title: Brain herniations into the dural venous sinus or calvarium: MRI findings, possible causes and clinical significance.
abstract: OBJECTIVE
  To determine frequency, imaging features and clinical significance of herniations of brain parenchyma into dural venous sinuses (DVS) and/or calvarium found on MRI.
  
  
  METHODS
  A total of 6160 brain MRI examinations containing at least one high-resolution T1- or T2-weighted sequence were retrospectively evaluated to determine the presence of incidental brain herniations into the DVS or calvarium. MRI sequences available for review were evaluated according to their capability to demonstrate these herniations. Patients' symptoms and clinical findings were recorded.
  
  
  RESULTS
  Twenty-one (0.32 %) brain parenchyma herniations into the DVS (n = 18) or calvarium (n = 3) in 20 patients were detected. The most common locations of the herniations were the transverse sinuses (n = 13) and those involving inferior gyrus of the temporal lobe (n = 9). High-resolution T1- and T2-weighted sequences were equally useful in the detection of these brain herniations. According to clinical symptoms, brain herniations were considered to be incidental but headaches were present in nine patients.
  
  
  CONCLUSIONS
  Brain herniations with surrounding cerebrospinal fluid (CSF) into the DVS and/or calvarium are incidental findings and not proven to be associated with any symptoms. Although rare, these herniations are more common than previously recognized and should not be confused with arachnoid granulations, clots or tumours.
  
  
  CONCLUSIONS
  • Brain herniations into the DVS are more common than previously assumed. • The most frequent locations are the transverse sinus. • These herniations are incidental findings. • The relationship between brain herniation into DVS and headache is uncertain. • High-resolution MR sequences are most useful in detection of brain herniations.
authors: Department of Radiology, Gulhane Military Medical School, 06018, Ankara, Turkey. bilbat_23@yahoo.com.
authors: Bilal
authors: B
authors: Battal
authors: Department of Radiology, Gulhane Military Medical School, 06018, Ankara, Turkey.
authors: Salih
authors: S
authors: Hamcan
authors: Department of Radiology, Gulhane Military Medical School, 06018, Ankara, Turkey.
authors: Veysel
authors: V
authors: Akgun
authors: Department of Radiology, Gulhane Military Medical School, 06018, Ankara, Turkey.
authors: Sebahattin
authors: S
authors: Sari
authors: Department of Neurology, Gulhane Military Medical School, Ankara, Turkey.
authors: Oguzhan
authors: O
authors: Oz
authors: Department of Radiology, Gulhane Military Medical School, 06018, Ankara, Turkey.
authors: Mustafa
authors: M
authors: Tasar
authors: Division of Neuroradiology, Department of Radiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
authors: Mauricio
authors: M
authors: Castillo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003392:Cranial Sinuses / Q000473:pathology*; D004677:Encephalocele / Q000209:etiology / Q000473:pathology*; D005260:Female; D006261:Headache / Q000209:etiology / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012886:Skull / Q000473:pathology*; D055815:Young Adult
keywords: Arachnoid granulation; Brain herniation; Dural venous sinus; Encephalocele; MR