直肠MRI对直肠癌术前T分期评估的研究进展

Progress in pre-operation tumor staging of rectal cancer by rectal MRI

直肠MRI是直肠癌术前分期的首选检查方法。高分辨T2WI可显示直肠癌的位置、形态及信号,通过判别肿瘤的浸润深度来评估直肠癌的T分期;还可以识别直肠癌壁外血管内侵犯、环周切缘阳性等预后不良因素,从而指导选择最佳治疗方案。增强T1WI可显示病变区是否存在完整的黏膜下强化带,结合形态学特征准确地区分T1及T2期肿瘤。基于直肠壁各层及周围结构的MRI征象,对直肠MRI评估直肠癌术前局部T分期的研究进展进行综述。

Rectal MRI is the preferred preoperative staging modality for rectal cancer.The location,morphology and signal intensity could be well shown on high resolution T2WI.Clinicians could assess the T staging of rectal cancer by identifying the tumor invasion depth.In addition,the risk factors of poor prognosis,such as extramural vascular invasion and positive circumferential resection margin,could be detected on high resolution T2WI,thus helps to select the optimal treatment strategy.Contrast-enhanced T1WI is used to evaluate rectal submucosal enhancing strip,and by combining with morphologic characteristics could accurately differentiate T1from T2stage tumor.This paper reviews the research progress of rectal MRI in evaluating preoperative local T staging of rectal cancer based on the MRI features of all the layers of rectal wall and perirectal tissues.