Differential diagnosis of erosive osteochondrosis and bacterial spondylitis in MRI

Purpose: To evaluate retrospectively criteria in the differential diagnosis of erosive osteochondrosis (EO) and infectious spondylitis (IS) on the basis of MRI. Methods: T-1-weighted sagittal images before and after Gd-DTPA application, T-2-weighted TSE or T-STIR images of 23 patients with proven IS and 41 patients with EO were evaluated. Criteria for this evaluation were morphology and extension of bone marrow edema, visibility of the low-intensity vertebral endplate, contrast enhancement and signal intensity in the disc space on T-2-weighted and T-STIR images. Results: Bone marrow edema was more extensive in IS than in EO. The mean rated value for bone marrow edema on a four-level scale (0-3) was for IS 2.91 (+/- 0.29), for EO 1.32 (+/- 0.76, p < 0.001). In 37/41 cases of EO and in 22/23 cases of IS Gd-DTPA enhancement was found in the disc space (n. s.). In EO the low intensity endplate was visible in all parts in 36/41 cases (87.8 %) on T-1-weighted images, in IS not in a single case (0%). On T-2-weighted or STIR images signal intensity of the discs was decreased in 82.1% of EO, 82.6% of segments in IS had water-equivalent signal intensity (p<0.001). Conclusion: If all the criteria are taken into consideration differential diagnosis of EO and IS on the basis of MRI findings is possible.