title: [Double-helical CT pitfall: the native hyperdense basilar artery].
abstract: OBJECTIVE
  The unenhanced signs of basilar thrombosis at computed tomography (CT) is the hyperdense visualization of the basilar artery due to intravascular thrombosis. In patients who are clinically asymptomatic, hyperdense visualization of the basilar artery can be observed, if scanned with a double helical CT. Purpose of the present study was to evaluate the diagnostic significance of these changes seen at double-helical CT.
  
  
  METHODS
  Ten patients patients underwent double-helical CT of a portion of the base of the skull. In each case, 5-mm and 10-mm fused slices were obtained. The patency of the visualized vessels was then documented using contrast-enhanced images.
  
  
  RESULTS
  The differences in attenuation between the 5-mm and 10-mm fused slices obtained at native examinations were a median 11 HU. Subsequent contrast enhanced studies documented patency of the examined vessels.
  
  
  CONCLUSIONS
  The present data show that the hyperdense basilar artery as a sign of thrombotic occlusion is not valid when thin, fused slices are obtained at double-helical CT.
authors.affiliation: Klinik und Poliklinik für Radiologie, Abt. Röntgendiagnostik, Ulm. reinhard.tomczak@medizin.uni-ulm.de
authors.forename: R
authors.initials: R
authors.lastname: Tomczak
authors.forename: U
authors.initials: U
authors.lastname: Traub
authors.forename: J
authors.initials: J
authors.lastname: Görich
authors.forename: H J
authors.initials: HJ
authors.lastname: Brambs
mesh_terms: D000328:Adult; D001488:Basilar Artery / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D020767:Intracranial Thrombosis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods*