title: Bone structure assessed by HR-pQCT, TBS and DXL in adult patients with different types of osteogenesis imperfecta.
abstract: Bone microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT) was assessed in adult patients with mild, moderate, and severe osteogenesis imperfecta (OI). The trabecular bone score (TBS), bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), and dual X-ray and laser (DXL) at the calcaneus were likewise assessed in patients with OI. Trabecular microstructure and BMD in particular were severely altered in patients with OI.
  
  
  BACKGROUND
  OI is characterized by high fracture risk but not necessarily by low BMD. The main purpose of this study was to assess bone microarchitecture and BMD at different skeletal sites in different types of OI.
  
  
  METHODS
  HR-pQCT was performed in 30 patients with OI (mild OI-I, n = 18 (41.8 [34.7, 55.7] years) and moderate to severe OI-III-IV, n = 12 (47.6 [35.3, 58.4] years)) and 30 healthy age-matched controls. TBS, BMD by DXA at the lumbar spine and hip, as well as BMD by DXL at the calcaneus were likewise assessed in patients with OI only.
  
  
  RESULTS
  At the radius, significantly lower trabecular parameters including BV/TV (p = 0.01 and p < 0.0001, respectively) and trabecular number (p < 0.0001 and p < 0.0001, respectively) as well as an increased inhomogeneity of the trabecular network (p < 0.0001 and p < 0.0001, respectively) were observed in OI-I and OI-III-IV in comparison to the control group. Similar results for trabecular parameters were found at the tibia. Microstructural parameters were worse in OI-III-IV than in OI-I. No significant differences were found in cortical thickness and cortical porosity between the three subgroups at the radius. The cortical thickness of the tibia was thinner in OI-I (p < 0.001), but not OI-III-IV, when compared to controls.
  
  
  CONCLUSIONS
  Trabecular BMD and trabecular bone microstructure in particular are severely altered in patients with clinical OI-I and OI-III-IV. Low TBS and DXL and their significant associations to HR-pQCT parameters of trabecular bone support this conclusion.
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria. roland.kocijan@bhs.at.
authors.forename: R
authors.initials: R
authors.lastname: Kocijan
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Muschitz
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Haschka
authors.affiliation: Department of Bone and Joint Diseases, Center for Bone Diseases, Lausanne University Hospital, Lausanne, Swizerland.
authors.forename: D
authors.initials: D
authors.lastname: Hans
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Nia
authors.affiliation: Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Geroldinger
authors.affiliation: Department of General, Visceral and Vascular Surgery, University of Jena, Jena, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ardelt
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Wakolbinger
authors.affiliation: Medical Department II, St. Vincent Hospital Vienna, Medical University of Vienna, Stumpergasse 13, 1060, Vienna, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Resch
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology*; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010013:Osteogenesis Imperfecta / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D011884:Radius / Q000000981:diagnostic imaging / Q000473:pathology; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: Bone microstructure; DXA; DXL; HR-pQCT; Osteogenesis imperfecta; TBS