Efficient Assessment of CR to Neoadjuvant Therapy in Locally Advanced Rectal Cancer using Amide Proton Transfer Weighted MRI: a Diagnostic Study

Motivation: Existing standard methods, including MRI, are inadequate for assessment of CR. Goal(s): To assess the value of Amide Proton Transfer-weighted (APTw) MRI in the assessment of CR to NAT in LARC. Approach: Conventional assessments of CR to NAT based on post-NAT T2WI and DWI, tumor segmentation, and histogram analysis based on post-NAT APTw images, were performed by two experienced radiologists independently. APTw-added combined model (combination of APT histogram, T2WI, and DWI) was constructed. Results: The AUC of the APTw-added combined model for assessing CR to NAT was significantly higher than that of conventional assessment (0.97 vs 0.71, P< .001). Impact: Our study revealed the clinical significance of APTw MRI as a promising imaging modality for assessing CR to NAT in LARC. APTw MRI can provide unique insights into tumor metabolism and microenvironment, surpassing the capabilities of traditional MRI.