What is the best imaging protocol for left-sided rib pain?

Imaging Protocol for Left-Sided Rib Pain

Start with a standard posteroanterior chest radiograph as your initial imaging test—this is the American College of Radiology's recommended first-line approach that balances diagnostic utility with cost-effectiveness while screening for life-threatening complications. 1, 2, 3

Initial Imaging Strategy

Chest Radiograph (PA View)

• Order a standard chest X-ray first, not dedicated rib views. 1, 2, 3
• The primary goal is detecting complications that affect morbidity and mortality: pneumothorax, hemothorax, major vascular injury, or pulmonary contusion—not simply counting every fracture. 3, 4
• Chest radiographs will miss approximately 50% of rib fractures, but this limitation is clinically acceptable because detecting the fracture itself rarely changes management. 2, 3
• Place radio-opaque skin markers on the site of maximal pain to help the radiologist localize abnormalities. 1, 2

What NOT to Order Initially

• Avoid dedicated rib radiography series as your first test—they miss fractures due to organ overlap (especially heart on left lower ribs) and injuries outside the imaging field, while adding cost without improving outcomes. 3, 5, 4
• Do not order CT chest routinely—while CT detects 65% of fractures versus 25% on X-ray, this increased detection does not alter patient management or outcomes in uncomplicated cases. 3

Secondary Imaging Options

When to Consider Additional Imaging

Dedicated Rib Views:

• Reserve for focal chest wall pain with negative chest X-ray when you need to confirm a specific rib lesion (fracture, infection, neoplasm). 1, 2
• In post-tussive chest pain, rib radiography detects fractures in 82.4% of cases, most commonly involving the 10th rib. 1, 2

Point-of-Care Ultrasound:

• Consider ultrasound as a superior alternative to rib views—it detects 29% of fractures missed on chest radiography and has 100% sensitivity compared to CT. 1, 2, 6
• Ultrasound demonstrates 94.9% accuracy versus only 35.4% for X-rays in detecting individual rib fractures. 6
• Limitations include difficulty visualizing posterior fractures, upper rib fractures, and reduced penetration in patients with large breasts. 1, 6
• Dynamic ultrasound is particularly valuable for slipping rib syndrome (89% sensitivity, 100% specificity). 1, 2

CT Chest:

• Reserve CT for patients requiring evaluation of other pulmonary diseases or when there is high suspicion for malignancy. 2
• In patients with known or suspected malignancy and normal chest radiograph, proceed to CT chest to characterize chest wall neoplasms and assess extent of involvement. 1

Clinical Pitfalls to Avoid

• Do not pursue imaging that won't change management—if the chest X-ray excludes complications and clinical examination suggests simple rib contusion or fracture, additional imaging to "find the fracture" adds no value. 7, 3
• Do not rely on fracture detection alone—focus on identifying complications that impact morbidity and mortality rather than cataloging every fracture. 3, 4
• Avoid radiation exposure without clinical benefit—particularly in younger patients, the incremental diagnostic yield of CT or multiple rib views rarely justifies the radiation dose. 3
• Consider alternative diagnoses—left-sided rib pain may represent cardiac, pulmonary, or abdominal pathology that chest radiography can help exclude. 1, 2

Special Considerations for Malignancy

• If malignancy is known or suspected, bone scintigraphy has 95% sensitivity for skeletal metastases and defines extent of involvement across the entire skeleton. 1, 2
• More than 50% of chest wall neoplasms are malignant, most commonly from metastases or direct invasion of thoracic tumors. 1