Investigating longitudinal changes in lumbar discs in a two-year interval using quantitative MRI

Study designLongitudinal study using quantitative MRI techniques. PurposeDisc degeneration leads to a cascade of pathological changes in the spine that might initiate pain. It is particularly important to monitor patients who already have chronic low back pain (CLBP) to observe accelerated degeneration in adjacent segments. Therefore, our goal was to monitor the progression of disc degeneration in CLBP patients over a two-year interval using quantitative MRI techniques. Overview of LiteratureEarlier studies investigated age-related changes in intervertebral discs using cross sectional designs or follow-ups with long time intervals. Furthermore, they used qualitative assessment of MRIs. MethodsOswestry disability index (ODI) questionnaire was administered, and MRI data were acquired from 12 patients with chronic low back pain. Median follow-up period was 2 years. Disc height loss was measured and changes in disc physiology and structure were probed using T1{rho} relaxation and diffusion MRI. Longitudinal changes in MRI metrics, ODI and their correlations were analyzed. ResultsAll lumbar discs had significant disc height loss between the baseline and follow-up scans. However, changes in two discs were not significant if stringent Bonferroni correction was used for multiple comparisons. Also, T1{rho} or diffusion values did not change significantly at the group level during this period. There were strong positive correlations between DHI and ADC changes in L4/L5, between ADC and T1{rho} changes in L2/L3, and between DHI and T1{rho} changes in L5/S1. More importantly, these quantitative metrics enabled us to identify changes in disc structure and physiology in individual patients. ConclusionQuantitative MRI provided complementary information to assess longitudinal changes in IVDs. Although changes were not clearly seen by visual assessments, some participants had significant disc height loss. The quantitative approaches presented here might aid clinicians with more accurate evaluation of the stage of IVD degeneration and monitor its progression.