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.
Gwak et al. (Sat,) studied this question.