Wearable Patch Ultrasound Probe for Diagnosis of Liver Stiffness

Chronic liver disease, including chronic viral hepatitis, non-alcoholic fatty liver disease (NAFLD), and alcohol-related liver disease, can progress to liver fibrosis and, ultimately, cirrhosis if left undetected and untreated. Accurate and timely assessment of liver fibrosis stage is essential for guiding clinical management, including treatment initiation, monitoring of disease progression, and screening for cirrhosis-related complications such as esophageal varices and hepatocellular carcinoma.

Liver biopsy has traditionally been considered the gold standard for assessing liver fibrosis; however, it is invasive, carries risk of complications, and is subject to sampling variability. Transient elastography (FibroScan) has emerged as a widely validated non-invasive alternative, providing a reliable estimate of liver stiffness that correlates with fibrosis stage. However, FibroScan requires a dedicated, non-portable device and a trained operator, and access may be limited in certain clinical settings, particularly outside of specialized hepatology centers.

Wearable ultrasound technology has advanced substantially in recent years, offering the potential for a simplified, patch-type probe that can be applied directly to the skin over the liver to estimate tissue stiffness. Such a device could potentially lower the technical barrier for liver stiffness assessment and expand access to non-invasive fibrosis screening. However, the diagnostic accuracy of this wearable patch-type ultrasound probe for detecting clinically significant fibrosis and cirrhosis has not yet been established in a clinical population.

This study is a prospective cross-sectional diagnostic accuracy study. Patients with chronic liver disease will be enrolled and will undergo liver stiffness measurement using both the investigational wearable patch-type ultrasound probe and FibroScan (transient elastography) at the same clinical visit. FibroScan results will be used as the reference standard to classify patients according to fibrosis stage, including significant fibrosis (≥F2) and cirrhosis (F4). The diagnostic performance of the wearable patch ultrasound probe will be evaluated by calculating sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve (AUC) for each clinically relevant fibrosis threshold, along with the corresponding optimal cut-off values. In addition, the correlation and agreement between liver stiffness values obtained from the wearable patch probe and FibroScan will be assessed using Pearson correlation coefficient and Bland-Altman analysis.

The results of this study are expected to provide preliminary evidence on whether the wearable patch-type ultrasound probe can serve as a reliable, accessible, non-invasive tool for the diagnosis of liver fibrosis and cirrhosis in patients with chronic liver disease.

Inclusion criteria

• Confirmed or suspected chronic liver disease (including but not limited to chronic viral hepatitis, non-alcoholic fatty liver disease, and alcohol-related liver disease)
• Scheduled to undergo, or have recently undergone, transient elastography (FibroScan) as part of routine clinical care
• Age ≥ 18 years
• Willing and able to provide signed informed consent

Exclusion criteria

• Ascites (may interfere with liver stiffness measurement by either device) Body mass index (BMI) ≥ 35 kg/m² (may reduce measurement reliability of transient elastography)
• Acute hepatitis or acute-on-chronic liver failure at the time of enrollment
• History of liver transplantation
• Hepatocellular carcinoma or other space-occupying liver lesions
• Pregnant women
• Skin lesions, infection, or scarring at the intended probe application site (right lobe of the liver, intercostal space)
• Unable to cooperate with the measurement procedure (e.g., severe cognitive impairment)