title: Neuroradiological findings and clinical features of fourth-ventricular meningioma: a study of 10 cases.
abstract: OBJECTIVE
  To present the neuroradiological and clinical findings of fourth-ventricular meningiomas to increase awareness of this entity.
  
  
  METHODS
  The computed tomography (CT; n=5), magnetic resonance imaging (MRI; n=9) features and clinical presentations of 10 patients with pathologically documented fourth-ventricular meningiomas were retrospectively analysed.
  
  
  RESULTS
  All tumours appeared as well-demarcated masses in the fourth ventricle at CT and MRI. The tumour shape was round in eight cases (80%) and irregular in two cases (20%). The CT images of five cases showed predominantly isoattenuation in three cases and high attenuation in two cases, with a mean attenuation value of 52 HU. In addition, calcifications were seen in three cases. At MRI, nine masses were isointense (n=6) or hypointense (n=3) to grey matter on T1-weighted images and mildly hyperintense (n=4), isointense (n=3), hypointense (n=1), and of mixed signal intensity (n=1) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Signal voids were visible in two cases. Enhancement after injection of contrast material was marked homogeneous (n=5) or heterogeneous (n=5) on CT or T1-weighted images. Three tumours had mild peritumoural oedema. Three tumours were associated with obstructive hydrocephalus. The pathological subtype of the 10 meningiomas was fibromatous (n=5), atypical (n=2), and one each of transitional, psammomatous, and clear-cell type.
  
  
  CONCLUSIONS
  Although fourth-ventricular meningioma is quite rare, it should be considered in differential diagnosis of neoplasms within the fourth ventricle. The relatively typical radiological appearance, combined the age and sex of patients, can suggest the diagnosis of fourth-ventricular meningioma.
authors.affiliation: Department of Radiology, Huashan Hospital, Fudan University, Shanghai, PR China.
authors.forename: B-Y
authors.initials: BY
authors.lastname: Zhang
authors.forename: B
authors.initials: B
authors.lastname: Yin
authors.forename: Y-X
authors.initials: YX
authors.lastname: Li
authors.forename: J-S
authors.initials: JS
authors.lastname: Wu
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: X-Q
authors.initials: XQ
authors.lastname: Wang
authors.forename: Dao-Ying
authors.initials: DY
authors.lastname: Geng
mesh_terms: D000328:Adult; D000368:Aged; D014695:Cerebral Ventriculography / Q000379:methods; D002648:Child; D005260:Female; D020546:Fourth Ventricle / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis*; D008579:Meningioma / Q000175:diagnosis*; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult