title: Alternatives to transtemporal approach of transcranial Doppler for the detection of right-to-left cardiac shunt.
abstract: BACKGROUND
  Transcranial Doppler (TCD) is reliable and reproducible for the diagnosis of right-to-left cardiac shunts (RLS).
  
  
  METHODS
  Various factors limiting the performance and diagnostic methods of RLS by TCD are discussed.
  
  
  RESULTS
  In patients with insufficient temporal acoustic windows, TCD may still be reliably used to monitor the microembolic signals at various alternative sites. Diagnostic yield of TCD may be further improved and better quantitative assessment of the 'functional potential' of the RLS by optimizing the preparation of the 'air-saline-blood' contrast-mixture, injecting the mixture in controlled body positions and using power M-mode TCD.
  
  
  CONCLUSIONS
  TCD may be used reliably for the detection as well as the quantification of RLS even in patients with insufficient temporal acoustic windows.
authors.affiliation: Division of Neurology, National University Hospital, Singapore. drvijay@singnet.com.sg
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Sharma
authors.forename: Hock L
authors.initials: HL
authors.lastname: Teoh
authors.forename: Bernard P L
authors.initials: BP
authors.lastname: Chan
mesh_terms: D004452:Echocardiography / Q000379:methods*; D006321:Heart / Q000503:physiopathology; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*