Presentation
History not provided.
Patient Data
In this cine grid sequence, the pericardium is not sliding past the myocardium as expected. This is shown by the lines extending through the pericardium and myocardium. They do not break at any point in the cardiac cycle.
(A septal bounce can also be seen)
Multiple annotated MRI images showing findings in constrictive pericarditis:
1. One frame of the grid cine sequence: The green arrow points to the gridline through the pericardium. The red arrow points to the gridline through the myocardium. The left ventricle is in early systole, but notice how the pericardium and myocardium are "tethered" at the angle of the line rather than becoming discontinuous.
2. Delayed post-contrast short-axis image shows delayed enhancement in the pericardium around the left and right ventricles (green arrows). The myocardium does not show delayed enhancement (red arrow).
3. Another view of thickened pericardium (green arrow). The red arrow points to normal myocardium.
4. This image shows how the edge artifact in an SSFP sequence can help highlight thickened and tethered pericardium. The inner edge artifact (light blue arrow) indicates the interface between the myocardium and the epicardial space/epicardial fat (bright). The outer edge artifact (dark blue arrow) is the interface between the pericardium and the epicardial fat. In some regions (small blue arrow) the edge disappears. The pericardium and the myocardium are continuous at these regions, with obliteration of the epicardial space.
Case Discussion
Cardiac MRI can be useful for evaluation of constrictive pericarditis, through a combination of anatomic and functional information. The functional component is critical because even though the classic threshold for thickened pericardium is >4 mm on CT and MRI, as many as 28% of cases with surgically proven constrictive pericarditis have a normal pericardial thickness (18% were normal on histologic examination) 1.
One of the main problems in constrictive pericarditis is the inability of the ventricles to expand in diastole (they are "constricted"). This can lead to the "septal bounce" seen on echocardiography and MRI. The grid sequence above can highlight the lack of a normal sliding movement of the pericardium, strongly suggesting constrictive pericarditis 2. Abnormal thickening of the pericardium, pericardial enhancement, and regions of confluence of the pericardium and myocardium (as seen on the above images) further suggest constrictive pericarditis.
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