Fig. 10.1
Anteroposterior (a) and lateral (b) chest roentgenogram showing calcification of the pericardium (arrows) in a patient with constrictive pericarditis
10.2.2 ECG Findings
10.2.3 CT Findings
A finding of pericardial thickening with calcification is reliable in helping to differentiate CP from restrictive cardiomyopathy. The parietal pericardium may be 4–20 mm thick, compared with a normal thickness of 1–2 mm [4]. CT is also useful for assessment of ventricular function, and it can define the distribution of pericardial thickening, which is useful when planning pericardiectomy [4].
Other characteristic anatomic features seen on CT include conical or tubular diastolic ventricular shape, associated pericardial effusion, and secondary sequelae of dilated atria, hepatic veins, and pulmonary veins [5].
10.2.4 MRI Findings
Accurate definition of pericardial thickness and distribution is also possible with MR (Fig. 10.2). A combined model of pericardial thickness and relative interventricular septal (IVS) excursion may provide the best overall results in prediction of CP [6]. Other characteristics with strong predictive value in the assessment of constriction include diastolic IVS bounce, change in the area of the left ventricle, and the eccentricity index [6].
Fig. 10.2
Black blood double inversion recovery image (a) and FIESTA cine (b) short-axis images show a thickened pericardium measuring greater than 4 mm (1). Notice how the pericardium appears adherent to the left ventricle (B) posteriorly, compared with the anterior pericardium (A). A surgical specimen showed that the pericardium was adherent to the left ventricle posteriorly
Real-time images will demonstrate ventricular interdependence owing to the dissociation of intracardiac and intrathoracic pressures seen in cases of CP. Assessment of hemodynamics and ventricular function is also feasible by tagged cine-MRI with the analysis of phase contrast sequences [7]. Regurgitant flow in the pulmonary veins and the superior and inferior venae cavae is typically seen (Fig. 10.3).
Fig. 10.3
Fiesta cine images through the inferior vena cava (a) and the right upper pulmonary vein (b) shows flow reversal (C), demonstrated by the turbulent flow. This reversal was confirmed on phase contrast imaging in this patient with surgically confirmed constrictive pericarditis
The diagnostic accuracy of MRI in identifying surgically confirmed constrictive pericarditis is excellent (Fig. 10.4) [4].
Fig. 10.4
Three-dimensional color-coded model from a cardiac MRA shows the enhancing thickened pericardium (arrow) circumferentially around the heart (LV salmon; RV purple; RA aqua; LA pink) in a patient with constrictive pericarditis
10.2.5 Ultrasonographic Findings
M-mode echocardiography shows characteristic changes from pericardial thickening and abnormal ventricular filling [4].
Increased pericardial thickness is suggested by parallel motion of the epicardium and the parietal pericardium, which are separated by a relatively echo-free space at least 1 mm thick [4].
A flat left ventricular (LV) posterior wall tracing represents absent LV filling in the last half of diastole. Rapid ventricular filling occurs early and stops abruptly.
Abrupt posterior motion of the ventricular septum may be seen in early diastole with inspiration (septal shudder and bounce), as well as (occasionally) premature opening of the pulmonary valve [4].
Two-dimensional (2D) echocardiography may show a thickened and double-lined pericardium with a flat interventricular septum [2].
Moderate biatrial enlargement can be seen, with mitral and tricuspid regurgitation, vena cava dilatation, and disproportionately small ventricles.
Abnormal flow patterns of the pulmonary vein, hepatic vein, and superior vena cava are also visible. There may be a sharp halt in ventricular diastolic filling, hypermobile atrioventricular (AV) valves, and abnormal contour between the posterior left ventricle and the posterior left atrium walls [4].
Pulsed Doppler usually shows a high velocity and deceleration rate of early right and left ventricular filling [4].
Mitral inflow velocity falls as much as 25–40 %, and tricuspid velocity greatly increases in the first beat after inspiration. The respiratory variation in pulmonary venous flow is even more pronounced [4].
Mitral valve E:A inflow velocity ratios may be increased—that is, the ratio of height of the early diastolic flow velocity peak (E) versus the height of the atrial diastolic flow velocity peak (A). These ratios are used as an indicator of ventricular diastolic function and should trend back to normal after pericardiectomy [3].
10.2.6 Cardiac Catheterization Findings
Cardiac catheterization may be required for definitive diagnosis in the presence of inadequate imaging evidence. In CP, it can demonstrate increased and nearly equalized atrial pulmonary capillary wedge pressure and ventricular end-diastolic pressures [3, 8].
An early diastolic dip in pressure followed by a plateau phase secondary to rapid early diastolic filling and subsequent restriction (also known as the “square root sign”) [8]
Rapid x and y descents in atrial and venous pressure tracings
A greater inspiratory decrease in pulmonary capillary wedge pressure compared with LV diastolic pressure [4]
Hemodynamic data meeting diagnostic criteria for CP [9, 10], which can differentiate CP from restrictive cardiomyopathy:
LV end-diastolic pressure does not exceed right ventricular (RV) end-diastolic pressure by more than 5 mmHg
RV end-systolic pressure does not exceed 50 mmHg
RV diastolic pressure is more than one third of RV systolic pressure
10.2.7 Imaging Recommendations
CT and MRI enable accurate measurements of pericardial thickness and ventricular function, but it is important to keep in mind that up to 20 % of patients with CP may present with normal-thickness pericardium [2, 11]. It is thus best to use a combination of CT/MRI and echocardiography to assess ventricular function and hemodynamics, and to determine the clinical significance of findings seen on CT/MRI. If a definitive diagnosis is not provided, cardiac catheterization can be used.
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