Multimodal MRI Characterization of Structural and Resting-State Functional Brain Alterations in Patients with Low...

Background/Objectives: Low back pain (LBP) is associated with central alterations, but convergence across structural, functional, and network measures remains unclear. We characterized multimodal differences. Methods: Resting-state fMRI included 69 participants (37 patients, 32 controls); VBM retained 23 patients and 32 controls after structural-image quality control. Structural, local functional, and thalamic-connectivity measures were assessed. Motion control used realignment-based exclusion and Friston-24 nuisance regression. Mean Power framewise displacement was additionally calculated for all participants and compared between groups, and VBM-retained and excluded patients were compared. Models adjusted for age and sex, plus total intracranial volume for VBM. Directional maps underwent one-tailed Gaussian random field correction (voxel p < 0.001; cluster p < 0.05), without cross-direction or cross-family correction. Extracted-value and imaging-clinical analyses were exploratory. Results: Mean framewise displacement did not differ between groups. Patients showed lower gray matter volume in thalamic-hippocampal regions and right cerebellar lobule VIII and lower local functional measures in thalamic, orbitofrontal-striatal, and right temporal regions. Thalamic connectivity with sensorimotor, parietal, supplementary motor, and middle cingulate regions was higher. Nominal analyses showed positive left thalamic connectivity cluster 1-VAS and negative left cluster 1-JOA and right clusters 1/2-JOA; none survived false-discovery-rate correction. Conclusions: Multimodal MRI delineated lower thalamic structural and local functional measures alongside higher thalamo-sensorimotor and thalamo-parietal connectivity. Nominal, directionally coherent clinical associations remain hypothesis-generating. This thalamus-centered pattern warrants replication in prospectively matched, clinically stratified cohorts.