胰腺癌侵犯横结肠系膜的解剖基础及其CT表现特征

目的基于横结肠系膜与胰腺的解剖关系,探讨胰腺癌侵犯横结肠系膜的CT表现特征。方法 (1)术中观察4例行上腹部手术而无横结肠系膜病变的病例,分别观察:横结肠系膜与胰腺的解剖关系,横结肠系膜血管的走行、分布及附着。(2)回顾性分析64例胰腺癌患者的CT资料,分别观察:肿瘤的大小、形态、位置;横结肠系膜的形态、密度、有无血管受累;横结肠系膜上和根部淋巴结的显示情况;横结肠受累范围等。结果 (1)结肠中动脉走行于横结肠系膜的两层之间,但近结肠侧附着于横结肠系膜后层;(2)胰腺癌侵犯横结肠系膜主要表现为:系膜肿块,系膜密度增高,系膜血管受累和系膜淋巴结增大;胰腺病变大小与横结肠系膜肿块的发生率有相关性(P0.01);(3)胰腺癌主要为纵向侵犯横结肠系膜;胰腺癌侵犯横结肠系膜致肿块形成的方式有3种:肿瘤沿着横结肠的腹膜下间隙蔓延;肿瘤沿着横结肠系膜的腹膜下间隙及横结肠系膜前叶蔓延;肿瘤沿着横结肠系膜的腹膜下间隙蔓延,并同时侵犯小肠系膜。结论胰腺癌侵犯横结肠系膜具有一定的CT表现特征和解剖基础,CT术前评价胰腺癌侵犯横结肠系膜有重要意义。

Anatomic basis and CT image features of transverse mesocolon involvement by pancreatic carcinoma

Objective　To study the CT image features of transverse mesocolon (TM) involvement by pancreatic carcinoma based on the anatomy.　Methods　(1) 4 patients, underwent the upper abdominal surgery and without transverse mesentric diseases were selected and observed. (2) CT images of 64 cases of pancreatic carcinoma with TM involvement were reviewed retrospectively. Emphasis was placed on the follows: (1) the anatomical relationship of TM and pancreas, and the course, distribution and attachment of TM's vessels. (2) The size, shape and location of the mass, and the appearance, density, vascular involvement of the TM, the lymph nodes in the TM and the extent of the TM involvement.　Results　(1) Middle colic vessels coursed between the two layers of the TM, and its' TM region attached to the posterior layer of the TM. (2) Mesenteric mass, increased mesenteric density, mesenteric vessels involvement and the enlarged lymph nodes in the transverse colon appeared in patients suffered from pancreatic carcinomas. The incidence of mesenteric masses was always concerned with the size of the pancreatic mass (p<0.01). (3) Pancreatic carcinomas usually invaded the root, body and margin of the TM. The tumor spread along the subperitoneal space and the anterior layer of the TM, and furthermore invaded into the small mesentery.　Conclusions　Specific CT images and anatomic features appeared once the TM involved by pancreatic carcinoma. CT is valuable for evaluating of TM involvement by pancreatic carcinoma.