From the Guidelines
A CT scan for a cough should be ordered when there are concerning symptoms that persist despite appropriate treatment, or when there are red flags suggesting a serious underlying condition, as recommended by the American College of Radiology 1. When evaluating a patient with chronic cough, it is essential to consider the duration and severity of symptoms, as well as any underlying risk factors for lung disease.
- A chest X-ray is usually the initial imaging modality of choice for patients with chronic cough lasting more than 8 weeks, as it can help identify underlying conditions such as pneumonia or lung cancer 1.
- However, if the chest X-ray is normal and clinical concern persists, a CT scan may be warranted to further evaluate the patient, especially if there are symptoms such as hemoptysis, unexplained weight loss, or risk factors for lung cancer 1.
- CT scans are also indicated when there is suspicion of interstitial lung disease, bronchiectasis, or when immunocompromised patients present with respiratory symptoms, as these conditions can be better visualized on CT imaging 1. Some key points to consider when deciding whether to order a CT scan for a cough include:
- The patient's symptoms and medical history, including any underlying conditions that may be contributing to the cough
- The results of any previous imaging studies, such as chest X-rays
- The presence of any red flags, such as hemoptysis or unexplained weight loss, that may indicate a more serious underlying condition
- The potential risks and benefits of CT imaging, including the exposure to radiation and the possibility of detecting incidental findings that may not be relevant to the patient's care 1. In general, a CT scan should be reserved for patients with chronic cough who have not responded to initial treatment and have a high suspicion of underlying lung disease, as recommended by the American College of Radiology 1.
From the Research
Indications for CT Scan in Cough
- Chronic cough is a common symptom of many diseases, and guidelines recommend chest X-ray as the first-line examination 2.
- However, chest X-ray is insensitive in diagnosing many diseases, and CT scan may be more helpful in excluding causes of long-term cough, such as bronchial tumors and pulmonary interstitial diseases 2.
- CT scan may be recommended as a first-line examination for patients with chronic cough, especially in regions where it is safe and affordable 2.
Diagnostic Yield of CT Scan in Cough
- A study found that chest CT scans were frequently prescribed for chronic cough patients with normal chest X-rays, and abnormal findings were frequently found (37.3%) 3.
- However, the diagnostic yield for malignancy or infectious disease was low (<1%) 3.
- Another study found that a quarter of chronic cough patients have an abnormal chest CT scan, but the effect of this on chronic cough management is limited 4.
Specific Conditions Where CT Scan is Indicated
- Hemoptysis (expectoration of blood from the lower respiratory tract) requires urgent and comprehensive evaluation, and CT angiography is a useful noninvasive imaging modality for initial assessment 5, 6.
- CT scan can help identify the underlying cause of hemoptysis, such as bronchiectasis, chronic bronchitis, lung malignancy, tuberculosis, and chronic fungal infection 6.
- CT angiography can also help guide subsequent management, such as bronchial artery embolization, in cases of massive hemoptysis 5, 6.