Radiologic Signs of Pericardial Effusion

Abstract

Many radiologic signs of pericardial effusion have been described. Except for the angiccardiographic signs, all of them fail often enough to leave the radiologist unsure of their value in any particular case. None of them, short of angiocardiography, is based on definite knowledge of the localization of the pericardial fluid, but rather on the total behavior of the central mediastinal shadow. The study to be reported here was designed to indicate: 1. Where in the pericardial sac effusion collects. 2. How it redistributes itself with change in bodily position. 3. Whether damping of pulsations in specific segments along the edge of the central mediastinal shadow can be related to the presence of pericardial effusion. Material and Methods Opaque pericardial effusions in dogs were produced in the following way. A thora-cotomy was performed under Pentothal anesthesia. Through a small slit in the pericardium, a polyethylene catheter was inserted into the pericardial cavity; 40–50 c.c. of 70 per cent Diodrast was slowly injected, the catheter was removed, and the pericardial opening was closed by a loop suture. A chest tube was inserted and the chest was closed. After it was seen that the lungs were well expanded and the pericardial closure did not leak, the chest tube was removed. The pericardial fluid increased in amount as the hypertonic contrast medium drew fluid into the cavity. The dogs were examined fluoroscopically in the recumbent and erect positions and in the four decubitus positions. The esophagus was outlined by a barium swallow. The distribution of the fluid and the presence or absence of pulsations along the pericardial borders were noted. The distribution of the opaque effusion was demonstrated on radiographs, and the nature of the pulsations was recorded on roentgen kymograms. Finally cineradiographs using the image intensifier were made. Results The opacified pericardial effusion appeared as a dense mantle about the heart when the dog was in the prone or supine projection (Fig. 1). There was no pulsation of any portion of the pericardial border, although the heart had the appearance of a vigorously pulsating polyp within the pericardial sac. In the lateral recumbent position most of the opaque effusion pooled anterior and anterosuperior to the heart, while a small amount appeared inferior to the heart; there was none behind the heart (Fig. 2). The superior sternopericardial ligament and the inferior sternopericardial or xipho-pericardial ligament were frequently discernible (Figs. 2 and 3). As seen from the side, the distribution of fluid when the dog was held erect was similar to that seen in the recumbent position, except that, if anything, more fluid collected anterior to the heart (Fig. 4). Lateral views of the prone (Fig. 5) and supine (Fig. 6) animal showed the same distribution of opaque fluid as in the other positions.