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RT Journal Article
SR Electronic
T1 Low-Dose Temporal Bone CT in Infants and Young Children: Effective Dose and Image Quality
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 1375
OP 1380
DO 10.3174/ajnr.A2524
VO 32
IS 8
A1 Nauer, C.B.
A1 Rieke, A.
A1 Zubler, C.
A1 Candreia, C.
A1 Arnold, A.
A1 Senn, P.
YR 2011
UL http://www.ajnr.org/content/32/8/1375.abstract
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. CTDICT dose indexCTDIvolvolumetric CTDICTDIcCTDI measured in the centerCTDIpCTDI measured in the peripheryCTDIwweighted CTDIDeffeffective doseDLPdose-length product