Characteristics of cervical intervertebral disc signal intensity: an analysis of T2-weighted magnetic resonance imaging in 5843 asymptomatic Chinese subjects

Purpose The study aimed to observe cervical intervertebral discs (IVDs) in asymptomatic subjects and to explore the factors associated with cervical intervertebral disc degeneration (IVDD). Methods Cervical spine MRI of 5843 subjects was retrospectively analyzed. On the sagittal T2-weighted MR images, the mean signal intensities of the nucleus pulposus were obtained. Standard signal intensity (SSI) of intervertebral discs was defined as the ratio of mean disc signal intensity to mean CSF signal intensity. Results In subjects under 70 years old, the SSI of IVD was lowest at the C5/6 level. In those over 70, the SSI of IVD was similar among the disc levels from C2/3 to C7/T1. The disc SSI decreased significantly with age in both genders. In subjects under 70 years old, the SSI of the discs at each level was higher in females than in males. In those over 70 years old, no difference was found in disc SSI between two genders at most disc levels. Logistic regression analysis showed that kyphotic and straight cervical spine, obesity and older age were associated with higher risk of having lower disc SSI. Conclusion To our knowledge, this is the largest cross-sectional study using MRI-based quantitative assessment to characterize cervical IVDD in asymptomatic subjects. Cervical IVDD was shown to progress with age and significantly correlated with gender, BMI and cervical alignment. Early intervention of related factors may help delay cervical IVDD and prevent future neck and shoulder pain.