Quantitative MRI in early intervertebral disc degeneration: T1rho correlates better than T2 and ADC with biomechanics, histology and matrix content.

Margriet G. Mullender,Theodoor H. Smit,Arno Bisschop,Magda de Graaf,Gustav J. Strijkers,Peter M. van de Ven,Cornelis P. L. Paul,Roderick M. Holewijn,Marco N. Helder

doi:10.1371/journal.pone.0191442

Margriet G. Mullender, Theodoor H. Smit

Open Access

https://doi.org/10.1371/journal.pone.0191442

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Abstract

IntroductionLow-back pain (LBP) has been correlated to the presence of intervertebral disc (IVD) degeneration on T2-weighted (T2w) MRI. It remains challenging, however, to accurately stage degenerative disc disease (DDD) based on T2w MRI and measurements of IVD height, particularly for early DDD. Several quantitative MRI techniques have been introduced to detect changes in matrix composition signifying early DDD. In this study, we correlated quantitative T2, T1rho and Apparent Diffusion Coefficient (ADC) values to disc mechanical behavior and gold standard early DDD markers in a graded degenerated lumbar IVD caprine model, to assess their potential for early DDD detection.MethodsLumbar caprine IVDs were injected with either 0.25 U/ml or 0.5 U/ml Chondroïtinase ABC (Cabc) to trigger early DDD-like degeneration. Injection with phosphate-buffered saline (PBS) served as control. IVDs were cultured in a bioreactor for 20 days under axial physiological loading. High-resolution 9.4 T MR images were obtained prior to intervention and after culture. Quantitative MR results were correlated to recovery behavior, histological degeneration grading, and the content of glycosaminoglycans (GAGs) and water.ResultsCabc-injected IVDs showed aberrancies in biomechanics and loss of GAGs without changes in water-content. All MR sequences detected changes in matrix composition, with T1rho showing largest changes pre-to-post in the nucleus, and significantly more than T2 and ADC. Histologically, degeneration due to Cabc injection was mild. T1rho nucleus values correlated strongest with altered biomechanics, histological degeneration score, and loss of GAGs.ConclusionsT2- and T1rho quantitative MR-mapping detected early DDD changes. T1rho nucleus values correlated better than T2 and ADC with biomechanical, histological, and GAG changes. Clinical implementation of quantitative MRI, T1rho particularly, could aid in distinguishing DDD more reliably at an earlier stage in the degenerative process.

Highlights

Low-back pain (LBP) has been correlated to the presence of intervertebral disc (IVD) degeneration on T2-weighted (T2w) magnetic resonance imaging (MRI)
It has been shown that in teenagers and young adolescents, early symptomatic degenerative disc disease (DDD) is prognostic for exacerbation of LBP complaints and progression of DDD in adulthood [7,8,9,10,11]
This leads to school- and work absenteeism, disability and/or medical intervention, all adding to the enormous socio-economic costs of LBP [1, 12, 13]

Summary

Introduction

Low-back pain (LBP) has been correlated to the presence of intervertebral disc (IVD) degeneration on T2-weighted (T2w) MRI. It remains challenging, to accurately stage degenerative disc disease (DDD) based on T2w MRI and measurements of IVD height, for early DDD. Several quantitative MRI techniques have been introduced to detect changes in matrix composition signifying early DDD. We correlated quantitative T2, T1rho and Apparent Diffusion Coefficient (ADC) values to disc mechanical behavior and gold standard early DDD markers in a graded degenerated lumbar IVD caprine model, to assess their potential for early DDD detection

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