When is a CT (Computed Tomography) scan of the chest, abdomen, and pelvis indicated?

Indications for CT Chest, Abdomen, and Pelvis in Trauma

CT chest, abdomen, and pelvis with IV contrast is indicated for hemodynamically stable trauma patients with high-energy mechanisms of injury, including high-velocity MVCs (>35 mph), rollover accidents, ejection from vehicle, motorcycle crashes, pedestrian-vehicle collisions, falls from >15 feet, or abnormal initial trauma radiographs. 1

Blunt Trauma Indications

High-Risk Mechanisms

• High-velocity motor vehicle collisions (>35 mph)
• Vehicle rollover
• Ejection from vehicle
• Motorcycle crashes
• Bicycle injuries with significant impact
• Pedestrian struck by vehicle
• Falls from heights >15 feet

Clinical Factors

• Abnormal chest or pelvic radiographs
• Positive FAST exam
• Hemodynamic stability (prerequisite for CT)
• Altered mental status limiting reliable physical examination
• Concerning physical findings (abdominal tenderness, seat belt sign, flank ecchymosis)

Specific Organ System Concerns

• Suspected solid organ injury (liver, spleen, kidney)
• Suspected vascular injury
• Suspected bowel or mesenteric injury
• Suspected diaphragmatic injury
• Suspected urinary tract injury

Penetrating Trauma Considerations

For penetrating torso trauma, CT with IV contrast helps determine:

• Wound trajectory
• Extent of organ involvement
• Vascular injuries
• Need for surgical intervention 1

CT Protocol Recommendations

Contrast Administration

• IV contrast is strongly preferred over non-contrast CT
• Portal venous phase (70 seconds after contrast) is optimal for solid organ injury assessment 1
• Arterial phase may be added when vascular injury is suspected
• Oral contrast is NOT recommended as it delays diagnosis without improving sensitivity 1

Technical Considerations

• Multidetector CT with thin slices allows for multiplanar reconstructions
• Radiodense markers should mark external wounds in penetrating trauma
• Consider delayed images when urinary tract injury is suspected

Limitations and Caveats

• CT should not delay resuscitation in unstable patients
• Hemodynamically unstable patients should undergo immediate surgical exploration rather than CT
• Initial negative FAST does not exclude significant injury; CT remains indicated with concerning mechanism 1
• CT has limited sensitivity for certain injuries (pancreatic, bowel, diaphragmatic)
• Radiation exposure is a consideration but should not prevent necessary imaging in trauma
• Contrast allergies may require premedication if time permits, but rarely contraindicate emergent CT

Alternative Imaging Approaches

• Initial trauma radiographs (chest, pelvis) help identify immediate life-threatening conditions but have low sensitivity compared to CT 1
• FAST exam is useful for triage but has lower specificity than CT and cannot reliably exclude solid organ or retroperitoneal injuries 1
• MRI is generally not appropriate for initial trauma evaluation due to time constraints 1

CT of the chest, abdomen, and pelvis with IV contrast remains the gold standard for comprehensive evaluation of stable trauma patients with concerning mechanisms or clinical findings, with high sensitivity for detecting clinically significant injuries that impact patient management and outcomes.