Fat-saturated MR imaging in the detection of inflammatory facet arthropathy (Facet synovitis) in the lumbar spine

Objective. The objectives of the study were: to illustrate the magnetic resonance (MR) imaging appearance of facet synovitis in the lumbar region using an MR fat-saturation technique; to determine how commonly facet synovitis is encountered when fat-saturation techniques are used; to classify the MR appearance of facet synovitis; and to test the correlation between the location of a lesion and the site of the patient's pain. Design. In total, 209 consecutive MR studies of the lumbar spine were retrospectively reviewed to document the prevalence of lumbar facet synovitis in daily imaging practice. The degree of facet synovitis was graded. Medical records of 30 additional symptomatic patients with MR evidence of unilateral, single-level facet synovitis were reviewed to determine the side of the patient's clinical symptoms. Results. Facet synovitis occurred in 41% of lumbar MR studies reviewed. No patient reviewed had evidence of active infection. Most often, signal changes were restricted to the affected joint. The side of the facet synovitis correlated with the side of the patient's clinical symptoms. Conclusion. Facet synovitis is a common condition and appears to correlate with the patient's pain. Detection of active inflammatory facet osteoarthropathy (facet synovitis) within and surrounding the facet joints is possible with MR imaging using a fat-saturation technique.