title: Transcranial Doppler with bubble study as a method to detect extracardiac right-to-left shunts in patients with ischemic stroke.
abstract: OBJECTIVE
  Paradoxical embolism through extracardiac right-to-left shunts (ECRLS) may represent an under-detected stroke mechanism. Stroke patients without evidence of cardiac right-to-left shunt (RLS) on echocardiogram may benefit from transcranial Doppler with bubble study (TCD-b) to aid in recognition of stroke etiology. This study assesses the usefulness of TCD-b in the stroke evaluation.
  
  
  METHODS
  Retrospective cohort study of consecutive patients undergoing TCD-b performed in our neurovascular laboratory from February 2005 to August 2009. Echocardiography results were reviewed in patients with positive TCD-b. Detailed medical record review was performed on patients with positive TCD-b and negative echocardiogram findings for RLS.
  
  
  RESULTS
  Of 502 patients undergoing TCD-b, 48.4% (n = 243) had a positive study suggesting the presence of RLS. Of these, 59.2% (n = 144) had an echocardiogram demonstrating a cardiac RLS, 26% (n = 63) had echocardiograms without evidence of cardiac RLS, and 14.8% (n = 36) had no echocardiogram. Data on the evaluation to determine source of potential shunting in patients with discrepant findings was available in 11(17.5%). Of these, 63.6% (7/11) had potential mechanisms for positive TCD-b: one pulmonary arteriovenous malformation (AVM), one arteriovenous fistula thrombus, one parietal AVM, and four had malignancy.
  
  
  CONCLUSIONS
  TCD-bubble studies may prove useful in uncovering treatable causes of stroke.
authors.affiliation: Cerebrovascular Center, Cleveland Clinic Foundation, OH.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Goutman
authors.forename: Irene L
authors.initials: IL
authors.lastname: Katzan
authors.forename: Rishi
authors.initials: R
authors.lastname: Gupta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015984:Causality; D015897:Comorbidity; D003287:Contrast Media; D019320:Embolism, Paradoxical / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D017585:Ultrasonography, Doppler, Transcranial / Q000706:statistics & numerical data*
chemical_list: D003287:Contrast Media