title: Osteoporosis in acute fractures of the cervical spine: the role of opportunistic CT screening.
abstract: OBJECTIVE
  Recently published data make it possible to generate estimates of bone mineral density (BMD) by using CT attenuation; this innovation can save time and reduce costs. Although advanced age is associated with reduced BMD, especially in patients with a fracture of C-2, relatively few patients ever undergo formal dual x-ray absorptiometry studies. To the authors' knowledge, this is the first study to assess the utility of this technique in elucidating BMD in patients with an acute fracture of the cervical spine.
  
  
  METHODS
  Patients who presented to a Level I trauma center with an acute fracture of the cervical spine and underwent abdominal (or L-1) CT scanning either at admission or in the 6 months before or after the injury were evaluated. Using a picture-archiving and communication system, the authors generated regions of interest of similar size in the body of L-1 (excluding the cortex) and computed mean values for CT attenuation. The values derived were compared with threshold values, which differentiate between osteoporotic and nonosteoporotic states; age-stratified groups were also compared.
  
  
  RESULTS
  Of the 91 patients whose data were reviewed, 51 were < 65 years old (mean 43.2 years) and 40 were ≥ 65 years old (mean 80.9 years). The overall mean CT attenuation values (in Hounsfield units [HU]), stratified according to age, were 193.85 HU for the younger cohort and 117.39 HU for the older cohort; the result of a comparison between these two values was significant (p < 0.001).
  
  
  CONCLUSIONS
  Using opportunistic CT scanning, this study demonstrates the relative frequency of osteoporosis in acute fractures of the cervical spine. It also objectively correlates overall BMD with the known higher frequency of C-2 fractures in older patients. This technique harnesses the presence of opportunistic CT scans of the abdomen, which potentially reduces the need for the extra time and cost that may be associated with dual x-ray absorptiometry scanning.
authors: Departments of 1 Neurological Surgery and.
authors: Osa
authors: O
authors: Emohare
authors: University of Minnesota Medical School, Minneapolis; and.
authors: Alison
authors: A
authors: Dittmer
authors: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, Minnesota.
authors: Robert A
authors: RA
authors: Morgan
authors: Orthopaedic Surgery, Regions Hospital, St. Paul;|Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, Minnesota.
authors: Julie A
authors: JA
authors: Switzer
authors: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, Minnesota.
authors: David W
authors: DW
authors: Polly
mesh_terms: D015502:Absorptiometry, Photon; D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D058866:Osteoporotic Fractures / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016103:Spinal Fractures / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
keywords: BMD = bone mineral density; DXA = dual-energy x-ray absorptiometry; HU = Hounsfield unit; QCT = quantitative CT; ROI = region of interest; aging; bone density; bone fractures; cervical spine; degenerative; geriatrics; odontoid process; osteoporosis; spine