title: Phenotypic characterization of skeletal abnormalities of Osteopotentia mutant mice by micro-CT: a descriptive approach with emphasis on reconstruction techniques.
abstract: OBJECTIVE
  The novel protein osteopotentia (Opt) has recently been described as an essential regulator of postnatal osteoblast maturation and might possibly be responsible for some of the rarer types of osteogenesis imperfecta. Our aim was the evaluation of micro CT for the qualitative morphological assessment of skeletal abnormalities of Osteopotentia-mutant mice in comparison to radiography and histology.
  
  
  METHODS
  Four homozygous mice with insertional mutations in the Opt gene and three wild-type controls were examined ex vivo using radiography and micro-CT. Two of the homozygous animals were evaluated histologically (trichrome reagent). For the micro-CT evaluation three-dimensional (3D) surface reconstructions and two-dimensional (2D) multiplanar reformations (MPRs) were applied.
  
  
  RESULTS
  The Opt-homozygous mice exhibited severe growth. The radiographic examinations showed osteopenia and fractures with hypertrophic callus formation and pseudarthroses of the forelimbs and ribs. Micro-CT confirmed these findings and was able to demonstrate additional fractures especially at smaller bones such as the metacarpals and phalanges. Additional characterization and superior delineation of cortices and fracture fragments was achieved by 2D MPRs. Histological correlation verified several of these imaging findings.
  
  
  CONCLUSIONS
  Micro-CT is able to screen Opt-mutant mice for osseous pathologies and furthermore characterize these anomalies. The modality seems superior to conventional radiography, but is not able to demonstrate cellular pathology. However, histology is destructive and more time- and material-consuming than micro-CT. Additional information may be gathered by 2D MPRs.
authors.affiliation: Department of Radiology, Klinikum Augsburg, 86156, Augsburg, Germany. froemer@bu.edu
authors.forename: Frank W
authors.initials: FW
authors.lastname: Roemer
authors.forename: Andreas
authors.initials: A
authors.lastname: Mohr
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Yebin
authors.initials: Y
authors.lastname: Jiang
authors.forename: Philipp
authors.initials: P
authors.lastname: Schlechtweg
authors.forename: Harry K
authors.initials: HK
authors.lastname: Genant
authors.forename: Michael L
authors.initials: ML
authors.lastname: Sohaskey
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D021621:Imaging, Three-Dimensional; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008817:Mice, Mutant Strains; D010013:Osteogenesis Imperfecta / Q000000981:diagnostic imaging* / Q000235:genetics; D010641:Phenotype; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D008565:Membrane Proteins; C550250:osteopotentia protein, mouse