Ultrashort time-to-echo MRI of the cartilaginous endplate: technique and association with intervertebral disc degeneration

Abstract

INTRODUCTION: An association between cartilaginous endplate (CEP) defects and intervertebral disk (IVD) degeneration has been previously suggested in animal and cadaveric studies. There have been no previous reports in the literature that describe the use of ultrashort time-to-echo (UTE) magnetic resonance imaging (MRI) to assess the CEP in humans in vivo. As such, the purpose of this study was to report the feasibility of the UTE MRI technique to assess CEP defects in humans in vivo using and to assess their relationship with IVD degeneration. MATERIALS AND METHODS: Nine volunteer subjects (mean age 43.9 years; range: 22 to 61 years) were recruited, representing 54 IVDs and 108 CEPs. The subjects underwent T2-weighted and UTE MRI to assess for the presence and severity of IVD degeneration, and for the presence of CEP defects, respectively, from T12 to S1. Intervertebral disk degeneration was graded according to the Schneiderman et al classification on T2-weighted MRI. CEP defects were defined on UTE MRI as discontinuity of high-signal over 4 consecutive images and were independently assessed by two observers. RESULTS: Total 37% out of 108 (34.3%) CEPs had defects, which mainly occurred at T12/L1, L1/L2, and L4/L5 (p = 0.008). Multivariate logistic regression revealed that lower BMI (p = 0.009) and younger (p = 0.034) individuals had a decreased likelihood of having CEP defects. A statistically significant association was found to exist between the presence of CEP defects and IVD degeneration (p = 0.036).A higher prevalence of degenerated IVDs with CEP defects were found at L4/5 and L5/S1, while degenerated IVDs with no CEP defects were found throughout the whole lumbar region. Mean IVD degeneration scores of the L4/5 and L5/S1 levels with CEP defects were higher in comparison to those with no CEP defects. CONCLUSION: Our study demonstrates the feasibility of using UTE MRI in humans in vivo to assess the integrity of the CEP. A statistically significant association was found to exist between the presence of CEP defects and IVD degeneration. In the lower lumbar region, more severe degeneration was found to occur in the IVDs with CEP defects than in those without defects. Such imaging technology may broaden the understanding of IVD degeneration and facilitate management options that target IVD repair/regeneration.