How to Use Multimodality Imaging for Pericarditis.

Pericarditis spans acute, recurrent/incessant, effusive, and constrictive phenotypes, and accurate assessment of inflammatory activity and chronicity is essential to guide therapy and anticipate outcomes. Although transthoracic echocardiography remains the first-line modality to evaluate pericardial effusion, tamponade physiology, and constrictive hemodynamics, it is limited for tissue characterization. Multimodality imaging integrates complementary strengths: cardiac magnetic resonance provides the most sensitive noninvasive assessment of pericardial edema and late gadolinium enhancement to phenotype active inflammation versus chronic fibrotic disease and to support prognostication (including identification of potentially reversible constriction); cardiac computed tomography offers superior anatomic detail for pericardial thickness, calcification, complex effusions, and preoperative planning for pericardiectomy, and can serve as an alternative when cardiac magnetic resonance is contraindicated; and 18F-fluorodeoxyglucose positron emission tomography/computed tomography adds targeted value by detecting metabolically active pericardial inflammation in diagnostically ambiguous or refractory cases and may inform escalation to advanced therapies. We synthesize practical, guideline-aligned applications of these modalities, highlight common pitfalls and system-level constraints, and propose a simplified framework using key imaging biomarkers edema/inflammation, neovascularization (late gadolinium enhancement), thickening, effusion/tamponade, constriction, and fibrosis/calcification to enable imaging-guided therapy, including treatment escalation and tapering strategies in recurrent disease and selection of patients for pericardiectomy.