title: Characterization of pseudarthrosis with ultrasound backscattered signals in rats.
abstract: OBJECTIVE
  To propose a novel model of pseudarthrosis in a small animal and to investigate the ability of backscatter parameters from ultrasound signals in differentiating normal bone from those ones with pseudarthrosis.
  
  
  METHODS
  Twelve Rattus norvegicus albinus free from pathogenic species (SPF) were randomly divided in two groups, with six animals each. In the Control group a surgical approach to the femur was made, followed by the synthesis of the muscle and skin layers. The Experimental group was submitted to an osteotomy of the femur and a vascularized flap of the fascia lata was interposed in the line of the fractured bone. Then the alignment and bone stabilization were accomplished, by using nylon stitch in U shape introduced in holes made in the proximal and distal fractured bone. Bone samples were scanned with ultrasound and signals were collected for each one to analyze the parameter Apparent Integrated Backscatter - AIB.
  
  
  RESULTS
  Radiological and anatomopathologic studies revealed the absence of bone consolidation with persistence of fiber-osteoid tissue. Values of the ultrasound parameter AIB from normal bones were statistically different from those with pseudarthrosis.
  
  
  CONCLUSIONS
  The experimental model was suitable for pseudarthrosis development in rats and the ultrasound backscatter parameters were able to identify such a bone disease in vitro.
authors.affiliation: Department of Surgery, Faculty of Medicine, UFRJ, Rio de Janeiro, Brazil. louiz_25@yahoo.com.br
authors.forename: Manoel Luiz
authors.initials: ML
authors.lastname: Ferreira
authors.forename: Daniel Patterson
authors.initials: DP
authors.lastname: Matusin
authors.forename: Christiano Bittencourt
authors.initials: CB
authors.lastname: Machado
authors.forename: Paulo César
authors.initials: PC
authors.lastname: Silva
authors.forename: Natalia Bernades
authors.initials: NB
authors.lastname: Mello
authors.forename: Alessandra Cintra
authors.initials: AC
authors.lastname: Amaral
authors.forename: Renata Schueler
authors.initials: RS
authors.lastname: Franco
authors.forename: Wagner Coelho de Albuquerque
authors.initials: WC
authors.lastname: Pereira
authors.forename: Alberto
authors.initials: A
authors.lastname: Schanaider
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D011542:Pseudarthrosis / Q000000981:diagnostic imaging*; D011897:Random Allocation; D051381:Rats; D018709:Statistics, Nonparametric; D014463:Ultrasonography