目的　运用CT技术，对成人门腔间隙（PCS）的前后径进行测量并探讨及其解剖学特点。  方法　收集41例行腹部增强CT扫描而无腹部病变的病例，分别测量、记录：PCS的起始端、终末端和肝脏尾状叶下缘平面的门腔间隙前后径的最小值；取脐部正中水平轴位CT图像，测量、记录脐部脂肪层最厚处的厚度。   结果　门腔间隙的起始端、终末端和肝脏尾状叶下缘平面的门腔间隙前后径的平均最小值分别为0. 427、0.529、0.344 cm。门腔间隙肝脏尾状叶下缘平面的前后径的最小值与腹壁脂肪厚度具有相关性（r=0.387, P＜0.05）；门腔间隙的起始端、终末端前后径的最小值与腹壁脂肪厚度无相关性（P＞0.05）。   结论　CT可充分显示门腔间隙的解剖细节。

Objective    To measure the anteroposterior diameter of the portacaval space (PCS) using the computed tomography (CT).    Methods    Abdominal CT scan was performed in 41 patients. The patients who had no disease revealed on CT images were considered as the normal individuals group, the patients with small renal cyst were included. Emphasis was placed on the following findings: the minimum anteroposterior diameter of the PCS on the plane of initial part, final end and lower margin of the caudate lobe of the live；The thickness of the fat layer in the navel based on the axial CT images.   Results    The minimum anteroposterior diameter of the PCS on the initial part, final end and lower margin of the caudate lobe of the live was 0.427, 0.529 and 0.344 cm，respectively. The minimum anteroposterior diameter of the PCS on the plane of the lower margin of the caudate lobe of the live was correlative with the thickness of the fat layer in the navel (r=0.387, P＜0.05). The minimum anteroposterior diameter of the PCS on the plane of the initial part and final end was not in correlation with the thickness of the fat layer in the navel (P＞0.05).　Conclusion    The CT can demonstrate the details of the PCS.