In a patient with persistent severe abdominal pain, ongoing nausea and vomiting, and no improvement after the initial work‑up, should the repeat abdominal CT be performed with intravenous (and oral) contrast or without contrast?

Repeat Abdominal CT Should Be Performed WITH Intravenous Contrast

For a patient with persistent severe abdominal pain and ongoing nausea/vomiting after initial work-up, the repeat abdominal CT should be performed with intravenous contrast, and oral contrast should be omitted. 1

Rationale for IV Contrast

The American College of Radiology strongly recommends IV contrast for suspected inflammatory conditions in the setting of persistent abdominal pain, as it:

• Increases detection of urgent pathology and directly changes diagnosis in 49% of cases 1
• Alters surgical management plans in 25% of patients 1
• Provides essential assessment of bowel wall enhancement abnormalities that indicate ischemia or strangulation—critical complications that can develop in patients with persistent symptoms 2
• Enables visualization of mucosal hyperenhancement, submucosal edema, and nodular wall thickening that are significantly less sensitive without IV contrast 1

In the context of persistent symptoms despite initial evaluation, IV contrast is particularly crucial because:

• Mesenteric ischemia requires IV contrast for detection, with reduced segmental bowel-wall enhancement being 100% specific for segmental bowel infarction 2
• Inflammatory processes including appendicitis, diverticulitis, and Crohn's disease require mural enhancement assessment, which is only possible with IV contrast 2, 1
• Abscess formation and other complications are detected with 100-280% increased sensitivity when IV contrast is used 1

Rationale for Omitting Oral Contrast

Oral contrast should be avoided in this clinical scenario for several important reasons:

• The American College of Radiology recommends avoiding oral contrast for acute nonlocalized abdominal pain, as IV contrast alone is sufficient 1
• Oral contrast delays scan acquisition and departmental throughput without providing diagnostic advantage in most cases of acute abdominal pain 2
• In acutely ill patients with ongoing nausea and vomiting, large volumes of oral contrast are poorly tolerated and may worsen symptoms 2, 1
• Modern multiplanar CT reconstructions provide excellent diagnostic confidence without oral contrast 2
• Research demonstrates that oral contrast is noncontributory to radiological diagnosis in 96.6% of patients with acute abdominal pain 3

The only exception would be if there is specific suspicion for bowel obstruction with need to identify a transition point, but this should be evident from the initial work-up 1.

Clinical Algorithm for Repeat CT

1. Default protocol: IV contrast-enhanced CT abdomen/pelvis without oral contrast 1
2. Scan both abdomen AND pelvis to capture the full extent of potential pathology 4
3. Use multiplanar reconstructions to increase accuracy in detecting transition zones and complications 4
4. Ensure adequate hydration before contrast administration if renal function permits 1

Critical Contraindications to Consider

Before ordering IV contrast, verify:

• Severe renal impairment is absent (known contraindication to IV contrast) 1
• No severe contrast allergy history 1
• If either contraindication exists and clinical suspicion for serious pathology remains high, proceed directly to diagnostic laparoscopy rather than relying on non-contrast imaging 4

Common Pitfalls to Avoid

• Do not order CT without IV contrast in this setting—it will miss critical vascular complications like ischemia and significantly reduce detection of inflammatory pathology 2, 1
• Do not delay imaging by insisting on oral contrast administration in a patient who is actively vomiting 2, 1
• Do not assume a negative initial CT rules out all pathology—repeat CT has a 5.9% diagnostic yield even after multiple negative studies, particularly when leukocytosis is present 2
• Maintain low threshold for surgical consultation if symptoms persist despite negative imaging, as clinical examination can be unreliable and imaging has limitations 4