title: Quantification of cerebral perfusion with "Real-Time" contrast-enhanced ultrasound.
abstract: BACKGROUND
  No noninvasive technique is currently capable of "real-time" assessment and monitoring of cerebral blood flow (CBF). We hypothesized that cerebral perfusion could be accurately measured and monitored in "real time" with contrast-enhanced ultrasound (CEU).
  
  
  RESULTS
  Cerebral perfusion was assessed in 9 dogs through a craniotomy with CEU at baseline and during hypercapnia and hypocapnia while normoxia was maintained. Cerebral microvascular blood volume (A), microbubble velocity (beta), and blood flow (Axbeta) were calculated from time-versus-acoustic intensity relations. Compared with baseline, hypercapnia and hypocapnia significantly increased and decreased CBF, respectively, as measured by CEU. These changes in blood flow were mediated by changes in both A and beta. A good correlation was found between Axbeta derived from CEU and CBF measured by radiolabeled microspheres (y=0.67x-0.04, r=0.91, P<0.001).
  
  
  CONCLUSIONS
  Changes in both cerebral microvascular blood volume and red blood cell velocity can be accurately assessed with CEU. Thus, CEU has the potential for bedside measurement and monitoring of cerebral perfusion in real time in patients with craniotomies or burr holes.
authors.affiliation: Cardiovascular Imaging Center, Cardiovascular Division, Department of Internal Medicine, Division of Neurosurgical Anesthesia, University of Virginia, Charlottesville, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Rim
authors.forename: H
authors.initials: H
authors.lastname: Leong-Poi
authors.forename: J R
authors.initials: JR
authors.lastname: Lindner
authors.forename: D
authors.initials: D
authors.lastname: Couture
authors.forename: D
authors.initials: D
authors.lastname: Ellegala
authors.forename: H
authors.initials: H
authors.lastname: Mason
authors.forename: M
authors.initials: M
authors.lastname: Durieux
authors.forename: N F
authors.initials: NF
authors.lastname: Kassel
authors.forename: S
authors.initials: S
authors.lastname: Kaul
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001921:Brain / Q000098:blood supply* / Q000502:physiology; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000008:administration & dosage; D004285:Dogs; D004453:Echoencephalography / Q000379:methods*; D006439:Hemodynamics; D007700:Kinetics
chemical_list: D003287:Contrast Media