Cardiac magnetic resonance radiofrequency tissue tagging for diagnosis of constrictive pericarditis: A proof of concept study

ObjectiveInvasive cardiac catheterization is the venerable “gold standard” for diagnosing constrictive pericarditis. However, its sensitivity and specificity vary dramatically from center to center. Given the ability to unequivocally define segments of the pericardium with the heart via radiofrequency tissue tagging, we hypothesize that cardiac magnetic resonance has the capability to be the new gold standard.MethodsAll patients who were referred for cardiac magnetic resonance evaluation of constrictive pericarditis underwent cardiac magnetic resonance radiofrequency tissue tagging to define visceral-parietal pericardial adherence to determine constriction. This was then compared with intraoperative surgical findings. Likewise, all preoperative cardiac catheterization testing was reviewed in a blinded manner.ResultsA total of 120 patients were referred for clinical suspicion of constrictive pericarditis. Thirty-nine patients were defined as constrictive pericarditis positive solely via radiofrequency tissue-tagging cardiac magnetic resonance, of whom 21 were positive, 4 were negative, and 1 was equivocal for constrictive pericarditis, as defined by cardiac catheterization. Of these patients, 16 underwent pericardiectomy and were surgically confirmed. There was 100% agreement between cardiac magnetic resonance–defined constrictive pericarditis positivity and postsurgical findings. No patients were misclassified by cardiac magnetic resonance. In regard to the remaining constrictive pericarditis–positive patients defined by cardiac magnetic resonance, 10 were treated medically, declined, were ineligible for surgery, or were lost to follow-up. Long-term follow-up of those who were constrictive pericarditis negative by cardiac magnetic resonance showed no early or late crossover to the surgery arm.ConclusionsCardiac magnetic resonance via radiofrequency tissue tagging offers a unique, efficient, and effective manner of defining clinically and surgically relevant constrictive pericarditis. Specifically, no patient who was identified with constriction via cardiac magnetic resonance underwent inappropriate sternotomy. However, catheterization had substantial and unacceptable false-positive and false-negative rates with important clinical ramifications.