Measuring intra-disc pressures in the spine from MRI images
A problem presented at the UK MMSG Southampton 2007.
- Presented by:
- (University of Southampton)
- (Medical Physics Group, Southampton University Hospitals NHS Trust)
- Participants:
Problem Description
The human spine is made of a series of bones linked together by various tissues such as the muscles, ligaments, nerves, etc. At the interface between the bones additional structures such as discs exist that give flexibility to the spine.
One of the main parameters that indicate disc function is assumed to be the internal pressure or pressure profile inside the disc itself. If disc pressure is to be measured invasively it requires an alteration of the very structures that give rise to and/or modify those internal pressures. An alternative may be to measure the pressure non-invasively making it possible to make such measurements in apparently normal and healthy volunteers.
We aim to examine the potential of measuring or estimating internal pressures of the vertebral disc from MRI (magnetic resonance imaging) images. Based on a basic understanding of how MRI images are generated, it is possible to envisage that a disc, as a self contained container with distributed water molecules inside, can present an image that describes this distribution. Given a change in the structure, the distribution of the water molecules are altered which gives rise to a different image making a diagnosis possible.
The mathematical challenge for the study group is to find relationships between the distribution of the water molecules and the pressure, taking account of the composite nature of the discs' internal structures.
Download the full problem description
Study Group Report
From the preliminary images available to the study group, it was concluded that:
- There appears to be nothing on the T2 images that changes when compression is applied except the geometry of the object.
- For the diffusion weighted images there appears to be some bright spots on the sides of the onion corresponding to areas where mobility of the water had reduced due to compression on the diffusion weighted maps.
- There appears to be nothing on Apparent Diffusion Coefficient images that changes with compression except for the geometry.