APTWI-differential analysis for breast cancer: Association with histopathologic characteristics and early prediction of neoadjuvant chemotherapy response.

The purpose of the study is to investigate the value of Amide proton transfer imaging(APTWI)-differential analysis in association with histopathologic characteristics, and the performance to early predict pathologic complete response (pCR) in participants with breast cancer (BC). Participants with BC who underwent pretreatment APTWI between November 2022 and April 2024 were prospectively enrolled. APT-specific signal quantification was achieved through differential analysis between model-fitted and experimentally acquired Z-spectrum at +3.5 ppm. Univariate analysis was used to identify APT values associated with histopathologic characteristics and pCR. The area under the receiver operating characteristic curve (AUC) analysis was performed to evaluate the diagnostic value of APTWI-DIGITAL on histopathologic characteristics and assess the predictive performance for pCR. The analysis ultimately included 123 participants with BC (mean age, 52 years±9 [SD]), 43 participants of whom received neoadjuvant chemotherapy (NAC) and 15 participants who achieved pCR. In the pre-treatment group, the APT values showed reasonable performance in identifying the positive status of KI67 proliferation index (P = 0.01, AUC = 0.69), and PR (P = 0.045, AUC = 0.60). In the NAC group, the APT values in the pCR participants showed a significant downward trend at the T1 (P = 0.01, AUC = 0.80), and was not significant between pCR and non-pCR at other timepoints. The findings suggest APTWI-differential analysis may be useful imaging biomarkers to characterize the immunohistochemical biomarkers and predict pCR to NAC in BC patients.