title: Torcular Herophili classification and evaluation of dural venous sinus variations using digital subtraction angiography and magnetic resonance venographies.
abstract: OBJECTIVE
  The configurations of cerebral veins and dural venous sinuses differ not only between individuals, but also between the two brain hemispheres of an individual, making the anatomical classification of the cerebral veins difficult. We evaluated the superior dural venous sinuses and classified their types and variations using magnetic resonance venography (MRV) and digital substraction angiography (DSA).
  
  
  METHODS
  A total of 394 patients were studied retrospectively. Superior dural venous sinuses were evaluated and the confluence of the sinuses was classified on 2-dimensional time-of-flight MRV, contrast-enhanced 3-dimensional spoiled gradient recalled echo magnetic resonance imaging, and/or cerebral DSA. Confluens sinuum was divided into three types: true confluence, partial confluence, and non-confluence.
  
  
  RESULTS
  Of the three types, partial confluence (type II) was most frequently seen. Co-dominance of the transverse sinuses was most frequently observed. An occipital sinus was observed in 15 % of the patients. There were statistically significant differences between the left transverse sinus agenesis and the presence of the occipital sinus (p < 0.001), between the co-presence of the partial confluence type torcular and the occipital sinus (p = 0.040), and between the co-presence of the fenestrated straight sinus and the occipital sinus (p = 0.010).
  
  
  CONCLUSIONS
  Although anatomical variations of dural venous sinuses are seen frequently, classification of venous sinuses helps surgeons in preoperative evaluation and management, and prevention of possible complications. In this study, we think that a comprehensive evaluation and classification of dural venous sinuses is a significant contribution to the literature.
authors.affiliation: Department of Radiology, Faculty of Medicine, Gaziosmanpaşa University, 60200, Tokat, Turkey, erkangokce@mynet.com.
authors.forename: Erkan
authors.initials: E
authors.lastname: Gökçe
authors.forename: Tansu
authors.initials: T
authors.lastname: Pınarbaşılı
authors.forename: Berat
authors.initials: B
authors.lastname: Acu
authors.forename: M Murat
authors.initials: MM
authors.lastname: Fırat
authors.forename: Ünal
authors.initials: Ü
authors.lastname: Erkorkmaz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods*; D002533:Cerebral Angiography / Q000379:methods*; D002550:Cerebral Veins / Q000002:abnormalities* / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D002648:Child; D003287:Contrast Media; D003392:Cranial Sinuses; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media