Radiography
A 27-year-old man diagnosed with reactive airway disease as a child was examined because of frequent respiratory infections. The posteroanterior chest radiograph shows ill-defined pulmonary nodular opacities, mild scoliosis, and moderate overaeration.
This high-resolution computed tomography (HRCT) scan study through the upper lung zones shows extensive bronchiectatic changes (same patient as in Image above). After several repeat tests, the sweat test demonstrated positive results, and cystic fibrosis was diagnosed.
This is a close-up radiograph of the left upper lung zone in a 31-year-old woman with chronic cough since childhood. Nodules are present in the left upper lung; the right upper lung was similarly involved.
The high-resolution computed tomography scan shows thick-walled, slightly ectatic bronchi (same patient as in Image 3 in Multimedia). The patient has cystic fibrosis, which was diagnosed in and treated since childhood.
A 65-year-old woman was examined for chronic cough. The lateral chest radiograph shows overaeration and increased markings over the heart.
This posteroanterior chest radiograph shows overaeration and somewhat-obscured heart borders (same patient as in Images 5 and 7 in Multimedia).
This high-resolution computed tomography scan through the upper lung zone of the right side demonstrates bronchiectatic changes (same patient as in Images 5 and 6 in Multimedia). Despite conventional antibiotic treatment, the patient continued to be symptomatic. Eventually, she underwent bronchoscopy, and sampled cultures grew Mycobacterium avium-intracellulare complex.
Findings
Radiography
Chest radiography helps to identify serious disease, and it was once the standard imaging modality. However, the radiographs may depict no abnormalities, or the findings may be nonspecific in patients with less-severe disease.9
Various abnormal radiographic findings have been described as follows:
- Parallel line opacities (tram tracks) caused by thickened dilated bronchi
- Ring opacities or cystic spaces as large as 2 cm in diameter resulting from cystic bronchiectasis (see Images 1-2), sometimes with air-fluid levels
- Tubular opacities caused by dilated fluid-filled bronchi (see Images 3-4)
- Increased size and loss of definition of the pulmonary vessels in the affected areas as a result of peribronchial fibrosis (see Image 5)
- Crowding of pulmonary vascular markings from the associated loss of volume, usually caused by mucous obstruction of the peripheral bronchi (see Images 6-7)
- Oligemia as a result of reduction in pulmonary artery perfusion (severe disease)
- Signs of compensatory hyperinflation of the unaffected lung (see Image 1)
Bronchography
Introduced in 1922, bronchography was the investigation of choice until the introduction of HRCT scanning in the mid 1980s. Currently, bronchography is rarely used. Bronchography is performed by instilling contrast material via a catheter or bronchoscope under fluoroscopic control and plain radiographic imaging. The procedure is unpleasant for the patient and is also associated with temporary impairment of ventilation, as well as allergic and foreign body reactions to the contrast medium. In addition, interpretation of bronchographic images is difficult, owing to underfilling and retained secretions.
Degree of Confidence
The accuracy of plain radiographic findings in the diagnosis of bronchiectasis is unknown, because the findings are variable and nonspecific and depend on the severity and extent of the bronchiectasis. However, good correlation exists between the severity of disease as seen on plain images and HRCT scans. Chest radiographic findings may be normal or nonspecific in patients with less-severe disease.
False Positives/Negatives
Many plain radiographic findings are nonspecific and may be seen in patients with idiopathic pulmonary fibrosis, sarcoidosis, histiocytosis X, rheumatoid lung, and other chronic interstitial lung disorders.
Computed Tomography
The high-resolution computed tomography scan shows thick-walled, slightly ectatic bronchi (same patient as in Image 3 in Multimedia). The patient has cystic fibrosis, which was diagnosed in and treated since childhood.
This high-resolution computed tomography scan through the upper lung zone of the right side demonstrates bronchiectatic changes (same patient as in Images 5 and 6 in Multimedia). Despite conventional antibiotic treatment, the patient continued to be symptomatic. Eventually, she underwent bronchoscopy, and sampled cultures grew Mycobacterium avium-intracellulare complex.
High-resolution computed tomography scan in a 75-year-old man with cystic bronchiectasis.
This high-resolution computed tomography scan in a 13-year-old female adolescent shows left lower-lobe bronchiectasis, which is secondary to tuberculosis.
The high-resolution computed tomography scan demonstrates findings of fluid-filled dilated bronchi in a 65-year-old man with bronchiectasis in the left lower lobe.
Findings
The HRCT imaging technique consists of obtaining 1- to 2-mm collimation scans at 10-mm intervals through the chest with a window level (WL) of –700 Hounsfield units (HU) and a window width (WW) of –1000 HU. The right middle lobe and lingular bronchi cross obliquely and are not optimally depicted on axial HRCT scans; as a result, a gantry angulation of 20° may be required.10,11,12,13
HRCT scan findings include the following:
- The internal bronchial diameter may be greater than that of the adjacent artery.
