A novel probe attached to the neck can accurately detect a large patent foramen ovale

We developed a novel probe (pastable soft ultrasound probe; PSUP) attached to the neck for right-to-left shunt (RLS) detection. The purpose of this study was to evaluate the diagnostic ability of the PSUP for RLS detection by comparison with transesophageal echocardiography (TEE).

The subjects were patients with ischemic strokes and transient ischemic attacks who underwent TEE. Based on TEE, patients with patent foramen ovale (PFO) were divided into two groups by the number of microbubbles (MBs): small PFO (1-29 MBs) and large PFO (≥30 MBs). Then, PSUP examination of one common carotid artery (CCA) was started using a procedure similar to TEE. RLS was diagnosed by PSUP when one or more microembolic signals were found in the CCA. The detection rate by size of PFO was compared between TEE and PSUP, and the diagnostic accuracy of PSUP was calculated.

From May 2014 to July 2016, 84 patients (63 males, median age 63 years) were included; 41 (49%) were diagnosed with PFO by TEE, while PSUP detected PFO in 31 (37%). Using TEE findings as the reference, PSUP for PFO showed sensitivity of 68%, specificity of 93%, and accuracy of 81%. On TEE, 22 patients had large PFOs, and 19 patients had small PFOs. The PSUP could identify large PFOs in grade I and II of International Consensus Criteria more accurately than small ones (58 and 86% vs. 29 and 14%, P = 0.003).

The PSUP has considerable accuracy for diagnosing large PFOs. PSUP should play an important role in detecting large PFOs.