The structural integrity of the nucleus pulposus (NP) of intervertebral discs was targeted by enzyme-specific degradations to correlate their effects to the magnetic resonance (MR) signal.
To develop quantitative MR
imaging as an accurate and noninvasive diagnostic tool to better understand and treat disc degeneration.
Summary of Background Data. Quantitative MR
analysis has been previously shown to reflect not only the disc matrix composition, but also the structural integrity of the disc matrix. Further work is required to identify the contribution of the structural integrity versus
the matrix composition to the MR signal.
The bovine coccygeal NPs were injected with either enzyme or buffer, incubated at 37°C as static, unloaded and closed 3-disc segments, and analyzed by a 1.5-Tesla MR scanner to measure MR parameters.
degradation of the NP significantly decreased the relaxation times, slightly decreased the magnetization transfer ratio, and slightly increased the apparent diffusion coefficient. Targeting the proteoglycan
and/or hyaluronan integrity by trypsin
did not significantly affect the MR parameters, except for an increase in the apparent diffusion coefficient of the disc after trypsin
Our results demonstrate that changes in the structural integrity of matrix proteins can be assessed by quantitative MR