Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 299
Fig. 3-51 Longitudinal sonograms of
the cranial abdomen of an 8-year-old
Labrador Retriever with a history of
ascites and lethargy of 10 days duration.
There is anechoic peritoneal
fluid. The liver is small, hyperechoic,
and irregular in contour (arrows).
The architecture of the liver is abnormal,
appearing uniformly granular.
This is indicative of chronic liver disease
with cirrhosis or fibrosis and
ascites. Diagnosis: Cirrhosis of the
liver. A cause was not determined.
Fig. 3-52 Longitudinal sonograms
of the liver of a 3-year-old spayed
female Great Dane with a history of
lethargy, anorexia, icterus, vomiting,
and melena. The architecture of the
liver is coarse with loss of the normal
portal vein echoes. This is indicative
of diffuse liver disease, which may be
due to chronic fibrosis or cirrhosis.
Diagnosis: Cirrhosis of the liver secondary
to toxin.
common for the echogenicity of the liver of fat cats to be higher, or brighter, than that of
the falciform fat. Blurring of vascular margins and increased attenuation of the ultrasound
beam were also observed. 271 In our experience the comparison of echogenicity
between the liver and falciform fat has not been as useful as the identification of blurring
of vascular margins. Hepatic lipidosis may rarely produce a focal rather than a diffuse
hyperechoic lesion (Fig. 3-53).
Focal changes in echogenicity may be poorly defined or well defined. Both solid and
cystic or cavitating lesions may be identified. These focal changes are also somewhat nonspecific
and may occur in association with lymphoma, primary or metastatic neoplasia,
abscesses, or nodular hyperplasia (Figs. 3-54 to 3-56). 265,266,269,272-286 Focal anechoic
lesions with well-defined walls and distal enhancement are most likely hepatic cysts. In
Persian cats there is an autosomal dominant disease that usually causes cysts in the kidneys,
but the liver may also be involved with cyst formations (Fig. 3-57). Although some tumors,
abscesses, and hematomas may appear anechoic, these lesions more often have internal
echoes, a less distinct or irregular wall, and do not show as much distinct posterior enhancement.
Hypoechoic lesions may be nodular hyperplasia, tumors, abscesses, or hematomas.
Hyperechoic lesions may be due to nodular hyperplasia; tumor; abscess; hematoma; foreign
body; parenchymal, vascular, or ductal gas; or focal or multifocal mineral deposition or
choleliths. The presence of shadowing or reverberation artifact is helpful in recognizing the
foreign body, gas, or mineral that produces these artifacts and facilitates distinguishing
them from nodular hyperplasia, tumors, abscesses, or hematomas, which usually do not
produce such artifacts. Examination of abdominal radiographs is extremely helpful in
determining if gas or mineral densities are present. Mineral densities that are not associated
with the gallbladder or bile ducts can be associated with granulomas, abscesses,
hematomas, or neoplasias. Air may be observed within a hepatic abscess or neoplasia.
Mixed hyperechoic and hypoechoic lesions are also nonspecific and may result from any of
the conditions discussed so far. Multifocal hyperechoic or hypoechoic lesions may be due