Distinguishing bone marrow edema patterns on MRI between spondyloarthritis and diffuse idiopathic skeletal...

Bone marrow edema (BME) in the vertebral body, a key feature of spondyloarthritis (SpA), is not uncommon in diffuse idiopathic skeletal hyperostosis (DISH). Our study aims to compare the vertebral BME patterns on MRI between DISH and SpA.

This retrospective study included 273 patients with DISH and 132 patients with SpA who underwent whole-spine MRI. Two radiologists jointly assessed primary imaging features on radiographs and MRI of the spines, followed by independent evaluations of BME characteristics including the presence, location, signal intensity and associated finding of BME to distinguish between DISH and SpA groups. Imaging characteristics of BME were compared with univariate and multivariate logistic regression tests using Generalized Estimating Equations.

Patients with DISH were significantly older than those with SpA (68.3 ± 9.3 vs. 38.9 ± 13.5 years, P < 0.001). BME was more prevalent in SpA than in DISH (31.8% vs. 20.9%, P = 0.016). In SpA, BME was significantly more likely to appear at the posterior corner (odds ratios (ORs) from multivariate logistic regression for reviewers 1 and 2: 46.01 and 38.95, respectively) or posterior band (ORs, 41.38 and 15.42), and demonstrate stronger hyperintensity (ORs, 7.66 and 7.99). BME with fatty changes was also associated with the diagnosis of SpA (ORs, 2.52 and 2.59).

Characteristic BME patterns on spine MRI, particularly posterior location, marked hyperintensity, and accompanying fatty changes, could help distinguish SpA from DISH in diagnostically challenging cases with overlapping MRI manifestations.