRI (DCE-MRI) in benign and malignant breast lesions, and to explore the differential diagnosis ability for different pathological types and molecular subtype lesions. Methods Sixty four females were retrospectively enrolled in the study of MRI diffusion kurtosis imaging and quantitative dynamic contrast enhancement between November 20 and May 2017. All of them were confirmed to have benign or malignant lesions after surgical resection or puncture. All patients underwent axial T1WI, DKI and DCE-MRI examinations. The mean kurtosis (MK) and mean diffusivity (MD) values were calculated by the DKI model, and the hemodynamic parameters were obtained by quantitative dynamic contrast enhancement, including volume transfer constant (Ktrans), rate constant (Kep), extravascular extracellular space distribute volume per unit tissue volume (Ve) and blood volume fraction (Vp). Pathological analysis was performed to monitor the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2) and nuclear proliferation index Ki67. The breast cancer was divided into Luminal A type, Luminal B type, HER-2 positive and triple-negative 4 subtypes. The differences of DKI parameters and DCE-MRI parameters between benign and malignant breast lesions were compared using two independent samples t test (normal distribution and homogeneity of variance) or Mann-Whitney U test (skewed distribution or variance). ROC analysis was used to evaluate the value of DKI and DCE-MRI parameters in differential diagnosis of benign and malignant breast lesions with pathological results as the gold standard. The Mann-Whitney U test and Kruskal-Wallis H test were used to compare the differences of DKI and DCE-MRI parameters among different prognostic factors and molecular subtypes of breast cancer. Spearman rank correlation analysis was used to evaluate the correlation between DKI and DCE-MRI parameters and different prognostic factors. Results Sixty-four cases were single lesions, with breast cancer in 23 cases and 41 cases of benign lesions. In breast cancer, there were 9 cases of Luminal A type, 7 cases of Luminal B type, 3 cases of HER-2 positive type and 4 cases of triple negative type. The positive numbers of ER, PR and HER-2 were 14, 11 and 10 cases respectively. Nineteen cases showed high expression of Ki67, while 4 cases showed low expression. There were significant differences in MK, MD, Ktrans and Kep between benign and malignant lesions (P 0.05).The area under the ROC for the differential diagnosis of benign and malignant breast lesions were 0.897, 0.808, 0.844 and 0.842, respectively. The combined multi-parameter differential diagnosis improved the efficacy. Combined with the above four parameters, the area under the ROC was 0.950. The diagnosis Sensitivity, specificity and accuracy were 0.870, 0.951 and 0.922 respectively. The Ktrans and Vp values of patients with ER positive and ER negative, as well as Ve value of deferent lymph node status, were significantly different (P 0.05). There was a moderate positive correlation between ER and Ktrans and Vp values. There was a low positive correlation between lymph node status and Ve value (r= 0.6, 0.5 and 0.4, respectively, P 0.05). There were no significant differences in DKI and DCE-MRI parameters among different subtypes of breast cancer patients (all P>0.05). Conclusion DKI combined with DCE-MRI can improve the differential diagnosis of breast lesions and some DCE-MRI parameters are related to prognostic factors. Key words: Breast neoplasms; Magnetic resonance imaging; Diffusion kurtosis imaging; Quantitative dynamic contrast enhancement