Facet joint signal change on MRI at levels of acute/subacute lumbar compression fractures

BACKGROUND AND PURPOSE: The prevalence of facet joint signal change in acute/subacute lumbar vertebral body compression fractures is unknown. We hypothesized that facet joint signal change on MR imaging is more common in facet joints associated with an acute/subacute lumbar compression fracture than those associated with normal vertebral bodies or ones that have a chronic compression fracture. MATERIALS AND METHODS: Three neuroradiologists and a neuroradiology fellow retrospectively graded facet joint inflammatory change on MR imaging in 900 facet joints in 75 patients with at least 1 painful osteoporotic lumbar compression fracture. Facet joint signal change was assessed on T2-weighted images with chemical fat-saturation, STIR images, and/or gadolinium-enhanced T1-weighted images with chemical fat-saturation. Each facet joint from the T12/L1 to L5/S1 level was assessed individually. An overall facet joint signal-change score, which is a composite measure of the grade of signal change for all 4 facet joints associated with a given lumbar vertebral level, was devised, and statistical significance was assessed via Wilcoxon rank sum tests. RESULTS: The overall facet joint signal-change scores were significantly higher at vertebral body levels affected by an acute/subacute compression fracture compared with control levels, which were associated with either normal bodies or chronic compression fractures. CONCLUSIONS: Our findings suggest an association between facet joint signal change on MR imaging and acute/subacute lumbar vertebral body compression fractures.