title: Use of routine thoracic and abdominal computed tomography scans for assessing bone mineral density and detecting osteoporosis.
abstract: OBJECTIVE
  Evaluation of computed tomography (CT) attenuation measurements for assessing bone mineral density (BMD) and predicting osteoporosis in thoracic and abdominal CT scans for various clinical indications using dual-energy X-ray absorptiometry (DXA) as reference standard.
  
  
  METHODS
  A total of 234 patients (147 women, 87 men) undergoing DXA and CT were examined retrospectively. Mean time between both studies was 0.5 years. CT-attenuation values in Hounsfield units (HU) were measured at the thoracic and lumbar spine (T1, T6, T12, L1-L5), at the femoral neck, and then assigned to their corresponding DXA scores.
  
  
  RESULTS
  Patients with DXA-defined osteoporosis or osteopenia showed significantly lower HU values of trabecular bone at all measured levels compared to healthy subjects (p < 0.001). HU values were highest at T1 and T6, lowest at L1-L3 and the femoral neck. There were no significant intraindividual differences between HU values in the sagittal, coronal or transversal plane. Significant differences between normal and abnormal BMD categories were verified for three CT scanners. More than half of all fractures were detected in patients with non-osteoporotic DXA T-scores.
  
  
  CONCLUSIONS
  Abdominal and particularly thoracic CT scans obtained for other clinical indications can sensibly be applied toward determining low BMD, detecting osteoporosis and identifying persons at increased fracture risk. Osteoporotic morbidity and mortality might be minimized. Superiorly to DXA, fragility fractures can be found without additional imaging or radiation exposure which can initiate early adequate treatment.
  
  
  CONCLUSIONS
  Key limitations of the study were as following: a retrospective, single-center study; small patient cohort - larger cohorts are needed to evaluate the sensitivity and specificity of diagnostic performance measurements; more complex CT evaluation of the hip for BMD assessment; DXA measurements were used as a reference standard, however, patients with unsuspected compression fractures but showing osteopenic or even normal BMD outline the limitations of DXA.
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.
authors: Milka
authors: M
authors: Marinova
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.|b b Klinikum Mutterhaus der Borromäerinnen , Trier , Germany.
authors: Bob
authors: B
authors: Edon
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.
authors: Karsten
authors: K
authors: Wolter
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.
authors: Barbara
authors: B
authors: Katsimbari
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.
authors: Hans H
authors: HH
authors: Schild
authors: a a Department of Radiology , Hospital & Medical School, University of Bonn , Bonn , Germany.
authors: Holger M
authors: HM
authors: Strunk
mesh_terms: D000005:Abdomen; D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D005272:Femur Neck; D050723:Fractures, Bone / Q000175:diagnosis; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Bone mineral density; CT scans; DXA; Fragility fractures; Hounsfield units; Osteoporosis