Vascular branching geometry relating to portal hypertension: a study of liver microvasculature in cirrhotic rats by X-ray phase-contrast computed tomography.

BACKGROUND

Portal hypertension is one of the major complications of cirrhosis. The changes in hepatic microvasculature are considered as critical pathophysiological characteristics of portal hypertension. X-ray phase-contrast computed tomography (PCCT) is a new imaging technique that can detect liver vessels at a micrometric level without contrast agents.

METHODS

In this study, male Sprague-Dawley rats with liver cirrhosis induced by carbon tetrachloride (CCl4) or bile duct ligation (BDL) were investigated with PCCT. The portal pressures of rats were recorded before euthanasia. The branch angle and Murray's deviation (MD) were measured based on the branching geometry of the three-dimensional (3D) microvasculature of liver cirrhosis in rats. Statistical analyses were performed to determine the correlation between branching geometry and portal pressure in liver fibrosis.

RESULTS

The results demonstrated that the branch angle and MD significantly increased in the CCl4 model and BDL model compared with their corresponding normal group or sham group. The portal pressure was significantly correlated with the branching morphologic features (all R≥0.761 and P<0.01).

CONCLUSIONS

The branch angle and MD could accurately distinguish portal pressure in cirrhotic rats, suggesting that branching geometric characteristics of the microvasculature may be a promising marker in the prognosis of portal hypertension in liver cirrhosis.