Methods: Data from 12 adults without any history of back pain were used in this study. Sagittal T2-weighted images of the lumbar spine were acquired in the supine and WB positions twice (in two separate sessions scheduled within a week). Linear, angular dimensions, and cross-sectional areas (CSAs) were measured using proprietary software. Supine and WB data acquired from the two imaging sessions were tested for intra-rater reliability. Quantified data were normalized for each session to test the significance of differences. ICC was calculated to test the reliability of the measurements. Results: Linear, angular, and CSA measurements demonstrated strong within-position (supine and WB) correlations (r -values, 0.75–0.97). Between-position (supine vs. WB) differences were significant for all measured dimensions (p<0.05). Between-session measurements demonstrated a strong correlation (r -values, 0.64–0.83). Calculated ICC showed strong agreement among the measurements. Conclusions Anatomical dimensions of the lumbar spine may demonstrate consistent and significant differences between supine and WB MRI for specific structural parameters.

STUDY DESIGN: Between-session reliability of a magnetic resonance imaging (MRI) based experimental technique to quantify lumbar inter-vertebral motion in humans. PURPOSE: We have developed a novel, dynamic, MRI-based approach for quantifying in vivo lumbar inter-vertebral motion. In this study, we present the protocol's reliability results to quantify inter-vertebral spine motion. OVERVIEW OF LITERATURE: Morphometric studies on intervertebral displacements using static, supine MRI and quantification of dynamic spine motion using different X-ray based radiography techniques are commonly found in the literature. However, reliability testing of techniques assessing real-time lumbar intervertebral motion using weight-bearing MRI has rarely been reported. METHODS: Ten adults without a history of back pain performed a side-bending task on two separate occasions, inside an open-MRI, in a weight-bearing, upright position. The images were acquired during the task using a dynamic magnetic resonance (MR) sequence. The MRI imaging space was externally calibrated before the study to recreate the imaging volume for subsequent use in an animation software. The dynamic MR images were processed to create side-bending movement animations in the virtual environment. Participant-specific three-dimensional models were manually superimposed over vertebral image silhouettes in a sequence of image frames, representing the motion trials. Inter-vertebral axes and translation and rotational displacements of vertebrae were quantified using the animation software. RESULTS: Quantification of inter-vertebral rotations and translations shows high reliability. Between-session reliability results yielded high values for the intra-class correlation coefficient (0.86–0.93), coefficient of variation (13.3%–16.04%), and Pearson's correlation coefficients (0.89–0.98). CONCLUSIONS: This technique may be developed further to improve its speed and accuracy for diagnostic applications, to study in vivo spine stability, and to assess outcomes of surgical and non-surgical interventions applied to manage pathological spine motion.
Adult ; Back Pain ; Humans ; Intervertebral Disc ; Low Back Pain ; Lumbar Vertebrae ; Magnetic Resonance Imaging ; Radiography ; Spine ; Translations ; Weight-Bearing