Diagnostic Efficacy of Magnetic Resonance Imaging and Echocardiography in Diagnosis of Constrictive Pericarditis

: Background: Diagnosis of Constrictive Pericarditis (CP) is a clinical challenge. Echocardiography and Magnetic Resonance Imaging (MRI) are the most commonly used modalities for evaluating pericardial diseases, such as CP. Objective: This study aimed to assess and compare the diagnostic accuracy of MRI and echocardiography in diagnosis of CP. Methods: This cross-sectional, retrospective study was conducted on 45 patients suspicious for CP [n = 36] or non-constrictive pericarditis [n = 9]. Among the 36 patients suspicious for CP, 20 underwent pericardiectomy. Accordingly, 19 patients were proved to have CP based on histopathological assessments and were considered as the CP-positive group. In addition, the nine patients who were suspicious for pericarditis without the clinical findings of pericardial constriction were included in the CP-negative group [adding to one patient who was negative for CP after surgery, there were a total of 10 CP-negative patients]. MRI, echocardiographic, and clinical findings were obtained from the hospital digital archive and were compared with each other. Diagnostic accuracy indices of echocardiography and MRI in diagnosis of CP were also calculated. Results: The mean age of the patients with proved CP and without CP was 48.1 ± 20.7 (12-77) and 50.6 ± 15.3 years (25 - 72), respectively. Additionally, 15 patients were male (78.9%), while six individuals were male (60%) in the CP-negative group. Among MRI and echocardiography variables, the diagnostic accuracy of MRI septal bounce was found to be the same as the gold standard. MRI pericardial thickening > 4 mm had the sensitivity of 100%, specificity of 80%, Positive Predictive value (PPV) of 90%, and Negative Predictive Value (NPV) of 100%. Echocardiographic parameters, including pericardial thickness, septal bounce, hepatic venous reversal flow, and respiratory variation in mitral flow, also showed high specificity (100%). Additionally, the Area Under the Curve (AUC) of MRI and echocardiography was 0.95 (95% CI = 0.85 - 1) and 0.89 (95% CI = 0.80 - 0.99), respectively (P = 0.43). Moreover, the sensitivity of MRI and echocardiography in diagnosis of CP was 100% and 78.9%, respectively (P = 0.045). Conclusion: MRI was found to be more sensitive than echocardiography in diagnosis of CP. Indeed, MRI septal bounce had the best diagnostic accuracy for diagnosis of CP.