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Erschienen in:
01.09.2015 | Original Article
MRI T2* mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model
Erschienen in: European Spine Journal | Ausgabe 9/2015
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Purpose
To evaluate intervertebral disc (IVD) degeneration and treatments, an objective diagnostic tool is needed. Recently, T2* relaxation time mapping was proposed as a technique to assess early IVD degeneration, yet the correlation with biochemical content and histological features has not been investigated previously. Our objective was to validate T2* mapping for disc degeneration by correlating this technique with accepted parameters of IVD degeneration.
Methods
Mildly and severely degenerated lumbar discs were obtained from an in vivo large animal study; two healthy goat spines were acquired as control. In total, 48 IVDs were analysed using T2-weighted MRI, T2* relaxation time mapping, biochemical assays, macroscopic and histological scoring. Correlations between variables were expressed with Spearman’s rho (ρ) coefficients.
Results
A complete range of degenerative grades were obtained (mean histological grade 2.2, range 0–6). A linear positive correlation was observed between T2* relaxation time and glycosaminoglycan content (ρ = 0.64, p < 0.001). T2* relaxation time decreased linearly with increasing degeneration as assessed with Pfirrmann scoring system (ρ = −0.67, p < 0.001), macroscopic (ρ = −0.33, p < 0.05) and histological (ρ = −0.45, p < 0.05) grading.
Conclusions
T2* mapping is an MRI technique for IVD evaluation which allows for measurements on a continuous scale thus minimising observer bias compared to grading systems. Although limited by a small sample size, this study showed a relatively good and linear correlation between T2* relaxation time and accepted parameters of disc degeneration. This suggests that T2* mapping is a promising tool to assess disc degeneration in clinical practice.