MRI Restaging of Rectal Cancer: the RAC (Response-Anal Canal-Crm) Analysis Joint Consensus Guidelines of the GRERCAR and GRECCAR Groups.

Purpose: To develop guidelines by international experts to standardize data acquisition, image interpretation, and reporting in rectal cancer restaging with magnetic resonance imaging (MRI). Materials and methods: Evidence-based data and experts' opinions were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts provided recommendations for reporting template and protocol for data acquisition were collected; responses were analysed and classified as "RECOMMENDED" versus "NOT RECOMMENDED" (if > 80% consensus among experts) or uncertain (if < 80% consensus among experts). Results: Consensus regarding patient preparation, MRI sequences, staging and reporting was attained using the RAND-UCLA Appropriateness Method. A consensus was reached for each reporting template item among the experts. Tailored MRI protocol and standardized report were proposed.Conclusion: These consensus recommendations should be used as a guide for rectal cancer restaging with MRI.& COPY; 2023 Published by Elsevier Masson SAS on behalf of Societe francaise de radiologie.