结肠肿瘤影像学诊断

溃疡型癌占进行期结肠癌的大多数，其典型X线表现是“苹果核征”（apple-core sign)，构成“苹果核征”狭窄段两端的是溃疡的环堤，中面的管腔狭窄段为癌性溃疡所形成的癌性隧道，浸润型结肠癌的发生率很低，在影像学诊断中要注意与其他疾病鉴别，隆起性病变蒂的存在是否定进行期癌的重要指征，无蒂性隆起病变，除病变的大小我，病变的基底部，整体形态，表面性状，有无中心凹陷，黏膜皱襞集中，肠管变形等对于良恶性鉴别和浸润深度的诊断有很大帮助，CT可在结肠癌的分期上能发挥较大作用，结肠淋巴瘤主要是沿黏膜下层向深层浸润，可引起显著的肠壁增厚，而肠腔狭窄常不明显，平滑肌源性肿瘤具有黏膜下肿瘤的特点，可呈球形,分叶状或不规则形突出于腔内或腔外，CT增强扫描对于鉴别良恶性有帮助，结肠脂肪瘤CT表现具有特征性，为与肠管关系密切，位于肠腔内具有脂肪密度的团块。

Imaging of the ColonTumors

Most of the colon cancers are of ulcerative type, with the typical x- ray manifestation of apple core sign. The apple core sign is formed by the round mount of the ulcer at the two ends of a stenosis of lumen in between, which is the cancer canal of ulcer. The infiltrative colon cancer is rare, so it should be differentiated from other diseases during radiological diagnosis. The existance of a pedicle in a protuberant lesion is an important sign against an advanced cancer. For protuberant lesions without pedical, the following signs are very helpful in differentiating benign from malignant as well as in determining the depth of invasion, including size, basal part, integrated shape, surface charater, with or without central depression, convergence of mucosa rugae and deformation of lumen. CT can play an important role in the staging of colon cancer. The colon lymphoma mainly infiltrate the submucosa and deeper layers and may cause prominent colonic wall thickening, but lumen stenosis is not obvious. Smooth muscle tumors are characteristic of submucosal tumors, appearing as spherical, lobulated or irregular protrusions into or out of the lumen. Enhanced CT in helpful is differentiating benign from malignant. The CT manifestation of colon lipoid tumor is marked by a density of fatty tissue and an intra-lumen mass closely related to the colonic wall.