Imaging manifestations of spinal fractures in ankylosing spondylitis.
OBJECTIVE
Spinal fractures in ankylosing spondylitis (AS) were difficult to diagnose before CT and MR imaging were available. The purpose of our investigation was to characterize spinal fractures and determine the value of different imaging modalities in AS.


METHODS
Twelve successive cases of spinal fractures were identified in MR imaging files of AS patients. Conventional radiographs were available for 12, CT scans for 7, and 3D-CT scans for 4. We carefully reviewed clinical histories and imaging presentations.


RESULTS
Fractures were found in the cervical spine in 3 patients and in the thoracolumbar spine in 9. The 3 columns of the spine were involved in 11 patients. A routine 4-mm axial CT was not enough to demonstrate all fractures and ligament tears. The sensitivities of 3D-CT scans for demonstration of the following problems were similar to that of MR imaging and were better than that of conventional radiographs: tearing of the posterior longitudinal ligament, the thoracic spinous process fracture, and the facet fracture. MR imaging depicted these following findings that usually were not shown on conventional radiographs or 3D-CT scans: cord deformity, soft tissue disruption, and ligament tears in the posterior column. MR imaging also showed avascular necrosis and occult fractures better than conventional radiographs or CT scans.


CONCLUSIONS
MR imaging shows abnormalities in AS that may not be clear or even detectable by using other imaging methods. With the capability to show lesions in the posterior column, MR imaging can serve to evaluate AS patients with spinal fracture for the possibility of 3-column involvement.
Wang
Yi-Fen
YF
Department of Radiology, National Yang Ming University, Taipei, Taiwan.
Teng
Michael Mu-Huo
MM
Chang
Cheng-Yen
CY
Wu
Hung-Ta
HT
Wang
Shih-Tien
ST
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000592:standards; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000592:standards; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D016103:Spinal Fractures / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D013167:Spondylitis, Ankylosing / Q000150:complications*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000592:standards