The radiological diagnosis of bronchiectasis: what's in a name?

Abstract

Diagnosis of bronchiectasis is usually made using chest computed tomography (CT) scan, the current gold standard method. A bronchiectatic airway can show abnormal widening and thickening of its airway wall. In addition, it can show an irregular wall and lack of tapering, and/or can be visible in the periphery of the lung. Its diagnosis is still largely expert based. More recently, it has become clear that airway dimensions on CT and therefore the diagnosis of bronchiectasis are highly dependent on lung volume. Hence, control of lung volume is required during CT acquisition to standardise the evaluation of airways. Automated image analysis systems are in development for the objective analysis of airway dimensions and for the diagnosis of bronchiectasis. To use these systems, clear and objective definitions for the diagnosis of bronchiectasis are needed. Furthermore, the use of these systems requires standardisation of CT protocols and of lung volume during chest CT acquisition. In addition, sex- and age-specific reference values are needed for image analysis outcome parameters. This review focusses on today's issues relating to the radiological diagnosis of bronchiectasis using state-of-the-art CT imaging techniques.

Longitudinal Assessment of Patients With Cystic Fibrosis Lung Disease With Multivolume Noncontrast MRI and Spirometry

“…Among MRI subscores, no correlation was found between the progression of bronchial wall thickening/bronchiectasis and the worsening of spirometric measures, while this was the subscore with the strongest correlation to FEV 1 and FEF 25‐75, across all timepoints. This finding may support the hypothesis that bronchiectasis in CF is an endstage local condition of progressive and diffuse airway disease, 33 and that local functional loss may precede the appearance of bronchiectasis. Previous studies investigated longitudinal changes of hyperpolarized helium‐3 MRI in five patients with CF over a 4‐years period 34 and in 14 children with CF over a 1–2 year period, 35 showing sensitivity to lung disease progression over time.…”

Diagnosis and Initial Investigation of Bronchiectasis

“…[42][43][44][45][46] No internationally accepted thresholds of minimal changes on chest HR-CT needed to define radiologically significant bronchiectasis exist. 47 Moreover, data show a poor correlation between disease severity and radiological extension of bronchiectasis. 48 The three major features of bronchiectasis on chest CT are reported in ►Table 2.…”

“…Visibility of airways in the lung periphery is suggestive of a dilation of the non-cartilage-containing small airways. 47,60 On routine examination, these airways can easily be overlooked as being abnormal because their walls are thin. However, visible airways in the 1-cm proximal to the mediastinal subpleural lung are also seen in a significant number of normal individuals and should be considered as a sign of bronchiectasis only when directly abutting the mediastinal pleural surface.…”

Imaging in non-cystic fibrosis bronchiectasis and current limitations

“…There are no standardised HRCT protocols for the evaluation of bronchiectasis. 18 For evaluating the airways, volumetric CT acquisition should be preferred, since it allows a precise assessment of the continuity of bronchial structures, while multiplanar reconstructions help differentiate bronchiectasis from cystic lung disorders ( e.g. pulmonary Langerhans cell histiocytosis; lymphangioleiomyomatosis).…”

“… 19–21 More recently, quantitative post-processing methods have been developed to objectively define bronchiectasis and quantify disease severity, but their application is mostly limited to a research setting. 18 …”