title: The clinical significance of equivocal findings on spinal MRI in children with medulloblastoma.
abstract: BACKGROUND
  Medulloblastoma (MB) is the most common malignant brain tumor of childhood, with cerebrospinal fluid spread the most common site of metastasis. Currently, children diagnosed with MB and evidence of spinal metastasis are treated with an increased dose of craniospinal radiation (CSI). This report reviewed equivocal abnormalities including nerve root clumping, linear vascular enhancement, nerve root enhancement and/or other vague findings on spinal magnetic resonance imaging (MRI) to elucidate their prognostic significance and aid in risk stratification.
  
  
  METHODS
  This retrospective cohort study identified children (≥3 years) diagnosed with MB between 1988 and 2012. Children treated with upfront CSI were included, and staging spine MRI must have been done preoperatively or within 72 hr of primary tumor resection. Initial MRI of the spine was assessed by two independent reviewers blinded to outcome to evaluate for equivocal findings. Survival analysis was done to determine impact on prognosis.
  
  
  RESULTS
  One hundred of 157 patients were eligible for the analysis. Equivocal findings were identified in 48 (48%) patients, with MRI done preoperatively in 45 (94%) patients. Analysis by subgroup identified a higher proportion of equivocal findings in the sonic hedgehog (SHH) subgroup (P = 0.007). Five-year overall survival (OS) in children with equivocal findings compared to those with normal MRI was not different, 80 vs. 84.8% respectively, while OS in M3 patients was worse at 54.7% (P = 0.02).
  
  
  CONCLUSIONS
  A higher proportion of equivocal findings was identified in the SHH subgroup. This institutional retrospective review demonstrates equivocal findings are common, not associated with decreased OS and should not prompt increased dose of CSI.
authors.affiliation: Division of Hematology/Oncology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Bennett
authors.affiliation: Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ramy
authors.initials: R
authors.lastname: Ashmawy
authors.affiliation: Division of Hematology/Oncology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Vijay
authors.initials: V
authors.lastname: Ramaswamy
authors.affiliation: Division of Clinical Research Services, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Derek
authors.initials: D
authors.lastname: Stephens
authors.affiliation: Division of Hematology/Oncology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Bouffet
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: Normand
authors.initials: N
authors.lastname: Laperriere
authors.affiliation: Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Taylor
authors.affiliation: Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Manohar
authors.initials: M
authors.lastname: Shroff
authors.affiliation: Division of Hematology/Oncology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ute
authors.initials: U
authors.lastname: Bartels
mesh_terms: D000293:Adolescent; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008527:Medulloblastoma / Q000000981:diagnostic imaging* / Q000401:mortality; D011379:Prognosis; D012189:Retrospective Studies; D013116:Spinal Cord / Q000000981:diagnostic imaging*; D013120:Spinal Cord Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary
keywords: MRI; medulloblastoma; staging