Cervical epidural spinal infection: MR imaging characteristics.

OBJECTIVE: Cervical epidural spinal infection, which includes diskitis, osteomyelitis, and/or epidural space infection, is an uncommon disease, and the MR imaging features have not been fully described. Accordingly, the objective of this study was to determine the MR imaging findings in a large series of patients with this condition, with emphasis on patients with pyogenic infection.

MATERIALS AND METHODS: During a 5-1/2-year interval, 12,695 MR examinations of the spine were performed in our department. A computer search retrospectively identified 60 patients with proved epidural spinal infection; 19 (32%) had involvement of the cervical spine. Pyogenic infection was present in approximately 90% of cases. One patient had an epidural abscess without an underlying osseous abnormality. The remaining 18 patients had cervical diskitis/osteomyelitis, as well as inflammation in the epidural space. All MR examinations were performed with a 1.5-T superconducting magnet by using a combination of spin-echo, fast spin-echo, and/or gradient-echo pulse sequences; 12 patients received IV gadopentetate dimeglumine. The MR examinations were retrospectively reviewed by a neuroradiologist for multiple imaging characteristics, including extent and location of osseous abnormalities, extent and location of inflammation in the epidural space, likelihood of abscess formation, and frequency of spinal cord compromise.

RESULTS: On MR images, an average of three vertebral bodies showed abnormal signal of the bone marrow. Inflammation in the epidural space extended an average of four levels and was most frequently anterior in location; MR images in six (50%) of 12 patients who received contrast material showed a large, peripherally enhancing epidural abscess. Thirteen (72%) of the 18 infections with osseous involvement occurred at or below the level of C4; the C5 and C6 levels were affected most frequently. Cord compression was identified in 14 (74%) of 19 patients; cord hyperintensity was seen in 12 (63%) of 19 patients and was well defined on T2-weighted FSE images.

CONCLUSION: The results of our study show that cervical epidural spinal infection is a more aggressive disease than previously recognized. MR findings are characterized by multilevel involvement, an anterior location, and frequent abscess formation. MR evidence of isolated involvement of the epidural space, without underlying osseous abnormality, is rare. There is a predilection for infection to affect the lower cervical segments. We observed a strong association between cervical epidural spinal infection and spinal cord compromise, which makes prompt diagnosis and treatment mandatory.