When is a chest x-ray (CXR) recommended?

When to Recommend a Chest X-Ray (CXR)

A chest X-ray is usually appropriate as the first-line imaging modality for patients with suspected sepsis, respiratory symptoms, suspected heart failure, suspected pulmonary disease, or when evaluating for other thoracic causes of chest pain. 1

Clinical Scenarios Where CXR is Recommended:

Respiratory Infections and Sepsis

• CXR is usually appropriate for initial imaging of patients with suspected or confirmed sepsis, especially those with cough, dyspnea, or chest pain 1
• In high TB prevalence countries, patients with cough should have a chest X-ray if resources allow, regardless of cough duration 1
• CXR is recommended in patients with suspected pneumonia who have risk factors such as:
  • Age ≥60 years 1
  • Abnormal vital signs (fever, tachycardia, tachypnea, hypoxemia) 1
  • Abnormal findings on physical examination (crackles, decreased breath sounds) 1

Cardiovascular Conditions

• CXR should be considered for individuals with signs and symptoms suggestive of heart failure 1
• CXR is appropriate when evaluating patients with chest pain to rule out non-coronary cardiac causes 1

Chronic Respiratory Symptoms

• CXR is usually appropriate as the first-line imaging for patients with chronic dyspnea of unclear etiology 1
• CXR is recommended at initial evaluation of suspected COPD 2
• CXR is appropriate for patients with chronic dyspnea with suspected disease of the pleura or chest wall 1
• CXR is appropriate for patients with chronic dyspnea with suspected diaphragm dysfunction 1

COVID-19 Evaluation

• During the COVID-19 pandemic, CXR was found to be useful for assessing disease progression and alternative diagnoses such as bacterial superinfection, pneumothorax, and pleural effusion in hospitalized patients 1
• CXR is particularly valuable when portable imaging is needed for infection control purposes 1

When CXR May Not Be Necessary:

• In young patients (<40 years) with acute respiratory illness, normal vital signs, and negative physical examination findings without hemoptysis, CXR may not be necessary as the incidence of pneumonia is low (approximately 3-4%) 1
• In the context of chronic coronary syndromes, CXR does not yield specific information for accurate diagnosis or risk stratification 1
• A normal CXR does not exclude pulmonary hypertension, and further imaging evaluation should be pursued if there are persistent unexplained symptoms 1

Limitations of CXR:

• CXR has limited sensitivity for detecting early or mild infectious processes, with studies showing sensitivity as low as 43.5% compared to CT for detecting pulmonary opacities 3
• CXR has poor sensitivity for detecting mild pulmonary hypertension 1
• In pediatric patients, the negative predictive value of CXR for excluding active inflammatory or infectious lung disease is limited (66.3%) 4

Follow-up Imaging:

• In patients with pleuritis, a repeat CXR should be performed approximately 4-6 weeks after initial treatment to establish a new radiographic baseline 5
• For patients who are clinically improving, there is no need to repeat a CXR prior to hospital discharge 5
• If a patient's clinical findings are not improving or deteriorating after initial therapy, repeat imaging should be performed sooner 5

Special Considerations:

• Elderly patients (≥60 years) should have a lower threshold for CXR as they are less likely to report symptoms compared to younger patients 1, 6
• In COPD evaluation, CXR helps detect other pathologies that may cause dyspnea and can detect lung cancer, changing management in the majority of cases with abnormal findings 2

When clinical suspicion for significant pathology remains high despite a normal CXR, further imaging with CT should be considered, as CXR has limited sensitivity for many pulmonary conditions 3, 1.