Low-dose nonenhanced head CT protocol for follow-up evaluation of children with ventriculoperitoneal shunt: Reduction of radiation and effect on image quality

U. K. Udayasankar, K. Braithwaite, M. Arvaniti, D. Tudorascu, W. C. Small, S. Little, Susan Palasis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

79 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)802-806
Number of pages5
JournalAmerican Journal of Neuroradiology
Volume29
Issue number4
DOIs
StatePublished - Apr 2008

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Clinical Neurology

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