Biochemical and microenvironmental characterization of the disc-vertebra complex in non-specific low back pain using non-fat-saturation multi-slice CEST MRI

This study aimed to characterize biochemical and microenvironmental changes within the Disc Vertebra Complex (DVC) in non-specific low back pain (NSLBP) patients using non-fat-saturation Multi-slices CEST MRI. By performing intra-group comparisons, we assessed associations between disc degeneration and vertebral biochemical variations.

Ninety-nine NSLBP patients (62 males, 37 females; median age 45) underwent lumbar spine MRI. Non-fat-saturation Multi-slices CEST imaging was used to assess fat fraction (FF), fat /water content and magnetization transfer contrast in vertebrates, and water content, glycosaminoglycan (GAG), amide proton transfer (APT), nuclear overhauser enhancement (NOE) and magnetization transfer contrast in discs. Metabolic and microenvironmental changes across vertebrae (L2-S1) and intervertebral discs (L2/3-L5/S1) were analyzed. Statistical comparisons were conducted across disc grades, weight categories, and disc abnormalities.

Significant biochemical variations were observed across vertebral levels, with decreasing water content and increasing FF from L2 to S1. The pH-sensitive markers (APT) showed caudal trends, indicating relative changes in proton environment. Protruding discs and discs with high-intensity zones (HIZ) showed reduced pH and hydration, alongside altered macromolecular structures. Adjacent vertebrae of protruding discs exhibited decreased water content, indicative of early bone marrow edema.

Non-fat-saturation Multi-slices CEST MRI enables holistic profiling of the disc–vertebra complex (DVC) and detects localized, grade-dependent biochemical heterogeneity. Notably, differences emerged between vertebrae and discs with and without protrusion / HIZ, alongside grade-dependent variations.