Best Imaging for Rib Fracture Evaluation
Start with a standard posteroanterior (PA) chest X-ray as the initial imaging test for all patients with suspected rib fracture, regardless of mechanism, because it identifies life-threatening complications (pneumothorax, hemothorax, pulmonary contusion, flail chest) that directly impact mortality and morbidity—not to detect every fracture. 1
Why Chest X-Ray First Despite Poor Fracture Detection
- Chest X-ray misses approximately 50% of rib fractures compared to CT, but this low detection rate does not alter patient management or outcomes in uncomplicated cases since isolated rib fractures are managed conservatively regardless of radiographic confirmation 1, 2
- The primary purpose of initial chest radiography is to detect critical complications that change management, not to definitively diagnose every fracture 1
- Never use a normal chest X-ray to exclude significant injury or rib fractures—fractures visible on radiography are associated with 3.8-fold increased pulmonary morbidity compared to CT-only detected fractures 1, 2
When to Escalate to CT Imaging
Order Contrast-Enhanced Chest CT When:
- High-energy mechanism (motor vehicle collision >35 mph, significant fall height) with clinical suspicion for intrathoracic or intra-abdominal injury 1
- Lower rib fractures (ribs 7-12) with multiple injuries—67% of these patients have associated abdominal organ injury even with normal physical examination 1
- First rib fractures, which warrant heightened suspicion for major vascular injury 1
- Hemodynamic instability, signs of ongoing blood loss, or widened mediastinum on chest X-ray 1
Order Non-Contrast Chest CT When:
- Multiple rib fractures requiring precise anatomic definition for management decisions (≥6 fractures, bilateral fractures, ≥3 severely displaced fractures) 1
- Abnormal chest radiograph in trauma setting without suspicion for vascular injury 1
Do NOT Order CT For:
- Low-energy injury with normal physical examination and stable vital signs 1
Point-of-Care Ultrasound as Alternative
- Ultrasound has 89.3% sensitivity and 98.4% specificity compared to CT for detecting rib fractures, significantly superior to chest X-ray's 40% sensitivity 3
- Ultrasound identifies 29% of fractures missed on initial chest X-ray and has a positive likelihood ratio of 55.7 for CT-diagnosed rib fracture 2, 3
- However, ultrasound is time-consuming, causes patient discomfort, and is unlikely to impact care in most cases—reserve for specific clinical scenarios where fracture confirmation would change management 1
Imaging Modalities to Avoid
- Never order dedicated rib radiography series—they provide no additional clinical benefit, prolong report turnaround time, miss fractures due to organ overlap or being outside imaging range, and negatively impact patient care 1, 4
- Nuclear medicine bone scan is not appropriate for acute trauma evaluation 1
High-Risk Features Requiring ICU Admission
- Age ≥65 years with multiple rib fractures 1
- Six or more fractured ribs, especially in elderly patients 1
- Three or more severely displaced fractures, bilateral fractures, or first rib fracture 1
Critical Pitfall to Avoid
The absence of rib fractures on imaging cannot rule out hepatic injury—right-sided lower rib fractures show no strong association with liver injury, and hepatic laceration can occur without fractures 1