Role of T2 mapping MRI in early lumbar intervertebral disc degeneration: a narrative review

Background Lumbar intervertebral disc degeneration (IVDD) is a major contributor to low back pain and disability worldwide. Conventional MRI, while the imaging standard, is limited in its capacity to detect biochemical alterations that precede structural failure. T2 relaxation time mapping a quantitative MRI technique has emerged as a sensitive, non-invasive biomarker capable of detecting early compositional changes in disc tissue. Objectives This narrative review aimed to synthesize the current evidence on the role of T2 mapping MRI in early lumbar IVDD, including its biophysical principles, acquisition protocols, correlation with established grading systems, comparison with other quantitative techniques, and clinical limitations. Methods A structured literature search was conducted across PubMed/MEDLINE, Scopus, and Google Scholar using the terms ‘T2 mapping’, ‘intervertebral disc degeneration’, ‘lumbar spine’, ‘quantitative MRI’, and ‘nucleus pulposus’. Studies published between 2005 and 2025 with relevance to T2 mapping in lumbar IVDD were included, with emphasis on articles from 2018 onwards. Results T2 values of the nucleus pulposus decrease progressively with advancing Pfirrmann grade. Multiple studies confirm a strong correlation between T2 relaxation times and disc water and proteoglycan content. Accelerated acquisition sequences have significantly reduced scan times, improving clinical feasibility. T2 mapping outperforms T2* mapping for early detection, though T1ρ (spin–lattice relaxation in the rotating frame) may be more sensitive for proteoglycan-specific changes. Conclusions Current evidence supports T2 mapping as a promising and reproducible quantitative MRI biomarker for the early detection of lumbar IVDD. Broader clinical implementation remains contingent on acquisition standardization, larger prospective cohorts, and normative reference data. Broader clinical implementation remains contingent on acquisition standardization, larger prospective cohorts, and normative reference data.