UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Bi-frequency symmetry difference electrical impedance tomography—a novel technique for perturbation detection in static scenes

McDermott, BJ; Avery, J; O'Halloran, M; Aristovich, KY; Porter, E; (2019) Bi-frequency symmetry difference electrical impedance tomography—a novel technique for perturbation detection in static scenes. Physiological Measurement , 40 (4) , Article 044005. 10.1088/1361-6579/ab08ba. Green open access

[thumbnail of McDermott+et+al_2019_Physiol._Meas._10.1088_1361-6579_ab08ba.pdf]
Preview
Text
McDermott+et+al_2019_Physiol._Meas._10.1088_1361-6579_ab08ba.pdf - Accepted Version

Download (2MB) | Preview

Abstract

Objective: A novel method for the imaging of static scenes using Electrical Impedance Tomography (EIT) is reported with implementation and validation using numerical and phantom models. The technique is applicable to regions featuring symmetry in the normal case, asymmetry in the presence of a perturbation, and where there is a known, frequency-dependent change in the electrical conductivity of the materials in the region. Methods: The stroke diagnostic problem is used as a motivating sample application. The head is largely symmetrical across the sagittal plane. A haemorrhagic or ischaemic lesion located away from the sagittal plane will alter this natural symmetry, resulting in a symmetrical imbalance that can be detected using EIT. Specifically, application of EIT stimulation and measurement protocols at two distinct frequencies detects deviations in symmetry if an asymmetrically positioned lesion is present, with subsequent identification and localisation of the perturbation based on known frequency-dependent conductivity changes. Anatomically accurate computational models are used to demonstrate the feasibility of the proposed technique using different types, sizes, and locations of lesions with frequency-dependent (or independent) conductivity. Further, a realistic experimental head phantom is used to validate the technique using frequency-dependent perturbations emulating the key numerical simulations. Results: Lesion presence, type, and location are detectable using this novel technique. Results are presented in the form of images and corresponding robust quantitative metrics. Better detection is achieved for larger lesions, those further from the sagittal plane, and when measurements have a higher signal-to-noise ratio. Conclusion: Bi-Frequency Symmetry Difference EIT is an exciting new modality of EIT with the ability to detect deviations in the symmetry of a region that occur due to the presence of a lesion. Notably, this modality does not require a time change in the region and thus may be used in static scenarios such as stroke detection.

Type: Article
Title: Bi-frequency symmetry difference electrical impedance tomography—a novel technique for perturbation detection in static scenes
Location: England
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/1361-6579/ab08ba
Publisher version: https://doi.org/10.1088/1361-6579/ab08ba
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Biomedical Imaging, Electrical Impedance Tomography, Reconstruction Algorithm
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/10069162
Downloads since deposit
61Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item