Engelen Sanne M E, Beets Geerard L, Beets-Tan Regina G H
Department of Radiology, University Hospital Maastricht, The Netherlands.
Onkologie. 2007 Mar;30(3):141-5. doi: 10.1159/000099026. Epub 2007 Feb 16.
Preoperative imaging in rectal cancer is very important, as accurate staging determines optimal treatment strategy. In this review, imaging modalities for locoregional and distant staging in rectal cancer are discussed. For local staging, superficial tumors are best staged using endorectal US (EUS), as EUS is the most accurate modality for assessment of tumor ingrowth into the rectal wall layers. The more advanced tumors are best imaged using MRI, because MRI accurately predicts the distance from tumor to mesorectal fascia, and thus the circumferential resection margin (CRM), as well as possible invasion into surrounding organs. For the prediction of the nodal status none of the three imaging modalities - EUS, MRI and CT - can be reliably used for clinical decision-making. Only MRI using lymph node specific contrast (such as ultrasmall paramagnetic iron oxide-enhanced MRI) seems promising for the detection of nodal disease. For the detection of distant metastases transabdominal ultrasound and chest X-ray are used as a primary screening tool. However, for the high prevalence group (stage III) both methods are insufficiently sensitive, and CT of the chest plus abdomen is preferred.
直肠癌的术前影像学检查非常重要，因为准确分期决定最佳治疗策略。在本综述中，将讨论直肠癌局部区域和远处分期的影像学检查方法。对于局部分期，浅表肿瘤最好采用直肠内超声（EUS）进行分期，因为EUS是评估肿瘤向直肠壁各层浸润的最准确方法。对于进展期肿瘤，最好采用MRI成像，因为MRI能准确预测肿瘤与直肠系膜筋膜的距离，从而确定环周切缘（CRM），以及是否可能侵犯周围器官。对于淋巴结状态的预测，EUS、MRI和CT这三种影像学检查方法均不能可靠地用于临床决策。只有使用淋巴结特异性造影剂的MRI（如超小顺磁性氧化铁增强MRI）在检测淋巴结疾病方面似乎很有前景。对于远处转移的检测，经腹超声和胸部X线用作初步筛查工具。然而，对于高患病率组（III期），这两种方法的敏感性均不足，首选胸部加腹部CT检查。
