[The 1H-NMR evaluation of biomechanical function in human lumbar disc]

The purpose of this study was to determine the usefulness of relaxation time of nuclear magnetic resonance in evaluating biomechanical functions of human lumbar discs. Using L3-L4 disc-body units obtained from fresh human cadavers en bloc, proton density imaging was performed with a NMR-CT. Furthermore, intradiscal pressure, tan delta, dynamic stiffness, and relaxation time were measured. The results were as follows: Proton density imaging was useful in detecting the degeneration of the human lumbar disc. Intradiscal pressure, tan delta, and relaxation time decreased with advancing age whereas dynamic stiffness increased. The correlation coefficient of relaxation time to tan delta and dynamic stiffness was 0.80 (p less than 0.01) and -0.67 (p less than 0.05), respectively, which reflected dynamic viscoelasticity of the human lumbar disc. In conclusion, relaxation time seems to be useful in evaluating biomechanical functions of human lumbar discs.