Page 327 - Feline diagnostic imaging

21.2 Contrast adiography 335

(a) (b)

(c) (d)

Figure 21.2 Normal radiographs of the feline gastrointestinal tract. (a) Lateral projection showing a normal empty stomach. Black
curved line indicates the cranial aspect of the colon. (b) Lateral projection showing gas and ingesta in a normal full stomach.
(c) Ventrodorsal projection of the abdomen of the cat shown in (a). Arrowheads indicate the greater curvature of the stomach.
(d) Ventrodorsal projection of the abdomen of the cat shown in (b). C, colon; L, liver; S, spleen; St, stomach.

If iodinated contrast is being used and there is a possibil- although iohexol caused more edema than 3% Gastrografin
ity that aspiration will occur, only low osmolar nonionic or saline [7]. The nonionic isoosmolar dimer iotrolan cur-
contrast agents should be used [6]. Because of the hyperos- rently may be the safest iodinated product in cases where
molarity of ionic contrast agents, aspiration can result in aspiration may occur [8–10]. Hyperosmolar contrast agents
fluid moving into the lungs and subsequent pulmonary should also be avoided in dehydrated animals because
edema. In addition to using a nonionic product, ensure hypertonicity can lead to dehydration or hypovolemic
that the nonionic contrast agent has an osmolarity similar shock. Animals that are vomiting or that have diarrhea
to that of blood. In a study on rats, intratracheal injection should be rehydrated prior to administration of these
of full‐strength Gastrografin® resulted in severe and agents. The main reason why iodinated contrast agents are
fatal pulmonary edema while similar injection of 3% not routinely used is that they have poorer coating of the
Gastrografin, saline, and iohexol did not cause death, mucosa than barium.