Comparison of two-dimensional versus real-time three-dimensional transesophageal echocardiography for evaluation of patent foramen ovale morphology

The aim of this study was to elucidate patent foramen ovale (PFO) morphology and the change of PFO size using real-time 3-dimensional (3D) transesophageal echocardiography (TEE). PFO is a 3D structure, and its shape changes during the cardiac cycle. Therefore, it may be difficult to estimate accurate PFO morphology using 2-dimensional (2D) TEE. The study included 50 patients with PFO who underwent 2D and 3D TEE. PFO heights (PHs) at entrance, mid, and exit were measured by 2D and 3D TEE. Systolic and diastolic areas were also measured by 3D TEE. PH by 3D TEE was larger than that by 2D TEE (entrance 0.32 ± 0.18 vs 0.21 ± 0.15 cm, p0.001; mid 0.25 ± 0.14 vs 0.15 ± 0.11 cm, p0.001; exit 0.19 ± 0.11 vs 0.11 ± 0.08 cm, p0.001). Systolic area was greater than diastolic area at each location (entrance 0.19 ± 0.17 vs 0.11 ± 0.11 cm(2), p = 0.001; mid 0.13 ± 0.11 vs 0.08 ± 0.06 cm(2), p = 0.001; exit 0.09 ± 0.09 vs 0.06 ± 0.05 cm(2), p = 0.01). Additionally, entrance area was greater than exit area in systole and diastole (systole 0.19 ± 0.17 vs 0.09 ± 0.09 cm(2), p0.001; diastole 0.11 ± 0.11 vs 0.06 ± 0.05 cm(2), p = 0.001). There were good correlations between PH by 3D TEE and PFO area (entrance r = 0.68, mid r = 0.71, exit r = 0.78) but weak correlations between PH by 2D TEE and PFO area (entrance r = 0.62, mid r = 0.50, exit r = 0.51). In conclusion, real-time 3D TEE could provide detailed and unique information on PFO morphology.