Three-Dimensional Agitated Saline Contrast Transesophageal Echocardiography for the Diagnosis of Patent Foramen Ovale

Background Patent foramen ovale (PFO) is a three-dimensional (3D) and dynamic structure, making it challenging to diagnose with 2D imaging. We aimed to develop a practical protocol for 3D agitated saline contrast (ASC) transesophageal echocardiography (TEE), evaluate its feasibility, and identify implications for the diagnosis of patent foramen ovale (PFO) in patients with ischemic stroke. Methods In 158 patients (52 women; age: 63.6 ± 14.0 years) with ischemic stroke who were referred for TEE to evaluate the cardiac source of embolism, TEE was performed using the EPIQ CVx ultrasound system (Philips Medical Systems, Andover, MA) with a 2–8 MHz transesophageal matrix array transducer (X8-2t). ASC tests were performed with 2D and 3D images. According to the results of each method, patients were classified into four groups: no shunt, possible PFO, definite PFO, and intrapulmonary shunt. Results The practical 3D ASC protocol consisted of two images: one in the 90°–120° bicaval view and another in the 40°–70° short-axis view. These images were acquired to include both the left upper pulmonic vein and interatrial septum at the mid-esophageal position. Image acquisition and analysis of 3D TEE images were feasible in 150 patients (94.9%). By applying the 3D ASC protocol, 32 patients (21.3%) were reclassified into another group, and 16 (10.7%) had their diagnosis changed. Definite PFO cases increased from 20 (13.3%) to 35 (23.3%) patients. Conclusion The practical 3D TEE protocol for diagnosing PFO was feasible in patients with ischemic stroke. Adding a practical 3D ASC protocol to 2D TEE aids in the accurate diagnosis of PFO.