A Real-Time Electrical Impedance Sensing Biopsy Needle

Abstract

Diagnostic confirmation of cancer in solid organs is based on biopsy findings. In a standard 12-core prostate biopsy protocol, conventional biopsy needles sample only 0.95% (∼0.228 cm³) of a typical 24-cm³ prostate gland. The primary objective of this study was to enhance the sensitivity of standard biopsy protocol by gauging electrical properties of tissue simultaneously with tissue extraction for histopathology analysis. A conventional biopsy (Bx) needle was instrumented with an electrical impedance spectroscopy (EIS) sensor to interrogate the tissue volume surrounding the needle tip. The EIS-Bx device was evaluated in a series of saline bath and ex vivo porcine experiments. It was found to sense a volume of 0.286 cm³ of tissue around the needle tip. EIS measurements were recorded from three ex vivo human prostates using the device, and the extracted biopsy cores were histologically assessed. Prostate conductivity σ ranged from 0.179 to 0.3310 S/m for benign tissues and 0.0746 to 0.0837 S/m for malignant tissues at frequencies ranging from 1 to 100 kHz. Relative permittivity ϵ(r) ranged from 2.10×10⁶ to 2.9 × 10⁴ for benign and 6.63×10⁵ to 5.3 × 10³ for cancer tissues over the same frequency range. Both are found to be significantly higher in normal prostate tissues than in malignant tissue (p< 0.00001).

Concentric Ring Probe for Bioimpedance Spectroscopic Measurements: Design and Ex Vivo Feasibility Testing on Pork Oral Tissues

“…Many previous studies have attempted to characterize different biological tissues using needle-type electrodes [ 15 , 26 , 27 , 28 ]. However, we used a non-invasive concentric ring-type surface electrode as a novel approach for measuring oral tissues.…”

Guidelines to electrode positioning for human and animal electrical impedance myography research

“…Among the limitations of this work, we assumed the electrodes were in direct contact with muscle to make the analysis feasible, an assumption that is satisfied in vitro 6263 and in vivo 496465666768. A more accurate impedance analysis should consider the anisotropic properties of the skin, subcutaneous fat and muscle layers69.…”

Biopsy Needle Integrated with Electrical Impedance Sensing Microelectrode Array towards Real-time Needle Guidance and Tissue Discrimination

“…The 4-electrode method has been commonly used for the impedance measurement of biological tissues in order to reduce the measurement error from electrode polarization effect 18 . However, the application of 4-electrode method to surgical instruments having small surface area is very difficult because micro-scaled EIS sensor should be integrated in the small area, thus the biopsy needle body has been used as an electrode itself in the previous reports 16 . In this report, the microelectrode array based EIS needle could reduce error due to electrode polarization effect as shown in Fig.…”