title: Sensitivity of Hyperdense Basilar Artery Sign on Non-Enhanced Computed Tomography.
abstract: OBJECTIVE
  The hyperdense basilar artery sign (HBAS) is an indicator of vessel occlusion on non contrast-enhanced computer tomography (NECT) in acute stroke patients. Since basilar artery occlusion (BAO) is associated with a high mortality and morbidity, its early detection is of great clinical value. We sought to analyze the influence of density measurement as well as a normalized ratio of Hounsfield unit/hematocrit (HU/Hct) ratio on the detection of BAO on NECT in patients with suspected BAO.
  
  
  METHODS
  102 patients with clinically suspected BAO were examined with NECT followed immediately by Multidetector computed tomography Angiography. Two observers independently analyzed the images regarding the presence or absence of HBAS on NECT and performed HU measurements in the basilar artery. Receiver operating characteristic curve analysis was performed to determine the optimal density threshold for BAO using attenuation measurements or HU/Hct ratio.
  
  
  RESULTS
  Sensitivity of visual detection of the HBAS on NECT was relatively low 81% (95%-CI, 54-95%) while specificity was high 91% (95%-CI, 82-96%). The highest sensitivity was achieved by the combination of visual assessment and additional quantitative attenuation measurements applying a cut-off value of 46.5 HU with 94% sensitivity and 81% specificity for BAO. A HU/Hct ratio >1.32 revealed sensitivity of 88% (95%-CI, 60-98%) and specificity of 84% (95%-CI, 74-90%).
  
  
  CONCLUSIONS
  In patients with clinically suspected acute BAO the combination of visual assessment and additional attenuation measurement with a cut-off value of 46.5 HU is a reliable approach with high sensitivity in the detection of BAO on NECT.
authors.affiliation: Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Marielle
authors.initials: M
authors.lastname: Ernst
authors.affiliation: Department of Radiology, Division of Neuroradiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Javier M
authors.initials: JM
authors.lastname: Romero
authors.affiliation: Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Jan-Hendrik
authors.initials: JH
authors.lastname: Buhk
authors.affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Cheng
authors.affiliation: Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Division of Pediatric Radiology University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Herrmann
authors.affiliation: Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Fiehler
authors.affiliation: Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Center for Radiology and Endoscopy, Department of Diagnostic and Interventional Radiology, Division of Pediatric Radiology University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Groth
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000000981:diagnostic imaging; D001488:Basilar Artery / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D012372:ROC Curve; D020521:Stroke / Q000150:complications