Quantitative MRI water content mapping of porcine intervertebral disc during uniaxial compression

Background: Intervertebral disc (IVD) diseases are major public health problem in industrialized countries where they affect a large proportion of the population. In particular, IVD degeneration is considered to be one of the leading causes of pain consultation and sick leave. The aim of this study was to develop a new method for assessing the functionality of IVD in order to diagnose IVD degeneration. Methods: For this purpose, we have designed a specific device that enables to mechanically load porcine IVD ex vivo in the 4.7-Tesla horizontal superconducting magnet of a magnetic resonance (MR) scanner. Proton density weighted imaging (ρ_H-MRI) of the samples was acquired. Findings: The post-processing on MR images allowed (1) to reconstruct the 3D deformation under a known mechanical load and (2) to infer the IVD porosity assuming an incompressible poroelastic model. Interpretation: This study demonstrates the ability to follow the change in morphology and hydration of an IVD using MR measurements, thereby providing valued information for a better understanding of IVD function.