Diagnosis of Patent Foramen Ovale Using Contrast-Enhanced Dynamic MRI: A Pilot Study

OBJECTIVE: The aim of this study was to evaluate the feasibility of dynamic contrast-enhanced MRI for detection of patent foramen ovale. SUBJECTS AND METHODS: Fifteen patients with and five patients without patent foramen ovale underwent transesophageal echocardiography and MRI, which were performed during the Valsalva maneuver. Grading results (grade 0, no patent foramen ovale and grades 1-3, minor to major enhancement due to intracardiac shunt) were assessed visually. Signal-intensity curves in the left atrium and in a pulmonary vein served to underline the diagnosis. RESULTS: The diagnoses of all patients with (15/15) and without patent foramen ovale (5/5) were correct compared with the findings of the reference transesophageal echocardiography. In 12 (60%) of 20 patients, the grading scores were identical, and in four (20%) of 20 patients, the scores differed by more than one grade. Overall, there was a good correlation of grading scores (r = 0.7, p < 0.05). Using signal-intensity curves, we found that the patients with patent foramen ovale showed an additional signal peak in the left atrium before the enhancement of the pulmonary vein because of an intracardiac shunt. In three of 15 patients with patent foramen ovale, an atrial septal aneurysm was correctly diagnosed. CONCLUSION: This pilot study shows that MRI is a new noninvasive method to detect patent foramen ovale and atrial septal aneurysm. A grading is possible but warrants further investigation regarding its predictive value and impact on treatment strategies.