What is the initial imaging modality for suspected rib or sternum (sternal) fracture?

Initial Imaging for Suspected Rib or Sternum Fracture

A standard chest X-ray (posteroanterior view when possible) is the appropriate initial imaging modality for suspected rib or sternum fractures in most clinical scenarios. 1

Clinical Context and Rationale

The American College of Radiology establishes clear guidance that chest radiography is "usually appropriate" as the initial imaging for suspected rib fractures across multiple clinical scenarios, including minor blunt trauma, post-cardiopulmonary resuscitation, and suspected pathologic fractures. 1

Why Chest X-ray Remains the Standard

The fundamental principle driving this recommendation is that isolated rib fractures have relatively low morbidity and mortality, with treatment being generally conservative. 1 The critical diagnostic goal is identifying life-threatening complications—pneumothorax, hemothorax, major vascular injury, or pulmonary contusion—rather than simply counting every fracture. 2 A standard chest radiograph effectively detects these complications while also identifying most clinically significant rib fractures. 1

What About CT Chest?

While CT is undeniably more sensitive for detecting rib fractures (detecting 65% of fractures versus only 25% on chest X-ray in post-CPR patients 1), there is no evidence that the increased fracture detection rate affects patient management or outcomes. 1 CT does identify fracture-related complications in approximately 15% of cases (pneumothorax, vascular injury, chest wall hematomas), but routine use for all suspected rib fractures is not justified. 1

CT chest should be reserved for:

• Patients with abnormal chest X-ray findings requiring further characterization 3
• High-risk mechanisms of injury 3
• Suspected pathologic fractures where CT without IV contrast serves as a complementary modality to characterize the lesion 1
• Intubated patients undergoing initial trauma assessment 4
• Patients with chest wall tenderness, reduced air entry, or abnormal respiratory effort where complications are more likely 4

Imaging Modalities to Avoid

Dedicated Rib Views

Do not order dedicated rib radiography series. 1 There is no strong indication that rib series provides significant additional value as an initial imaging modality. 1 These views miss fractures due to organ overlap (particularly heart and abdominal organs), fractures outside the imaging range, and trivial fractures. 5 The cost and radiation exposure are not justified when they rarely change management. 2

Ultrasound

While ultrasound can detect fractures not visible on radiographs (detecting 10% of fractures missed by chest X-ray in one study 1), it is not recommended as an initial imaging modality. 1 The examination is time-consuming (averaging 13 minutes), causes patient discomfort from probe pressure, and fracture identification is unlikely to impact care. 1

Nuclear Medicine Bone Scan

Bone scans are sensitive but not specific for rib fractures and are primarily used for detecting metastatic disease rather than acute trauma. 1 They remain positive for extended periods (79% at 1 year, 93% at 2 years) and cannot reliably distinguish acute from chronic fractures. 1 Reserve Tc-99m bone scans as complementary imaging for suspected pathologic fractures. 1

Special Considerations for Sternum Fractures

The same principles apply to sternal fractures—begin with standard chest radiography. 1 While the evidence provided focuses primarily on rib fractures, sternal fractures follow similar management principles where the key concern is identifying associated injuries (cardiac contusion, mediastinal injury) rather than simply documenting the fracture itself.

Common Pitfalls

• Ordering dedicated rib views reflexively: These add cost, radiation, and rarely change management. 2
• Assuming negative chest X-ray excludes fracture: Chest X-ray misses many fractures, but this rarely matters clinically since treatment is conservative regardless. 1, 2
• Using portable supine radiography when upright PA views are possible: Portable films significantly underdiagnose fractures and complications. 1, 2
• Ordering CT for every suspected rib fracture: Reserve CT for patients with concerning clinical findings or abnormal chest X-rays. 4, 3

Radiation Considerations

Radiation exposure should factor into imaging decisions, particularly in pediatric patients who face higher lifetime risk from radiation exposure. 1 Standard chest radiography provides adequate diagnostic information with minimal radiation compared to CT. 1