Load-induced alterations in posterior parts of intervertebral discs in patients with load-induced pain during MRI; a detailed study using T2 maps

To use the effect of axial loading, captured with quantitative MRI, to investigate differences between load-induced behaviors of intervertebral discs (IVDs) in patients with non-specific low back pain (LBP) experiencing load-induced pain during MRI and those who do not. In total, 178 LBP patients were imaged in the supine position with T2 mapping with and without loading. Intensity of daily pain and pain during imaging was graded from 0 to 10 Numerical Rating Scale (NRS). Patients were stratified according to whether or not they reported load-induced pain during imaging. Load-induced T2-value alterations in entire IVDs, and in central/posterior parts on levels L3/L4 to L5/S1 were compared between the groups using repeated measures analysis of variance and Fold-change. Results were adjusted for IVD-degeneration grade. Among the 120 patients reporting load-induced pain (mean NRS during examination: 5.8 vs. mean NRS for daily level: 5.7), 84% perceived it as concordant with their daily pain. In contrast, 58 patients reported no load-induced pain (mean NRS during examination 2.3 vs. mean NRS for daily pain level 5.4). Higher load-induced T2-value increases were observed in entire IVDs at L5/S1 (relative difference of 2% [95% CI; 0–5%]; p = .038) and in posterior regions at L3/L4 (relative difference of 4% [95% CI; 0–7%]; p = .033) among patients with load-induced pain compared to those without. Higher load-induced global and posterior T2-value increments in IVDs in LBP patients with load-induced pain suggest different biomechanical IVD-phenotypes between the two groups. Findings might be valuable in the ongoing work of identifying a non-invasive imaging-biomarker for pain in LBP patients.