Should a chest computed tomography (CT) scan be performed with contrast in a patient with sudden onset rib pain after a fall, with unknown age and medical history, including unknown renal function and potential allergy to contrast agents?

Chest CT for Rib Pain After Fall: Contrast Decision

For a patient with sudden onset rib pain after a fall, order chest CT WITHOUT contrast if CT is clinically indicated, as the primary goal is detecting rib fractures and associated complications (pneumothorax, hemothorax, pulmonary contusion), none of which require intravenous contrast for diagnosis. 1

Initial Imaging Approach

• Start with a standard chest X-ray (posteroanterior view) as the first-line imaging modality for suspected rib fractures, as it detects life-threatening complications including pneumothorax, hemothorax, and pulmonary contusion that directly impact morbidity and mortality 2

• Chest X-ray misses approximately 50% of rib fractures, but this does not alter patient management or outcomes in uncomplicated cases 2, 3

• Any rib fracture or pulmonary contusion visible on initial chest X-ray significantly increases the incidence of pulmonary morbidity (odds ratio 3.8), making it a better predictor of subsequent complications than CT-detected fractures alone 3

When CT Without Contrast Is Appropriate

Noncontrast chest CT should be reserved for specific clinical scenarios:

• High-energy mechanism of injury with clinical suspicion for intrathoracic injury 2

• Multiple rib fractures requiring precise anatomic definition for management decisions 1

• Lower rib fractures (ribs 7-12) with concern for abdominal organ injury, though this would typically require contrast-enhanced imaging of the abdomen/pelvis rather than chest 2

• Abnormal chest radiograph in the setting of trauma, which has clinically significant rates of major injury on CT 1

CT detects rib fractures with much higher sensitivity than chest X-ray (detecting 65% versus 25% in some studies), but noncontrast technique is sufficient for fracture detection 1, 3

When Contrast IS Required

Intravenous contrast for chest CT is specifically reserved for:

• Clinical suspicion of intrathoracic vascular injury (aortic injury, major vessel disruption) 1

• Suspected solid organ injury requiring vascular phase imaging 1

• High-velocity mechanism suggesting possible vascular trauma (>35 mph motor vehicle collision, significant fall height) 1

The ACR explicitly states that CT chest with IV contrast is reserved for children with clinical suspicion of intrathoracic traumatic injury, with contrast allowing detection of vascular injuries 1—this same principle applies to adults 1

Critical Clinical Decision Points

For simple fall-related rib pain without high-energy mechanism:

• If chest X-ray is normal and patient is hemodynamically stable with no respiratory distress, CT is often unnecessary 1, 2

• If CT is obtained for radiographically occult fractures in elderly patients, noncontrast technique is appropriate as these fractures do not require contrast for detection 4

• Radiographically occult rib fractures (CT-positive, X-ray-negative) in elderly fall patients show no difference in ICU admission, hospital length of stay, or mortality compared to those without fractures 4

Red flags requiring contrast-enhanced imaging:

• First rib fracture (warrants heightened suspicion for major vascular injury) 2

• Multiple bilateral fractures suggesting high-energy trauma 1

• Hemodynamic instability or signs of ongoing blood loss 1

• Widened mediastinum on chest X-ray 1

Common Pitfalls to Avoid

• Do not routinely order contrast for simple rib fracture evaluation—noncontrast CT detects most injuries including rib fractures, pneumothorax, hemothorax, and pulmonary contusion 1

• Contrast-enhanced CT has lower sensitivity for detecting vascular injuries only when compared to dedicated CTA with arterial phase timing 1

• Unknown renal function is a relative contraindication to contrast administration; obtain basic metabolic panel before contrast if renal function is unknown 5

• Allergy history must be clarified—true contrast allergy requires premedication protocols or avoidance; shellfish allergy is NOT a contraindication to iodinated contrast 5

Age-Specific Considerations

For elderly patients (≥65 years):

• Age ≥65 with multiple rib fractures has significantly higher morbidity and mortality due to poor cardiopulmonary reserve 2

• Six or more fractured ribs, especially in elderly patients, require ICU admission 2

• Lower threshold for admission, but noncontrast CT remains appropriate for fracture detection unless vascular injury is suspected 2, 4