Technical Difficulties Due to Poor Acoustic Insonation during Transcranial Doppler Recordings in Amerindians and Individuals of European Origin. A Comparative Study

Abstract

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.

Temporal bone thickness and texture are major determinants of the high rate of insonation failures of transcranial doppler in amerindians (the Atahualpa Project)

“…This high number of failures was not related to external factors, because the same operators (using the same equipment and protocol) previously found a three times greater prevalence of poor insonation through temporal windows in the same population of Amerindians than in a group of age-and sex-matched individuals of European ancestry. 9 In the present study, we found a negative impact of both temporal bone thickness and heterogeneous texture on the quality of insonation. For every millimeter of increase in thickness, subjects were 2.9 times more likely to have a suboptimal/absent window.…”

“…9 In the present study, we evaluated CT findings in the same population of Amerindians to assess whether anatomic characteristics of the temporal bones accounted for the high prevalence of poor insonation.…”

The association of sleep-disordered breathing with high cerebral pulsatility might not be related to diffuse small vessel disease. A pilot study

“…Thirteen of the 38 persons had absent transtemporal windows precluding insonation of both MCAs and therefore were excluded. (These high rates of absent windows were related to increased thickness and heterogeneity of temporal squama in our population of Amerindians [ 14 , 15 ].…”

Intracranial arterial stenosis in Ecuadorian Natives/Mestizos. A population-based study in older adults (The Atahualpa Project)

“…Transcranial Doppler is a non-invasive screening method, but failures related to poor insonation through transtemporal windows limit its value in non-White populations (Nader, Andrade, Espinosa, Zambrano, & Del Brutto, 2015). Therefore, MRA appears to be the best option to assess the burden of IAS at the population level.…”