title: MRI-based morphometric analysis of posterior cranial fossa in the diagnosis of chiari malformation type I.
abstract: OBJECTIVE
  The diagnosis of Chiari malformation type I (CMI) relies on MRI identification of a tonsillar descent (TD) through the foramen magnum, reflecting the overcrowding of an underdeveloped posterior cranial fossa (PCF). However, TD occurs in some patients with normal-sized PCF and, conversely, some patients with borderline or no TD have small PCF. We thus sought to identify a set of prototypic PCF measures for the diagnosis of CMI.
  
  
  METHODS
  We performed nineteen measurements of the PCF on sagittal MRI of 100 cases with cerebellar TD ≥5 mm and 50 control individuals, compared the average values in both cohorts and used logistic regression to devise a probability model to predict CMI status.
  
  
  RESULTS
  Significant decrements were detected for several PCF-related measures in the patients' cohort. We developed a probability model that combined seven of these parameters to predict diagnosis with 93% sensitivity and 92% specificity.
  
  
  CONCLUSIONS
  The addition of simple morphometric measurements in the diagnostic work-up of patients with suspected CMI may facilitate radiological diagnosis. Moreover, identification of the subset of CMI that arise from basichondrocranium underdevelopment is important for both, selection of the most appropriate therapeutic approach as well as proper CMI categorization in research studies.
authors: Pediatric Neurology Research Group, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona.
authors: Aintzane
authors: A
authors: Urbizu
authors: Maria-Antonia
authors: MA
authors: Poca
authors: Xavier
authors: X
authors: Vidal
authors: Alex
authors: A
authors: Rovira
authors: Juan
authors: J
authors: Sahuquillo
authors: Alfons
authors: A
authors: Macaya
mesh_terms: D000328:Adult; D000368:Aged; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000473:pathology*; D015331:Cohort Studies; D003388:Cranial Fossa, Posterior / Q000473:pathology*; D003627:Data Interpretation, Statistical; D004677:Encephalocele / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Chiari malformation type I; MRI; ROC; morphometry