应用CT血管造影（CTA）和血管三维重建技术评估肠系膜下动脉（IMA）及其分支的解剖结构、变异及走行等情况，以期为腹腔镜结直肠手术提供术前参考和术中指导。

采用回顾性研究的方法，收集2019年1月~2020年6月于中国医学科学院肿瘤医院结直肠外科就诊，具有完整影像资料和病历资料，能够进行血管三维重建的结直肠癌患者共177例。其中男性125例，女性52例，年龄（61.47±10.57）岁，平均身高（169.46±7.09）cm，平均体重（70.98±11.38）kg，平均BMI为（24.63±3.13）kg/m²。统计并分析患者临床特征、IMA分型、IMA各属支［左结肠动脉（LCA）、乙状结肠动脉（SA）、直肠上动脉（SRA）］的出现概率、LCA与肠系膜下静脉（IMV）走行关系，测量IMA根部发出点至腹主动脉分叉距离和LCA至IMA根部发出点水平距离。

SA和SRA为固定出现的动脉，LCA具有缺如可能。IMA分为四型（Ⅰ型103例，Ⅱ型41例，Ⅲ型24例，Ⅳ型9例）。LCA分为四型（Ⅰ型129例，Ⅱ型33例，Ⅲ型6例，Ⅳ型9例）。在IMA根部水平位置，LCA与IMV的走行关系分为三个类型（Ⅰ型71例，Ⅱ型76例，Ⅲ型21例）。IMA起始点至主动脉分叉的距离平均为（4.48±0.87）cm。LCA到与IMA发出点的水平距离平均为（3.22±1.64）cm。

CTA和血管三维重建技术可以准确地评估IMA及其分支的解剖结构、变异及走行等情况，建议术前行血管三维重建，为腹腔镜结直肠手术提供术前参考和术中指导。

To evaluate the anatomical structure, variation and relationship of the inferior mesenteric artery (IMA) and its branches by using CTA and three-dimensional reconstruction technology, in order to provide preoperative reference and intraoperative guidance for laparoscopic colorectal surgery.

A retrospective study was carried out. A total of 177 patients with colorectal cancer who had complete imaging data and medical records and were able to perform three-dimensional reconstruction of blood vessels were collected from the Department of Colorectal Surgery, Cancer Hospital Chinese Academy of Medical Sciences from January 2019 to June 2020. There were 125 males and 52 females, mean age was (61.47±10.57) years old, mean height was (169.46±7.09) cm, mean body weight was (70.98±11.38) kg and mean body mass index was (24.63±3.13) kg/m². Patient demographics, the classification of the inferior mesenteric artery, the occurrence probability of each branch of IMA (left colic artery, sigmoid artery, superior rectal artery) and the relationship between the left colic artery and the inferior mesenteric vein were collected and analyzed. The distance from the aortic bifurcation to the origin of IMA and the distance from the LCA to the origin of IMA were measured.

A total of 177 patients eligible for enrollment were included in the study. SA and SRA are fixed arteries, and LCA might be lacking. The inferior mesenteric artery is divided into four types (103 cases for type Ⅰ, forty one cases for type Ⅱ, twenty four cases for type Ⅲ and nine cases for type Ⅳ). The left colic artery is divided into four types (129 cases for type I, thirty three cases for type Ⅱ, six cases for type Ⅲ and nine cases for type Ⅳ). At the level of the root of the inferior mesenteric artery, the running relationship between the left colic artery and the inferior mesenteric vein is divided into three types (seventy one cases for type Ⅰ, seventy six cases for type Ⅱ and twenty one cases for type Ⅲ). The average distance from the inferior mesenteric artery to the bifurcation of the aorta was (4.48±0.87) cm. The average horizontal distance from LCA to the inferior mesenteric artery was (3.22±1.64) cm.

CTA and vascular three-dimensional reconstruction technology can accurately assess the anatomical structure, variation and relationship of the IMA and its branches. It is recommended to perform CTA and three-dimensional reconstruction of blood vessels before surgery to provide preoperative reference and intraoperative guidance for laparoscopic colorectal surgery.