Cardiac magnetic resonance imaging:
Periodic changes of the cardiac chambers and ventricular walls were
visualized and interpreted by an experienced observer blinded to
echocardiographic findings and clinical information. The imaging was
performed in the supine position on all subjects using a 1.5 T (Magnetom
Symphony) or a 3 T (Magnetom Trio, both from Siemens Medical Solutions,
Erlangen, Germany) whole-body clinical MRI system. All images were
tracked for end-systolic and end-diastolic endocardial contours.
Modified Simpson’s rule was used to determine RV volumes. Three
electrodes positioned on the left anterior hemithorax and cardiac
synchronization was acquired. Commercially accessible (Argus version
4.01, Syngo MR B 13, Siemens Medical Solutions, Erlangen, Germany)
software accomplished an evaluation of images. A mid-ventricular axial
view, a cine breath-hold vertical long axis, and a cine breath-hold
horizontal long axis established cardiac short axis. During short
end-expiratory breath-holds, the ventricles were imaged in 8 mm
increments using adjacent short-axis slices from the base to apex while
the basal short-axis slice was placed beyond the mitral valve plane.
Long axis views verified the short-axis acquisitions for comprehensive
coverage of ventricles.