What is the best approach for a chest CT in a 53-year-old patient with new onset wheezing, with and without contrast (intravenous contrast media)?

Chest CT for New Onset Wheezing in a 53-Year-Old: Contrast vs Non-Contrast

For a 53-year-old with new onset wheezing, start with chest radiography first, and if CT is needed, perform CT chest WITHOUT IV contrast as the initial imaging study. 1

Initial Imaging Approach

• Begin with chest radiography (PA and lateral) as the first-line imaging modality for new onset wheezing in adults. 1, 2
• Chest radiography serves to exclude pneumonia, masses, pneumothorax, and other structural abnormalities that may present with wheezing. 1
• In adults over 40 years with significant tobacco history and new-onset wheezing, imaging is particularly important to evaluate for malignancy. 2

When CT Chest is Indicated

CT chest should be reserved for specific clinical scenarios rather than routine initial evaluation:

• Abnormal findings on chest radiography requiring further characterization. 1
• Persistent symptoms despite empiric treatment of common causes (asthma, COPD). 1, 3
• Clinical suspicion for structural airway abnormalities, bronchiectasis, or tracheal stenosis. 1, 3
• High clinical suspicion for malignancy in patients >40 years with tobacco history. 2

CT Without IV Contrast is Preferred

For evaluation of new onset wheezing, CT chest WITHOUT IV contrast is the appropriate choice:

• Non-contrast CT is adequate for evaluating airways, pulmonary parenchyma, and interstitium in patients with dyspnea or suspected diffuse lung disease. 1
• Non-contrast CT can detect bronchial wall thickening (present in 57-62% of chronic airway disease cases), air trapping, bronchiectasis, and emphysema. 3, 1
• Expiratory phase imaging should be included to detect air trapping and mosaic attenuation patterns that indicate small airways disease—these findings are only visible on expiratory cuts. 3

When IV Contrast Adds Limited Value

• IV contrast does not improve evaluation of airways, bronchial wall thickening, or parenchymal abnormalities that cause wheezing. 1
• Contrast-enhanced CT is primarily useful for evaluating mediastinal masses, hilar lymphadenopathy, and vascular structures—but these are secondary considerations unless there is specific clinical suspicion. 1
• The ACR guidelines note that "venous phase CT chest with IV contrast has limited added value in the initial imaging of COPD compared with chest CT without IV contrast." 1

Critical Diagnostic Considerations for New Onset Wheezing

Always consider upper airway obstruction in adults with new-onset wheezing:

• Tracheal stenosis, extrinsic compression from mediastinal masses, or substernal goiter can present as new-onset wheezing. 4
• CT with thin-section imaging (≤1.5 mm slice thickness) is essential for adequate airway evaluation. 1
• Flow-volume loops on pulmonary function testing should be obtained to detect upper airway obstruction. 4

Common Pitfalls to Avoid

• Don't assume asthma or COPD without imaging in adults >40 years with new-onset wheezing—malignancy and structural airway lesions must be excluded. 2, 4
• Don't order CT with and without contrast—there is no added diagnostic value for wheezing evaluation, and this unnecessarily increases radiation exposure and cost. 1
• Don't skip expiratory phase imaging if small airways disease is suspected—air trapping and mosaic attenuation require expiratory imaging for detection. 3
• Don't order CT as the initial test—chest radiography should be performed first unless there is high clinical suspicion for complications requiring urgent CT. 1

Specific Algorithm for Decision-Making

1. All patients: Start with chest radiography (PA and lateral). 1, 2
2. If chest radiograph is normal and symptoms persist: Consider pulmonary function testing with bronchodilator challenge and flow-volume loops. 2, 4
3. If chest radiograph shows abnormalities OR symptoms persist despite treatment: Proceed to CT chest WITHOUT IV contrast with expiratory phase imaging. 1, 3
4. Reserve CT WITH IV contrast for: Suspected mediastinal mass, hilar lymphadenopathy, or when evaluating for malignancy with chest wall or vascular invasion. 1