title: Vertebral fracture assessment by DXA is inferior to X-ray in clinical severe osteoporosis.
abstract: Spine fractures are diagnosed by X-ray or vertebral fracture assessment (VFA) by dual-energy X-ray absorptiometry (DXA) scanning. The use of VFA evaluation by DXA is still debated. We demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine and therefore with a reduced diagnostic performance in detecting fractures.
  
  
  
  Vertebral fracture assessment (VFA) by DXA has been evaluated for many years, and its use in clinical practice is still debated. In a cross-sectional setting, we aimed to compare VFA with traditional radiography in vertebral fracture (VF) diagnosis in severe osteoporotic patient.
  
  
  
  A total of 207 patients referred to the outpatient clinic for teriparatide treatment were screened, out of whom 35 (16.9 %) severe osteoporotic patients were identified (mean age 67.5 ± 11.3 years and median T-score -3.2 interquartile range (IQR) (-1.9 to -3.7). VF diagnosis was performed independently using VFA and X-ray in accordance with the semiquantitative (SQ) approach. The same technician performed the primary interpretation on both sets of images, after which a radiologist and an endocrinologist reviewed the evaluation for a conclusive judgement.
  
  
  
  In total, 180 radiographic fractures were detected, corresponding to 5.1 fractures per individual. Using VFA, 18.5 % of vertebrae were considered unreadable, compared to 2.0 % on X-ray. The accuracy of VFA in VF detection using X-ray as a reference resulted in sensitivity and specificity of 75.5 and 86.7 %, respectively. Sensitivity decreased from the lumbar to thoracic level. Nevertheless, VFA only identified fractures consistently between Th11 and L3.
  
  
  
  Our data, based on a severe osteoporotic population, demonstrate that VFA is inferior relative to X-ray in visualizing vertebrae properly in the upper spine, resulting in vertebrae not being assessable for analysis and a reduced diagnostic performance in detecting fractures. Improvements in DXA techniques are needed for it to be comparable with X-ray in VF diagnosis.
authors.affiliation: Research Centre of Ageing and Osteoporosis, Department of Endocrinology PE, Rigshospitalet, Copenhagen, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Deleskog
authors.affiliation: Department of Radiology, Frederiksberg University Hospital, Copenhagen, Denmark.
authors.forename: N Ø
authors.initials: NØ
authors.lastname: Laursen
authors.affiliation: Research Centre of Ageing and Osteoporosis, Department of Endocrinology PE, Rigshospitalet, Copenhagen, Denmark.
authors.forename: B R
authors.initials: BR
authors.lastname: Nielsen
authors.affiliation: Research Centre of Ageing and Osteoporosis, Department of Endocrinology PE, Rigshospitalet, Copenhagen, Denmark. Peter.schwarz@regionh.dk.|Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark. Peter.schwarz@regionh.dk.
authors.forename: P
authors.initials: P
authors.lastname: Schwarz
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging*; D011859:Radiography; D016103:Spinal Fractures / Q000000981:diagnostic imaging*; D014965:X-Rays
keywords: Dual-energy X-ray absorptiometry; Semiquantitative assessment; Severe osteoporosis; Vertebral fracture assessment; Vertebral fractures