pressure and increase the likelihood of detection of the PFO. The shunts may be quantified based on the number of bubbles seen in the left atrium during the study. Sources vary on the exact number of bubbles, but fewer than 10 is consistent with a small shunt, 10 to 20 bubbles is a moderate shunt, and more than 20 or 25 bubbles is a large shunt. Based on meta-analyses of published data, the sensitivity of TTE for PFO detection is 46% and the specificity is 99%. 2 The transesophageal

more »

... am (TEE) is considered the gold standard study for diagnosis of a PFO with sensitivity of 89% and specificity of 92%. 3