- There may be a lack of bronchial tapering (the same diameter as the parent branch for > 2 cm).
- The bronchi may be within 1 cm of costal pleura or abut the mediastinal pleura (more specific but less sensitive than an increased ratio).
- Bronchial wall thickening may be seen (in 68% of patients).
- A cystic cluster of thin-walled cystic spaces may be present, often with air-fluid levels (see Image 10).
- In cylindrical bronchiectasis, bronchi coursing horizontally are seen as parallel lines, and vertically oriented bronchi are seen as circular lucencies that are larger than the adjacent pulmonary artery (signet-ring appearance) (see Image 11).
- Varicose bronchiectasis may be seen as nonuniform bronchial dilatation.
Other findings include the following:
- Areas of increased and decreased perfusion and attenuation
- Tracheomegaly
- Enlarged mediastinal nodes
- Fluid-filled bronchi are revealed as tubular or branching structures when they course horizontally or are revealed as nodules when they are perpendicular to the plane of the CT scan section (see Image 12).
Degree of Confidence
High-resolution CT (HRCT) scanning has a sensitivity of 96% and a specificity of 93%,8 as compared with bronchography, the previous criterion standard.
Bronchial measurements may vary with the use of different WLs and WWs.
Some patients without bronchiectasis have a 1.49:1 bronchus-to-artery ratio; however, the ratio is reliable only if it is greater than 1.5. If the ratio is less than 1.5, other signs, such as bronchial wall thickening and lack of tapering, should be present for the diagnosis of bronchiectasis.
False Positives/Negatives
The variability of the bronchus-to-artery ratio at high altitudes and in patients with pulmonary hypertension may result in an overdiagnosis because of vasoconstriction in these conditions.
Bronchial wall thickening is optimally seen with a WW of –1000 HU and a WL of –700 HU; higher WL and other WW readings are associated with artifactual wall thickening. This finding is not specific and is also seen in patients with asthma and in those who smoke.
In patients with consolidation, dilated bronchi may not be seen. Cardiac and respiratory artifacts may obscure the results or mimic subtle bronchiectasis in the left lower lobe. Rarely, histiocytosis X and cavitating pulmonary masses mimic cystic bronchiectasis. Traction bronchiectasis occurs in patients with interstitial fibrosis and results from fibrous tethering of the bronchial wall. Traction bronchiectasis is not a true bronchial disorder.
Angiography
Findings
Hemoptysis is symptomatic of a potentially life-threatening condition and warrants urgent and comprehensive evaluation of the lung parenchyma, airways, and thoracic vasculature.
Multidetector-row CT angiography permits noninvasive, rapid, and accurate assessment of the cause and consequences of hemorrhage into the airways and helps guide subsequent management. The combined use of thin-section axial scans and more complex reformatted images allows clear depiction of the origins and trajectories of abnormally dilated systemic arteries that may be the source of hemorrhage and that may require embolization.
Bronchiectasis, chronic bronchitis, lung malignancy, tuberculosis, and chronic fungal infection are some of the most common underlying causes of hemoptysis and are easily detected with CT angiography.
More on Bronchiectasis |
| Overview: Bronchiectasis |
 Imaging: Bronchiectasis |
| Follow-up: Bronchiectasis |
| Multimedia: Bronchiectasis |
| References |
| Further Reading |
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References
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Further Reading
Related eMedicine topics
Bronchiectasis (from Pulmonology)
Bronchiectasis (from Pediatrics: General Medicine)
Pneumonia, Bacterial
Pneumonia, Viral
Chronic Obstructive Pulmonary Disease
Clinical guidelines
Chronic Cough due to Bronchiectasis: ACCP Evidence-Based Clinical Practice Guidelines
Pulmonary Rehabilitation: Joint ACCP/AACVPR Evidence-Based Clinical Practice Guidelines
Clinical studies
Efficacy of Budesonide-Formoterol in Bronchiectasis
Airway Clearance in Bronchiectasis: is Non-Invasive Ventilation a Useful Adjunct in Moderate to Severe Disease?
Keywords
bronchiectasis, bronchial tree disease, pulmonary disease, abnormal dilatation of bronchi, pulmonary infections, cystic fibrosis, Young syndrome, primary ciliary dyskinesia, allergic bronchopulmonary aspergillosis, hypogammaglobulinemia, bronchopulmonary sequestration, Williams-Campbell syndrome, Mounier-Kuhn syndrome, Swyer-James syndrome, yellow nail syndrome, rheumatoid arthritis, Sjögren syndrome
