PT - JOURNAL ARTICLE AU - C.B. Nauer AU - A. Rieke AU - C. Zubler AU - C. Candreia AU - A. Arnold AU - P. Senn TI - Low-Dose Temporal Bone CT in Infants and Young Children: Effective Dose and Image Quality AID - 10.3174/ajnr.A2524 DP - 2011 Jul 14 TA - American Journal of Neuroradiology 4099 - http://www.ajnr.org/content/early/2011/07/14/ajnr.A2524.short 4100 - http://www.ajnr.org/content/early/2011/07/14/ajnr.A2524.full AB - BACKGROUND AND PURPOSE: 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. MATERIALS AND 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.