Effects of high intensity focused ultrasound on the intervertebral disc

Johan K Persson

Research output: ThesisDoctoral Thesis (compilation)

4 Citations (SciVal)
124 Downloads (Pure)

Abstract

The purpose of this study was to study and try to optimise high intensity focused ultrasound treatment of the intervertebral disc.

We demonstrated that it was possible to heat intervertebral discs with HIFU delivered by 50 or 5 mm diameter ultrasound transducers.

Finite element studies indicated that it would be possible to heat the disc to a temperature of 65ºC or above through an extradiscal minimally invasive procedure with a 5 mm diameter ultrasound transducer.

Computational studies were in general validated by experiments. In vivo studies showed no sign of discomfort or abnormality to the treated animals. Histological changes due to collagen shrinkage in the discs were found, and no damage to the nerve or muscle could be found.

The attenuation coefficient in bovine annulus fibrosus was found to be in the range of 1.1 to 1.3 dB cm-1 MHz-1 and the absorption coefficient 0.4 to 0.7 dB cm-1 MHz-1, which is approximately half of the attenuation coefficient. This indicates that a significant proportion of the ultrasound is scattered, due to the anisotropic nature of the annulus fibrosus.

Using magnetic resonance thermometry in a bovine in vitro model, the possibility to measure the temperature distribution in the disc during HIFU treatment was demonstrated. This method can be used to evaluate future ultrasound transducers and treatment protocols.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Orthopaedics (Lund)
Supervisors/Advisors
  • Lidgren, Lars, Supervisor
Award date2006 Sep 21
Publisher
Print ISBNs91-85559-28-8
Publication statusPublished - 2006

Bibliographical note

Defence details

Date: 2006-09-21
Time: 13:15
Place: Föreläsningssal F4 Centralblocket Universitetssjukhuset i Lund

External reviewer(s)

Name: Ask, Per
Title: Professor
Affiliation: Dep of Biomedical Engineering, Linköpings Universitet

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<div class="article_info">J Persson, B Strömqvist, G Zanoli, I McCarthy and L Lidgren. <span class="article_issue_date">2002</span>. <a href="javascript:downloadFile(547115)" class="article_link">Ultrasound nucleolysis: An in vitro study.</a> <span class="journal_series_title">Ultrasound in medicine and Biology</span>, <span class="journal_volume">vol 28</span> <span class="journal_pages">pp 1189-1197</span>.</div>
<div class="article_info">J Persson, E Hansen, L Lidgren and I McCarthy. <span class="article_issue_date">2005</span>. <a href="javascript:downloadFile(547116)" class="article_link">Modelling of the heat distribution in the intervertebral disk</a> <span class="journal_series_title">Ultrasound in medicine and Biology</span>, <span class="journal_volume">vol 31</span> <span class="journal_pages">pp 709-717</span>.</div>
<div class="article_info">O Forslund, J Persson, B Strömqvist, L Lidgren and I McCarthy. <span class="article_issue_date">2006</span>. <span class="article_title">Effects of high intensity focused ultrasound on the intervertebral disc: A potential therapy for disc herniations</span> <span class="journal_series_title">Journal of Clinical Ultrasound</span>, <span class="journal_volume">vol 34</span> <span class="journal_pages">pp 330-338</span>. (accepted)</div>
<div class="article_info">J Persson, L Lidgren and I McCarthy. <span class="article_issue_date">2006</span>. <span class="article_title">Ultrasound attenuation and absorption in the intervertebral disc</span> <span class="journal_series_title">Ultrasonics</span>, (submitted)</div>
<div class="article_info">J Persson, J Olsrud, O Forslund, B Strömqvist and I McCarthy. <span class="article_issue_date">2006</span>. <span class="article_title">Heating of the intervertebral disc by high intensity focused ultrasound, evaluated with MRI. A technical note</span> <span class="journal_series_title">Spine</span>, (submitted)</div>

Subject classification (UKÄ)

  • Orthopedics

Keywords

  • medical instrumentation
  • tomography
  • radiology
  • Clinical physics
  • Biofysik
  • Biophysics
  • Thermal therapy
  • Disc herniation
  • Intervertebral disc
  • High intensity focused ultrasound
  • Klinisk fysiologi
  • radiologi
  • tomografi
  • medicinsk instrumentering

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