The lateral chest radiograph in the detection of pericardial effusion: a reevaluation

The purpose of this study was to evaluate the usefulness of 10 previously published plain film signs for diagnosing pericardial effusion and to determine whether the posteroanterior (PA) or lateral chest radiograph was the better view for detecting pericardial effusion. A retrospective study of 100 consecutive adult patients with pericardial effusions confirmed by echocardiography and/or computed tomography was undertaken. Five signs were found to be useful in detecting pericardial effusion on plain films, and the lateral chest radiograph was found to be better than the PA view in detecting pericardial effusion. The water-bottle configuration, widening of the carinal angle, and the differential-density sign were helpful in diagnosing pericardial effusion on the PA view. However, these signs were only seen in moderate-to-large effusions. The displaced epicardial fat pad sign and the posteroinferior bulge sign on the lateral view improved the detection of moderate-to-large pericardial effusions, and were also present in many of the cases with small pericardial effusions. Recognition of specific signs of pericardial effusion on the lateral chest radiograph may significantly improve the plain film detection of pericardial effusion.