title: Low-dose temporal bone CT in infants and young children: effective dose and image quality.
abstract: OBJECTIVE
  The temporal bone is ideal for low-dose CT because of its intrinsic high contrast. The aim of this study was to retrospectively evaluate image quality and radiation doses of a new low-dose versus a standard high-dose pediatric temporal bone CT protocol and to review dosimetric data from the literature.
  
  
  METHODS
  Image quality and radiation doses were compared for 38 low-dose (80 kV/90-110 mAs) and 16 high-dose (140 kV/170 mAs) temporal bone CT scans of infants to 5-year-old children. The CT visualization quality of 23 middle and inner ear structures was subjectively graded by 3 neuroradiologists and 3 otologists by using a 5-point scale with scores 1-2 indicating insufficient and scores 3-5 indicating sufficient image quality. Effective doses of local and literature-derived protocols were calculated from dosimetric data by using NRPB-SR250 software.
  
  
  RESULTS
  Insufficient image-quality scores were more frequent in low-dose scans versus high-dose scans, but the difference was only statistically significant for otologists (6.0% versus 3.4%, P = .004) and not for neuroradiologists (1.2% versus 0.7%, P = .84). Image quality was critical for small structures (such as the stapes or lamella at the internal auditory canal fundus). Effective doses were 0.25-0.3 mSv for low-dose scans, 1.4-1.8 mSv for high-dose scans, and 0.9-2.6 mSv for literature-derived protocols.
  
  
  CONCLUSIONS
  The image quality of the new low-dose protocol remains diagnostic for assessing middle and inner ear anatomy despite a 3- to 8-fold dose reduction over previous and literature-derived protocols. However, image quality of small structures is critical and may be perceived as insufficient.
authors.affiliation: Institute for Diagnostic and Interventional Neuroradiology, University of Berne, Switzerland.
authors.forename: C B
authors.initials: CB
authors.lastname: Nauer
authors.forename: A
authors.initials: A
authors.lastname: Rieke
authors.forename: C
authors.initials: C
authors.lastname: Zubler
authors.forename: C
authors.initials: C
authors.lastname: Candreia
authors.forename: A
authors.initials: A
authors.lastname: Arnold
authors.forename: P
authors.initials: P
authors.lastname: Senn
mesh_terms: D002675:Child, Preschool; D006801:Humans; D007223:Infant; D011829:Radiation Dosage; D012189:Retrospective Studies; D013701:Temporal Bone / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000592:standards*