Dual Orientation 16-MHz Single-Element Ultrasound Needle Transducers for Image-Guided Neurosurgical Intervention

Abstract

Image-guided surgery is today considered to be of significant importance in neurosurgical applications. However, one of its major shortcomings is its reliance on preoperative image data, which does not account for brain deformations and displacements that occur during surgery. In this work, we propose to tackle this issue through the incorporation of an ultrasound device within the type of biopsy needles commonly used as an interventional tool to provide immediate feedback to neurosurgeons during surgical procedures. To identify the most appropriate path to access a targeted tissue site, single-element transducers that look either forward or sideways have been designed and fabricated. Micromolded 1-3 piezocomposites were adopted as the active materials for feasibility tests and epoxy lenses have been applied to focus the ultrasound beam. Electrical impedance analysis, pulse-echo testing, and wire phantom scanning have been carried out, demonstrating the functionality of the needle transducers at [Formula: see text]. The capabilities of these transducers for intraoperative image guidance were demonstrated by imaging within soft-embalmed cadaveric human brain and fresh porcine brain.

The feasibility of micro‐ultrasound as a tool to image peripheral nerves

“…. Micro-ultrasound using a single element transducer has been used to identify the epidural space [12], demonstrated in a needle to aid neurosurgical guidance to targets in fresh porcine and soft embalmed cadaver models [13], and, using a real-time imaging system, to visualise cutaneous nerves in the hand and wrist [18] .…”

“…Two possible examples are an ultrasound transducer at the tip of the needle that generates a single image line [12,13], or an optical coherence tomography system, which has a 15-lm resolution but is limited to a Figure 4 Histology images. Upper row shows fresh median nerve from cadaver A. Fascicle architecture is more obvious in upper images.…”

“…Ultrasound transducer frequencies between 20 MHz and 100 MHz are commonly used for pre‐clinical imaging , and are able to provide resolution of anatomy between 150 μm and 30 μm, respectively. Micro‐ultrasound using a single element transducer has been used to identify the epidural space , identify targets in fresh porcine and soft‐embalmed cadaver brain , and also to view cutaneous nerves in the hand and wrist using a real‐time imaging system .…”

“…. Micro-ultrasound using a single element transducer has been used to identify the epidural space [12], demonstrated in a needle to aid neurosurgical guidance to targets in fresh porcine and soft embalmed cadaver models [13], and, using a real-time imaging system, to visualise cutaneous nerves in the hand and wrist [18] .The objective of this study was to assess the feasibility of micro-ultrasound imaging as a method to visualise fascicles within nerves resected from fresh and soft embalmed cadavers, and to observe any displacement or disruption of the neural anatomy caused by anaesthetic needle penetration. Our secondary objectives were to assess the integrity of fresh and Thiel soft embalmed nerves [17] on handling and during needle insertion, and compare micro-ultrasound imaging with histology sections.…”

Intraoperative Ultrasound Technology in Neuro-Oncology Practice—Current Role and Future Applications

“…Technical advances in probe technology in the future, may yield ultrasound transducers incorporated within the biopsy needle itself. 61 Intraoperative angiography…”