Severe portal hypertension in cirrhosis: evaluation of perfusion parameters with contrast-enhanced ultrasonography

Abstract

Objective: To investigate the role of contrast-enhanced ultrasonography (CEUS) and Doppler ultrasonography (DUS) in the diagnosis of severe portal hypertension (PH) in patients with liver cirrhosis (LC).

Methods: Patients with PH scheduled to receive hepatic venous pressure gradient (HVPG) measurement were recruited for this study. Hepatic DUS and CEUS were performed successively. Several Doppler and CEUS parameters were explored for correlation with HVPG values and their association with severe PH (≥ 12 mmHg of HVPG). Comparison of the parameters between the severe and non-severe PH groups and their correlation with HVPG values was evaluated. A receiver operating characteristic (ROC) curve analysis was also performed to investigate the performance in order to diagnose severe PH.

Results: Fifty-three consecutive patients were enrolled in this study. Among them, 43 patients did not have significant ascites. Compared with the non-severe PH group, portal venous velocity and intrahepatic transit time (ITT) were significantly reduced in the severe PH group (all p<0.05). Difference between inspiratory and expiratory hepatic venous damping indices (ΔHVDI), hepatic venous arrival time (HVAT) and ITT moderately correlated with HVPG (r = -0.358, -0.338, and -0.613, respectively). Areas under the curves for severe PH were 0.94 of ITT and 0.72 of HVAT, respectively (all p<0.05). ITT under 6 seconds indicated severe PH with a sensitivity of 92% and a specificity of 89%.

Conclusions: Hepatic CEUS may be more useful in estimating the HVPG value and determining the presence of severe PH compared to DUS, and ITT was the most accurate parameter to diagnose severe PH.

Fig 1. Diagram of study design and recruitment of the patients.

Fig 2. Measurement of vascular arrival time.

Serial contrast enhanced ultrasonograms of a 49-year old man with Child C liver cirrhosis show microbubbles appearing in the hepatic artery (arrows in A, B, C) at 23 seconds (13 seconds after contrast injection) and hepatic vein (open arrows in D, E, F) at 27 seconds. After drawing the ROI, the acoustic intensity of the region of interest in the vessels is tracked stack images and measured per second. The arrival times is defined as the time to reach to 10% above the baseline intensity.(G) Hepatic arterial and venous arrival time is 13 and 17 seconds, respectively, resulting in an intrahepatic transit time of 4 seconds.

Fig 3. Peak signal intensity (PSI) and time to peak (TTP).

A contrast enhanced ultrasonogram of a 53-year old man with Child C liver cirrhosis shows a region of interest (ROI) located on the hepatic parenchyma.(A) Two parameters are obtained from the time-intensity curve. PSI is defined as the difference between the maximum acoustic intensity and baseline, and TTP is defined as the time to reach PSI from the time of injection.(B).

Fig 4. Receiver operating characteristic curves of Doppler and perfusion parameters for estimating severe portal hypertension.

The area under the curve (AUC) of intrahepatic transit time (ITT) is larger than any others (0.924), and the second and third largest AUCs are portal venous velocity (PVV; 0.731) and hepatic venous arrival time (HVAT; 0.726), respectively.