Objective To explore the value of amide proton transfer-weighted imaging(APTw) and T2 mapping in assessing microsatellite instability(MSI) in endometrial adenocarcinoma. Methods The patients with clinically suspected endometrial cancer were prospectively enrolled and underwent APTw and T2 mapping before operation.Two radiologists independently outlined the regions of interest and measured the quantitative parameters.The intragroup correlation coefficients were calculated to assess the agreement of MRI parameters measured by the two radiologists.The independent samples t-test and Mann-Whitney U test were conducted to compare quantitative variables between the MSI and microsatellite stability(MSS) groups.The receiver operator characteristic curve was established to evaluate the prediction performance of different parameters.The DeLong test was implemented to compare the area under the curve(AUC) between single parameters and their combination. Results Twenty-one patients in the MSI group and 37 patients in the MSS group were finally enrolled in this study.The results showed excellent agreement between two radiologists in assessing MRI parameters.The MSI group had higher APTw values[(2.72±0.52)% vs.(2.08±0.39)%,P<0.001]and lower T2 values[92.25(90.82,99.91) ms vs.101.80(96.15,112.13) ms,P<0.001]than the MSS group.The receiver operating characteristic curve showed that the AUC of APTw and T2 values were 0.821(95%CI=0.698-0.909) and 0.793(95%CI=0.666-0.888),respectively.No significant difference in diagnostic efficacy was observed between the two sequences(P=0.692).The combination of APTw and T2 mapping yielded the highest AUC of 0.897(95%CI=0.789-0.961),which was higher than that of APTw and T2 mapping alone(P=0.042,P=0.025,respectively). Conclusions APTw and T2 mapping are valuable in assessing the MSI of endometrial adenocarcinoma,and the combination of the two demonstrates higher diagnostic efficacy,thus providing a basis for the selection of preoperative therapeutic modalities for the patients.