Pericarditis MRI
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American Roentgen Ray Society Images of Pericarditis MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
The Appearance of the Normal Pericardium on Cardiac MRI
The low water content pericardium appears as a thin dark band that is bordered by a bright band on both sides on T1 weighted spin imaging. These surrounding bright bands are associated with the surrounding epicardial and pericardial fat. The thickness of the normal pericardium is 2 to 4 mm.
The Appearance of the Inflamed Pericardium on Cardiac MRI
Following the administration of gadolinium the pericardium is enhanced due to inflammation.
The Appearance of the Pericardium in Constrictive Pericarditis
Pericardial thickening on cardiac MRI has become the diagnostic modality of choice in the assessment of constrictive pericarditis with a sensitivity of 88%, specificity of 100%, and diagnostic accuracy of 93%. The pericardium is of a lower intensity signal in constrictive pericarditis than in acute pericarditis.
Other signs of pericardial constriction on cardiac MRI include the following:
- Dilatation of the inferior vena cava, hepatic veins, and right atrium
- A compressed and or elongated right ventricle
Cardiac MRI in pericardial effusions
It is important to distinguish the thickness of the pericardium from any pericardial effusion, which commonly appears black on spin echo images but bright on gradient echo cines. Moderate-sized effusions are often associated with a pericardial space anterior to the right ventricle of size greater than 5mm. Cine images can detect cardiac tamponade by revealing diastolic collapse of right sided and sometimes left-sided cardiac chambers. Regarding the composition of pericardial effusions, transudates have low signal on T1-weighted images but high signal on T2-weighted and gradient echo images. Exudates display an intermediate signal on both types of sequences. Hemorrhagic effusions may show a wide range of signal intensity on spin-echo sequences that depends on the age of the effusion.
Cardiac MRI in other pericardial pathologies
Other types of pericardial pathology detectable by CMR include pericardial cysts; metastasis and primary tumors of the pericardium; and intracardiac tumors such as myxomas, lipomas, and teratomas. The signal intensity of fluid within pericardial cysts increases progressively with echo time, leading to accurate detection. Pericardial calcification, on the other hand, is not well-detected by CMR. Calcium appears black on CMR and therefore may resemble a localized area of pericardial thickening; cardiac CT is preferred for visualizing pericardial calcification.