CT analysis of influencial factors on normal anteroposterior diameter of portacaval space

Abstract

Objective To analyze the influencial factors of the anteroposterior diameter (APD) of the portacaval space (PCS) through inferior margin of the hepatic caudate lobe (PCS-IHCL) on the CT images. Methods Abdominal CT images of 64 patients without vertebral body and PCS lesions in the Affiliated Hospital of Weifang Medical University from January 2011 to July 2016 were collected and analyzed retrospectively. In this study, there were 35 males and 29 females, aged 23-64 years, mean 46.8 years. Emphasis was placed on the following findings based on the axial contrast-enhanced CT images: the minimal APD of the PCS-IHCL, the maximal diameter of APD of the portal vein and the inferior vena cava, APD of the lymph nodes and the maximal transverse diameter of the adjacent centrum, the thickness of the fat layer in the navel and the maximal APD of the hepatic caudate lobe in the level of inferior vena cava's left border. The relativity between the minimal APD of the PCS-IHCL and other data were analyzed and the correlation was studied using linear regression analysis. Results According to the axial CT images, the minimal APD of the PCS-IHCL was (0.345±0.246) cm; the maximal APD of the portal vein was (1.277±0.126) cm; the maximal APD of the inferior vena cava was (1.633±0.339) cm; and the maximal diameter of the adjacent centrum was (4.214±0.455) cm; there were 11 cases showing 13 lymph nodes, the maximal diameter was (0.627±0.100) cm. The maximal diameter of the hepatic caudate lobe in the PCS was (2.325±0.533) cm, and the thickness of fat in the navel was (1.594±0.601) cm. The APD of the PCS-IHCL had no correlation with gender, age, the maximal diameter of APD of the portal vein and the inferior vena cava, APD of the lymph nodes and the maximal transverse diameter of the adjacent centrum(all P values>0.05), but had correlated positively to the thickness of the fat layer in the navel and the APD of the hepatic caudate lobe (t=4.649, 2.403, all P values<0.05). Set the minimal APD of the PCS-IHCL( ^,Y)) as the dependant variable, the maximal APD of the hepatic caudate lobe (X1) and the thickness of the fat layer in the navel (X2) as the independent variable, the regression equation was: ^,Y)=-0.689+ 0.180X1+ 0.122X2, R2=0.472. Conclusions PCS-IHCL has its unique anatomical features. The influencial factors of the APD of the PCS-IHCL are the maximal APD of the hepatic caudate lobe and the abdominal fat content. Focusing on the observation and measurement of PCS-IHCL on CT images, which has guiding significance in the diagnosis and treatment of diseases in PCS and adjacent organs. Key words: Tomography, X-ray computed; Liver; Portacaval space; Influencial factor