CT Chest/Abdomen/Pelvis Protocol Recommendations
The recommended protocol for a CT Chest/Abdomen/Pelvis (CT C/A/P) scan is a single-pass venous phase acquisition with IV contrast administration.
Optimal CT C/A/P Protocol
IV Contrast Administration
- Contrast type: Non-ionic iodinated contrast media (e.g., iohexol, ioversol) 1
- Volume: 100-150 mL (standard adult dose) 1
- Timing: Portal venous phase imaging at approximately 70 seconds post-injection 1
Acquisition Parameters
- Patient positioning: Supine with arms above head (if possible) 1
- Breathing instructions: Hold breath during acquisition 1
- Oral contrast: Generally not required for routine venous phase imaging 1
- Consider only when specific bowel delineation is needed
Evidence Supporting Single-Pass Venous Phase Protocol
The American College of Radiology guidelines strongly support a single-phase examination with IV contrast administered in the portal venous phase (typically acquired 70 seconds after contrast administration) for CT C/A/P studies 1. This approach provides several advantages:
- Diagnostic accuracy: A single-pass venous phase CT C/A/P protocol offers improved thoracic assessment with no loss of abdominal diagnostic confidence 2
- Radiation reduction: Significant dose reductions compared to traditional multi-phase protocols 2
- Efficiency: Streamlined workflow and reduced scan time 2
Recent research has demonstrated that replacing traditional protocol CT (arterial chest and venous abdomen/pelvis) with a single-pass venous phase CT C/A/P protocol provides equivalent or superior diagnostic information in oncology patients 2.
Clinical Applications and Considerations
Cancer Detection and Staging
- CT C/A/P with IV contrast is the preferred modality for comprehensive cancer staging 3
- For suspected recurrence of small-cell lung cancer, CT chest, abdomen, and pelvis with IV contrast is recommended 3
Sepsis Evaluation
- For patients with suspected sepsis with no specific symptoms suggestive of origin, CT abdomen and pelvis with IV contrast is usually appropriate after normal or equivocal chest radiography 3
Special Considerations
- Renal function: For patients with eGFR < 30 mL/min/1.73m², consider non-contrast CT, alternative imaging modalities, or nephrology consultation 1
- Contrast reactions: Check for history of severe contrast reactions before administration 1
Common Pitfalls to Avoid
Inappropriate timing: Scanning too early may result in suboptimal venous enhancement, while excessive delay reduces vessel opacification 1
Unnecessary multiphase imaging: The American College of Radiology suggests that unnecessary multiphase imaging would not appreciably add to the contrast-enhanced CT evaluation in most cases 1
Overlooking contraindications: Always check for history of severe contrast reactions 1
Inadequate patient preparation: Ensure proper positioning and breathing instructions for optimal image quality 1
Overuse of oral contrast: Modern CT technology often eliminates the need for routine oral contrast administration 1
By following this evidence-based protocol for CT C/A/P studies, clinicians can achieve optimal diagnostic accuracy while minimizing radiation exposure and improving workflow efficiency.