Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

102 Small Animal Radiolo g y and Ultrasono graphy
Fig. 2-74 A transverse anterior thoracic
ultrasonogram was performed
on a 14-year-old neutered male
domestic long-haired cat suffering
from dyspnea. A solid mass (M) is
noted displacing the great vessels (v)
in the anterior mediastinum dorsally,
as well as a moderate volume of
pleural effusion (PE). Diagnosis:
Lymphoma.
Fig. 2-75 A 7-year-old German
Shepherd dog with anorexia, weight
loss, and hypercalcemia. Radiographs
revealed a moderate to severe
hydrothorax. A right parasternal
long-axis view revealed a mass (m)
immediately cranial to the heart base
(aorta [ao]). Hydrothorax (h) is also
present. Diagnosis: Lymphoma.
M E D I A S T I N A L F LU I D
Fluid, such as blood, edema, or exudate, may accumulate in the cranial, middle, and caudal
mediastinum with or without the presence of pleural fluid. 184-186 Detection is very difficult in
obese animals. This diagnosis should 0be considered in a thin animal with a widened cranial,
middle, or caudal mediastinum. Sonography can provide confirmation of this diagnosis.
Mediastinal density does not increase markedly as the mediastinum becomes filled
with fluid or replaced by a mass. The increased density can be detected only when the
mediastinum displaces the air-filled lung.