Establishing an model of MR-T1ρ imaging technology to quantify nucleus pulposus tissue proteoglycans: a preliminary study.

BACKGROUND

The aim of the present study was to construct an model of degenerated nucleus pulposus with different combinations of biochemical components, and to find an model for the early degeneration of nucleus pulposus suitable for the detection of magnetic resonance T1rho (MR-T1ρ) sequence for the early diagnosis of degeneration of lumbar intervertebral disc.

METHODS

The proteoglycan concentration gradient in the first experimental group was 5%, with a concentration range of 7 samples models from 5% to 35%. The second experimental group had 15 samples with a 1% concentration gradient of proteoglycan (range, 10-24%), with a higher water content compared with the first group. The third experimental group contained 20 samples with a concentration gradient of 1% proteoglycan (range, 10-29%), with 75% water content. All of the models were scanned using a 3.0T GE MR. To analyze the correlation between the proteoglycan content of the model and the T1ρ value, we investigated the feasibility and stability of modeling.

RESULTS

There was no correlation between the model proteoglycan concentration and T1ρ value in the first experimental group; however, there was a significant negative correlation between the proteoglycan concentration and T1ρ value in the second experimental group (Y=-3.02X+131.8, R=0.852, P<0.05). In the third experimental group, the proteoglycan concentration was significantly positively correlated with T1ρ value (Y=3.05X+11.99, R=0.834, P<0.05). The comparison of the T1ρ values in the third experimental group before and 3 months after yielded an intraclass correlation coefficient value of 0.980, indicating that the biochemical components in the third experimental group were still stable after 3 months of storage. The slope of the regression equation between the Pfirrmann grading and T1ρ value in the third experimental group was not statistically different from the volunteer group (F=0.54, P=0.814), suggesting that the lumbar disc nucleus pulposus tissue of model samples fitted well with the volunteer group.

CONCLUSIONS

In this experiment, we successfully constructed an model of nucleus pulposus tissue proteoglycan that can be used for the quantitative evaluation of the MR-T1ρ imaging.