Liver shear wave elastography using a mechanical index exceeding regulatory limits is safe and effective

Area of Science:

• Hepatology
• Medical Imaging
• Ultrasound Technology

Background:

• Metabolic dysfunction-associated steatotic liver disease (MASLD) affects one-third of the global population.
• Ultrasound shear wave elastography (SWE) for liver fibrosis quantification in obese patients is often unreliable due to beam attenuation.
• Accurate non-invasive fibrosis assessment is critical for managing MASLD.

Purpose of the Study:

• To evaluate the safety and efficacy of increased push mechanical index (IPMI) SWE, exceeding U.S. Food and Drug Administration limits, for improved liver fibrosis assessment.
• To determine if IPMI SWE can overcome limitations of conventional SWE in obese individuals.
• To assess potential liver injury associated with IPMI SWE.

Main Methods:

• A single-center prospective trial enrolled healthy adults stratified by body mass index (BMI).
• Participants underwent conventional SWE (MI 1.4) and IPMI SWE (MI 2.5).
• Liver function tests (LFTs) were monitored serially to assess for liver injury (AST, ALT, ALP changes).

Main Results:

• IPMI SWE did not cause significant changes in liver function tests (AST, ALT, ALP) compared to baseline, meeting non-inferiority criteria.
• IPMI SWE demonstrated a significant reduction in measurement variability (29.2% relative reduction in IQR/median ratio) and fewer required measurement attempts.
• Shear wave speed measurements were comparable between conventional SWE and IPMI SWE.

Conclusions:

• Increased push mechanical index (IPMI) SWE is safe in healthy volunteers, showing no evidence of liver injury.
• IPMI SWE significantly reduces measurement variability and improves reliability compared to conventional SWE.
• Further development of IPMI SWE is recommended to enhance examination quality and reliability for assessing liver fibrosis in obese patients with MASLD.