Bi-frequency symmetry difference EIT - feasibility and limitations of application to stroke diagnosis
Author(s)
McDermott, Barry James
Ohalloran, Martin
Avery, James
Porter, Emily
Type
Journal Article
Abstract
OBJECTIVE: Bi-Frequency Symmetry Difference (BFSD)-EIT can detect, localize and identify unilateral perturbations in symmetric scenes. Here, we test the viability and robustness of BFSD-EIT in stroke diagnosis. METHODS: A realistic 4-layer Finite Element Method (FEM) head model with and without bleed and clot lesions is developed. Performance is assessed with test parameters including: measurement noise, electrode placement errors, contact impedance errors, deviations in assumed tissue conductivity, deviations in assumed anatomy, and a frequency-dependent background. A final test is performed using ischemic patient data. Results are assessed using images and quantitative metrics. RESULTS: BFSD-EIT may be feasible for stroke diagnosis if a signal-to-noise ratio (SNR) of ≥60dB is achievable. Sensitivity to errors in electrode positioning is seen with a tolerance of only ±5mm, but a tolerance of up to ±30mm is possible if symmetry is maintained between symmetrically opposite partner electrodes. The technique is robust to errors in contact impedance and assumed tissue conductivity up to at least ±50%. Asymmetric internal anatomy affects performance but may be tolerable for tissues with frequency-dependent conductivity. Errors in assumed external geometry marginally affect performance. A frequency-dependent background does not affect performance with carefully chosen frequency points or use of multiple frequency points across a band. The Global Left-Hand Side (LHS) & Right-Hand Side (RHS) Mean Intensity metric is particularly robust to errors. CONCLUSION: BFSD-EIT is a promising technique for stroke diagnosis, provided parameters are within the tolerated ranges. SIGNIFICANCE: BFSD-EIT may prove an important step forward in imaging of static scenes such as stroke.
Date Issued
2020-08-01
Date Acceptance
2019-12-19
Citation
IEEE Journal of Biomedical and Health Informatics, 2020, 24 (8), pp.2407-2419
ISSN
2168-2194
Publisher
Institute of Electrical and Electronics Engineers
Start Page
2407
End Page
2419
Journal / Book Title
IEEE Journal of Biomedical and Health Informatics
Volume
24
Issue
8
Copyright Statement
© 2019 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.See https://www.ieee.org/publications/rights/index.html for more information.
Sponsor
Imperial College Healthcare NHS Trust- BRC Funding
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/31869810
Grant Number
RDB04
Subjects
Science & Technology
Technology
Life Sciences & Biomedicine
Computer Science, Information Systems
Computer Science, Interdisciplinary Applications
Mathematical & Computational Biology
Medical Informatics
Computer Science
Tomography
Electrodes
Numerical models
Conductivity
Head
Brain modeling
Finite element analysis
Electrical impedance tomography
reconstruction algorithm
stroke imaging
ACUTE ISCHEMIC-STROKE
RECONSTRUCTION ALGORITHMS
TOMOGRAPHY
TISSUE
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2019-12-19