Page 364 - Feline diagnostic imaging

372 22 Gastrointestinal Disease

(a) (b)

(c) (d)

Figure 22.27 Intestinal perforation. An 11-year-old domestic longhair presented with a three-day history of constipation and
swelling in the perineal region. A diverticulum or perineal hernia (P) was suspected. (a) On the left lateral projection, there was an
ill-defined area of gas and soft tissue opacity (arrow) associated with the colon in the caudal pelvic cavity. A large amount of
fecaloid material was present in the rectal area and in the soft tissues caudal to the caudal vertebrae. (b) Right lateral projection.
(c) Ventrodorsal projection. (d) Ultrasound images showed gas (arrow) that did not appear to be associated with the colon (C).

22.4.8 Perforation of the Gastrointestinal Tract because of increased subject contrast between soft tissue and
gas compared to that seen between soft tissue and normally
Perforation can result in fluid and/or gas being visible in the surrounding fat. Gas shapes appear sharp‐edged and have
peritoneal cavity (Figure 22.27) [51]. On radiographs, free geometric shapes such as a triangle rather than the rounded
fluid causes a loss of serosal detail, which ranges from shapes (ovals, circles) seen with intraluminal gas. Air–fluid
serosal surfaces appearing indistinct to a complete loss of interface can be seen if the abdomen is exposed with a hori-
detail. Free gas is most obvious when it accumulates between zontal beam and both air and fluid are present. Small bub-
the liver and diaphragm, causing the liver and diaphragm to bles may be trapped in the mesentery, spleen, or other
be seen as separate entities. Where gas is present, serosal sur- tissues. On ultrasonography, fluid resulting from perforation
faces may appear brighter and more distinct than usual appears cellular. Free gas results in reverberation artifact.