Subject-specific image analysis and computational modelling of the human Achilles tendon
(2021) BMEM01 20211Department of Biomedical Engineering
- Abstract
- Achilles tendon rupture is becoming more prevalent with an increasing population of middle aged people participating in recreational sports. A torn Achilles tendon will likely not regain its original function, and it is unknown what treatment options are optimal. The Achilles tendon structure and how the tendon heals after a rupture varies between humans. A potentially useful tool in understanding Achilles tendon healing is the use of computational models.
Data from an ongoing unpublished study (by Pernilla Eliasson) with 41 patients with ruptured Achilles tendon was made available for this project, five of these were selected for analysis. In the study, all patients did early motion training and a test group had early load training as... (More) - Achilles tendon rupture is becoming more prevalent with an increasing population of middle aged people participating in recreational sports. A torn Achilles tendon will likely not regain its original function, and it is unknown what treatment options are optimal. The Achilles tendon structure and how the tendon heals after a rupture varies between humans. A potentially useful tool in understanding Achilles tendon healing is the use of computational models.
Data from an ongoing unpublished study (by Pernilla Eliasson) with 41 patients with ruptured Achilles tendon was made available for this project, five of these were selected for analysis. In the study, all patients did early motion training and a test group had early load training as well. The study included computer tomography (CT) images of the Achilles tendon, along with tensile loading data. The access to this patient data resulted in two aims for this project.
One aim was to develop a pipeline for modelling subject-specific healing human Achilles tendons. Another aim of this project was to perform image analysis on healing human Achilles tendons from computed tomography images of these five patients, to study dimensions and tissue density throughout healing.
From CT images taken at 7, 19 and 52 weeks post rupture, the healing Achilles tendon was segmented. The free tendon length was also measured at the three time points. The segmented tendon was analysed for cross sectional area and tissue density. Segmentations of tendons were also prepared for finite element modelling. Using subject-specific experimentally measured tensile load data that had been obtained from roentgen stereophotogammic analysis (RSA), two material models were applied to the geometry, one linear elastic and one viscoelastic. The subject-specific tendon models were used for simulating tensile load and creep.
The results from the image analysis suggest that the cross sectional area and the tendon length increased within 7 weeks post rupture. The tissue density distribution was similar throughout the tendon. The simulations predicted maximum stress and strain at the smallest cross sectional area and at the boundary conditions.
In order to get more accurate and in vivo like results from the simulations more experimental data is required. One year post rupture the tissue density had gone back to normal, but an increase in cross sectional area remained, suggesting that the tendon had not fully recovered. Due to the small sample size of five patients, no conclusions could be drawn about the two treatments protocols. (Less) - Popular Abstract (Swedish)
- Individspecifik bildanalys och beräkningsmodell av läkande hälsena
Hälsenan är den största senan i kroppen och hälseneruptur är en av de vanligaste sen-
skadorna. Efter en ruptur läker senan med en ärrad vävnad och återfår inte sin intakta struktur. Detta innebär en stor risk för att hälsenan inte återfår sin funktion. I dagsläget brister kunskapen om vilken behandlings-metod som återställer hälsenan bäst. Samtidigt har antalet hälsenerupturer i Sverige ökat, framförallt hos medelålders personer. För att kunna ta reda på den bästa behandlingen är det viktigt att kunna undersöka hur senan läker.
Datortomografi är en form av röntgenteknik som används för att få tredimensionella medicinska bilder av delar av kroppen. I projektet hade... (More) - Individspecifik bildanalys och beräkningsmodell av läkande hälsena
Hälsenan är den största senan i kroppen och hälseneruptur är en av de vanligaste sen-
skadorna. Efter en ruptur läker senan med en ärrad vävnad och återfår inte sin intakta struktur. Detta innebär en stor risk för att hälsenan inte återfår sin funktion. I dagsläget brister kunskapen om vilken behandlings-metod som återställer hälsenan bäst. Samtidigt har antalet hälsenerupturer i Sverige ökat, framförallt hos medelålders personer. För att kunna ta reda på den bästa behandlingen är det viktigt att kunna undersöka hur senan läker.
