title: MRI of cervical spine injuries complicating ankylosing spondylitis.
abstract: OBJECTIVE
  The objective was to study characteristic MRI findings in cervical spine fractures complicating ankylosing spondylitis (AS). Technical issues related to MRI are also addressed.
  
  
  METHODS
  A review of 6,774 consecutive cervical spine multidetector CT (MDCT) scans obtained during 6.2 years revealed 33 ankylosed spines studied for suspected acute cervical spine injury complicating AS. Of these, 20 patients also underwent MRI.
  
  
  RESULTS
  On MRI, of these 20 patients, 19 had a total of 29 cervical and upper thoracic spine fractures. Of 20 transverse fractures traversing both anterior and posterior columns, 7 were transdiskal and exhibited less bone marrow edema than did those traversing vertebral bodies. One Jefferson's, 1 atlas posterior arch (Jefferson's on MDCT), 2 odontoid process, and 5 non-contiguous spinous process fractures were detectable. MRI showed 2 fractures that were undetected by MDCT, and conversely, MDCT detected 6 fractures not seen on MRI; 16 patients had spinal cord findings ranging from impingement and contusion to complete transection.
  
  
  CONCLUSIONS
  Magnetic resonance imaging can visualize unstable fractures of the cervical and upper thoracic spine. Paravertebral hemorrhages and any ligamentous injuries should alert radiologists to seek transverse fractures. Multiple fractures are common and often complicated by spinal cord injuries. Diagnostic images can be obtained with a flexible multipurpose coil if the use of standard spine array coil is impossible due to a rigid collar or excessive kyphosis.
authors.affiliation: Töölö Hospital, Department of Radiology, Helsinki Medical Imaging Center, Helsinki University Central Hospital, Topeliuksenkatu 5, Helsinki, Finland. Mika.Koivikko@hus.fi
authors.forename: Mika P
authors.initials: MP
authors.lastname: Koivikko
authors.forename: Seppo K
authors.initials: SK
authors.lastname: Koskinen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013124:Spinal Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D013167:Spondylitis, Ankylosing / Q000150:complications* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed