title: The early phases of bone healing can be differentiated in a rat osteotomy model by focused transverse-transmission ultrasound.
abstract: Here we describe the use of a 5-MHz focused transmission system to image the bone repair region and to distinguish the early healing phases in a rat osteotomy (OT) model. Twelve-month-old female rats underwent a 2-mm OT. After 6 wk of consolidation, 2-D projection images of time-of-flight, speed of sound, and ultrasound attenuation were measured in vitro. The tissue types in the OT gap region were assessed by site-matched histology sections and micro-computed tomography (μCT). In the cases investigated, OT gap regions containing fibrous tissue (group A) were found to have similar properties compared with adjacent muscle tissue, whereas regions filled with cartilage and mineralized callus tissues (group B) differed significantly. Analysis of variance revealed that the healing group had a stronger effect on acoustic parameters (F < 35) than on μCT-based parameters (F < 22). This pilot study reports the feasibility of transverse transmission quantitative ultrasound in assessment of the onset of cartilage formation during callus formation.
authors.affiliation: Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rohrbach
authors.forename: Bernd
authors.initials: B
authors.lastname: Preininger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hesse
authors.forename: Hinnerk
authors.initials: H
authors.lastname: Gerigk
authors.forename: Carsten
authors.initials: C
authors.lastname: Perka
authors.forename: Kay
authors.initials: K
authors.lastname: Raum
mesh_terms: D000465:Algorithms; D000818:Animals; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D017102:Fracture Healing / Q000502:physiology*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
keywords: Bone; Broadband ultrasound attenuation; Endochondral ossification; Fracture healing; Micro-computed tomography; Osteotomy; Quantitative ultrasound; Small animal model; Speed of sound; Transverse transmission