Abstract：
Rectal MRI provides a detailed depiction of pelvic anatomy; specifically, the relationship of the tumor to key anatomic structures, including the mesorectal fascia, anterior peritoneal reflection, and sphincter complex. However, anatomic inconsistencies, pitfalls, and confusion exist, which can have a strong impact on interpretation and treatment. These areas of confusion include the definition of the rectum itself, specifically differentiation of the rectum from the anal canal and the sigmoid colon, and delineation of the high versus low rectum. Other areas of confusion include the relative locations of the mesorectal fascia and peritoneum and their significance in staging and treatment, the difference between the mesorectal fascia and circumferential resection margin, involvement of the sphincter complex, and evaluation of lateral pelvic lymph nodes. The impact of these anatomic inconsistencies and sources of confusion is significant, given the importance of MRI in depicting the anatomic relationship of the tumor to critical pelvic structures, to triage surgical resection and neoadjuvant chemoradiotherapy with the goal of minimizing local recurrence. Evolving treatment paradigms also place MRI central in management of rectal cancer. ©RSNA, 2024.
摘要：
直肠MRI提供了骨盆解剖的详细描述;特别是，肿瘤与关键解剖结构的关系，包括直肠系膜筋膜,腹膜前反射,和括约肌复合体。然而,解剖不一致,陷阱,混乱存在，这对解释和治疗有很大的影响。这些混乱的领域包括直肠本身的定义，特别是直肠与肛管和乙状结肠的区别，以及高直肠和低直肠的轮廓。其他混淆区域包括直肠系膜筋膜和腹膜的相对位置及其在分期和治疗中的意义。直肠系膜筋膜和环状切除边缘的差异，括约肌复合体的参与，并对盆腔外侧淋巴结进行评价。这些解剖不一致和混乱的来源的影响是巨大的，鉴于MRI在描绘肿瘤与重要骨盆结构的解剖关系方面的重要性，分诊手术切除和新辅助放化疗，以尽量减少局部复发。不断发展的治疗范式也将MRI置于直肠癌治疗的中心。©RSNA,2024.
