EUS-Guided ATI and SWE in Individuals With Normal FibroScan

Vibration-controlled transient elastography (FibroScan) with Liver Stiffness Measurement (LSM) and Controlled Attenuation Parameter (CAP) is widely used for the non-invasive assessment of liver fibrosis and steatosis. Although these techniques have demonstrated good diagnostic performance, they have several limitations, including technical failure in obese individuals, reduced accuracy in the presence of ascites or narrow intercostal spaces, and the inability to obtain real-time image-guided measurements from specific areas of the liver.

Endoscopic ultrasound (EUS) provides high-resolution imaging of both hepatic lobes through the stomach and duodenum, allowing quantitative assessment of liver tissue under direct visualization. Recent advances have enabled the integration of Attenuation Imaging (ATI), which quantifies hepatic steatosis, and Shear Wave Elastography (SWE), which measures liver stiffness by estimating tissue elasticity and shear wave velocity, into EUS platforms. These techniques may overcome several limitations of conventional transabdominal elastography and have the potential to provide more reliable liver tissue characterization.

Before EUS-guided ATI and SWE can be evaluated as diagnostic tools for liver disease, normal reference values in individuals without liver disease must be established. Currently, there are limited data regarding normal EUS-guided ATI and SWE measurements, particularly in healthy adults with normal FibroScan findings. Establishing these reference ranges is essential for interpreting future studies involving patients with hepatic steatosis and chronic liver disease.

This prospective, single-center, observational pilot feasibility study aims to establish preliminary reference values for EUS-guided ATI and SWE in adults undergoing diagnostic EUS for non-hepatobiliary indications who have normal FibroScan examinations. A total of 100 participants will be enrolled after confirming normal liver stiffness (LSM <7.5 kPa) and steatosis (CAP <238 dB/m), along with adequate FibroScan quality criteria.

During the clinically indicated EUS examination, quantitative liver assessment will be performed without introducing additional invasive procedures beyond standard EUS. Attenuation Imaging will be obtained from both the right and left hepatic lobes, with five valid measurements acquired per lobe. Shear Wave Elastography will also be performed in both lobes, with ten valid measurements obtained per lobe. Measurements will be accepted only if predefined quality criteria are met, including acceptable correlation coefficients, propagation maps, and reliability indices. Acquisition time, technical success, and measurement reproducibility will also be recorded.

The primary outcome of the study is to establish preliminary reference values for EUS-guided ATI, SWE elasticity (kPa), and SWE velocity (m/s) for both hepatic lobes. Secondary objectives include evaluating the technical feasibility and reliability of EUS-guided quantitative liver assessment, assessing agreement between right and left hepatic lobe measurements, determining correlations between ATI and FibroScan CAP, evaluating correlations between SWE and FibroScan LSM, and documenting acquisition times for both techniques.

The findings from this pilot study will provide foundational reference data for EUS-guided quantitative liver imaging and support the design of larger validation studies investigating the role of EUS-guided ATI and SWE in the diagnosis and monitoring of hepatic steatosis and fibrosis.

• Endoscopic Ultrasound (EUS) (Procedure): A clinically indicated diagnostic endoscopic ultrasound will be performed according to standard institutional practice. During the examination, the liver will be visualized from the stomach and duodenum to allow quantitative liver assessment.
• EUS-guided Attenuation Imaging (ATI) (Procedure): Attenuation Imaging (ATI) will be performed during the diagnostic EUS to quantitatively assess hepatic steatosis. Five valid ATI measurements will be obtained from both the right and left hepatic lobes under direct EUS visualization. Measurements meeting predefined quality criteria will be used for analysis.
• EUS-Guided Shear Wave Elastography (SWE) (Procedure): Shear Wave Elastography (SWE) will be performed during the diagnostic EUS to assess liver stiffness. Ten valid measurements will be obtained from both the right and left hepatic lobes. Shear wave velocity (m/s) and tissue elasticity (kPa) will be recorded, and only measurements meeting predefined quality criteria will be included in the analysis.
• FibroScan (Procedure): Participants will undergo same-day FibroScan examination before EUS to confirm normal liver stiffness and steatosis. Controlled Attenuation Parameter (CAP) and Liver Stiffness Measurement (LSM) will be recorded, with at least 10 valid measurements and acceptable quality metrics required for study eligibility.

Primary outcomes

• Reference values for EUS-guided Attenuation Imaging (ATI) [During the index EUS procedure (Day 0)]: To establish preliminary reference values for EUS-guided Attenuation Imaging (ATI) in the right and left hepatic lobes of adults with normal FibroScan findings. ATI values will be reported as mean ± standard deviation (SD), median (interquartile range \[IQR\]), and 95% reference intervals.
• Reference values for EUS-guided Shear Wave Elastography (SWE) elasticity [During the index EUS procedure (Day 0)]: To establish preliminary reference values for EUS-guided SWE elasticity (kPa) in the right and left hepatic lobes. Results will be reported as mean ± SD, median (IQR), and 95% reference intervals.
• Reference values for EUS-guided Shear Wave Elastography (SWE) velocity [During the index EUS procedure (Day 0)]: To establish preliminary reference values for EUS-guided SWE shear wave velocity (m/s) in the right and left hepatic lobes. Results will be reported as mean ± SD, median (IQR), and 95% reference intervals.

Secondary outcomes

• Technical success rate [During the index EUS procedure (Day 0)]: To determine the proportion of participants in whom acceptable EUS-guided ATI and SWE measurements are successfully acquired according to predefined quality criteria.
• Measurement reliability [During the index EUS procedure (Day 0)]: To evaluate the reliability and reproducibility of EUS-guided ATI and SWE measurements using predefined quality parameters.
• Agreement between right and left hepatic lobe measurements [During the index EUS procedure (Day 0)]: To assess agreement between ATI and SWE measurements obtained from the right and left hepatic lobes.
• Correlation between ATI and FibroScan CAP [During the index EUS procedure (Day 0)]: To evaluate the correlation between EUS-guided ATI measurements and FibroScan Controlled Attenuation Parameter (CAP).
• Correlation between SWE and FibroScan Liver Stiffness Measurement (LSM) [During the index EUS procedure (Day 0)]: To evaluate the correlation between EUS-guided SWE measurements and FibroScan Liver Stiffness Measurement (LSM).
• Acquisition time [During the index EUS procedure (Day 0)]: To determine the time required to complete EUS-guided ATI and SWE measurements during the diagnostic EUS examination.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adults aged 18 years or older.
* Undergoing clinically indicated diagnostic endoscopic ultrasound (EUS).
* Same-day FibroScan examination available.
* Controlled Attenuation Parameter (CAP) <238 dB/m.
* Liver Stiffness Measurement (LSM) <7.5 kPa.
* At least 10 valid FibroScan measurements.
* FibroScan interquartile range (IQR)/median ≤30%.
* Able and willing to provide written informed consent.

Exclusion Criteria:

* Known chronic liver disease.
* Hepatitis B or Hepatitis C infection.
* Significant alcohol consumption.
* Decompensated cirrhosis.
* Portal vein thrombosis.
* Ascites.
* Focal liver lesion.
* Previous liver surgery.
* Pregnancy.
* Inadequate FibroScan examination.
* Poor-quality EUS-guided Attenuation Imaging (ATI) or Shear Wave Elastography (SWE) acquisition.
* Incomplete study data or withdrawal of informed consent.

• Study Protocol (PDF, 2026-06-24)
• Informed Consent Form (PDF, 2026-06-24)