Poor cartilage endplate (CEP) composition plays a significant role in disc degeneration severity and can affect disc health both with and without deficits in vertebral perfusion. This is the key message to come out of new research published in the European Spine Journal by Aaron Fields (University of California, San Francisco, USA) et al.
The study was designed to use compositional biomarkers derived from quantitative magnetic resonance imaging (MRI) to establish how CEP composition and vertebral bone marrow fat fraction (BMFF) relate to disc degeneration.
The researchers note that the composition of the subchondral bone marrow and CEP “could affect intervertebral disc health by influencing vertebral perfusion and nutrient diffusion. However, the relative contributions of these factors to disc degeneration in patients with chronic low back pain (cLBP) have not been quantified,” they add.
MRI data from a total of 60 patients with cLBP were included in this prospective observational study (28 female, 32 male; age: 40 ± 11.9 years, 19–65 [mean ± standard deviation, min–max]).
Ultra-short echo-time MRI was used to calculate CEP T2* relaxation times (reflecting biochemical composition), while water-fat MRI was used to calculate vertebral BMFF, and T1ρ MRI was used to calculate T1ρ relaxation times in the nucleus pulposus (NP T1ρ, reflecting proteoglycan content and degenerative grade).
Univariate linear regression was used to assess the independent effects of CEP T2* and vertebral BMFF on NP T1ρ. Mixed effects multivariable linear regression accounting for age, sex, and BMI was used to assess the combined relationship between variables.
The study found that CEP T2* and vertebral BMFF were independently associated with NP T1ρ (p=0.003 and p=0.0001, respectively). After adjusting for age, sex, and BMI, NP T1ρ remained significantly associated with CEP T2* (p=0.0001) but not vertebral BMFF (p=0.43).