The shear modulus of the nucleus pulposus measured using magnetic resonance elastography: A potential biomarker for intervertebral disc degeneration

Abstract

Summary Purpose This study aims to: 1) measure the shear modulus of nucleus pulposus (NP) in intact human vertebra-disc-vertebra segments using a magnetic resonance elastography (MRE) setup for a 7T whole-body scanner, 2)quantify the effect of disc degeneration on the NP shear modulus measured using MRE, and 3) compare the NP shear modulus to other MR-based biomarkers of disc degeneration. Methods Thirty intact human discs segments were classified as normal, mild, or severely degenerated. The NP shear modulus was measured using a custom-made setup that included a novel inverse method less sensitive to noisy displacements. T2 relaxation time was measured at 7T. The accuracy of these parameters to classify different degrees of degeneration was evaluated using ROC curves. Results The MRE measure of shear modulus in the NP was able to differentiate between normal, mild degeneration, and severe degeneration. The T2 relaxation time was able to differentiate between normal and mild degeneration, but it could not distinguish between mild and severe degeneration. Conclusion This study shows that the NP shear modulus measured using MRE is sensitive to disc degeneration and has the potential of being used as a clinical tool to quantify the mechanical integrity of the intervertebral disc.

Non-invasive biomechanical characterization of intervertebral discs by shear wave ultrasound elastography: a feasibility study

“…Non-invasive biomechanical characterization of the disc could represent a novel biomarker for disc assessment, as was previously suggested by Cortes et al (Cortes et al, 2014): the relationship between pain and biochemical or structural characteristics of the disc is complex (Freemont, 2009), but mechanical properties could be affected by both these aspects. For instance, mechanical traumas such as whiplash can cause disc pathologies which are difficult to diagnose because of the high prevalence of physiological disc degeneration with age (Pettersson et al, 1997).…”

“…Preliminary in-vitro work has shown correlations between magnetic resonance images and disc mechanical properties (Campana et al, 2011;Cortes et al, 2014;Mwale et al, 2008;Périé et al, 2006;Recuerda et al, 2012), but in-vivo applications are still lacking. Moreover, cost and accessibility of magnetic resonance imaging represent an issue when considering large scale routine clinical use.…”

Lumbar annulus fibrosus biomechanical characterization in healthy children by ultrasound shear wave elastography

“…Biomechanical characterization of the intervertebral disc (IVD) in vivo could represent a novel non-invasive biomarker [13] for a range of spinal pathologies. Investigations in this sense, especially in the younger population, have been slowed down by the difficulties of assessing disc mechanical properties in vivo.…”

“…Spinal flexibility and intervertebral stiffnesses have been assessed by traction, bending or fulcrum tests [10][11][12] tests; these techniques, however, do not allow direct measurement of IVD biomechanical properties and require invasive radiographic techniques. Non-invasive techniques based magnetic resonance elastography are being developed to investigate disc mechanical properties [13][14][15].…”

Intervertebral Disc Characteristic on Progressive Neurological Deficit

“…Therefore, early diagnosis of disc degeneration is critical for the success of any modality of treatment strategy. 8,9 The etiologic factors of nocioceptive and disability caused by pathological disc is still currently debatable. 2,10 A common belief is that changes the diffusion of water will result in structural changes in nucleus pulposus, annulus and end plate that are altered the internal disc stability.…”