中文摘要：

目的：探讨结直肠原发神经内分泌癌（NECs）的CT征象，以提高结直肠原发NECs的术前诊断。方法：回顾性分析经病理确诊的32例原发性结直肠NECs患者和46例结直肠腺癌患者的CT表现，比较两组患者发病年龄、性别、肿瘤发生部位、病变大小、肠壁增厚形式、平扫、增强CT值、肠周浸润情况、有无肠梗阻及其他器官转移等的差异。结果：与结直肠腺癌组比较，结直肠原发NECs组患者发病年龄小（t=3．634，P〈0．001），两组在肠壁增厚形式、病灶大小、病灶强化程度等方面差异有统计学意义（P〈0.05），在性别、病灶发生部位、有无肠梗阻、有无区域淋巴结转移、有远处转移等方面差异无统计学意义（P〉0．05）。结论：结直肠NECs发病年龄较轻，其CT表现为息肉／肿块样病灶，密度均匀，增强动脉期表现为中度或显著强化，静脉期进一步强化时。应考虑到结直肠NECs的可能，并可出现显著强化的肝脏转移病灶。

英文摘要：

Objective： To explore the CT findings of primary colorectal neuroendocrine carcinomas （NECs）, and to improve the imaging diagnosis of them. Methods： CT findings of 32 patients with primary colorectal NECs and 46 patients with colorectal adenocarcinoma confirmed by surgery and pathology were analyzed retrospectively. The differences of age, gender, tumor location, size of the lesion, the thickening pattern of the intestinal wall, the pattern of contrast-enhancement, the peri-intestinal invasion, the occurrence of intestinal obstruction and metastasis to other organs were compared between the two groups. Results： Compared with the colorectal adenocarcinoma group, patient of colorectal NECs group was younger（t=3.634, P〈0.001）. There were statistically significant differences of focal thickening, size of the lesion and contrast-enhancement （P〈0.05）. While in gender, lesion location, occurrence of intestinal obstruction, lymph node metastasis, or metastasis, there was no statistically significant difference （P〉0.05）. Conclusion： Primary colorectal NECs are often found in young patients. Their CT manifestations include a polypoid lesion and is characterized by significant contrast-enhancement. Significantly contrast-enhanced metastasis may occur in liver.