# Cardiac CT Angiography in Diagnosing Patent Foramen Ovale: A Study on Patients with Suspected Patent Foramen Ovale-Associated Stroke

## TL;DR

This study shows that cardiac CT scans can help diagnose a heart condition called patent foramen ovale, especially in patients with larger blood flow between heart chambers.

## Contribution

The study identifies that cardiac CTA's effectiveness in detecting PFO depends on the size of the right-to-left shunt.

## Key findings

- Cardiac CTA had a sensitivity of 70% and a specificity of 100% for detecting PFO compared to TEE.
- Patients with moderate-to-large shunts had a 90% CTA sensitivity for PFO detection.
- Small shunts were more likely to result in false-negative CTA results.

## Abstract

Background: Cardiac computed tomographic angiography (CTA) detects patent foramen ovale (PFO) with variable accuracy. This study investigated factors affecting CTA detectability for PFO in patients with suspected PFO-associated stroke. Methods: Consecutive patients with cryptogenic stroke and positive findings on contrast transcranial Doppler (cTCD) examinations were enrolled between November 2020 and April 2023 in this retrospective study. Each participant underwent transesophageal echocardiography (TEE) and cardiac CTA. Patients with confirmed PFO on TEE were categorized into two groups based on CTA detectability: the CTA-positive group (PFO identified by CTA) and the CTA-negative group (PFO missed by CTA). Univariate and multivariate logistic regression analyses were performed to identify predictors of CTA false-negative results. Results: Among 108 patients (mean age 46.7 ± 14.9 years, 47.2% male), the prevalence of PFO by TEE was 94.4% (102/108). Compared to TEE, cardiac CTA had a sensitivity of 70% (95% CI 61–79%), a specificity of 100% (95% CI 54–100%), a positive predictive value of 100% (95% CI 95–100%), and a negative predictive value of 16% (95% CI 6–32%). Among patients with PFO confirmed by TEE (n = 102), the incidence of moderate to large right-to-left shunts (RLS) was significantly higher in the CTA-positive group than in the CTA-negative (77.5% vs. 22.5%, p < 0.001). After adjusting for confounders, patients with moderate to large shunts showed a significantly lower likelihood of a CTA false-negative result compared to those with small shunts (OR 0.113, 95% CI 0.035–0.365, p < 0.001). In patients with moderate to large RLS, the sensitivity of cardiac CTA for diagnosing PFO increased to 90.16% (95% CI 82.69–97.64%). Conclusions: Cardiac CTA could be an effective complementary modality for selected patients with suspected PFO-associated stroke. Its diagnostic performance appears more reliable for identifying PFO in patients with moderate-to-large RLS than in those with small RLS.