MRI T2 mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model

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