CT scan transforming into a healthy liver, representing virtual hepatic measurement.

The Future of Liver Health: Is Virtual Hepatic Measurement Ready to Replace Invasive Procedures?

Avery Sinclair in Health & Wellness June 2025 • 5 min read.

"A breakthrough in non-invasive technology offers new hope for patients with portal hypertension, but is it ready for widespread adoption?"

Portal hypertension, a frequent and severe complication of cirrhosis, leads to conditions like hepatic encephalopathy, ascites, and gastroesophageal variceal bleeding. The root of the problem lies in increased resistance within the liver's sinusoids, caused by fibrosis and architectural changes. Measuring hepatic venous pressure gradient (HVPG) through right hepatic vein catheterization has been the standard for assessing portal venous pressure.

HVPG, calculated by subtracting the free hepatic venous pressure from the wedged pressure, becomes clinically significant at 10 mm Hg or higher, predicting patient outcomes. Studies show that HVPG is a more reliable predictor than other clinical variables, such as the Model for End-Stage Liver Disease (MELD) score and serum albumin levels. It also helps evaluate treatment response; a reduction of at least 20% or a level below 12 mm Hg significantly lowers the risk of variceal bleeding.

Despite its importance, HVPG measurement isn't routine due to its cost, perceived risks, and limited availability, spurring the search for a non-invasive alternative over the past two decades. Recent research introduces a promising new approach: virtual HVPG, measured using multiphase contrast-enhanced CT. This method could transform how we diagnose and manage portal hypertension, offering a safer, more accessible option for patients worldwide.

Virtual HVPG: A New Horizon in Diagnosis

CT scan transforming into a healthy liver, representing virtual hepatic measurement.

In the latest issue of Radiology, Qi and colleagues (5) detail the development and validation of a non-invasive method for measuring HVPG, leveraging multiphase contrast-enhanced CT scans. Building upon earlier work, they conducted a prospective, multicenter study using Doppler ultrasound and contrast-enhanced CT of the liver during arterial, portal, and hepatic venous phases to create virtual HVPG measurements. The study included patients who underwent conventional HVPG measurement, Doppler US, and liver biopsy.

The researchers applied two computational methods to a manually reconstructed three-dimensional model of the portal-hepatic venous system. The first, finite element analysis, assesses the distribution of field variables like pressure and displacement within small elements of a three-dimensional model. The second, computational fluid dynamics, employs mathematical models to define how fluids interact with adjacent structures. By combining these methods with main portal vein velocity data from venous Doppler US, they estimated pressure across the three-dimensional model.

Key aspects of the virtual HVPG model include:

Finite Element Analysis: Measures pressure distribution in 3D models.
Computational Fluid Dynamics: Uses mathematical models for fluid interactions.
Doppler US Integration: Incorporates portal vein velocity for accurate pressure estimation.
CT Imaging: Leverages contrast-enhanced CT scans for detailed anatomical data.

To test the model's reliability, Qi and colleagues validated virtual HVPG's performance in a separate group of 79 participants from two other centers. The virtual HVPG showed impressive results in predicting CSPH within the training set, achieving an area under the receiver operating characteristic curve of 0.83, compared to 0.89 in the validation cohort. When considering all participants, virtual HVPG outperformed six other non-invasive methods for diagnosing CSPH, including transient elastography (FibroScan) and CT-based portal pressure scores. There was a statistically significant, albeit moderate, correlation between virtual HVPG and invasive HVPG (R = 0.61, P < .001).

Looking Ahead: The Future of Virtual HVPG

The development of noninvasive methods for measuring HVPG represents an exciting and promising area of research. As virtual HVPG continues to be refined and validated, it holds the potential to transform the diagnosis and management of portal hypertension, offering a safer, more accessible alternative for patients worldwide. Further studies in larger, more diverse patient cohorts are essential to fully realize the clinical potential of virtual HVPG and integrate it into routine clinical practice. Virtual HVPG could improve patient outcomes through earlier detection of CSPH and more accurate response evaluations. I encourage Dr Qi and colleagues to evaluate their methods in a larger and more diverse cohort of patients so that virtual HVPG may one day become a reality in the clinic.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1148/radiol.2018182351, Alternate LINK

Title: Virtual Hepatic Venous Pressure Gradient With Ct: Ready For Prime Time?

Subject: Radiology, Nuclear Medicine and imaging

Journal: Radiology

Publisher: Radiological Society of North America (RSNA)

Authors: Ashkan A. Malayeri

Published: 2019-02-01

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Everything You Need To Know

1

What are the primary complications associated with portal hypertension, and what is the traditional method for assessing this condition?

Portal hypertension arises from increased resistance within the liver's sinusoids due to fibrosis and architectural changes, frequently resulting from cirrhosis. This increased resistance leads to severe complications such as hepatic encephalopathy, ascites, and gastroesophageal variceal bleeding. Diagnosing and monitoring portal hypertension traditionally involves measuring the hepatic venous pressure gradient (HVPG) through right hepatic vein catheterization, an invasive procedure.

2

How is the hepatic venous pressure gradient (HVPG) calculated, and what makes it a significant indicator in assessing liver health?

HVPG, or hepatic venous pressure gradient, is calculated by subtracting the free hepatic venous pressure from the wedged pressure. A clinically significant HVPG is 10 mm Hg or higher, which is indicative of portal hypertension. It is a more reliable predictor of patient outcomes compared to other clinical variables like the Model for End-Stage Liver Disease (MELD) score and serum albumin levels. Furthermore, a reduction of at least 20% in HVPG or achieving a level below 12 mm Hg significantly lowers the risk of variceal bleeding.

3

What is virtual HVPG, and how does it offer a new approach to diagnosing and managing portal hypertension?

Virtual HVPG is a non-invasive method for measuring hepatic venous pressure gradient (HVPG) using multiphase contrast-enhanced CT scans. It involves creating a three-dimensional model of the portal-hepatic venous system and applying computational methods like finite element analysis and computational fluid dynamics. By integrating data from venous Doppler ultrasound, it estimates pressure across the model. Virtual HVPG aims to offer a safer and more accessible alternative to traditional invasive HVPG measurement for diagnosing and managing portal hypertension.

4

Can you elaborate on the key components and methodologies involved in creating the virtual HVPG model?

The virtual HVPG model combines finite element analysis, computational fluid dynamics, Doppler US integration, and CT imaging. Finite element analysis measures pressure distribution in 3D models. Computational fluid dynamics employs mathematical models for fluid interactions. Doppler US integration incorporates portal vein velocity for accurate pressure estimation. CT imaging leverages contrast-enhanced CT scans for detailed anatomical data. These components work together to provide a non-invasive estimation of HVPG.

5

How accurate and reliable is virtual HVPG compared to traditional methods and other non-invasive techniques for diagnosing CSPH?

Virtual HVPG showed an area under the receiver operating characteristic curve of 0.83 in the training set and 0.89 in the validation cohort for predicting CSPH. Compared to other non-invasive methods, including transient elastography (FibroScan) and CT-based portal pressure scores, virtual HVPG demonstrated superior performance in diagnosing CSPH. It also showed a statistically significant, albeit moderate, correlation with invasive HVPG (R = 0.61, P < .001). This indicates its potential as a reliable non-invasive tool, but further validation in larger, more diverse cohorts is needed.