Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

224 Small Animal Radiolo g y and Ultrasono graphy
Fig. 2-208 A 6-year-old male cat with a 4-month history of
intermittent pyrexia and cough. On the lateral (A) and ventrodorsal
(B) radiographs there is a soft-tissue density in the
right caudal lung lobe. There are multiple air-containing cavities
within this soft-tissue density (arrows). The margins of the
soft-tissue density are well-defined. The radiographic findings
indicate a large cavitated mass. This may represent a pulmonary
abscess or a neoplasm. Diagnosis: Abscessed right caudal lung
lobe.
A
B
the evaluation. A decrease in lung perfusion may be focal or diffuse. A diffuse reduction in
lung perfusion is associated most often with right-to-left cardiac shunts such as
Eisenmenger’s complex; decreased pulmonary blood flow, or pulmonic stenosis; and
decreased circulating blood volume, or hypovolemia.
Focal reduction in pulmonary perfusion usually is due to pulmonary thrombosis.
Although associated radiographic changes are uncommon, radiographic signs occasionally
may be present. These signs include uneven vascular diameters, unequal-sized pulmonary
arteries when right and left lung lobes are compared, a small pulmonary vein when compared
with the adjacent pulmonary artery, absence of vascular shadows within a normalsized
lung lobe, and an enlarged central pulmonary artery with abrupt reduction in arterial
diameter (Fig. 2-211). 548-553 Right-sided cardiomegaly with or without main pulmonary
artery enlargement and pleural fluid may be present also.