SS Annunziata Hospital, Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio", Via dei Vestini, 66100 Chieti, Italy.
Department of Radiology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy.
Eur J Radiol. 2020 Oct;131:109238. doi: 10.1016/j.ejrad.2020.109238. Epub 2020 Aug 29.
To provide a practical overview regarding the state-of-the-art of the magnetic resonance imaging (MRI) protocol for rectal cancer imaging and interpretation during primary staging and restaging after neoadjuvant chemoradiation therapy (CRT), pointing out technical skills and findings that radiologists should consider for their reports during everyday clinical activity.
Both 1.5T and 3.0T scanners can be used for rectal cancer evaluation, using pelvic phased array external coils. The standard MR protocol includes T2-weighted imaging of the pelvis, high-resolution T2-weighted sequences focused on the tumor and diffusion-weighted imaging (DWI). The mnemonic DISTANCE is helpful for the interpretation of MR images: DIS, for distance from the inferior part of the tumor to the anorectal-junction; T, for T staging; A, for anal sphincter complex status; N, for nodal staging; C, for circumferential resection margin status; and E, for extramural venous invasion.
Primary staging with MRI is a cornerstone in the preoperative workup of patients with rectal cancer, because it provides clue information for decisions on the administration of CRT and surgical treatment. Restaging after CRT is crucial for treatment planning, and findings on post-CRT MRI correlate with the patient's prognosis and survival. It may be useful to remember the mnemonic word "DISTANCE" to check and describe all the relevant MRI findings necessary for an accurate radiological definition of tumor stage and response to CRT.
"DISTANCE" assessment for rectal cancer staging and treatment response estimation after CRT may be helpful as a checklist for a structured reporting.
提供一份关于直肠癌成像的磁共振成像（MRI）协议的最新技术概述，包括在新辅助放化疗（CRT）前后的分期和再分期期间的成像和解释，强调放射科医生在日常临床活动中应在报告中考虑的技术技能和发现。
1.5T 和 3.0T 扫描仪均可用于直肠癌评估，使用盆腔相控阵外部线圈。标准 MRI 协议包括盆腔 T2 加权成像、聚焦于肿瘤的高分辨率 T2 加权序列和弥散加权成像（DWI）。记忆技巧“DISTANCE”有助于 MRI 图像的解释：DIS，用于肿瘤下部到肛门直肠交界处的距离；T，用于 T 分期；A，用于肛门括约肌复合体状态；N，用于淋巴结分期；C，用于环周切缘状态；E，用于外膜静脉侵犯。
MRI 对直肠癌的分期是术前评估的基石，因为它为 CRT 和手术治疗的决策提供了线索信息。CRT 后的再分期对于治疗计划至关重要，CRT 后 MRI 的发现与患者的预后和生存相关。记住“DISTANCE”这个记忆词来检查和描述所有与肿瘤分期和 CRT 反应相关的 MRI 发现可能是有用的。
对于 CRT 后直肠癌分期和治疗反应评估的“DISTANCE”评估可能有助于作为结构化报告的检查表。
