Hepatic Elastography in Critical Illness: Moving from Physiological Signal to Clinical Utility

Abstract

How to cite this article: Mandal PK, Rao DSN, Priye S. Hepatic Elastography in Critical Illness: Moving from Physiological Signal to Clinical Utility. Indian J Crit Care Med 2026;30(5):450–451.

The Editor,

We have read with great interest the recent viewpoint on the emerging value of 2D shear wave elastography (2D-SWE) in the intensive care unit (ICU).¹ The prospect of using hepatic elastography as a “window” to view the critically ill patient is exciting; however, there is a need for cautious interpretation of physiological theory into clinical application and validation of the concept.

The liver is an especially vulnerable organ in the setting of critical illness because of its unique physiology related to venous return, inflammation, metabolism, and pharmacology. During shock, especially septic shock and right ventricular failure, hepatocellular damage can occur long before any alteration of liver biochemistry.^2,3 This presents a potential diagnostic dilemma that could be overcome using elastography. Nevertheless, increased liver stiffness does not necessarily imply liver dysfunction. Liver stiffness reflects a complex physiologic process that depends on factors such as congestion, edema, inflammation, cholestasis, and chronic parenchymal disease, but it does not directly reflect metabolic activity.

The real value of liver elastography is in its use as a component of an entire hemodynamic profile of systemic venous congestion. With recent developments in the field of critical care ultrasound, the paradigm has shifted from single-parameter analysis to the multiparametric assessment of systemic venous congestion using dynamic measurements of the inferior vena cava and Doppler studies of the hepatic, portal, and renal veins.^4,5 Here, the measurement of liver stiffness can be considered another dynamic index of venous congestion, especially in those with right ventricular failure and/or excess fluid volume status.

The issue of interpretive specificity continues to pose problems. Most critically ill patients have undiagnosed chronic liver diseases, one of which is metabolic disorder-related fatty liver disease, which is very common and usually asymptomatic.⁶ In such cases, a single elevated stiffness reading would represent the underlying disease process, not an acute physiological disturbance. The application of hepatic elastography from an Indian ICU standpoint would have particular significance. The presence of sepsis, fever of unknown origin, undiagnosed chronic liver disease, late referrals, and limited access to advanced hemodynamic monitoring in many ICUs makes hepatic elastography even more relevant.

The ICU setting itself adds further variance as well. The use of positive pressure ventilation, elevated positive end-expiratory pressure, increased abdominal pressures, patient position, vasoactive drug administration, and tissue swelling may all affect elastographic assessments.⁷ In the absence of standard acquisition protocols, which should ideally occur in a stable physiologic state, serial measurements may be difficult to interpret. Repeatability and reduced variability, regardless of operator influence, will be paramount before recommending widespread implementation.

Another crucial limitation lies in the potential lack of appropriateness of liver stiffness cutoffs defined in the outpatient population for the critically ill population. The critically ill population is a unique physiologic state defined by congestion, inflammation, and hypoperfusion, among other factors. This would render absolute values somewhat useless, and serial values interpreted in relation to physiologic changes may provide more information.

Hepatic elastography also has potential as a modality for monitoring. Changes in liver stiffness through sequential assessment could indicate the development of venous congestion, hypoperfusion of the hepatosplanchnic region in the setting of vasopressors, or response to de-resuscitation strategies.^2,3,5,7 This technique might be especially useful in those with combined shock presentations in which the presence of congestion vs distribution or low flow cannot be easily distinguished.

However, this technique lacks robust outcome-based data at present. Most studies are based on observations, while randomized trials testing the effectiveness of elastography are missing. Future studies should address important clinical questions, such as whether hepatic elastography would help phenotyping shock patients or guide fluid therapy.

In summary, hepatic elastography shows promise as a new tool in critical care monitoring. Its value lies in providing a physiological signal rather than a definitive diagnosis. Closing the gap between physiology and clinical use will require standardization, multimodal correlation, and rigorous outcomes research. In the interim, 2D-SWE should be viewed as an adjunct to, not a substitute for, thorough clinical examination.

Orcid

Pranav K Mandal https://orcid.org/0009-0002-3834-0812

Dabbiru Sreenvas Nageswar Rao https://orcid.org/0009-0009-1492-9498

Shio Priye https://orcid.org/0000-0002-1764-5580