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. 2018 Oct 9;6(3):105–114. doi: 10.2478/jtim-2018-0024

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© 2018 J. David Spence, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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Grading of right-left shunt in PFO by transcranial Doppler (TCD) Transcranial Doppler screen shots of Spencer shunt grades are shown for example of cases missed by trans-esophageal echocardiography with sedation. It can be seen that the presence of bubbles in the cerebral arteries is obvious; besides the visual output on the screen, a loud signal is heard from the audio output with each bubble crossing the patent foramen ovale. Grade 0, no microemboli detected; grade 1, 1–10 microemboli; grade 2, 11–30 microemboli; grade 3, 31–100 microemboli; grade 4, 101–300 microemboli; and grade 5, >300 microemboli. (Reproduced by permission of Elsevier from: Tobe J, Bogiatzi C, Munoz C, Tamayo A, Spence JD. Transcranial Doppler is Complementary to Echocardiography for Detection and Risk Stratification of Patent Foramen Ovale. Can J Cardiol 2016; 32: 986 e9-e16.)