Optimal techniques for obtaining superior liver specimens at endoscopic ultrasound-guided biopsy: a pilot study on pigs.

Background: Endoscopic ultrasound (EUS)-guided liver biopsy has been an effective method for acquiring liver tissue. However, currently, there is no consensus on the technical details of biopsy sampling. This study aimed to optimize the EUS-guided liver biopsy techniques to improve specimen quality.

Methods: EUS-guided liver biopsies were performed in four porcine subjects with four technical aspects: negative pressure suction, number of actuations, two puncture manipulations, and two types of puncture needles. The primary outcomes were total specimen length (TSL) and complete portal tracts (CPTs), the secondary outcomes included longest specimen length (LSL), number of specimen pieces, specimen fragmentation, blood contamination, and bleeding.

Results: Forty-four biopsy samplings were performed. In Phase I, specimens obtained with 1-mL suction demonstrated significantly superior TSL, CPTs, and LSL compared with other suction techniques according to multiple comparisons. In Phase II, median TSL and CPTs with fewer than three actuations were significantly higher compared with those with at least three actuations (P < 0.05). In Phase III, the modified "click-puncture" yielded superior median CPTs, TSL, and LSL in comparison with conventional puncture (P < 0.05). In Phase IV, a fine-needle aspiration (FNA) needle was effective with a low risk of bleeding and foreign-tissue embedding (P < 0.05).

Conclusions: Optimal techniques for specimen quality in EUS-guided liver biopsy include using 1-mL suction, no more than three actuations, and employing a modified "click-puncture" manipulation. While FNA and fine-needle biopsy needles achieved comparable specimen quality, the FNA needle demonstrated the prevention of bleeding and foreign-tissue embedding.