To compare the value of diffusion kurtosis imaging (DKI) mode and mono-exponential mode in predicting the response to neoadjuvant chemotherapy (NAC) for locally advanced breast carcinoma using DWI.

From January 1, 2013 to December 31,2016, eighty patients with locally advanced breast carcinoma were enrolled into this prospective clinical study. The diagnosis was confirmed on the basis of histopathological results. The clinical stage stayed at Ⅱ or Ⅲ.The patients would receive breast-conserving surgery after NAC. All the patients underwent DWI examination by using both mono-exponential mode and DKI mode before chemotherapy was initiated. The parameters included ADC, mean diffusivity (MD) and mean kurtosis (MK). Within 1 to 3 days before or after MRI examination, the patients underwent aspiration biopsy, received 4 to 8 cycles of NAC and followed by surgery. According to histologic grading before NAC, the patients were classified into well-differentiated and poor-differentiated group. According to the comparison between pathological results acquired from biopsy before NAC and specimen acquired after surgery, the patients were classified into pathologic complete response (pCR) and pathologic non-complete response (non-pCR) according to treatment effect. The imaging parameters were compared between the pCR and the non-pCR group using t test. The predicting ability of two imaging modes was compared and analyzed with ROC analysis. The relationships between multiple imaging parameters, pathologic, clinical characteristics of tumor and treatment effect were analyzed using logistic multi-variate regression analysis, and further analyzed using Wald test.

There were 30 cases of pCR and 50 cases of non-pCR. The ADC and MD values were lower in the pCR group than in the non-pCR group (P<0.05). MK value was higher in the pCR group than in the non-pCR group (P<0.05). ROC analysis showed that the area under ROC curve of ADC, MD and MK in predicting treatment effect were 0.732, 0.866 and 0.683 respectively. Logistic regression analysis showed that, according to predicting ability, MD, ADC and MK successively were the independent predictors for the early response to chemotherapy.

Compared with mono-exponential mode, DKI mode can reflect the real micro-environment and water diffusion restriction within the tumor area more reliably and accurately, and is more suitable to serve as an imaging technique for predicting the response to NAC for locally advanced breast carcinoma.

Breast neoplasms; Neoadjuvant chemotherapy; Diffusion-weighted imaging; Mono-exponential mode; Diffusion kurtosis imaging mode