Patent foramen ovales (PFO) and atrial septal defects (ASD) are typically diagnosed by an ultrasound of the heart, or echocardiography
. Echocardiography allows for the visualization of the hole, determination of the direction of the shunt, and estimation of the amount of shunt.
Other imaging tests such as a transesophageal echo (TEE), cardiac CT, and cardiac MRI (CMR) are utilized if an echocardiogram is inconclusive or if supportive information is required.
Cardiac catheterization (and to a lesser extent, CMR) can be performed to give a more accurate estimation of the degree of shunt when the decision to treat is unclear.