Should I order a CT abdomen/pelvis with and without IV contrast, and how do I include a run‑off (non‑contrast) phase in the order?

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CT Abdomen/Pelvis Ordering for Suspected Bleeding or Acute Pathology

For suspected active bleeding (GI bleeding, trauma, or vascular injury), order CTA abdomen and pelvis WITHOUT AND WITH IV contrast—this includes a non-contrast phase followed by arterial phase imaging, which is what "run-off" typically refers to in this context. 1

Understanding the Protocol Components

Why "Without and With" Matters for Bleeding

The non-contrast phase (the "without" part) is essential for detecting:

  • Sentinel clot or high-attenuation blood that could be mistaken for contrast extravasation on enhanced images alone 1
  • Baseline attenuation of structures before contrast administration
  • Active hemorrhage detection with 92% sensitivity when combined with arterial phase imaging 1

The Society of Abdominal Radiology Gastrointestinal Bleeding Disease-Focused Panel reached 100% consensus that non-contrast images are mandatory for CTA performed on single-energy CT for overt bleeding 1. The multiphasic protocol (unenhanced + arterial + portal venous phase) achieves the highest sensitivity at 92% compared to 83% for single-phase protocols 1.

How to Order It

Specify on your order:

  • "CTA abdomen and pelvis without and with IV contrast"
  • Or: "Multiphasic CTA abdomen/pelvis for bleeding"
  • Include clinical indication: "suspected active GI bleeding" or "suspected vascular injury"

This automatically includes:

  1. Non-contrast phase (the "without")
  2. Arterial phase (early contrast, ~25-30 seconds post-injection)
  3. Portal venous or delayed phase (70-90 seconds post-injection) 1

When NOT to Use "Without and With"

Standard CT Abdomen/Pelvis (Non-CTA)

For most non-bleeding acute abdominal conditions, order CT abdomen/pelvis WITH IV contrast only (single portal venous phase). 2, 3

The addition of a non-contrast phase to routine CT:

  • Adds radiation exposure without diagnostic benefit in most cases 4
  • Delays diagnosis and increases ED throughput time 5
  • Is not supported by literature for routine abdominal pain evaluation 1, 6

Exception: When evaluating for kidney stones, order CT abdomen/pelvis WITHOUT IV contrast only—contrast obscures stone detection 6

Common Clinical Scenarios

Suspected GI Bleeding

  • Order: CTA abdomen/pelvis without and with IV contrast
  • Detects bleeding rates: as low as 0.3 mL/min 1
  • Avoid oral contrast: renders exam non-diagnostic by diluting blood 1

Acute Abdominal Pain (No Bleeding)

  • Order: CT abdomen/pelvis with IV contrast (single phase)
  • Non-contrast phase adds no value and increases radiation 2, 3
  • Recent data shows no difference in diagnostic uncertainty between contrast-enhanced and non-contrast CT (14.1% vs 13.9%, p=0.96) 3

Penetrating Trauma

  • Order: CTA abdomen/pelvis with IV contrast (arterial phase)
  • Non-contrast phase typically not needed 4
  • Exception: If evaluating trajectory or foreign bodies, consider adding non-contrast phase

Suspected Intramural Bowel Hemorrhage

  • Order: CT abdomen/pelvis without AND with IV contrast
  • Non-contrast phase shows hyperattenuation of hemorrhagic bowel wall that becomes isodense after contrast 7

Critical Pitfalls to Avoid

  1. Don't order "without and with" for routine abdominal pain—you're doubling radiation for no diagnostic gain 6, 2

  2. Don't give oral contrast for suspected bleeding—it masks intraluminal hemorrhage and delays care 1

  3. Don't confuse "CTA" with "CT with contrast"—CTA specifically refers to arterial phase timing optimized for vascular imaging 1

  4. Don't order non-contrast CT alone for suspected bleeding—you'll miss active extravasation that requires intervention 1

  5. For stone disease, never add IV contrast—it decreases sensitivity from 97% to 81% for small stones 6

The "Run-Off" Term

In vascular imaging, "run-off" traditionally refers to lower extremity arterial imaging extending from aorta to feet. In abdominal imaging, when clinicians say "run-off," they typically mean:

  • Delayed phase imaging (portal venous or later) to assess for continued contrast extravasation
  • This is automatically included when you order "CTA without and with IV contrast" 1

Bottom line: The standard multiphasic CTA protocol already includes what you need—just specify "without and with IV contrast" and the indication for bleeding.

References

2
Guideline

acr appropriateness criteria<sup>®</sup> acute nonlocalized abdominal pain.

Journal of the American College of Radiology, 2018

4
Guideline

acr appropriateness criteria® penetrating torso trauma.

Journal of the American College of Radiology, 2024

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.