Radiography: barium series

• Administration of positive contrast agent to provide information about the lumen of the gastrointestinal tract and to give crude assessment of gastrointestinal transit time.
• Visualisation of mucosal surfaces of gastrointestinal tract.
• Allows assessment of gastrointestinal wall thickness.

Uses

• Identification of position of gastrointestinal tract if not visible on plain radiographs, eg in suspect diaphragmatic hernia Diaphragm: traumatic hernia , ascites.
• Allows some assessment of gastrointestinal transit time.
• Identification of radiolucent gastrointestinal foreign bodies Intestine: linear foreign bodies.
• Investigation of:
  • Vomiting Vomiting.
  • Abdominal mass Abdominal organomegaly.
  • Abdominal pain.
  • Melena.
  • Weight loss.

Advantages

• Simple.
• Relatively non-invasive.

Disadvantages

• Time-consuming and moderately expensive, ( cost may be comparable to exploratory laparotomy).
• May give minimal information if total gastrointestinal obstruction as barium may not reach the site of obstruction.
• Often normal in cases of chronic diarrhea.
• Does not provide information about large intestine (a barium enema Radiography: large intestine contrast or pneumocolon is required).

Technical problems

• Requires considerable experience and knowledge of normal appearance of study to interpret films.

Alternative techniques

• Fluoroscopy (provides more information about motility).
• Ultrasonography (may give more accurate assessment of intestinal wall).
• Endoscopy.
• Radiopaque markers (BIPs) - require fewer radiographs to provide information on gastric emptying and GI motility, but does not give anatomic or morphologic information.
• Scintigraphy (provides more information on gastrointestinal function and can assess solid and liquid phase gastric emptying. May also be useful in identifying site of GI bleeding).

Time required

Preparation

• 20 min.

Procedure

• Up to 24 hours depending on results.

Decision taking

Criteria for choosing test

• Is the examination appropriate?
• Can you make the diagnosis without it?
• Will your management of the case be affected by the outcome of the examination?

Risk assessment

• Is animal sufficiently stable to tolerate prolonged procedure before diagnosis.
  If laparotomy is anticipated may be prudent to perform endoscopy/laparotomy instead.
• Assess hydration of animal prior to study.
• If suspect gastrointestinal tract rupture it is theoretically safer to use a water-soluble contrast agent.
• However gastrointestinal tract rupture will require surgery and abdominal lavage so leakage of barium is of minor importance.
  Iodine-based contrast agents may exacerbate hypovolemia and tend to get diluted as they pass through gastrointestinal tract, producing increasingly poor contrast. They may readily pass through partial obstruction and therefore hide diagnosis.