title: Diffusion abnormalities on intraoperative magnetic resonance imaging as an early predictor for the risk of posterior fossa syndrome.
abstract: BACKGROUND
  Posterior fossa syndrome (PFS) is an important complication of posterior fossa surgery in children. The pathophysiology of this condition remains unclear, but there is evidence implicating surgical injury of the proximal efferent cerebellar pathway (pECP) and the cerebellar vermis to PFS. We aimed to evaluate if diffusion abnormalities involving these structures on the final intraoperative MRI can predict the development of PFS.
  
  
  METHODS
  Diffusion-weighted imaging from 31 posterior fossa resections were anonymized and evaluated for abnormalities involving the dentate nucleus, superior cerebellar peduncle, and the mesencephalic tegmentum forming the pECP, vermis, and middle cerebellar peduncle. The case notes were independently evaluated for evidence of PFS.
  
  
  RESULTS
  The diffusion imaging in 28 cases was of optimal quality for evaluation. Diffusion abnormalities were identified in 10 cases, 7 of which involved the pECP. Retrospective evaluation revealed evidence of PFS in 6 cases. There was a significant association between abnormalities involving pECP structures (P = .001) and development of PFS. Bilateral involvement of pECP (P = .006) was a highly specific risk factor for predicting the development of PFS. Diffusion abnormality of the inferior vermis was significantly associated with PFS (P = .001) but may not represent a risk factor in isolation.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of identifying children at risk for developing PFS at the earliest stage post tumor resection and thus adds to the growing evidence base on its pathophysiology.
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Shivaram
authors.initials: S
authors.lastname: Avula
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Ram
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Barry
authors.initials: B
authors.lastname: Pizer
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Benedetta
authors.initials: B
authors.lastname: Pettorini
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Laurence
authors.initials: L
authors.lastname: Abernethy
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Deborah
authors.initials: D
authors.lastname: Garlick
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (S.A., L.A., D.G.); Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (R.K.); Department of Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK (Barry Pizer); Department of Neurosurgery, Alder Hey Children's N.H.S Foundation Trust, Liverpool, UK (Benedetta Pettorini, C.M.).
authors.forename: Conor
authors.initials: C
authors.lastname: Mallucci
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003388:Cranial Fossa, Posterior / Q000473:pathology* / Q000601:surgery; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007223:Infant; D015192:Infratentorial Neoplasms / Q000601:surgery*; D008297:Male; D019635:Neurosurgical Procedures / Q000009:adverse effects; D011183:Postoperative Complications / Q000175:diagnosis*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: cerebellar mutism syndrome; diffusion-weighted imaging; efferent cerebellar pathway; intraoperative MRI; posterior fossa syndrome