What are the radiographic findings of chronic obstructive pulmonary disease (COPD)?

Radiographic Findings of COPD

Plain chest radiography in COPD demonstrates hyperinflation with flattened and depressed hemidiaphragms on posteroanterior view and increased retrosternal airspace on lateral view, though it lacks sensitivity for early disease and should not be used to exclude the diagnosis. 1, 2

Plain Chest Radiography Findings

Hyperinflation Signs

• Depression and flattening of the diaphragm on posteroanterior film is the hallmark finding 1, 2
• Increased retrosternal airspace on lateral chest radiograph indicates hyperinflation 1, 2
• Increased thoracic cage ratio and thoracic cross-sectional area may be visible 3

Emphysema-Specific Features

• Bullae and irregular radiolucency of lung fields with absence of vasculature appear in severe emphysema, though recognition is subjective and quality-dependent 1, 2
• These findings are considered specific for emphysema in COPD patients, but radiographic extent correlates poorly with necropsy severity 1
• Vascular attenuation and distortion may be visible 3

Cardiovascular Complications

• Right descending pulmonary artery diameter >16 mm suggests pulmonary hypertension 1, 2
• Enlargement of central pulmonary arteries and right heart chambers indicates cor pulmonale 1, 2
• "Tear-drop heart" configuration may be present due to hyperinflation 4

Important Clinical Caveats

Diagnostic Limitations

• Plain chest radiography is not sensitive for diagnosing early or mild COPD 1, 4
• A normal chest radiograph does not exclude COPD and is frequently normal in early disease 1
• The chest radiograph is primarily useful for excluding alternative diagnoses and identifying complications rather than establishing COPD diagnosis 1

Clinical Utility

• At initial presentation, chest radiography can exclude lung cancer, pneumonia, and other conditions mimicking COPD 1
• During acute exacerbations, chest radiography is essential to confirm or exclude complicating pneumonia or pneumothorax 1
• Approximately 14% of chest radiographs ordered during COPD evaluation detect potentially treatable causes of dyspnea other than COPD 1

Computed Tomography Findings

CT Advantages Over Plain Radiography

• High-resolution CT is more sensitive than chest radiography for determining type, extent, and distribution of emphysema and bronchial wall abnormalities 1
• CT can identify early COPD changes in asymptomatic and spirometrically normal smokers 1
• Low attenuation areas on CT represent emphysematous destruction and can be quantified 1, 4

Emphysema Patterns on CT

• CT can distinguish centriacinar, panacinar, and paraseptal emphysema patterns 1, 3, 4
• Centriacinar emphysema is the most common subtype identified 3
• Bullae size and number can be accurately quantified 1

Additional CT Findings

• Directly visible small airways are the most common finding (seen in 90% of patients) 3
• Mosaic attenuation pattern indicates air trapping 3
• Bronchial wall thickening and gas trapping can be identified 1
• Expiratory CT reflects airflow limitation and correlates with dyspnea levels 1

CT Limitations in Routine Practice

• CT scanning is not recommended for routine clinical assessment of COPD 1
• Its role is limited to evaluation of bullae and investigation of coexisting bronchiectasis 1
• Quantitative CT techniques remain complex and lack standardization across equipment manufacturers 1