title: CT of facial fracture fixation: an experimental study of artefact reducing methods.
abstract: OBJECTIVE
  This study aimed to determine the optimal post-operative CT imaging method that enables best visualization of facial bony structures in the vicinity of osteosynthesis material.
  
  
  METHODS
  Conducted at Töölö Hospital (Helsinki, Finland), this study relied on scanning a phantom with CBCT, 64-slice CT and high-definition multislice CT with dual-energy scan (providing monochromatic images of 70-, 100-, 120- and 140-keV energy levels) and iterative reconstruction (IR) methods. Two radiologists assessed the image quality, and the assessments were analyzed. In addition, a physicist performed a semi-quantitative analysis of the metal-induced artefacts.
  
  
  RESULTS
  The three subjects most easily assessed were the loose screw and both the bone structure and the fracture further away from the screw and the plate. Soft tissues adjacent to the screw and the plate remained more difficult for assessment. Both image interpreters agreed that the artefacts disturbed their assessments under dual energy. Metal artefacts disturbed the least under multislice CT with IR [adaptive statistical iterative reconstruction (ASiR) and VEO]. Neither interpreter found metal suppression helpful in CBCT.
  
  
  CONCLUSIONS
  CBCT with or without a metal artefact reduction algorithm was not optimal for post-operative facial imaging compared with multislice CT with IR. Multislice CT with ASiR filtering offered good image quality performance with fast image volume reconstruction, representing the current sweet spot in post-operative maxillofacial imaging.
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Elina M
authors: EM
authors: Peltola
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Teemu
authors: T
authors: Mäkelä
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Ville
authors: V
authors: Haapamäki
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Anni
authors: A
authors: Suomalainen
authors: 2 Department of Plastic Surgery, Cleft Palate and Craniofacial Center, Helsinki University Hospital, Helsinki, Finland.
authors: Junnu
authors: J
authors: Leikola
authors: 3 Department of Clinical Science, Intervention and Technology, Karolinska University Hospital, Stockholm, Sweden.
authors: Seppo K
authors: SK
authors: Koskinen
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Mika
authors: M
authors: Kortesniemi
authors: 1 Department of Radiology, HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Mika P
authors: MP
authors: Koivikko
mesh_terms: D016477:Artifacts; D001860:Bone Plates; D001863:Bone Screws; D005592:Fracture Fixation; D006801:Humans; D012887:Skull Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: CBCT; facial injuries; imaging; multidetector CT; phantoms