title: Contrast transcranial Doppler compared to transesophageal echocardiography in detection of right-to-left shunt.
abstract: OBJECTIVE
  To assess contrast transcranial Doppler (TCD) for detection of right-to-left shunt (RLSh).
  
  
  METHODS
  We studied 30 patients aged between 25-45 years admitted to Al-Zahra Hospital, affiliated to Isfahan University of Medical Sciences, between May 2003 and May 2005. All patients underwent transesophageal echocardiography (TEE) with contrast and contrast TCD.
  
  
  RESULTS
  Eleven (36.6%) patients had RLSh detected by TEE with contrast, and 19 (63.3%) patients had no shunt by TEE. Eighteen patients (60%) patients had no RLSh by contrast TCD, and 12 (40%) patients had RLSh by contrast TCD. Ten (33.3%) patients had RLSh by contrast TCD and TEE with contrast procedures. One patient had RLSh by TEE, and it was negative on TCD test, and 2 patients were positive on TCD test and negative in TEE. With contrast TEE as the gold standard, the sensitivity of contrast TCD was 90.9% and specificity was 89.4%, with an accuracy of 90%. Meanwhile, the positive predictive value of contrast TCD was 83.3% and the negative predictive value was 94.4%.
  
  
  CONCLUSIONS
  In our study, the negative predictive value of contrast TCD was excellent. Therefore, this examination is able to exclude RLSh with a high level of confidence.
authors.affiliation: Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran. Tel. +98 (918) 1623022. Fax. +98 (311) 6684510. E-mail: ali_hamzehloo@yahoo.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Hamzehloo
authors.forename: Seid A
authors.initials: SA
authors.lastname: Mousavi