Three-dimensional agitated saline contrast transesophageal echocardiography for the diagnosis of patent foramen ovale

Patent foramen ovale (PFO) is a three-dimensional (3D) and dynamic structure, making diagnosis challenging with 2D imaging. We aimed to develop a practical 3D agitated saline contrast (ASC) transesophageal echocardiography (TEE) protocol, assess its feasibility, and evaluate its diagnostic implications in ischemic stroke patients. In 158 ischemic stroke patients (52 women; age: 63.6 ± 14.0 years) undergoing TEE to assess embolic sources, 2D and 3D ASC tests were performed using the EPIQ CVx ultrasound system (Philips Medical Systems, Andover, MA) with a 2-8 MHz transesophageal matrix array transducer (X8-2t). Patients were categorized into four groups: no shunt, possible PFO, definite PFO, and intrapulmonary shunt. The practical 3D ASC protocol included bicaval (90°-120°) and short-axis (40°-70°) views at the mid-esophageal level, visualizing the left upper pulmonary vein and interatrial septum. Image acquisition was feasible in 150 patients (94.9%). By applying the 3D ASC protocol, 32 patients (21.3%) were reclassified into another group. Definite PFO cases increased from 20 (13.3%) to 35 (23.3%). The 3D ASC TEE protocol is feasible and improves the accuracy of PFO diagnosis in ischemic stroke patients, offering added value over 2D TEE.