Page 355 - Feline diagnostic imaging

22.4 Small ntestinal Disorders 363
22.4.3 Inflammatory Changes nonsteroidal antiinflammatory drugs. The lesion is not
usually appreciated on survey radiography, especially if
Chronic enteritis can have numerous causes but after par- the animal is emaciated. A pocket or crater might be seen
asites and infectious causes have been excluded, consid- in the intestinal wall when an upper GI series is per-
eration should be given to feline inflammatory bowel formed. Asymmetry and rigidity help differentiate true
disease (IBD) or food‐responsive enteropathy. A clinical ulcers from Peyer’s patches.
index has been proposed that can help differentiate the The sonographic appearance of mucosal fibrosis was
two conditions [32]. There are minimal radiographic reported in 11 cats that had full‐thickness intestinal biopsies
signs associated with mild inflammatory disease without [37]. A hyperechoic band was seen in the mucosa running
ulceration. Survey radiography is usually unremarkable parallel to the hyperechoic submucosa. Wall layering was
and the amount of gas is variable. Transit time may be present but altered as indicated by thickening of the muscu-
shorter when an upper GI series is performed. The laris and/or submucosa and increased echogenicity of the
mucosal surface may be mildly irregular. Barium may mucosa. All cats had signs related to the GI tract. Similar
layer on the bowel wall if a lot of mucus is present. The clinical signs were present in an additional 24/35 cats that
width of the lumen may be decreased. On ultrasonogra- had this mucosal change noted on ultrasonography.
phy (Figure 22.16), the intestinal wall may be symmetri-
cally thickened but thickening of the muscularis propria
in older cats is more suggestive of lymphoma than IBD 22.4.4 Infiltrative Disease and Masses
[33]. Wall layering may be altered. There may be increased
or decreased echogenicity (hemorrhage, edema) or a Infiltrative diseases and masses include neoplasia, GI
change in relative layer thickness. In severe cases, a loss eosinophilic sclerosing fibroplasia [19,38,39], granuloma-
of wall layering is seen but this usually affects a focal tous disease [14], parafungal diseases like pythiosis [40],
area of bowel and less severe change is visualized else- mycosis, and plasmacytic‐lymphocytic enteritis. Biopsy is
where. Hyperechoic mucosal speckles have been reported. necessary for differentiation of these diseases.
Associated lymphangectasia can appear as hyperechoic
lines perpendicular to the long axis of the lumen. 22.4.4.1 Neoplasia
Lymphocytic, eosinophilic, and plasmacytic infil- The most common neoplasms affecting the feline
trates may be obtained from fine needle aspiration. intestine are lymphoma (Figure 22.18), adenocarcinoma
Some cats may have coexisting pancreatic change (Figure 22.19), mast cell tumor (Figure 22.20), and gastro-
(decreased echogenicity, peripancreatic increased echo- intestinal stromal tumors (GIST) (Figure 22.21) [17,41–44].
genicity, hypoechoic regions, hypoechoic, or mixed Lymphoma in cats causes wall thickening which may or
echogenicity nodules, cystic structures) on ultrasonog- may not be concentric whereas adenocarcinoma typically
raphy and elevated feline pancreatic lipase immunore - causes concentric wall thickening resulting in decreased
activity (fPLI) [32,34]. Not uncommonly, elevated fPLI lumen size and sometimes partial or complete obstruction.
is present without visible sonographic evidence of pan- Mast cell tumors can occur in the small intestine but in
creatitis [34]. other organs like the spleen, they may be associated with
Although corrugation can be associated with enteritis or ulceration of the small intestine. More than one type of
pancreatitis, other causes should be considered. Corrugation neoplasia can be present.
of the small intestine without wall thickening was reported Unless obstruction occurs or there is a focal mass, neo-
in six cats [35]. Four had changes in the pancreas and plasia may not be visible on survey radiography. In a study
two had free abdominal fluid. In the same report, pancrea- of 18 cats with intestinal adenocarcinoma [42], 12 had
titis, abdominal effusion, neoplasia, enteritis, and bowel abnormalities on survey radiography including a mass
ischemia were described in 18 dogs. effect, dilated intestinal loops, and loss of serosal detail.
Feline infectious peritonitis (FIP) can cause ultrasono- Five cats had thoracic radiography that revealed evidence
graphic changes in the intestine although enlargement of of metastatic disease in two.
the kidneys or lymph nodes, a hypoechoic perirenal region, Roentgen signs in an upper GI series include dilated
and abdominal effusion are more commonly seen bowel proximal to the affected area, a mass effect with
(Figure 22.17). In one series of cats diagnosed with FIP, two displacement of other parts of the gastrointestinal tract,
cats had thickening of the small intestinal wall and there and narrowing of the affected intestine. Affected bowel
was loss of wall layering in the colon of a third cat [36]. may exhibit a narrowed lumen and an irregular mucosa
Ulcers may be associated with neoplasms, granuloma- resulting in apple core‐like lesions. There may be sharp
tous disease, parasites, uremia, and administration of points or spicules in the contrast column. The bowel