title: Post-operative pediatric cerebellar mutism syndrome and its association with hypertrophic olivary degeneration.
abstract: BACKGROUND
  The dentato-thalamo-cortical (DTC) pathway is recognized as the anatomical substrate for postoperative pediatric cerebellar mutism (POPCMS), a well-recognized complication affecting up to 31% of children undergoing posterior fossa brain tumour resection. The proximal structures of the DTC pathway also form a segment of the Guillain and Mollaret triangle, a neural network which when disrupted causes hypertrophic olivary degeneration (HOD) of the inferior olivary nucleus (ION). We hypothesize that there is an association between the occurrence of POPCMS and HOD and aim to evaluate this on MR imaging using qualitative and quantitative analysis of the ION in children with and without POPCMS.
  
  
  METHODS
  In this retrospective study we qualitatively analysed the follow up MR imaging in 48 children who underwent posterior fossa tumour resection for presence of HOD. Quantitative analysis of the ION was possible in 28 children and was performed using semi-automated segmentation followed by feature extraction and feature selection techniques and relevance of the features to POPCMS were evaluated. The diagnosis of POPCMS was made independently based on clinical and nursing assessment notes.
  
  
  RESULTS
  There was significant association between POPCMS and bilateral HOD (P=0.002) but not unilateral HOD. Quantitative analysis showed that hyperintensity in the left ION was the most relevant feature in children with POPCMS.
  
  
  CONCLUSIONS
  Bilateral HOD can serve as a reliable radiological indicator in establishing the diagnosis of POPCMS particularly in equivocal cases. The strong association of signal change due to HOD in the left ION suggests that injury to the right proximal efferent cerebellar pathway plays an important role in the causation of POPCMS.
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation, Liverpool, UK.
authors.forename: Shivaram
authors.initials: S
authors.lastname: Avula
authors.affiliation: Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, UK.
authors.forename: Michaela
authors.initials: M
authors.lastname: Spiteri
authors.forename: Ram
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Lewis
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation, Liverpool, UK.
authors.forename: Srikrishna
authors.initials: S
authors.lastname: Harave
authors.affiliation: Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, UK.
authors.forename: David
authors.initials: D
authors.lastname: Windridge
authors.affiliation: Department of Radiology, Alder Hey Children's NHS Foundation, Liverpool, UK.
authors.forename: Chan
authors.initials: C
authors.lastname: Ong
authors.forename: Barry
authors.initials: B
authors.lastname: Pizer
keywords: Cerebellar mutism syndrome (CMS); hypertrophic olivary degeneration; posterior fossa syndrome (PFS); postoperative pediatric cerebellar mutism syndrome