Toward Microendoscopic Electrical Impedance Tomography for Intraoperative Surgical Margin Assessment

Abstract

No clinical protocols are routinely used to intraoperatively assess surgical margin status during prostate surgery. Instead, margins are evaluated through pathological assessment of the prostate following radical prostatectomy, when it is too late to provide additional surgical intervention. An intraoperative device potentially capable of assessing surgical margin status based on the electrical property contrast between benign and malignant prostate tissue has been developed. Specifically, a microendoscopic electrical impedance tomography (EIT) probe has been constructed to sense and image, at near millimeter resolution, the conductivity contrast within heterogeneous biological tissues with the goal of providing surgeons with real-time assessment of margin pathologies. This device consists of a ring of eight 0.6-mm diameter electrodes embedded in a 5-mm diameter probe tip to enable access through a 12-mm laparoscopic port. Experiments were performed to evaluate the volume of tissue sensed by the probe. The probe was also tested with inclusions in gelatin, as well as on a sample of porcine tissue with clearly defined regions of adipose and muscle. The probe's area of sensitivity consists of a circular area of 9.1 mm2 and the maximum depth of sensitivity is approximately 1.5 mm. The probe is able to distinguish between high contrast muscle and adipose tissue on a sub-mm scale (~500 μm). These preliminary results suggest that EIT is possible in a probe designed to fit within a 12-mm laparoscopic access port.

Physiological Motion Compensation for Neuroscience Research Based on Electrical Bio-Impedance Sensing

“…EBI is a recently developed impedance-based non-invasive technique for quantifying the composition of biological tissue [29]- [31]. It is used in various applications, such as in eye surgery for puncture detection [32] and proximity sensing [33], abnormal tissue detection and measurement in the prostate [34], the neck [35], lymph nodes [36], and muscle contraction [37]. The sensing principle of EBI is highly compatible with the kind of micro-pipettes used for patch clamping [15] and is therefore used in this study as a proximity detector to observe the motion of a structure at the front of the pipette.…”

Development and evaluation of a robotic system for lumbar puncture and epidural steroid injection

“…In eye surgery for puncture detection, Schoevaerdts et al ( 2019 ) integrate electrodes in a puncture needle to monitor the bio-impedance variance. Halter and Kim ( 2014 ) generate electrical bio-impedance tomography for abnormal tissue detection. And Van Assche et al ( 2023 ) use EBI as proximity sensing in neuroscience research.…”

“…In eye surgery for puncture detection, Schoevaerdts et al (2019) integrate electrodes in a puncture needle to monitor the bio-impedance variance. Halter and Kim (2014) We refer to some related studies using various approaches to detect the subarachnoid space. Several methods use tactile devices that monitor the force feedback and its change or derivative as the needle tip penetrates through different soft tissue layers (Singh et al, 1994;Ambastha et al, 2016;Li et al, 2021;Wang and Li, 2022).…”

Design of a drop-in EBI sensor probe for abnormal tissue detection in minimally invasive surgery

“…Although several EBI sensing devices have been proposed and developed in previous studies [ 22 , 23 ], they are generally large. As for some other existing electrode probes such as ZedScan (Zilico Ltd.) and in [ 36 , 37 ], the design of the electrodes may not fit to the MIS environment.…”