title: Assessment of cerebral blood flow by means of blood-flow-volume measurement in the internal carotid artery: comparative study with a 133xenon clearance technique.
abstract: OBJECTIVE
  We sought to evaluate a new, angle-independent ultrasonic device for assessment of blood flow volume (BFV) in the internal carotid artery (ICA).
  
  
  METHODS
  Nineteen patients and 4 healthy volunteers were enrolled in a comparative study conducted in the Care Unit of the Division of Neurosurgery at UCLA Medical Center. All patients had been admitted because of severe brain injury: 15 patients with severe head trauma (Glasgow Coma Scale score< or =8) and 4 patients with subarachnoid hemorrhage due to aneurysm rupture. In all patients and subjects, cerebral blood flow (CBF) values obtained with the 133xenon-clearance technique were compared with BFV measurements in the ipsilateral ICA.
  
  
  RESULTS
  Hemispheric CBF values showed a close and linear correlation with BFV measurements (r=0.76, P<0.0001). Global CBF values showed a higher correlation with the total BFV value obtained from both ICAs (r=0.84, P<0.0001). With 37 mL x min(-1) x 100 g(-1) as a cutoff value for the ischemic range, a BFV value of 220 mL/min would yield a positive predictive value of 91.7% and a negative predictive value of 82.6% (sensitivity 73.3%, specificity 95%). Conversely, BFV sensitivity and specificity were 60% and 96%, respectively, for the hyperemic range defined by a CBF value >55 mL x min(-1) x 100 g(-1) (positive predictive value of 85.7% and negative prediction value of 85.7%).
  
  
  CONCLUSIONS
  BFV measurements with this new technology proved to accurately correlate with CBF values evaluated by the 133xenon-clearance technique. These results support the implementation of this technique for bedside assessment of cerebral hemodynamics in critically ill neurosurgical patients.
authors.affiliation: Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 30095, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Soustiel
authors.forename: T C
authors.initials: TC
authors.lastname: Glenn
authors.forename: P
authors.initials: P
authors.lastname: Vespa
authors.forename: B
authors.initials: B
authors.lastname: Rinsky
authors.forename: C
authors.initials: C
authors.lastname: Hanuscin
authors.forename: N A
authors.initials: NA
authors.lastname: Martin
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001811:Blood Volume Determination / Q000295:instrumentation; D001930:Brain Injuries / Q000503:physiopathology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology*; D018608:Ultrasonography, Doppler / Q000295:instrumentation* / Q000379:methods; D014980:Xenon Radioisotopes / Q000493:pharmacokinetics
chemical_list: D014980:Xenon Radioisotopes