Arterial Spin Labeling Cerebral Blood Flow as a Correlate of Clinically Significant Hydrocephalus in Children with Brain Tumors

Allyson Alexander1, Kristen Yeom, MD1, Robert Lober, MD, PhD1, Michael Edwards, MD1

1Stanford, CA United States

Keywords: children, hydrocephalus, brain tumor, blood flow, Imaging

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Abstract

     Hydrocephalus does not always directly correlate with ventricular size. Hydrocephalus, resulting in increased intracranial pressure (ICP), theoretically results in decreased cerebral blood flow (CBF), but this has not been previously quantified, and it is unclear whether CBF is restored when hydrocephalus is resolved. Arterial spin labeled (ASL) CBF is a magnetic resonance imaging (MRI) perfusion technique which uses inversion of proton spins in blood to quantify CBF.
     We hypothesized that ASL CBF would correlate with symptomatic hydrocephalus in pediatric patients with brain tumors.
     Nine patients were identified (median age 6.5 years, range 0.2 to 17.3).  
     Children presenting with elevated ICP from a new brain tumor diagnosis that had both baseline and follow-up ASL CBF MRI were retrospectively reviewed.ASL was performed using a pseudocontinuous labeling period of 1500 ms, followed by a 1500 ms post-label delay on 3T MRI. Quantitative ASL CBF within each tumor was obtained by placing regions of interest (ROI) over the cerebrum. Patients were classified as symptomatic if they required surgical intervention for hydrocephalus (tumor resection or cerebrospinal fluid diversion) within seven days of the ASL MRI.
     Mean ASL CBF was significantly higher at symptomatic time points compared to asymptomatic time points in each patient (symptomatic = 25.0 ± 10.8 ml/100 g/min, asymptomatic = 35.9 ± 10.5 ml/100 g/min, p < 0.05).
     This is a retrospective study.
     ASL CBF was significantly reduced during symptomatic hydrocephalus.
     ASL CBF perfusion MRI may serve a future role in the evaluation of hydrocephalus, as a potential noninvasive method to follow changes in intracranial pressure.


Acknowledgements

Project Roles:

A. Alexander (), K. Yeom (), R. Lober (), M. Edwards ()