Page 527 - Clinical Small Animal Internal Medicine

48 Gastrointestinal Imaging 495

(a) (b)
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(c) (d) (e)

Figure 48.27 Jejunojejunal intussusception. Lateral (a) and ventrodorsal (b) radiographs of a thin dog. A reduced serosal detail is present.
Gas‐dilated loops of small intestine are noted in the cranial abdomen. In the caudal abdomen, a soft tissue attenuating mass effect with
very small, irregular shaped loops of small intestine is noted. Transverse (c,d) ultrasound images revealed a series of hypoechoic and
hyperechoic concentric rings with a small amount of central fluid and gas consistent with an intussusception. Additionally, in one
segment of jejunum, hyperechoic distal shadowing material (e) consistent with foreign material is present.

Ultrasound may reveal a series of hyperechoic and studies, circumferential narrowing of the lumen of the
hypoechoic concentric rings with a central hyperechoic small intestine might be present.
area on transverse images (“target” or “onion ring” sign). Ultrasonographic findings in intestinal tumors vary
On longitudinal ultrasound images, a similar pattern of widely and include focal or diffuse intestinal wall thick­
hyperechoic and hypoechoic lines may be noted, in addi­ ening, loss of normal wall layering, increased thickness
tion to circumferential inward folding of the intestinal of the wall layers, altered echogenicity (Figure 48.28),
wall at the site of the intussusception. and loss of peristalsis. However, minimal sonographic or
no sonographic changes of the intestinal wall have also
Tumors of the Small Intestine been noted in lymphoma. Involvement of regional lymph
Intestinal tumors account for approximately 3–10% of nodes may be present, characterized by increased size,
the tumors in cats and dogs. Approximately 75% of feline altered shape, and echogenicity. These observations may
intestinal tumors are caused by lymphoma, compared increase the suspicion for intestinal neoplasia, and help
to approximately 30% of intestinal tumors in the dog. stage disease.
In dogs, adenocarcinoma, lymphoma, and tumors of
smooth muscle origin are most frequently seen. Intestinal Adhesions
If the intestinal neoplasm is small in size and does not There is limited information about the imaging of adhe­
cause obstructive disease, abdominal radiographs are sions in veterinary patients. If intestinal adhesions lead
often normal. If the intestinal mass is large or causes to mechanical ileus, dilated loops of small intestine may
obstructive disease, radiographic signs consistent with be noted. Radiographically, stacking of loops of small
mechanical ileus are noted. On contrast radiographic intestine, which do not change position with repositioning