Image reconstruction of upper limb bone fractures using electrical impedance tomography on python framework

Abstract

vital:149039, valet-20221106-143426 Description Minor bone fractures could occur due to traumatic incidents such as injuries, vehicle accidents, and falls. The commonly used devices to diagnose for bone fracture are X-ray, Computerized Tomography (CT)-Scan, Positron Emission Tomography (PET)-Scan, and Magnetic Resonance Imaging (MRI). For a series of post diagnosis of bone fracture, it can be health threatening to expose the patient to ionization radiation repeatedly. This research proposes to utilize Electrical Impedance Tomography (EIT) as an invasive modality to monitor the recovery of bone fracture. The aim is to develop EIT circuit to measure the electrical impedance on the phantom model of the upper limb with fractured bones using saline solution and 3D printed bones, the phantom model is reconstructed in 2D images on each cross-section layer using pyEIT and analyze the performance of the reconstructed model of fractured bone. This initiative begins with the development of the EIT circuit system, which consist of sinusoidal waveform generator 100 kHz to 10 MHz frequency range, 32-channel multiplexer unit, instrumentation amplifier with slew rate 35 V/µs, bandpass filter range of frequency from 10 kHz to 4 MHz, Root Mean Square (RMS) to Direct Current (DC) converter, 24-bit analog-to-digital converter, flexible Printed Circuit Board (PCB) 32 electrodes per layer, power supply and microcontroller. The EIT circuit is used to acquire voltage measurement using neighboring and opposite data collection techniques from the phantom tank which consist of saline solution (0.9% NaCl) and was tested on 3D printed Acrylonitrile Butadiene Styrene (ABS) bone and lamb bone. The EIT image of the phantom was reconstructed using pyEIT in three-layers slices on 3D plane. Then, the images were analyzed its performance using root mean square error (RMSE) and correlation coefficient. The RMSE value of the reconstructed images at the frequency of 400 kHz was 0.2785 ± 0.01. From the correlation coefficient between the ABS bone and lamb bone, there are significant similarity in terms of impedance between both materials with Pearson correlation with minimum values of 0.636. It would be beneficial to use the ABS material to simulate the different shape of bone fracture to be reconstructed in EIT system. The fractures are observable on several images. In addition, the depth of the bone is can also be distinguished.