Datortomografi är en form av röntgenteknik som används för att få tredimensionella medicinska bilder av delar av kroppen. I projektet hade vi tillgång till datortomografibilder av den läkande hälsenan tagna vid 7, 19 och 52 veckor efter ruptur. Dessa användes för att få fram 3D-geometrier av hälsenan.
Från datortomografibilderna undersöktes förlängning, förändring i tvärsnittsarea och vävnadstäthet i hälsenan. Utifrån enkla mekaniska tester gjorda i samband med de tre tidpunkterna kunde hälsenans mekaniska egenskaper approximeras. Tillsammans med hälsenans 3D-geometri kunde patientspecifika beräkningsmodeller, så kallade finita element- modeller, utvecklas.
Finita element-modeller är viktiga ur forsknings- perspektiv då de ger möjlighet att studera hur vävnaden påverkas under specifika händelseförlopp och rörelser i kroppen som annars kan vara svåra eller omöjliga att mäta. I detta projekt studerades töjnings- och spänningsfördelningen då hälsenan utsätts för en dragande kraft, vilken liknar senans belastning i kroppen.
Vi har tagit fram en metod där man kan studera egenskaper i den läkande hälsenan utifrån medicinska bilder och genom ett biomekaniskt perspektiv. Genom att undersöka en handfull patienter såg vi förändringar i senlängd, tvärsnittsarea och vävnadstäthet under läknings-
processen hos alla patienterna. Vi kunde också se att töjningarnas och spänningarnas storlek och position förändrades med tiden. Metoden vi utvecklat kan appliceras på ett större antal patienter, vilket förhoppningsvis kan ge ytterligare information om hur hälsenan läker. Denna metod skulle också kunna användas för att utvärdera hur olika rehabiliteringar fungerar, i jakten på att finna bästa möjliga behandlingsmetod för hälseneruptur. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9060261
- author
- Panzar, Johanna LU and Thörn, Erika LU
- supervisor
- organization
- course
- BMEM01 20211
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- image analysis, Achilles tendon, FE model, biomechanics, CT image
- language
- English
- additional info
- 2021-12
- id
- 9060261
- date added to LUP
- 2021-07-02 09:50:16
- date last changed
- 2022-06-30 03:40:48
@misc{9060261,
abstract = {{Achilles tendon rupture is becoming more prevalent with an increasing population of middle aged people participating in recreational sports. A torn Achilles tendon will likely not regain its original function, and it is unknown what treatment options are optimal. The Achilles tendon structure and how the tendon heals after a rupture varies between humans. A potentially useful tool in understanding Achilles tendon healing is the use of computational models.
Data from an ongoing unpublished study (by Pernilla Eliasson) with 41 patients with ruptured Achilles tendon was made available for this project, five of these were selected for analysis. In the study, all patients did early motion training and a test group had early load training as well. The study included computer tomography (CT) images of the Achilles tendon, along with tensile loading data. The access to this patient data resulted in two aims for this project.
One aim was to develop a pipeline for modelling subject-specific healing human Achilles tendons. Another aim of this project was to perform image analysis on healing human Achilles tendons from computed tomography images of these five patients, to study dimensions and tissue density throughout healing.
From CT images taken at 7, 19 and 52 weeks post rupture, the healing Achilles tendon was segmented. The free tendon length was also measured at the three time points. The segmented tendon was analysed for cross sectional area and tissue density. Segmentations of tendons were also prepared for finite element modelling. Using subject-specific experimentally measured tensile load data that had been obtained from roentgen stereophotogammic analysis (RSA), two material models were applied to the geometry, one linear elastic and one viscoelastic. The subject-specific tendon models were used for simulating tensile load and creep.
The results from the image analysis suggest that the cross sectional area and the tendon length increased within 7 weeks post rupture. The tissue density distribution was similar throughout the tendon. The simulations predicted maximum stress and strain at the smallest cross sectional area and at the boundary conditions.
In order to get more accurate and in vivo like results from the simulations more experimental data is required. One year post rupture the tissue density had gone back to normal, but an increase in cross sectional area remained, suggesting that the tendon had not fully recovered. Due to the small sample size of five patients, no conclusions could be drawn about the two treatments protocols.}},
author = {{Panzar, Johanna and Thörn, Erika}},
language = {{eng}},
note = {{Student Paper}},
title = {{Subject-specific image analysis and computational modelling of the human Achilles tendon}},
year = {{2021}},
}