What are the contraindications for oral contrast in Computed Tomography (CT) abdomen scans?

From the Guidelines

Oral contrast for CT abdomen scans is contraindicated in patients with suspected high-grade small-bowel obstruction, as it does not add to diagnostic accuracy and can delay diagnosis, increase patient discomfort, and increase the risk of complications, particularly vomiting and aspiration. The use of oral contrast in CT abdomen scans has several contraindications, including:

• Suspected high-grade small-bowel obstruction, as the nonopacified fluid in the bowel provides adequate intrinsic contrast 1
• Bowel perforation, bowel obstruction, or active gastrointestinal bleeding, as oral contrast may worsen these conditions or delay necessary surgical intervention
• Dysphagia or impaired swallowing mechanisms, due to aspiration risk
• Severe allergic reactions to iodinated or barium contrast agents
• Inflammatory bowel conditions like active colitis, as oral contrast may worsen symptoms
• Emergency surgery, as oral contrast delays surgical intervention
• Pregnancy, especially in the first trimester, due to potential fetal risks
• Decreased level of consciousness or inability to follow instructions, due to increased aspiration risk
• Significant gastrointestinal motility disorders, as oral contrast may experience prolonged transit time and delayed imaging. The contraindications for oral contrast in CT abdomen scans are primarily based on the potential for oral contrast to worsen certain conditions, delay necessary treatment, or pose risks that outweigh diagnostic benefits in specific patient populations 1.

From the FDA Drug Label

PRECAUTIONS General Diagnostic procedures which involve the use of radiopaque contrast agents should be carried out under the direction of personnel with the prerequisite training and with a thorough knowledge of the particular procedure to be performed Cases of hyperthyroidism have been reported with the use of oral contrast media Administration of an intravascular iodinated radiopaque diagnostic agent to a hyperthyroid patient precipitated thyroid storm; a similar situation could follow administration of oral preparations of iodides Consideration should be given to the potential for precipitation of water-soluble contrast agents under conditions that may promote hyperacidity (i.e., fasting, emotional upset, or stress).

The contraindications for oral contrast in Computed Tomography (CT) abdomen scans include:

• Hyperthyroidism: as oral contrast media may precipitate thyroid storm
• Euthyroid goiterous patients: caution should be exercised when administering enteral gastrointestinal radiopaque agents
• Pregnancy: diatrizoate salts cross the placenta and are evenly distributed in fetal tissues 2
• Allergic to iodine: patients should inform the physician if allergic to iodine 2

Key considerations:

• Patients with multinodular goiters may be at risk of increased hormone synthesis in response to excess iodine
• Hyperacidity conditions (e.g. fasting, emotional upset, or stress) may promote precipitation of water-soluble contrast agents 2

From the Research

Contraindications for Oral Contrast in CT Abdomen Scans

• The use of oral contrast in CT abdomen scans has been a topic of discussion, with some studies suggesting its use may not be necessary in certain cases 3.
• However, there are certain contraindications to consider, such as:
  • Chronic kidney disease (CKD), as the use of contrast agents may increase the risk of contrast-induced nephropathy (CIN) 4, 5, 6.
  • Severe kidney function impairment, as the risk of CIN is increased in these patients 4, 6.
  • Diabetes, as the risk of CIN is also increased in diabetic patients 4.
• Other factors to consider when deciding whether to use oral contrast in CT abdomen scans include:
  • Patient throughput and preference 3.
  • Image quality and diagnostic confidence 7.
  • The type and volume of contrast agent used 4, 6.
• It is essential to weigh the benefits and risks of using oral contrast in each individual case, taking into account the patient's medical history and current condition 7, 3.