Technical difficulties due to poor acoustic insonation during transcranial doppler recordings in amerindians and individuals of european origin. a comparative study

Background: There is no information on transcranial Doppler (TCD) failures due to poor insonation among native inhabitants of Latin America. Methods: Seventy Ecuadorian natives and 70 age- and sex-matched individuals of European origin underwent TCD. The same investigators performed all exams using the same equipment and protocol. Using the McNemar's test for correlated proportions, we compared TCD failures related to poor insonation across ethnic groups. Results: Out of 140 participants, 56 (40%) had one or more suboptimal/absent acoustic windows. These persons were older (p = 0.01) and were more often women (p < 0.0001) than those with all optimal windows (irrespective of race/ethnicity). In the matched-pair analysis, Amerindians were more likely to have suboptimal/absent acoustic windows than individuals of European origin (OR: 2.8, 95% CI: 1.3-6.5, p = 0.006). Conclusion: Amerindians are almost three times more likely to have insonation failures related to poor acoustic windows than their European counterparts.