title: Extent of spontaneous cross-flow via the anterior communicating artery in steno-occlusive carotid artery disease.
abstract: OBJECTIVE
  Our purpose was to evaluate the agreement of transcranial color-coded duplex sonography (TCCS) measurements and intra-arterial digital subtraction angiography (DSA) findings in determining the extent of spontaneous cross-flow via the anterior communicating artery (AcoA) in patients with internal carotid artery (ICA) stenosis.
  
  
  METHODS
  Thirty adult patients with suspected uni- or bilateral high-grade carotid artery stenosis were prospectively examined by DSA and angle-corrected TCCS. The extent of cross-flow was determined considering retrograde flow in the ipsilateral anterior cerebral artery (ACA) and sideto-side differences of the A1-segments of the ACA and middle cerebral arteries (MCAs) by both techniques. Cross-flow was angiographically categorized by means of a four-step scale. DSA findings were correlated with side-to-side differences in mean blood flow velocity as well as flow direction measured by TCCS.
  
  
  RESULTS
  Twenty-seven of 30 patients had a uni- or bilateral ICA stenosis of >49%. Excellent agreement between TCCS and DSA was evaluated for the detection of lack (grades 0 and 1) or presence (grades 2 and 3) of reversed flow in the ACA (sensitivity 100%, specificity 93%, positive predictive value 94%). Post hoc analysis of the mean velocities in the ACA and MCA revealed a side-to-side difference of 25 cm/s as a cutting point allowing for definition of a corresponding four-grade scale for ultrasound. However, full agreement, i.e.same grade of cross-flow detected by both techniques, was only found in 17(57%) of 30 cases.
  
  
  CONCLUSIONS
  Non-invasive TCCS is reliable for detecting reversed flow in the ACA in patients with ICA stenosis. However, there is only a moderate agreement between angiography and TCCS in quantifying the extent of spontaneous anterior cross-flow because different information on the intracranial hemodynamics may be obtained.
authors.affiliation: Department of Radiology and Neuroradiology, Klinikum Augsburg, Germany. Gernot.SAD@gmx.de
authors.forename: Gernot
authors.initials: G
authors.lastname: Schulte-Altedorneburg
authors.forename: Tilman
authors.initials: T
authors.lastname: Becker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods; D020771:Anterior Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods