RT Journal Article
SR Electronic
T1 Low-Dose Nonenhanced Head CT Protocol for Follow-Up Evaluation of Children with Ventriculoperitoneal Shunt: Reduction of Radiation and Effect on Image Quality
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 802
OP 806
DO 10.3174/ajnr.A0923
VO 29
IS 4
A1 Udayasankar, U.K.
A1 Braithwaite, K.
A1 Arvaniti, M.
A1 Tudorascu, D.
A1 Small, W.C.
A1 Little, S.
A1 Palasis, S.
YR 2008
UL http://www.ajnr.org/content/29/4/802.abstract
AB BACKGROUND AND PURPOSE: Children with a shunt for hydrocephalus often undergo multiple follow-up head CT scans, increasing the risk for long-term effects of ionizing radiation. The purpose of our study was to evaluate if an unenhanced low-dose head CT could consistently provide acceptable image quality and diagnostic information.MATERIALS AND METHODS: Ninety-two children (mean age, 9 years; range, 8 months to 21 years; 45 boys and 47 girls) with a shunt for hydrocephalus and no clinical evidence of shunt malfunction who were referred for a follow-up nonenhanced head CT were included in the study. All studies were performed on a 4-section multidetector CT. Two CT studies were selected retrospectively for each patient, 1 performed at standard dose (220 mA) and 1 at low dose (80 mAs). Two radiologists independently evaluated and graded both standard-dose and low-dose studies for various image quality parameters. Attenuation and noise levels were measured, and gray-white differentiation and contrast-to-noise ratio (CNR) were calculated.RESULTS: Low-dose CT resulted in 63% mean dose reduction. All low-dose CT scans were diagnostically acceptable. Image quality parameters were significantly lower at low dose (P = .0001) except for the parameters for streak artifacts (P = .46) and need for further imaging (P = .47), which were higher. Mean noise levels were significantly higher (P = .001) in low-dose studies, whereas CNR was significantly higher in standard dose CT (P = .001). A moderate to perfect agreement was noted between the 2 readers with regard to image quality assessment (65%–99%).CONCLUSION: Low-dose nonenhanced head CT consistently provides diagnostically acceptable images with relevant diagnostic information in children with VP shunts resulting in substantial dose savings.