title: MR imaging evaluation of inferior olivary nuclei: comparison of postoperative subjects with and without posterior fossa syndrome.
abstract: OBJECTIVE
  Posterior fossa syndrome is a severe postoperative complication occurring in up to 29% of children undergoing posterior fossa tumor resection; it is most likely caused by bilateral damage to the proximal efferent cerebellar pathways, whose fibers contribute to the Guillain-Mollaret triangle. When the triangle is disrupted, hypertrophic olivary degeneration develops. We hypothesized that MR imaging patterns of inferior olivary nucleus changes reflect patterns of damage to the proximal efferent cerebellar pathways and show association with clinical findings, in particular the presence or absence of posterior fossa syndrome.
  
  
  METHODS
  We performed blinded, randomized longitudinal MR imaging analyses of the inferior olivary nuclei of 12 children with and 12 without posterior fossa syndrome after surgery for midline intraventricular tumor in the posterior fossa. The Fisher exact test was performed to investigate the association between posterior fossa syndrome and hypertrophic olivary degeneration on MR imaging. The sensitivity and specificity of MR imaging findings of bilateral hypertrophic olivary degeneration for posterior fossa syndrome were measured.
  
  
  RESULTS
  Of the 12 patients with posterior fossa syndrome, 9 had bilateral inferior olivary nucleus abnormalities. The 12 patients without posterior fossa syndrome had either unilateral or no inferior olivary nucleus abnormalities. The association of posterior fossa syndrome and hypertrophic olivary degeneration was statistically significant (P < .0001).
  
  
  CONCLUSIONS
  Hypertrophic olivary degeneration may be a surrogate imaging indicator for damage to the contralateral proximal efferent cerebellar pathway. In the appropriate clinical setting, bilateral hypertrophic olivary degeneration may be a sensitive and specific indicator of posterior fossa syndrome.
authors.affiliation: From the Departments of Radiological Sciences (Z.P., J.H.H., U.L.).
authors.forename: Z
authors.initials: Z
authors.lastname: Patay
authors.forename: J
authors.initials: J
authors.lastname: Enterkin
authors.forename: J H
authors.initials: JH
authors.lastname: Harreld
authors.forename: Y
authors.initials: Y
authors.lastname: Yuan
authors.forename: U
authors.initials: U
authors.lastname: Löbel
authors.forename: Z
authors.initials: Z
authors.lastname: Rumboldt
authors.forename: R
authors.initials: R
authors.lastname: Khan
authors.forename: F
authors.initials: F
authors.lastname: Boop
mesh_terms: D002540:Cerebral Cortex / Q000473:pathology; D002648:Child; D004525:Efferent Pathways / Q000473:pathology; D005500:Follow-Up Studies; D006801:Humans; D015192:Infratentorial Neoplasms / Q000473:pathology* / Q000601:surgery*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009410:Nerve Degeneration / Q000473:pathology; D009847:Olivary Nucleus / Q000473:pathology* / Q000601:surgery*; D011183:Postoperative Complications / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013577:Syndrome; D013788:Thalamus / Q000473:pathology