Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 89
A
B
C
Fig. 2-62 A 2-year-old female cat was brought in with a history of dyspnea and muffled heart
sounds. Lateral (A), ventrodorsal (B), (C) thoracic radiographs were obtained. In the ventrodorsal
radiograph, the margins of the lung lobes are visible (open arrows), outlined by a fluid density that separates
them from the lateral thoracic wall and outlines the interlobar fissures. The cardiac silhouette is
obscured. In the lateral radiograph, the diaphragmatic margins are obscured on the thoracic side—the
fat in the abdomen identifies the abdominal side of the diaphragm (closed arrows). The radiographic
changes are indicative of pleural fluid. Because the cranial mediastinum could not be evaluated on the
ventrodorsal radiograph, an erect ventrodorsal radiograph was obtained using a horizontally directed
x-ray beam. The lung lobes moved into the cranial thorax with gravitation of the pleural fluid caudally.
This radiographic finding indicates that an anterior mediastinal mass was not present. Diagnosis:
Pleural fluid. A thoracocentesis was performed and pyothorax was diagnosed.