Abstract: Objective:To investigate the value of MRI with rectal irrigation in diagnosis and preoperative staging of rectal cancer.Methods:Thirty-two patients with suspected rectal cancer were detected by MRI with rectal irrigation.All patients were scaned under T1WI and T2WI of axial and sagittal plane.Ten cases were detected through MRI with rectal irrigation.The tumor characteristics,surrounding infiltrating and lymph node enlargement were measured,which were compared with pathology.Results:The overall diagnosis accuracy of T staging by MRI with rectal irrigation was 87.5% and the diagnosis accuracy of less than or equal to T2,T3 and T4 were 78.6%,93.3% and 100.0%,respectively.The sensitivity and specificity of lymph nodes invasion were 56.5% and 98.4%.The shape,size and position of rectal neoplasms and stricture of rectal lumen could be clearly displayed under MRI.Conclusions:MRI with rectal irrigation can accurately judge the preoperative stage of rectal neoplasms,which can help to make reasonable treatment and prognosis assessment.It is a supplement for routine scan.