Should a CT scan with or without contrast be used to diagnose a pelvic fracture?

CT With Contrast is Required for Pelvic Fracture Evaluation

For diagnosing pelvic fractures in hemodynamically stable patients, CT of the abdomen and pelvis WITH intravenous contrast in the portal venous phase (70 seconds post-injection) is the standard of care and should be performed immediately. 1, 2

Why Contrast is Essential

Contrast-enhanced CT is mandatory because it serves dual critical purposes: detecting the fracture itself AND identifying life-threatening arterial bleeding that requires emergent intervention. The key outcomes that determine survival are:

• Active arterial hemorrhage detection: Contrast extravasation during arterial phase imaging identifies patients requiring emergent angioembolization, with sensitivity 82-100% and specificity 75-100% 1, 3, 4
• Mortality reduction: Time to bleeding control is the single most important factor—mortality increases 1% for every 3 minutes of delay, and jumps from 16% to 64% if embolization takes >60 minutes 1
• Vascular injury characterization: Contrast CT has 100% negative predictive value—if no extravasation is seen, the pelvis will NOT be a source of hemorrhagic shock 3

Technical Protocol

The American College of Radiology specifies portal venous phase imaging (70 seconds after IV contrast) as the standard protocol for optimal solid organ and vascular injury characterization. 1, 2

• Add arterial phase imaging when assessing for active arterial bleeding and pseudoaneurysm formation 2
• Avoid noncontrast CT as it has significantly lower sensitivity for detecting visceral organ and vascular injuries 1, 2
• Consider delayed phase imaging (when hemodynamically stable) to evaluate for urinary tract injuries, which occur in 3.5-19% of pelvic fractures 1, 2

Clinical Decision Algorithm

Hemodynamically Stable Patients

Proceed directly to CT abdomen/pelvis with IV contrast—do not delay. 1, 2

• CT provides 100% sensitivity and specificity for bone fractures 1
• Identifies contrast extravasation requiring angiography 1, 3
• Pelvic hematoma ≥500 cm³ suggests arterial injury even without visible contrast blush 1

Hemodynamically Unstable Patients

Perform portable AP pelvis X-ray and E-FAST first, then stabilize and proceed to CT with contrast. 1, 2

• Pelvic X-ray identifies life-threatening injuries requiring immediate external fixation but has only 50-68% sensitivity 1
• Once minimally stabilized, CT with contrast remains essential to guide angioembolization 1, 2

Critical Pitfalls to Avoid

Never perform noncontrast CT for pelvic trauma evaluation—this is a dangerous practice that misses active bleeding. 1, 2

• Noncontrast CT cannot detect arterial extravasation, which is the primary determinant of mortality 1
• The 100% negative predictive value of contrast-enhanced CT means you can confidently rule out pelvic hemorrhage as a shock source 3

Do not rely on pelvic X-ray alone in stable patients—it misses 32% of fractures and provides no information about active bleeding. 1

If gross hematuria or blood at urethral meatus is present, add CT cystography (retrograde bladder contrast instillation) as routine contrast excretion misses up to 22% of bladder injuries. 1

Additional Considerations

3D CT bone reconstruction should be obtained to guide surgical planning, particularly for sacral fractures and sacroiliac joint dislocations, with 93.8% successful screw positioning rates. 1

In patients with contrast extravasation on CT, angiography with embolization should be performed within 60 minutes of hospital admission to optimize survival. 1