From the Guidelines
The best investigation for bronchiectasis is high-resolution computed tomography (HRCT) of the chest. HRCT is the gold standard diagnostic tool as it can clearly visualize the characteristic findings of bronchiectasis, including bronchial wall thickening, bronchial dilatation (where the bronchial lumen diameter exceeds that of the adjacent pulmonary artery), and the "signet ring" sign (dilated bronchi adjacent to a smaller pulmonary artery in cross-section) 1. While chest X-rays may show some changes, they lack sensitivity and can miss early or mild bronchiectasis. HRCT should be performed without contrast unless there are specific concerns about vascular abnormalities. Once bronchiectasis is confirmed, additional investigations are typically needed to determine the underlying cause, which may include:
- Pulmonary function tests
- Sputum cultures
- Immunoglobulin levels
- Sweat chloride testing (for cystic fibrosis)
- Alpha-1 antitrypsin levels Early and accurate diagnosis with HRCT allows for appropriate management to prevent disease progression and reduce exacerbations 1. The most recent guidelines also support the use of HRCT as the preferred examination for evaluation of suspected bronchiectasis 1.
Some key points to consider when interpreting HRCT results include:
- The presence of bronchial wall thickening, bronchial dilatation, and the "signet ring" sign
- The extent of bronchiectasis and the number of lobes affected
- The presence of any complications, such as pneumonia or atelectasis
- The need for additional investigations to determine the underlying cause of bronchiectasis
It's worth noting that the evidence for the use of HRCT in bronchiectasis is based on a combination of observational studies and expert opinion, as there are limited randomized controlled trials available on this topic 1. However, the consensus among experts is that HRCT is the best investigation for bronchiectasis due to its high sensitivity and specificity, and its ability to provide detailed information about the extent and severity of the disease.
From the Research
Investigation for Bronchiectasis
The best investigation for bronchiectasis is high-resolution computed tomography (HRCT) as it provides detailed images of the lungs and airways, allowing for the confirmation, localization, and management of the condition 2, 3.
Key Features of HRCT
HRCT can confirm the diagnosis of bronchiectasis with high sensitivity and specificity, and may contribute to the investigation of other inflammatory disorders of the airways 3.
- HRCT findings include abnormal widening and thickening of the airway wall, irregular wall, and lack of tapering 4.
- HRCT can also reliably detect obstructing bronchial lesions such as tumors or broncholithiasis 3.
Comparison with Other Imaging Modalities
While spiral CT has a high sensitivity of 91% to detect bronchiectasis, HRCT is the method of first choice due to its greater sensitivity and lower radiation dose 5.
- Chest radiograph is often done at the initial suspicion, but it is supplemented by HRCT to confirm the diagnosis 2.
Clinical and Functional Correlation
HRCT quantification of bronchiectasis has been shown to correlate with clinical and functional parameters, such as exacerbation frequency, 24-hour sputum volume, and lung function tests 6.
- Extent of bronchiectasis, severity of bronchial wall thickening, and presence of small-airway abnormalities are associated with lung function and clinical parameters 6.