Presentation
Non-ST-elevation myocardial infarction (NSTEMI) and coronary stent placement into the left anterior descending artery (LAD). Pericardial effusion and systolic dysfunction on echocardiography. Known history of hypertension, diabetes and hyperuricemia. Elevated inflammatory markers (c-reactive protein and white blood cell count).
Patient Data
PA chest x-ray shows an increased cardiothoracic ratio (52%).
There is blunting of the costophrenic angles bilaterally, and some bilateral linear opacities in the lower zone due to bilateral pleural fluid also in the interlobar fissures.
Lateral chest x-ray shows blunting of the costophrenic angles due to small pleural effusion and a pericardial fat stripe also known as a sandwich- or oreo cookie sign representing pericardial effusion.
Findings:
Heart rate: 49 bpm, BSA: 2,01 m²
Image quality: some respiratory movement during the T1 mapping
Morphology and functional analysis:
- LV-EDVI: 74 mL/m²
- LV-ESVI: 29 mL/m²
- LV-SVI: 45 mL/m²
- LV-EF: 60%
- Cardiac output: 4.4 L/min
- Cardiac index: 2.2 L/min/m²
- LV-ED mass + papillary muscle: 67 g/m²
- Septum thickness: 10 mm
No regional left ventricular wall motion abnormalities.
Visually normal atrial size.
No intercavitary thrombi.
Myocardial tissue properties:
No regional or global myocardial edema.
No subendocardial, intramyocardial or subepicardial late gadolinium enhancement is visible.
T1 mapping native: 1005±28 ms [948-1060 ms*], extracellular volume (ECV): ≈ 26.3%
*native T1 reference range based on local data
Moderate circular pericardial effusion.
Pericardial enhancement. Pericardial thickening (3-4 mm).
Small bilateral pleural effusions.
Impression:
Moderate pericardial effusion and pericardial enhancement indicating pericarditis.
No signs of acute myocardial inflammation.
Viable myocardium, no subendocardial scar seen.
Lateral chest x-ray:
Pericardial fat stripe, also known as sandwich or oreo cookie sign:
The epicardial (red arrows) and paracardial fat (blue arrows) is separated by a “stripe” of increased density (light green *), representing pericardial fluid.
Late gadolinium enhancement (LGE):
- no intramyocardial or subepicardial late gadolinium enhancement
- moderate pericardial effusion with pericardial thickening and enhancement of the parietal (red arrowheads) and visceral (blue arrowheads) pericardium
- good viability, especially in the anterior wall in the territory of the left anterior descending artery (LAD)
Short tau inversion recovery (STIR) imaging / early gadolinium enhancement (EGE):
- pericardial thickening and edema (red arrows)
- no focal myocardial edema can be seen
- T2 signal intensity ratio between myocardium and skeletal muscle within the same image was normal
- no signs of myocardial hyperemia
T1 mapping native and postcontrast:
- native T1 ≈1005 ms, z-score of ≈0 (within normal limits)
- the application of gadolinium leads to a shortening of T1
- extracellular volume (ECV) was < 30% in all segments ~26.3% (within normal limits)
Case Discussion
This case illustrates pericardial effusion with pericarditis in a patient, who underwent percutaneous coronary intervention (PCI) because of a non-ST elevation myocardial infarction (NSTEMI).
Chest x-ray shows:
- a pericardial fat stripe or oreo cookie sign
- small bilateral pleural effusions
Cardiac MRI findings are:
- a moderate, circular pericardial effusion
- pericardial thickening, pericardial edema and enhancement
The patient was conservatively treated and had a decrease of the pericardial effusion and improvement of symptoms as well as systolic dysfunction. In absence of any other specific cause and high-risk features the etiology was felt to be most likely idiopathic vs post-myocardial infarction pericarditis. Eventually, the patient was sent home with the recommendation of restriction in physical activity and echocardiographic follow-up.
Perimyocarditis is a typical differential of pericarditis especially in the setting of elevated troponins 4. However, no main diagnostic findings for myocardial inflammation as recommended in line with the original or updated Lake Louise criteria 5,6 could be demonstrated and the elevation in troponins can by all means explained with the non-ST-elevation myocardial infarction (NSTEMI).
Another differential diagnosis to think about in a patient with pericardial effusion in a non-ST-elevation myocardial infarction would be Stanford type A aortic dissection 7.