Indication for CT Scan in Suspected Bronchiectasis

Limitations of Chest Radiography

Chest radiography is relatively insensitive for detecting bronchiectasis, although it is often performed as initial imaging in patients with respiratory symptoms 1
Up to 34% of chest radiographs may be interpreted as normal in patients with confirmed bronchiectasis by CT scan 3
Chest radiography offers limited characterization of the severity and morphology of bronchiectasis 1
Linear opacities and fibro-atelectatic plaques visible on radiography may mask underlying bronchiectasis 3

Non-contrast CT scan is the reference examination for detecting bronchiectasis, characterized by bronchi wider than adjacent arteries of the same order, absence of normal bronchial tapering from center to periphery of the lung, or identification of bronchi within 1 cm of the pleural surface 2
The 2010 British Thoracic Society guidelines for non-cystic fibrosis bronchiectasis recommend high-resolution CT scan as the examination of choice for evaluating suspected bronchiectasis 2, 4
CT scan allows for precise quantification of the extent and severity of bronchiectasis using various techniques and software 2
The severity of bronchiectasis on CT scan is correlated with measures of airway obstruction 2

A relatively large prospective cohort study of 608 patients with bronchiectasis showed that involvement of at least 3 lobes on CT scan was associated with a poorer prognosis 4
CT scan may play a role in suggesting a more thorough clinical evaluation of the causes of bronchiectasis and associated outcomes, such as prompting a search for non-tuberculous mycobacterial infection in an appropriate clinical context 4
CT scan also allows for identification of other associated pulmonary abnormalities that may not be visible on standard radiography 5

For suspected bronchiectasis, a non-contrast thoracic CT scan with 1.5 mm thin slices is recommended to identify and characterize associated chronic diffuse lung diseases 2
CT scan protocols for interstitial lung disease with thin slices are particularly suited for visualizing bronchiectasis 2

In cases with suspected bronchiectasis, CT scan is justified to confirm or rule out the presence of bronchiectasis, especially when chest radiography shows linear opacities or fibro-atelectatic plaques 1, 2
Stability or slight worsening compared to previous exams also justifies a more precise characterization by CT scan 6