Modelling and characterisation of a ultrasound-actuated needle for improved visibility in ultrasound-guided regional anaesthesia and tissue biopsy

Y. Kuang, A. Hilgers, M. Sadiq, S. Cochran, G. Corner, Z. Huang (Lead / Corresponding author)

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    Abstract

    Clear needle visualisation is recognised as an unmet need for ultrasound guided percutaneous needle procedures including regional anaesthesia and tissue biopsy. With inadequate needle visibility, these procedures may result in serious complications or a failed operation. This paper reports analysis of the modal behaviour of a previously proposed ultrasound-actuated needle configuration, which may overcome this problem by improving needle visibility in colour Doppler imaging. It uses a piezoelectric transducer to actuate longitudinal resonant modes in needles (outer diameter 0.8-1.2 mm, length > 65 mm). The factors that affect the needle's vibration mode are identified, including the needle length, the transducer's resonance frequency and the gripping position. Their effects are investigated using finite element modelling, with the conclusions validated experimentally. The actuated needle was inserted into porcine tissue up to 30 mm depth and its visibility was observed under colour Doppler imaging. The piezoelectric transducer is able to generate longitudinal vibration with peak-to-peak amplitude up to 4 μm at the needle tip with an actuating voltage of 20 Vpp. Actuated in longitudinal vibration modes (distal mode at 27.6 kHz and transducer mode at 42.2 kHz) with a drive amplitude of 12-14 Vpp, a 120 mm needle is delineated as a coloured line in colour Doppler images, with both needle tip and shaft visualised. The improved needle visibility is maintained while the needle is advanced into the tissue, thus allowing tracking of the needle position in real time. Moreover, the needle tip is highlighted by strong coloured artefacts around the actuated needle generated by its flexural vibration. A limitation of the technique is that the transducer mode requires needles of specific lengths so that the needle's resonance frequency matches the transducer. This may restrict the choice of needle lengths in clinical applications.

    Original languageEnglish
    Pages (from-to)38-46
    Number of pages9
    JournalUltrasonics
    Volume69
    Early online date3 Mar 2016
    DOIs
    Publication statusPublished - 1 Jul 2016

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    Keywords

    • Colour Doppler imaging
    • Needle visibility
    • Piezoelectric transducer
    • Regional anaesthesia
    • Tissue biopsy

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