目的 探讨直肠腺瘤的MRI影像 学特征，提高对直肠腺瘤的诊断水平。 方法 对26例经手术病理证实的直肠腺瘤 病人的临床资料进行回顾性分析。结果 26例直肠腺瘤中管状腺瘤4例，管状绒毛 状腺瘤17例，绒毛状腺瘤5例。MRI影像 特征有：从黏膜层向腔内呈团块状或菜 花状生长，肠壁无增厚，宽基底生长； 平扫T1WI以低信号为主，T2WI以稍高信 号为主，b=800s/mm2 时DWI轻度扩散受 限呈稍高信号，增强扫描以轻中度强化 为主；病灶与直肠壁相贴时留下通气的 间隙20例，可作为直肠腺瘤的特征性表 现。结论 MRI有助于直肠腺瘤的诊断及鉴 别。

Objective To explore the MRI imaging of rectal adenoma and clinical analysis, and to improve the level of diagnosis. Methods 26 cases with rectal adenoma pathologically proved were analysed retrospectively. Results The pathological types of 26 cases included 4 cases of tubular adenoma, 17 cases of tubulovillous adenoma and 5 cases of villous adenoma. The MRI manifestations were as followed: crumb or cauliflower growing from the mucous membrane layer to the lumen, no thickening of rectal wall, wide base. On un-enhanced T1WI the lesions showed hypointense mainly, on T2WI showed slightly hyperintense mainly, on b=800s/mm2 DWI showed mild diffusion limited as slightly hyperintense. After contrast administration, the lesions showed slightly-moderately enhancement mainly. There was a venting gap between the tumor and the rectal wall in 20 cases, which were regarded as the characteristic feature of rectal adenoma. Conclusion MRI was of value in the diagnosis and differential diagnosis of rectal adenoma.