Abstract
STUDY DESIGN
Comparison of sodium concentration ([Na]) and proton T2 relaxation time between normal and degenerated discs in a rabbit model.
OBJECTIVE
The purpose of this article was to evaluate quantitative [Na] and T2 characteristics of discs associated with degenerative changes.
SUMMARY OF BACKGROUND DATA
Intervertebral disc degeneration is a common chronic condition that may lead to back pain, limited activity, and disability. Noninvasive imaging method to detect early intervertebral disc degeneration is vital to follow disease progression and guide clinical treatment and management.
METHODS
Dual-tuned magnetic resonance imaging of rabbit discs was performed using 3T. Thirteen rabbits were included in the study; 6 control rabbits (24 normal discs) and 7 rabbits with annular puncture-induced disc degeneration (9 degenerated discs, 19 intact internal-control discs). Dual-tuned magnetic resonance imaging of discs was performed at baseline and 12-week poststab. [Na] and T2 were measured and compared among 3 groups of discs.
RESULTS
The mean [Na] were 274.8 ± 40.2 mM for the normal discs, 247.2 ± 27.7 mM for the internal-control discs, and 190.6 ± 19.1 mM for the degenerated discs. The corresponding T2 for 3 groups were 97.1 ± 12.1 ms, 93.7 ± 11.9 ms, and 79.0 ± 9.1 ms, respectively. The [Na] is highly correlated with the T2 in the degenerated discs (r = 0.90, P < 0.01). The mean percent decreases from the normal to degenerated discs were in 30.6% in [Na] and 18.6% in T2, whereas those from the internal-control to degenerated discs were 22.9% in [Na] and 15.6% in T2.
CONCLUSION
Although both [Na] and T2 changes in discs were associated with the disc-punctured rabbits, greater change in [Na] is observed at 12-week poststab compared with T2 change. Because T2 and [Na] reflect different disc properties, performing both imaging under same condition will be helpful in the evaluation of disc degeneration.
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