Right-to-Left Shunt Evaluation in Cardiac Patent Foramen Ovale Using Bubble Contrast Transcranial Color-Coded Doppler: A Cryptogenic Stroke Case

Abstract

Traditional diagnosis of patent foramen ovale (PFO) in the heart has involved the use of transcranial Doppler (TCD). However, TCD is essentially a blind test that cannot directly visualize the location of blood vessels. Since TCD relies on qualitative assessments by examiners, there is room for errors, such as misalignment of the ultrasound’s angle of incidence with the actual blood vessels. This limitation affects the reproducibility and consistency of the examination. In this study, we presented an alternative approach for assessing right-to-left shunt (RLS) associated with PFO using contrast transcranial color-coded Doppler (C-TCCD) with bubble contrast. The patient under consideration had been diagnosed with an ischemic stroke through imaging, but the subsequent cardiac work-up failed to determine the cause. Employing C-TCCD for RLS screening revealed a confirmed RLS of Spencer’s three grades. Subsequently, transesophageal echocardiography (TEE) was conducted to evaluate PFO risk factors, confirming an 8 mm PFO size, a 21 mm tunnel length, a hypermobile interatrial septum, and persistent RLS. The calculated high-risk PFO score was 4 points, categorizing it as a very high risk PFO. This case underscores the importance of C-TCCD screening in detecting RLS associated with PFO, especially in cryptogenic stroke patients, when identifying the underlying cause of ischemic stroke becomes challenging.

Predictive value of right heart contrast echocardiography combined with STAF in cardioembolism

“…It has been demonstrated that patent foramen ovale is a prevalent form of structural cardiac anomaly and represents an important risk factor for developing CE [4]. Right heart contrast echocardiography allows the visualization of unique highreflectance microbubbles in the left heart following the intravenous administration of a specialized contrast agent, which facilitates the detection of patent foramen ovale and is therefore a valuable tool for assessing cerebral infarction, particularly in CE patients [5,6]. In parallel, the Score for Targeting Atrial Fibrillation (STAF) has demonstrated promising utility as a straightforward and convenient diagnostic instrument.…”

The size distribution of the agitated saline microbubbles for contrast transcranial Doppler generated using standard manual methods

“…MBs are used as contrast agents in the c-TCD test, which is prepared by mixing an isotonic saline solution with air and subsequently injected into a cubital vein for the purpose of this examination. In the presence of a rightto-left shunt, the air-containing echo contrast agent will bypass pulmonary circulation and induce microembolic signals in the basal cerebral arteries (Webb & Gatzoulis, 2006;Ji & Seoung, 2023). In 2000, Jauss and Zanette published the c-TCD recommendation process at an international Consensus Meeting.…”