Bronchiolitis (plural: bronchiolitides) is a broad term that refers to any form of inflammation of the bronchioles. It is often used in situations where there inflammation primarily occurs in airways smaller than 2 mm 6. It can carry variable clinical, functional and morphological expression. Bronchiolar disease may be a primary or a secondary condition.
According to some authors, there is some overlap with the term small airways disease 5.
Usually not detected at chest radiography but may manifest with non-specific findings such as ill-defined small or hazy clustered nodules or areas of air trapping characterized by hyperlucency and/or oligemia 6.
CT - HRCT
The presence of bronchiolitis is best assessed with HRCT. CT features include one of a combination of
- centrilobular micronodules (often seen as tree-in-bud opacities),
- bronchial wall thickening
- bronchiolar dilatation (often referred to as bronchiolectasis)
- mosaic attenuation (and/or air trapping if expiratory imaging is used)
One method of classifying various forms of bronchiolitis is as follows 1:
- inflammatory bronchiolitis
Exact radiographic features are best discussed under each sub-topic.
Other specific forms according to underlying pathology include:
- 1. Pipavath SJ, Lynch DA, Cool C et-al. Radiologic and pathologic features of bronchiolitis. AJR Am J Roentgenol. 2005;185 (2): 354-63. AJR Am J Roentgenol (full text) - Pubmed citation
- 2. Hwang JH, Kim TS, Lee KS et-al. Bronchiolitis in adults: pathology and imaging. J Comput Assist Tomogr. 21 (6): 913-9. J Comput Assist Tomogr (link) - Pubmed citation
- 3. Essadki O, Grenier P. [Bronchiolitis: computed tomographic findings]. J Radiol. 1999;80 (1): 17-24. J Radiol (link) - Pubmed citation
- 4. Beigelman-aubry C, Touitou D, Mahjoub R et-al. [CT imaging features of bronchiolitis]. J Radiol. 2009;90 (11 Pt 2): 1830-40. J Radiol (link) - Pubmed citation
- 5. Franquet T, MüLler NL. Disorders of the small airways: high-resolution computed tomographic features. Semin Respir Crit Care Med. 2003;24 (04): 437-44. doi:10.1055/s-2003-42378 - Pubmed citation
- 6. Winningham PJ, Martínez-Jiménez S, Rosado-de-Christenson ML, et all. A. Bronchiolitis: A Practical Approach for the General Radiologist. Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (3): 777-794. doi:10.1148/rg.2017160131 - Pubmed