Children with hydrocephalus, on average, obtain two head imaging assessments annually until the age of 20. Their lifetime increase risk of fatal cancer is estimated to be 1 excess case of fatal cancer per 97 patients if standard head CT is used, or 1 excess case of fatal cancer per 230 patients if low-dose head CT is used. Head ultrasound (in infants with open fontanelles), and rapid sequence MRI (in all other children) do not require ionizing radiation and adequately assess for radiographic change in ventricle size. A rapid sequence MRI can be obtained without sedation and in under 3 minutes. It is therefore recommended that ultrasound (in infants with open fontanelles), or rapid sequence MRI (in all other children) be used for surveillance imaging in hydrocephalus at minimum, and ideally in emergency assessments as well when available. In the emergent setting, or when MRI is not available, low-dose non-contrast CT is appropriate.
Sources:
DeFlorio RM, et al. Techniques that decrease or eliminate ionizing radiation for evaluation of ventricular shunts in children with hydrocephalus. Semin Ultrasound CT MR. 2014 Aug;35(4):365-73. PMID: 25129213.
Koral K, et al. Strengthening the argument for rapid brain MR imaging: estimation of reduction in lifetime attributable risk of developing fatal cancer in children with shunted hydrocephalus by instituting a rapid brain MR imaging protocol in lieu of Head CT. AJNR Am J Neuroradiol. 2012 Nov;33(10):1851-4. PMID: 22555583.
O’Neill BR, et al. Rapid sequence magnetic resonance imaging in the assessment of children with hydrocephalus. World Neurosurg. 2013 Dec;80(6):e307-12. PMID: 23111234.
Patel DM, et al. Fast-sequence MRI studies for surveillance imaging in pediatric hydrocephalus. J Neurosurg Pediatr. 2014 Apr;13(4):440-7. PMID: 24559278.
Tekes A, et al. How to Reduce Head CT Orders in Children with Hydrocephalus Using the Lean Six Sigma Methodology: Experience at a Major Quaternary Care Academic Children’s Center. AJNR Am J Neuroradiol. 2016 Jun;37(6):990-6. PMID: 26797143.