Objective: To evaluate haemodynamics in cirrhotic patients with portal hypertension using spectral CT imaging. Methods: 118 cirrhotic patients with portal hypertension were included in the study group (further divided into Child-Pugh A, B and C subgroups). The control group consisted of 21 subjects with normal liver functionality. All subjects underwent three-phase spectral CT scans. Material decomposition images with water and iodine as basis material pairs were reconstructed. The iodine concentrations for the hepatic parenchyma in both arterial and portal venous phases were measured. The arterial iodine fraction (AIF) was obtained by dividing the iodine concentration in the hepatic arterial phase by that in the portal venous phase. AIF values from the study and control groups were compared using analysis of variance and between subgroups using a post-hoc test with Bonferroni correction, with a statistical significance of p<0.05. Results: The AIF was 0.25 +/- 0.05 in the control group, and 0.29 +/- 0.10, 0.37 +/- 0.12 and 0.43 +/- 0.14 in the study group with Child-Pugh Grades A, B and C, respectively. The difference in AIF between the control and study groups was statistically significant. The differences were statistically significant between the subgroups with multiple comparisons except between the control group and the Child-Pugh A group (p=0.685). Conclusion: AIF measured in spectral CT could be used to evaluate the liver haemodynamics of cirrhotic patients. Advances in knowledge: The AIF, provided by spectral CT, could be used as a new parameter to observe liver haemodynamics.