Non-invasive assessment of liver function in cirrhosis using iodine density difference between the portal vein and hepatic vein on spectral CT: correlation with Child-Pugh grades

Abstract

Objective: To explore the feasibility and clinical significance of assessing liver function damage in patients with post-hepatitis cirrhosis using spectral CT by measuring the iodine density difference and CT value difference between the portal vein and hepatic vein.

Methods: A study was conducted involving 65 patients with post-hepatitis cirrhosis (30 with Child-Pugh grade A, 28 with grade B, and 7 with grade C) and 82 healthy controls. All underwent dual-phase enhanced spectral CT scans of the upper abdomen. Post-processing with IntelliSpace Portal software yielded iodine density (ID), 45 keV virtual monoenergetic (VMI), and conventional CT (HU) images. The mean iodine densities of the portal vein (ID_P) and hepatic vein (ID_V) were measured, and the difference in ID (ID_d-value), VMI (VMI_d-value), and HU (HU_d-value) between the portal vein and hepatic vein was calculated. These values were compared between the control group and different Child-Pugh grades of cirrhosis, as well as between the compensated cirrhosis group (Child-Pugh grade A) and the decompensated cirrhosis group (grade B/C). The ability to diagnose decompensated cirrhosis was evaluated by plotting ROC curves.

Results: The ID_d-value, VMI_d-value, and HU _d-value were significantly higher in the cirrhosis group compared to the control group and were also higher in the grade B/C group compared to the grade A group (all p<0.05). Among all patients with cirrhosis, the AUROC values for diagnosing grade B/C using ID_d-value, VMI_d-value, HU_d-value, NID_d-value, NVMI _d-value, and NHU_d-value were 0.774, 0.798, 0.736, 0.775, 0.774, and 0.757, respectively (all p < 0.05).

Conclusions: The iodine density difference (ID_d-value) and CT value difference (VMI_d-value and HU _d-value) between the portal vein and hepatic vein, as measured by spectral CT, demonstrate a significant positive correlation with the Child-Pugh classification of liver function in cirrhotic patients. These quantitative parameters provide a simple and non-invasive approach for assessing liver function in cirrhotic patients.

Clinical trial number: Not applicable.

Keywords: Hepatic vein; Iodine density; Liver cirrhosis; Liver function; Portal vein; Spectral CT.

Fig. 1

Enhanced portal venous phase axial iodine density imaging (A, D, G-I), 45 keV virtual monoenergetic imaging (B, E), and conventional CT images (C, F). In Fig. 1.C, the hepatic veins are not well visualized, whereas in Fig. 1.A, the iodine density difference between the hepatic veins and liver parenchyma is more pronounced. This suggests that iodine density mapping provides significantly better visualization of vascular structures compared to conventional CT imaging. ROIs were placed in the left and right portal vein (D-F, yellow circle, mean area approximately 40–60 mm²), as well as in the left, intermediate, and right hepatic veins near the second hepatic hilum (A-C, yellow circle, mean area approximately 10–40 mm²), avoiding the vessel wall and being placed in the center of the vessel. Iodine density images were used to measure vascular diameters. The inner diameter of the portal vein was measured at its midpoint (G), the splenic vein diameter was measured at its midpoint (H), and the superior mesenteric vein diameter was measured 2 cm distal to its confluence with the splenic vein (I)

Fig. 2

Comparisons of quantitative indices, including ID_v, ID_p, and ID_d−value, among control and study group with Child-Pugh grade A, B and C. A. ID_v in grade A, B, and C were all lower than those in the control group. B. ID_p in grade A was lower than the control group, but there were no statistically significant differences in ID_p between the control group and grade B or C. C. ID_d−value in grade A, B, and C groups were all higher than those in the control group, and ID _d−value increased with the severity of liver function impairment

Fig. 3

Diagnostic performance of ID_d−value, VMI_d−value and HU_d−value in predicting the presence of decompensated cirrhosis (Child-pugh grade B/C)