title: Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like Malformation, Secondary Syringomyelia and Associated Brachycephaly in the Cavalier King Charles Spaniel.
abstract: OBJECTIVE
  To characterise the symptomatic phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and brachycephaly in the Cavalier King Charles Spaniel using morphometric measurements on mid-sagittal Magnetic Resonance images (MRI) of the brain and craniocervical junction.
  
  
  METHODS
  This retrospective study, based on a previous quantitative analysis in the Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI of hindbrain and cervical region. Associated brachycephaly was estimated using 26 measurements, including rostral forebrain flattening and olfactory lobe rotation, on 72 T2-weighted MRI of the whole brain. Both study cohorts were divided into three groups; Control, CM pain and SM and their morphometries compared with each other.
  
  
  RESULTS
  Fourteen significant traits were identified in the hindbrain study and nine traits in the whole brain study, six of which were similar to the GB and suggest a common aetiology. The Control cohort had the most elliptical brain (p = 0.010), least olfactory bulb rotation (p = 0.003) and a protective angle (p = 0.004) compared to the other groups. The CM pain cohort had the greatest rostral forebrain flattening (p = 0.007), shortest basioccipital (p = 0.019), but a greater distance between the atlas and basioccipital (p = 0.002) which was protective for SM. The SM cohort had two conformation anomalies depending on the severity of craniocervical junction incongruities; i) the proximity of the dens (p <0.001) ii) increased airorhynchy with a smaller, more ventrally rotated olfactory bulb (p <0.001). Both generated 'concertina' flexures of the brain and craniocervical junction.
  
  
  CONCLUSIONS
  Morphometric mapping provides a diagnostic tool for quantifying symptomatic CM, secondary SM and their relationship with brachycephaly. It is hypothesized that CM pain is associated with increased brachycephaly and SM can result from different combinations of abnormalities of the forebrain, caudal fossa and craniocervical junction which compromise the neural parenchyma and impede cerebrospinal fluid flow.
authors.affiliation: School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom.
authors.forename: Susan P
authors.identifier: http://orcid.org/0000-0001-8727-8440
authors.initials: SP
authors.lastname: Knowler
authors.affiliation: School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom.
authors.forename: Chloe
authors.initials: C
authors.lastname: Cross
authors.affiliation: Stone Lion Veterinary Hospital, Wimbledon,United Kingdom.
authors.forename: Sandra
authors.initials: S
authors.lastname: Griffiths
authors.affiliation: akm-stats, Glasgow, Scotland, United Kingdom.
authors.forename: Angus K
authors.initials: AK
authors.lastname: McFadyen
authors.affiliation: Fitzpatrick Referrals, Godalming, Surrey, United Kingdom.
authors.forename: Jelena
authors.initials: J
authors.lastname: Jovanovik
authors.affiliation: Fitzpatrick Referrals, Godalming, Surrey, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Tauro
authors.affiliation: CHU Sainte Justine Research Center and University of Montreal, Quebec, Canada.
authors.forename: Zoha
authors.initials: Z
authors.lastname: Kibar
authors.affiliation: Fitzpatrick Referrals, Godalming, Surrey, United Kingdom.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Driver
authors.affiliation: School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom.
authors.forename: Roberto M
authors.initials: RM
authors.lastname: La Ragione
authors.affiliation: School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom.|Fitzpatrick Referrals, Godalming, Surrey, United Kingdom.
authors.forename: Clare
authors.initials: C
authors.lastname: Rusbridge
mesh_terms: D000818:Animals; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000000981:diagnostic imaging / Q000235:genetics / Q000662:veterinary*; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D001947:Breeding; D002508:Cephalometry; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology; D003398:Craniosynostoses / Q000000981:diagnostic imaging / Q000235:genetics / Q000662:veterinary*; D016002:Discriminant Analysis; D004283:Dog Diseases / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D004285:Dogs; D005260:Female; D005539:Foramen Magnum / Q000000981:diagnostic imaging / Q000473:pathology; D020022:Genetic Predisposition to Disease; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D009830:Olfactory Bulb / Q000000981:diagnostic imaging / Q000473:pathology; D010641:Phenotype; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012249:Rhombencephalon / Q000000981:diagnostic imaging* / Q000473:pathology; D012886:Skull / Q000000981:diagnostic imaging* / Q000473:pathology; D019291:Skull Base / Q000000981:diagnostic imaging / Q000473:pathology; D013595:Syringomyelia / Q000000981:diagnostic imaging / Q000209:etiology / Q000235:genetics / Q000662:veterinary*