What is the best imaging modality for diagnosing constrictive pericarditis?

Best Imaging Modality for Constrictive Pericarditis

Cardiac Magnetic Resonance (CMR) is the preferred imaging modality for diagnosing constrictive pericarditis due to its comprehensive assessment of pericardial morphology, tissue characterization, and functional consequences. 1

Diagnostic Approach to Constrictive Pericarditis

First-Line Imaging

• Echocardiography: Initial screening test that can identify:
  • Thickened pericardial layers
  • Inspiratory ventricular septal motion toward left ventricle (septal bounce)
  • Dilated atria
  • Marked dilation and diminished collapse of IVC and hepatic veins
  • Premature opening of pulmonary valve 1

Definitive Imaging

• Cardiac Magnetic Resonance (CMR):
  • Provides comprehensive assessment of pericardial disease 1
  • Allows both morphological and functional evaluation
  • Enables tissue characterization to detect inflammation and fibrosis
  • Can assess ventricular coupling through real-time cine imaging 1

Key CMR Features for Constrictive Pericarditis:

1. Morphological assessment:

   • Pericardial thickening (best visualized on dark-blood T1-weighted imaging)
   • Abnormalities typically most pronounced at base of ventricles and atrioventricular grooves 1

2. Functional assessment:

   • Real-time cine imaging showing septal shift toward left ventricle during inspiration
   • Assessment of ventricular coupling 1

3. Tissue characterization:

   • Late gadolinium enhancement (LGE) to detect pericardial inflammation
   • T2-weighted imaging for pericardial edema 1

4. Predictive model:

   • Combined assessment of pericardial thickness and relative interventricular septal excursion provides excellent diagnostic accuracy (C statistic 0.98,100% sensitivity, 90% specificity) 2

Supplementary Imaging

• Computed Tomography (CT):

  • Excellent for detecting pericardial calcifications
  • Essential in preoperative planning, especially in patients with prior cardiothoracic surgery 1
  • Helpful for depicting the extension of calcifications 1

• FDG-PET/CT:

  • May help predict response to medical treatment in transient constrictive pericarditis
  • Using pericardial maximized standardized uptake value of 3.0 as cutoff 1

Clinical Pearls and Pitfalls

Diagnostic Pearls

• A multiparametric CMR approach allows distinction between:

  • Active inflammation
  • Chronic pericarditis with constriction
  • Effusive-constrictive pericarditis 3

• CMR can help differentiate constrictive pericarditis from restrictive cardiomyopathy:

  • Pericardial thickening present in constrictive pericarditis (88% of cases)
  • Absent in restrictive cardiomyopathy 4

Common Pitfalls

• Shallow breaths during real-time cine imaging may result in false-negative results
• Vigorous inspiration may cause false-positive results 1
• Relying solely on pericardial thickness can be misleading as some cases of constrictive pericarditis may have only mild to moderate thickening 1
• Failing to distinguish between transient constrictive pericarditis (which may respond to anti-inflammatory therapy) and chronic constrictive pericarditis (which typically requires pericardiectomy) 5

Prognostic Value

• Presence of myocardial late gadolinium enhancement is associated with adverse events 3
• Quantitative pericardial delayed hyperenhancement has shown improved discrimination for clinical remission compared with other clinical variables 1

In summary, while echocardiography serves as a valuable initial screening tool, CMR provides the most comprehensive assessment for diagnosing constrictive pericarditis with its ability to evaluate pericardial morphology, tissue characteristics, and functional consequences. CT offers complementary information, particularly for surgical planning and detection of calcifications.