Bio-Inspired Active Electrolocation Sensors for Inspection of Tube Systems

Abstract

At night, weakly electric fish Gnathonemus petersii use active electrolocation to scan their environment with self generated electric fields. Nearby objects distort the electric fields and are recognized as electric images on the electroreceptive skin surface of the animal. By analyzing the electric image, G. petersii can sense an object’s distance, dimensions and electrical properties. The principles and algorithms of active electrolocation can be applied to catheter-based sensor systems for analysing wall changes in fluid filled tube systems, for example atherosclerotic plaques of the coronary blood vessels. We used a basic atherosclerosis model of synthetic blood vessels and plaques, which were scanned with a ring electrode catheter applying active electrolocation. Based on the electric images of the plaques and the evaluation of bio-inspired image parameters, the plaque’s fine-structure could be assessed. Our results show that imaging through active electrolocation principally has the potential to detect and characterize atherosclerotic lesions.

An active electrolocation catheter system for imaging and analysis of coronary plaques

“…The dimensions of the assessed parameters mentioned above for each synthetic plaque are listed in table 1. Note that the atherosclerosis model (artificial blood vessels and plaques) used in this and previous studies [11,14,39] could only to a certain extend mimic the dimensions of a real coronary artery and the complex electrical properties of real arteries and plaques [5,9,10,42,43]. Hence some plaque dimensions such as the overall plaque and core size, were oversized and the complex electrical properties were oversimplified due to using materials that caused mainly resistive effects.…”

“…Our previous studies [11,14,39] have shown that width and shape of amplitude images depended on the overall size of a synthetic plaque as well as the distance between the sender (S) and the selected receiver (R1 or R3) of the catheter. When the sender-receiver distance was greater than the plaque size (for e.g.…”

“…When the sender-receiver distance was greater than the plaque size (for e.g. when plaque types P1-4 were recorded with catheter receiver R3) amplitude images featured a 'W'-shaped profile [14] with two prominent modulation peaks termed peak amplitudes (PA, see figure 3). The left-sided and strongest modulation peak of such amplitude images (PA S in figure 3(b)) was generated when the sender (S) passed the plaque, whereas the right-sided, local modulation peak (PA R in figure 3(b)) occurs by receiver (R)-plaque interaction.…”

“…The feasibility of distinguishing different plaque conditions based on their electrical impedance has already been indicated in some research studies [9,10]. Besides our medical approach [11][12][13][14], active electrolocation has also been adapted for use in robotics [15], piping inspection [16] and bubble detection sensors [17].…”

“…In our previous biomimetic studies, some of the theoretical principles of electric image generation and evaluation outlined above have been used in an early prototypical four ring-electrode catheter system, applying a natural G. petersii EOD for imaging and providing 1D dynamic electric images [11,14,39]. Initial electric image recordings were performed in a simple atherosclerosis model with synthetic blood vessels (made from conductive agarose gel) and plaques (composed of fat cores covered by agarose caps).…”