T1-Mapping with High-Spatial-Resolution T2-Weighted Imaging Differentiates Mucinous from Nonmucinous Adenocarcinoma in Rectal Cancer

Motivation: Differentiating mucinous adenocarcinoma (MC) from adenocarcinoma not otherwise specified (AC) is crucial due to distinct prognostic and treatment responses. Goal(s): To assess high-spatial-resolution T2-weighted imaging (HR-T2WI) and T1-mapping effectiveness in distinguishing MC from AC in rectal cancer. Approach: In this prospective study of 92 patients (55 AC, 37 MC), radiologists assessed HR-T2WI scans, and pre- and post-contrast T1 relaxation times were measured. Diagnostic efficacy was evaluated using receiver operating characteristic curve analysis. Results: HR-T2WI achieved 81.08% sensitivity and 94.55% specificity. The combined HR-T2WI and T1p model yielded a 0.927 area under the curve, improving diagnostic performance over individual techniques Impact: This study suggests combining HR-T2WI and T1-mapping as a non-invasive method for diagnosing MC in rectal cancer, potentially reducing false-negative biopsies. Future research can explore its role in treatment response prediction and outcome assessment.