Faculté des Sciences appliquées
Faculté des Sciences appliquées

Master thesis : Electrical impedance tomography for external wound monitoring : measurements, signal processing and image reconstruction

Mendolia, Loris ULiège
Promotor(s) : Redouté, Jean-Michel ULiège
Date of defense : 5-Sep-2022/6-Sep-2022 • Permalink :
Title : Master thesis : Electrical impedance tomography for external wound monitoring : measurements, signal processing and image reconstruction
Translated title : [fr] Tomographie par impédance électrique pour le suivi de plaies externes : mesures, traitement de signal et reconstruction d'image
Author : Mendolia, Loris ULiège
Date of defense  : 5-Sep-2022/6-Sep-2022
Advisor(s) : Redouté, Jean-Michel ULiège
Committee's member(s) : Marquet, Lara ULiège
Phillips, Christophe ULiège
Language : English
Number of pages : 140
Keywords : [en] Wound monitoring
[en] Skin impedance measurements
[en] Electrical impedance tomography
[en] Impedance spectrum signal processing
Discipline(s) : Engineering, computing & technology > Electrical & electronics engineering
Human health sciences > Laboratory medicine & medical technology
Research unit : Laboratoire Microsys de l'Institut Montéfiore
Name of the research project : Projet Vitapatch
Target public : Researchers
Professionals of domain
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en ingénieur civil biomédical, à finalité spécialisée
Faculty: Master thesis of the Faculté des Sciences appliquées


[en] Assessing the state of chronic open wounds and monitoring their healing in the long term is an important but delicate task in the medical world. Manipulating and perturbing traumatized tissues too often hinders the healing process and prolongs the burden for the patient and the medical system. Conversely, ignoring complications such as bacterial infection or necrotic tissue for too long can lead to dramatic consequences, from the need for amputation to septic shock and death.
Nowadays, chronic wound monitoring is still a matter of frequent visual inspections, which requires medical expertise and intrusions into the daily lives of patients.

The Vitapatch research project, for which this thesis has been carried out, aims at solving this issue by creating easily deployable smart sensor patches capable of long-term continuous monitoring of a chronic wound in a non-invasive manner.

This thesis explores the use of bioimpedance spectroscopy to assess the state of human skin, and electrical impedance tomography as an image reconstruction tool to provide a non-intrusive visual assessment of wound healing.
After briefly reminding the concepts of electrical impedance and conduction of electricity, the physiological and electrical properties of human skin and tissues are presented, and the impacts of a wound on these properties are discussed. Then, the methodology for bioimpedance measurements is explained, with specific care toward long-term medical applications. Following, the prototype bioimpedance spectroscopy circuit created by Microsys is analyzed and simulated. After that, the required signal processing steps to make this circuit work are presented, and the journey towards experimental validation of the processing routine is described. Proceeding, electrical impedance tomography is introduced, different algorithms are assessed through simulations and a preliminary application is presented. Adaptations of the EIT problem to wound imaging are performed, and image reconstruction on a finite-element model of wounded skin is simulated. Finally, an experimental setup for wound assessment on phantom skin is presented. Repeated hardware delays and unfinished or faulty components have prevented the completion of real-life experiments, but simulations show promising prospects for a nontraditional approach to impedance spectroscopy and signal processing, as well as for skin modeling and applications of electrical impedance tomography to non-invasive wound imaging.



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Access Vitapatch_concept.png
Description: Concept du projet Vitapatch
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Access PCB.jpg
Description: Vitapatch prototype PCB
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Access Current_sim.png
Description: Current injection simulation for skin EIT
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Access Experimental_setup_pork_skin.jpg
Description: Experimental setup for wound image reconstruction using pork skin
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Access MENDOLIA_Loris_Master_Thesis_Summary.pdf
Description: Résumé du travail
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Access Regressed_spectrum.pdf
Description: Least-squares boosting for PRBS spectroscopy noise removal
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Access Tank_image.pdf
Description: Electrical impedance tomography in a water tank
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Access Skin_FEM.pdf
Description: FEM model of human skin layers with surface EIT electrodes
Size: 93.9 kB
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Access Wound_image_sim.pdf
Description: Simulated image reconstruction of a wound on the skin FEM model
Size: 396.92 kB
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  • Mendolia, Loris ULiège Université de Liège > Master ing. civ. biomed., à fin.


Committee's member(s)

  • Marquet, Lara ULiège Université de Liège - ULiège > Département des sciences de la motricité > Médecine physique, réadaptation et traumatologie du sport
    ORBi View his publications on ORBi
  • Phillips, Christophe ULiège Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Dép. d'électric., électron. et informat. (Inst.Montefiore)
    ORBi View his publications on ORBi
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  • Total number of downloads 307

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