Initial Chest Radiography in Chronic Cough with Normal Pulmonary Function Tests

Recommendation for Initial Imaging

The American College of Radiology (ACR) recommends that a chest X‑ray be obtained as part of the first‑line evaluation for chronic cough even when pulmonary function tests are normal, to screen for serious pulmonary pathology such as malignancy, infection, or structural abnormalities. 1
The ACR describes chest radiography as a foundational imaging study that should precede empiric treatment trials for chronic cough, ensuring that potentially serious disease is not missed before therapy is started. 2
Normal pulmonary function testing does not rule out radiographically visible lesions (e.g., masses, infiltrates, early malignancy) because PFTs assess airflow and volumes but cannot detect structural abnormalities. 1

The ACR notes that chest X‑ray has relatively low sensitivity for detecting pulmonary abnormalities associated with chronic cough, with a negative predictive value ranging from 64 % to 79 % for airway diseases. 2
Compared with computed tomography (CT), chest X‑ray misses up to 34 % of bronchiectasis cases and demonstrates only 69 %–71 % sensitivity for airway abnormalities. 2
ACR guidance cautions against relying on a normal chest X‑ray alone to exclude pulmonary causes of chronic cough, especially airway disease and early interstitial lung disease. 2

Presence of red‑flag features—hemoptysis, unexplained weight loss, fever, or recurrent pneumonia—warrants proceeding directly to chest CT rather than an initial X‑ray. 4
A heavy smoking history or high‑risk occupational exposures (e.g., asbestos, silica) are criteria for immediate CT according to the ACR. 5
Palpable supraclavicular lymphadenopathy or other concerning physical‑exam findings also justify direct CT evaluation. 4
Immunosuppression or an existing chronic pulmonary disease (e.g., COPD, interstitial lung disease) are additional triggers for upfront CT scanning per ACR recommendations. 5

When the chest X‑ray is normal and no red‑flag features are present, the ACR advises initiating empiric treatment trials for the most common causes of chronic cough (upper‑airway cough syndrome, cough‑variant asthma, gastro‑esophageal reflux disease) based on clinical probability. 1
Chest CT should be reserved for patients who do not respond to empiric therapy or when clinical suspicion for underlying pulmonary disease remains high despite a normal radiograph. 2
The ACR indicates that chest CT performed without a specific clinical indication in chronic‑cough patients generally yields non‑contributory findings in the majority of cases. 1

Do not consider a normal chest X‑ray sufficient to rule out pulmonary etiologies of chronic cough, particularly airway abnormalities and early interstitial disease, because of the modality’s limited sensitivity. 2
Routine CT for all chronic‑cough patients with a normal X‑ray is unnecessary; data show that while about 37 % of such patients have abnormal CT findings, less than 1 % have major findings (e.g., malignancy or serious infection) that require immediate intervention. (Evidence from ACR guidelines.) 1
In patients older than 70 years, incidental bronchiectasis is identified on CT in up to 20 % of cases, often subclinical and unrelated to the cough, underscoring the need to interpret CT findings in clinical context. 1