title: Communicating Hydrocephalus Associated with Small- to Medium-Sized Vestibular Schwannomas: Clinical Significance of the Tumor Apparent Diffusion Coefficient Map.
abstract: BACKGROUND
  The etiology of hydrocephalus associated with the small- to medium-sized vestibular schwannomas is still controversial. We investigated tumor-specific factors related to the association of hydrocephalus with small- to medium-sized vestibular schwannomas.
  
  
  METHODS
  Among the 77 patients with vestibular schwannoma smaller than 30 mm, 9 patients demonstrated associated communicating hydrocephalus. Patient medical records, radiologic data, and histopathologic specimens were reviewed retrospectively. The age of the patients, and size, mean apparent diffusion coefficient (ADC) value, and histologic features of the tumors were compared with those of patients without hydrocephalus.
  
  
  RESULTS
  The symptoms related to hydrocephalus improved in all patients after tumor removal. Both the mean size and ADC values exhibited a statistically significant difference between the tumors with and without hydrocephalus (P < 0.01).
  
  
  CONCLUSIONS
  The size and ADC value of the tumor were significantly related to the association with hydrocephalus. The increased tumor ADC value was considered to be the result of degenerative change and suggested the involvement of protein sloughing in the etiology of the associated hydrocephalus.
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Hyogo, Japan. Electronic address: mtani@med.kobe-u.ac.jp.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Taniguchi
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Hyogo, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nakai
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Hyogo, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kohta
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Hyogo, Japan.
authors.forename: Hidehito
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Neurosurgery, Kobe University Graduate School of Medicine, Hyogo, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kohmura
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging* / Q000208:ethnology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007564:Japan / Q000453:epidemiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000000981:diagnostic imaging*; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
keywords: Apparent diffusion coefficient; Communicating hydrocephalus; Vestibular schwannoma