“…Recently, with the advent of phase-contrast MR imaging technique, relative obstruction of CSF flow at the foramen magnum has been demonstrated in patients with Chiari I malformation, 10 whereas spatial and temporal heterogeneity of CSF flows at the foramen have been reported by Haughton et al 12 and Iskandar et al 13 Previous authors proposed the above observable changes in CSF flow patterns in patients with Chiari malformation were correlated with the anatomic anomalies, such as tonsillar herniation and crowding of the posterior aspect of the foramen magnum. 10,11,21 Iskandar et al 13 suggested that specific foramen magnum flow hallmarks might be associated with certain symptomatic states in children with Chiari I malformation.…”