title: Yield of transcranial Doppler in acute cerebral ischemia.
abstract: OBJECTIVE
  The objective of this study was to evaluate the yield of emergent transcranial Doppler (TCD) for the evaluation of acute cerebral ischemia.
  
  
  METHODS
  We performed urgent bedside non-contrast-enhanced TCD in patients with acute cerebral ischemia before or immediately after baseline CT scanning. A fast-track scanning protocol (</=15 minutes) and detailed diagnostic criteria were developed for portable single-channel TCD testing. TCD results were compared with angiography.
  
  
  RESULTS
  Of 130 consecutive patients studied, 36 were eligible for thrombolytic therapy; 46 with ischemic strokes and 48 with transient ischemic attacks were not eligible for thrombolysis. TCD identified occlusions in 69% of thrombolysis-eligible patients, compared with 24% and 0% of patients with strokes and transient ischemic attacks, respectively, not eligible for thrombolysis (P<0.01). Stenosis was present in 17%, 33%, and 35%, and normal vessels were found in 14%, 43%, and 65% in the respective patient subgroups. TCD also identified abnormal pulsatility of flow (12 patients), abnormal flow velocities (12), microembolic signals (5), or early recanalization (5) (34 of 130; 26%). In 65% of all patients, TCD was compared with angiography (digital subtraction angiography, MR angiography, or CT angiography). Despite a 15% rate of absent temporal windows, TCD had 88% accuracy for abnormal (occlusion and stenosis) versus normal vessels: sensitivity 87.5%, specificity 88.6%, positive predictive value 87. 5%, and negative predictive value 88.6%.
  
  
  CONCLUSIONS
  A proximal occlusion on TCD was found in 69% of thrombolysis-eligible patients. In 26% of all patients, TCD provided further relevant information that, in addition to angiography, helped to refine the severity of a stenosis and determine stroke pathogenesis. Emergent TCD is both sensitive and specific in determining arterial occlusion and stenosis in acute cerebral ischemia.
authors.affiliation: Center for Noninvasive Brain Perfusion Studies and the Stroke Treatment Team, University of Texas-Houston Medical School, USA. avalexandrov@worldnet.att.net
authors.forename: A V
authors.initials: AV
authors.lastname: Alexandrov
authors.forename: A M
authors.initials: AM
authors.lastname: Demchuk
authors.forename: T H
authors.initials: TH
authors.lastname: Wein
authors.forename: J C
authors.initials: JC
authors.lastname: Grotta
mesh_terms: D000208:Acute Disease; D001783:Blood Flow Velocity; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D002560:Cerebrovascular Circulation; D003951:Diagnostic Errors; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D018810:Magnetic Resonance Angiography; D015588:Observer Variation; D011237:Predictive Value of Tests; D011673:Pulsatile Flow; D015203:Reproducibility of Results; D015912:Thrombolytic Therapy; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D005343:Fibrinolytic Agents