title: Real-time cerebral angiography: sensitivity of a new contrast-specific ultrasound technique.
abstract: OBJECTIVE
  To test a new contrast-specific sonography imaging method that offers visualization of the intracranial vasculature in a manner similar to that seen on angiography.
  
  
  METHODS
  Thirty patients (35 sonography studies total) were included in the study after they provided written informed consent. The patients were scanned through the temporal bone window from both sides after intravenous injection of an ultrasound contrast agent (UCA; perflexane lipid microspheres [Imagent]). The goal was to visualize the intracranial arteries, including the middle (M1-M3), anterior (A1 and A2), and posterior (P1-P3) cerebral arteries, using an axial scanning plane. The studies were performed using a contrast-specific imaging mode, based on a phase inversion technique (transcranial ultrasound angiography [tUSA]). For sensitivity, the results were compared with x-ray angiography as the "gold standard." For interobserver reliability, 24 of 35 sonography studies were evaluated by 2 physicians with little training in transcranial sonography and by a seasoned sonographer.
  
  
  RESULTS
  The sensitivity of tUSA ranged between 0.778 (95% confidence interval [CI] of 0.577-0.914) and 0.963 (95% CI of 0.810-0.999). The sensitivities were similar among physicians with little training in transcranial sonography and the seasoned sonographer, indicating high inter-rater reliability. Overall, tUSA provided high anatomic resolution and vascular delineation even of small vessels in the millimeter range. At peak intensity, no UCA-related artifacts were observed.
  
  
  CONCLUSIONS
  tUSA provides images of the intracranial arteries similar to those obtained at angiography with high anatomic resolution, reasonable sensitivity, and interobserver reliability.
authors.affiliation: Department of Radiology, University of California San Diego, CA 92103-8756, USA. thoelscher@ucsd.edu
authors.forename: T
authors.initials: T
authors.lastname: Hölscher
authors.forename: J A
authors.initials: JA
authors.lastname: Sattin
authors.forename: R
authors.initials: R
authors.lastname: Raman
authors.forename: W
authors.initials: W
authors.lastname: Wilkening
authors.forename: C V
authors.initials: CV
authors.lastname: Fanale
authors.forename: S E
authors.initials: SE
authors.lastname: Olson
authors.forename: R F
authors.initials: RF
authors.lastname: Mattrey
authors.forename: P D
authors.initials: PD
authors.lastname: Lyden
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D002941:Circle of Willis / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D005466:Fluorocarbons; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; C078626:perflexane