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A two-compartment gel phantom for optimization and quality assurance in clinical BOLD fMRI

  • Johan Olsrud
  • Anders Nilsson
  • Peter Mannfolk
  • Anthony Waites
  • Freddy Ståhlberg
Publishing year: 2008
Language: English
Pages: 279-286
Publication/Series: Magnetic Resonance Imaging
Volume: 26
Issue: 2
Document type: Journal article
Publisher: Elsevier

Abstract english

Clinical applications of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) depend heavily on robust paradigms, imaging methods and analysis procedures. In this work, as a means to optimize and perform quality assurance of the entire imaging and analysis chain, a phantom that provides a well known and reproducible signal change similar to a block type fMRI experiment is presented. It consists of two gel compartments with slightly different T(2) that dynamically enter and leave the imaged volume. The homogeneous gel in combination with a cylindrical geometry results in a well-defined T(2) difference causing a signal difference between the two compartments in T(2)-weighted MR images. From time series data obtained with the phantom, maps of percent signal change (PSC) and t-values are calculated. As an example of image parameter optimisation, the phantom is demonstrated to be useful for accurate determination of the influence of echo time (TE) on BOLD fMRI results, taking the t-value as a measure of sensitivity. In addition, the phantom is proposed as a tool for quality assurance (QA) since reproducible time series and t-maps are obtained in a series of independent repeat experiments. The phantom is relatively simple to build and can therefore be used by any clinical fMRI center.


  • Radiology, Nuclear Medicine and Medical Imaging
  • Phantom
  • Agarose gel
  • BOLD
  • Optimization
  • fMRI


  • ISSN: 1873-5894
Freddy Ståhlberg
E-mail: freddy [dot] stahlberg [at] med [dot] lu [dot] se


Medical Radiation Physics, Lund

+46 46 17 31 19

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Diagnostic Radiology, (Lund)

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MR Physics