title: Clinical and magnetic resonance imaging characteristics of quadrigeminal cysts in dogs.
abstract: BACKGROUND
  Quadrigeminal cysts (QC) are the most common intracranial intra-arachnoid cysts in dogs, primarily affecting small breeds. Clinical significance is controversial.
  
  
  OBJECTIVE
  Male, brachycephalic, small breed dogs are predisposed to QC, and objective measurement of parenchymal compression can distinguish clinically relevant QC from incidental findings.
  
  
  METHODS
  A total of 4,100 client-owned dogs.
  
  
  METHODS
  A retrospective study that recorded signalment, history, clinical signs, and magnetic resonance imaging features. The degree of brain compression was evaluated in the presence of relevant clinical signs. The percentage compression of cerebellum and forebrain was calculated by comparing the expected to the actual diameter and longitudinal dimension, respectively.
  
  
  RESULTS
  QC were diagnosed in 28 dogs, of which 21 (75%) were small breed dogs. Fifteen dogs (54%) were brachycephalic. Eighteen dogs were male, and 10 were female. Cerebellar, occipital lobe, or compression in both areas occurred in 86% (24/28 dogs). Clinical signs included focal and generalized seizures in 5 dogs and cerebellar signs in 6 dogs. Mean occipital lobe compression was 17% (SD = 4) in clinically affected and 10% (SD = 3) in normal dogs (P = .006). Occipital lobe compression >14% was always associated with clinical signs. The mean cerebellar compression was 18%, but there was no association between compression and clinical signs. The animals were more likely to develop clinical signs if both areas were compressed (P = .04).
  
  
  CONCLUSIONS
  Parenchymal compression by QC can be incidental, and other central nervous system diseases must be excluded when assessing the clinical significance of QC. However, occipital lobe compression over 14% is likely to cause clinical signs.
authors.affiliation: Centre for Small Animal Studies, Animal Health Trust, Newmarket, Suffolk, UK. lara.matiasek@aht.org.uk
authors.forename: Lara A
authors.initials: LA
authors.lastname: Matiasek
authors.forename: Simon R
authors.initials: SR
authors.lastname: Platt
authors.forename: Steve
authors.initials: S
authors.lastname: Shaw
authors.forename: Ruth
authors.initials: R
authors.lastname: Dennis
mesh_terms: D000818:Animals; D016080:Arachnoid Cysts / Q000473:pathology / Q000662:veterinary*; D001927:Brain Diseases / Q000473:pathology / Q000662:veterinary*; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D012189:Retrospective Studies; D003336:Tectum Mesencephali / Q000473:pathology*