Right-to-left shunt detection via synchronized contrast transcranial Doppler combined with contrast transthoracic echocardiography: A preliminary study

Figure 3 Comparison of transthoracic echocardiography at rest. A: At rest, a moderate right-to-left shunt (RLS) is observed on contrast transthoracic echocardiography; B: A large RLS (> 30 microbubbles) is observed following the Valsalva maneuver (VM); C: Contrast transcranial Doppler only detects a small RLS during VM; D: Enhanced transesophageal ultrasonography identifies a patent foramen ovale (arrow).