=====Cryptogenic brain abscess (CBA)=====
Some patients exhibit cryptogenic [[brain abscess]] (CBA) in the absence of any such congenital disease or other infections. [[Patent foramen ovale]] (PFO) is a very common disease that exhibits right-to-left shunt. 

CBA might be caused by paradoxical embolization of a bacterial mass via PFO. Thus, more patients with CBA need to undergo [[transesophageal echocardiography]] (TEE) to detect PFO.