An ultrasonically actuated fine-needle creates cavitation in bovine liver

Ultrasound-Enhanced Fine-Needle Biopsy Improves Yield in Human Epithelial and Lymphoid Tissue

OBJECTIVE

Needle biopsy is a common technique used to obtain cell and tissue samples for diagnostics. Currently, two biopsy methods are widely used: (i) fine-needle aspiration biopsy (FNAB) and (ii) core needle biopsy (CNB). However, these methods have limitations. Recently, we developed ultrasound-enhanced fine-needle aspiration biopsy (USeFNAB), which employs a needle that flexurally oscillates at an ultrasonic frequency of ∼32 kHz. The needle motion contributes to increased tissue collection while preserving cells and tissue constructs for pathological assessment. Previously, USeFNAB has been investigated only in ex vivo animal tissue. The present study was aimed at determining the feasibility of using USeFNAB in human epithelial and lymphoid tissue.

METHODS

Needle biopsy samples were acquired using FNAB, CNB and USeFNAB on ex vivo human tonsils (N = 10). The tissue yield and quality were quantified by weight measurement and blinded pathologists' assessments. The biopsy methods were then compared.

RESULTS

The results revealed sample mass increases of, on average, 2.3- and 5.4-fold with USeFNAB compared with the state-of-the-art FNAB and CNB, respectively. The quality of tissue fragments collected by USeFNAB was equivalent to that collected by the state-of-the-art methods in terms of morphology and immunohistochemical stainings made from cell blocks as judged by pathologists.

CONCLUSION

Our study indicates that USeFNAB is a promising method that could improve tissue yield to ensure sufficient material for ancillary histochemical and molecular studies for diagnostic pathology, thereby potentially increasing diagnostic accuracy.

Needle bevel geometry influences the flexural deflection magnitude in ultrasound-enhanced fine-needle biopsy

It has been recently demonstrated that use of ultrasound increases the tissue yield in ultrasound-enhanced fine-needle aspiration biopsy (USeFNAB) as compared to conventional fine-needle aspiration biopsy (FNAB). To date, the association between bevel geometry and needle tip action has not been widely explored. In this study, we studied the needle resonance characteristics and deflection magnitude of various needle bevel geometries with varying bevel lengths. With a conventional lancet, having a 3.9 mm long bevel, the tip deflection-to-power ratio (DPR) in air and water was 220 and 105 µm/W, respectively. This was higher in comparison to an axi-symmetric tip, having a bevel length of 4 mm, which achieved a DPR of 180 and 80 µm/W in air and water, respectively. This study emphasised the importance of relationship between flexural stiffness of bevel geometry in the context of various insertion media and, thus, could provide understanding on approaches to control post-puncture cutting action by modifying the needle bevel geometry, essential for the USeFNAB application.