Résumé
Objective To improve the diagnosis of rectal villous tumors by analyzing MRI images.Methods MRI images of 15 patients with rectal villous tumors which had been surgically resected were reviewed retrospectively(9 cases of tubulovillous adenomas,6 cases of villous adenomas).Results Among 15 lesions,7 patients with villous tumors were characterized villous-like mass with wide stem,5 patients were nodular in shape,3 patients were papillary mass,and all of 15 patients showed hypointence on T1 WI,and slightly hypointence on T2WI.On DWI,9 lesions showed low signal in center of tumor and with significant increasing signal at the boundaries of the lesion,and other 6 patients showed slightly hyperintence homogeneously.On enhanced MRI,7 patients with villous tumors showed frond pattern enhancement,5 patients showed slightly homogeneous enhancement,and 3 patients showed cerebriform pattern enhancement.11 lesions had focal dysplasia varying degrees and 4 lesions had focal carcinomatous invasion which were greater than 3 cm in diameter,in which MRI revealed villous-like in shape with frond pattern enhancement in 2 lesions,and papillary shape with cerebriform enhancement in the other 2 lesions.Conclusion MRI appearances of rectal villous tumors are variable.MRI helps with the identification of specific features of rectal villous tumors and malignant degeneration.