EUS-guided liver biopsy – a novel technique (GIE, Jan-2026)

### Indications of EUS-Guided Liver Biopsy

EUS-guided liver biopsy (EUS-LB) is increasingly utilized as a minimally invasive technique for obtaining liver tissue samples. Common indications for EUS-LB include:

1. Evaluation of unexplained liver abnormalities, such as elevated liver enzymes or abnormal imaging findings.

2. Diagnosis and staging of liver diseases, including nonalcoholic fatty liver disease (NAFLD), autoimmune hepatitis, and cirrhosis.

3. Assessment of focal liver lesions to distinguish benign from malignant pathology.

4. Sampling in patients with challenging anatomies or high risk for adverse events associated with percutaneous or transjugular liver biopsy.

### Difference Between 22-Gauge and 19-Gauge Needles

The gauge of the needle used during EUS-LB significantly impacts specimen quality and procedural outcomes:

1. **19-Gauge Needle**:

• Traditionally preferred for EUS-LB due to its ability to obtain larger tissue samples with higher adequacy rates.
• Provides specimens with longer aggregate length and higher counts of complete portal tracts (CPTs), which are critical for accurate pathological evaluation.
• Associated with higher rates of blood contamination and may pose a greater risk of adverse events, particularly in patients with challenging anatomies.

2. **22-Gauge Needle**:

• Historically considered inferior due to smaller sample sizes and lower adequacy rates compared to 19-gauge needles.
• Emerging evidence suggests that the use of novel techniques, such as hydrostatic sampling, can improve performance and tissue adequacy, making 22-gauge needles a viable option.
• Offers advantages in patients with high-risk profiles or difficult anatomical considerations due to its smaller size and reduced invasiveness.

### Hydrostatic Sampling Technique (HST)

The hydrostatic sampling technique (HST) is a novel method that enhances the quality of tissue samples obtained during EUS-LB. Key features include:

1. Improved tissue adequacy: In the study provided, the HST achieved high adequacy rates (≥93%) for both 22-gauge and 19-gauge needles, meeting clinical standards.

2. Reduced blood contamination: The 22-gauge HST demonstrated significantly less blood contamination compared to both 19-gauge HST and wet suction (WS).

3. Comparable performance to traditional techniques: The HST allows 22-gauge needles to achieve similar specimen adequacy as 19-gauge needles, making it a promising option for patients at high risk for procedural complications.

### Conclusion

The findings in the study suggest that the hydrostatic sampling technique is a significant advancement in EUS-guided liver biopsy. Specifically:

1. The HST enables the use of 22-gauge needles with tissue adequacy rates comparable to 19-gauge needles, while reducing blood contamination.

2. This technique may be particularly beneficial for patients with challenging anatomies or high risk of adverse events, providing a safer and equally effective alternative to traditional biopsy approaches.

3. The adoption of HST could expand the indications and applicability of EUS-LB, making it a more versatile and patient-centered diagnostic tool.