MR imaging of vertebral osteomyelitis revisited

OBJECTIVE. The purpose of this study was to reevaluate previously reported MR imaging findings for vertebral osteomyelitis that include decreased signal intensity in the disk and adjacent vertebral bodies on T1-weighted images, increased signal intensity in the disk and adjacent vertebral bodies on T2-weighted images, loss of endplate definition on T1-weighted images, and contrast enhancement of the disk, adjacent vertebral bodies, and involved paraspinal and epidural soft tissues. MATERIALS AND METHODS. Medical records, radiographs, and MR scans of 37 patients with vertebral osteomyelitis with 41 levels of involvement were reviewed for agreement with reported MR imaging findings. RESULTS. Ninety-five percent of the levels (39/41) showed decreased vertebral body signal intensity on T1-weighted images; 95% (39/41) had loss of endplate definition; 95% (37/39) had increased disk signal intensity on T2-weighted images; and 56% (22/39) had increased vertebral body signal intensity on T2-weighted images. Eighty-five percent of the levels (35/41) and 84% of patients (31/37) had both signal intensity changes of the vertebral body on T1-weighted images and signal intensity changes of the disk on T1- and T2-weighted images. Only 46% of the levels (19/41) and 49% of patients (18/37) had both vertebral body and disk changes on T1- and T2-weighted images. Contrast enhancement of the disk and vertebral body was seen in 94% of patients (17/18). Ring enhancement of paraspinal and epidural processes was found to correlate at surgery with abscess, and homogeneous enhancement was found to correlate with phlegmon. CONCLUSION. Hypointense signal intensity in the vertebral body on T1-weighted images, abnormal disk signal intensity on both T1- and T2-weighted images, and contrast enhancement are the findings that indicate spinal infection most reliably.