The role of coronary CT angiography in diagnosis of patent foramen ovale.

The interatrial septum consists of a fusion of the two separate leaves of a flap valve system, which provides continued fetal circulation in utero. In approximately 70% of the population, the septum primum and secundum in the interatrial septum fuse shortly after birth and form an intact barrier (1). A failure in the fusion of this flap valve system after birth may lead to a patent foramen ovale (PFO). The connection between the right and left atrium (RA and LA, respectively) forms an anatomical tract for cryptogenic stroke caused by paradoxical emboli (2). Transesophageal echocardiography (TEE) is a semi-invasive imaging modality that is typically preferred for PFO diagnosis. In particular, contrast-enhanced TEE is a reliable method for the identification of PFO patients with right to left shunts. Although contrast-enhanced TEE is utilized in PFO diagnosis as the reference standard, some studies claim that transthoracic echocardiography (TTE), which is a noninvasive procedure, has comparable sensitivity (3–6). Although coronary computed tomography angiography (CTA) is primarily utilized to image coronary arteries, this technique can also be used to visualize other cardiac structures, at a very high resolution, in a routine coronary artery scan (2). As computed tomography (CT) technology has advanced, clinicians have discovered that PFO is a frequent finding in routine coronary CTA, and interest in this issue has arisen. The high spatial and temporal resolution provided by advancements in CT technology has enabled easy evaluation of the interatrial septum as well (7–9). Atrial septal aneurysms (ASA) represent another pathologic anatomical condition, with reported incidences of 1% and 4.6%–10% in autopsy studies patients undergoing TEE, respectively (10). ASAs may also exist in PFO and are related to both PFO and cryptogenic stroke (2). The present study aimed to examine the incidence of PFO and ASA in the Turkish population using coronary CTA, to assess the diagnostic feasibility of coronary CTA for PFO diagnosis by conducting a comparison with TTE; and determine the diagnostic role and characteristics of the interatrial tunnel, free flap valve (FFV), and shunts.