Bronchiolar Disorders Arun Devakonda, MD, Suhail Raoof, MD, FCCP, Arthur Sung, MD, FCCP, William D. Travis, MD, FCCP, David Naidich, MD, FCCP  CHEST  Volume 137, Issue 4, Pages 938-951 (April 2010) DOI: 10.1378/chest.09-0800 Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 1 Anatomy of secondary pulmonary lobule. (Reproduced with permission from CHEST.8) CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 2 A 2:1 target reconstruction showing a routine 1-mm section though the left mid lung in a patient with Kartagener syndrome (note the middle lobe is collapsed on the left side) with an adjacent 5-mm maximum projection intensity image showing the tree-in-bud pattern with exquisite detail. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 3 Direct signs of bronchiolar disease include evidence of dilatation of bronchiolar lumen, thickening of bronchiolar wall, or obstruction of bronchiolar lumen. By observing mosaic attenuation, it can be inferred (indirect sign) that bronchiolar disease may be present. HRCT = high-resolution CT. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 4 A high-resolution target reconstructed 1-mm images in a patient with classic hypersensitivity pneumonitis. Evident are multiple, small, ill-defined, ground-glass opacities. There is no evidence of peripheral branching (tree-in-bud) opacities or subpleural nodules as is seen in patients with infectious bronchiolitis or primary perilymphatic disease. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 5 A four-on-one set of inspiratory and expiratory paired images showing extensive air trapping in a patient with constrictive bronchiolitis. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 6 Algorithmic approach to bronchiolar disease. The algorithm takes into consideration important history and physical findings that should tip the clinician to suspect bronchiolar disease. The plain chest radiograph (CXR) may not always show evidence of hyperinflation. Small airways dysfunction on PFT should trigger a request for an HRCT scan of the chest, performed during inspiration and exhalation. Further classification is based on the pattern seen on the HRCT scan. A tree-in-bud pattern generally signifies an infectious bronchiolitis. On the other hand, centrilobular nodules in a smoker point toward RB-ILD, whereas the same pattern in nonsmokers may indicate HP. Evidence of air trapping on the HRCT scan may be due to constrictive or obliterative bronchiolitis. Finally, if histologic confirmation is required, especially in conditions such as subacute HP, constrictive or obliterative bronchiolitis, RB-ILD, or bronchoalveolar cell carcinoma, a tissue diagnosis may be obtained. Generally, surgical biopsy is preferred because of difficulty in recognizing and classifying bronchiolitis in transbronchial biopsies. Conditions diagnosed by lavage (PLCH) or where infections are suspected (Mycobacterium avium-intracellulare, bacterial, parasitic, and fungal), or BAL may be performed. In lung transplant patients suspected of having constrictive bronchiolitis, five or more pieces of tissue, obtained by transbronchial biopsy, are recommended. ABPM = allergic bronchopulmonary mycosis; BAC = bronchoalveolar cell carcinoma; CF = cystic fibrosis; CHF = congestive heart failure; HP = hypersensitivity pneumonitis; PFT = pulmonary function test; PLCH = pulmonary Langerhans cell histiocytosis; RB-ILD = respiratory bronchiolitis-interstitial lung disease; TBBx = transbronchial biopsy. See Figure 3 legend for expansion of other abbreviation. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 7 Plain CXRs of a middle-aged man with a history of working in shipyards as a welder for 30 years. He was severely short of breath on exertion and did not show significant improvement with oral steroids. Surgical biopsy was read as peribronchiolar chronic inflammation including lymphoid aggregates, consistent with respiratory bronchiolitis. Of note, the posteroanterior film (A) shows linear opacities at both bases, but a paucity of radiographic signs, such as flattening of diaphragms, to suggest hyperinflation. On the lateral image, (B), the retrosternal air space is not significantly increased, although both images show reticular opacities. The CT images (C) show, in addition, mosaic attenuation, suggestive of air trapping. These images highlight the importance of suspecting bronchiolar diseases based on the history and symptoms elicited from patients, even in the absence of clear signs on plain CXRs. See Figure 6 legend for expansion of abbreviation. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 8 Diffuse panbronchiolitis: This bronchiole shows a marked chronic inflammatory infiltrate involving the bronchiolar wall and extending into the surrounding interstitium (hematoxylin-eosin, ×4). In addition to many lymphocytes and plasma cells, there are numerous foamy histiocytes in the peribronchiolar interstitium (top left). CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 9 The image was taken from a patient who had a smoking history. A diagnosis of respiratory bronchiolitis-interstitial lung disease was made. Note the focal areas of ground-glass opacities alternating with more lucent areas. The lucent areas are abnormal and represent air trapping. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 10 The image is taken from a patient with pulmonary Langerhans cell histiocytosis. Note the dilated bronchi, which are larger than the accompanying pulmonary arteries. In addition, there are thick-walled cysts in the periphery of the lungs in both upper lobes. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 11 A 1-mm axial image of a patient with documented follicular bronchiolitis showing asymmetric involvement with a few discernible centrilobular changes. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 12 The lumen of this bronchiole from a bone marrow transplant patient shows marked narrowing by prominent submucosal fibrosis (hematoxylin-eosin, × 20). CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions

Figure 13 Axial (A) and coronal (B) images in a patient with mosaic attenuation due to Swyer-James syndrome with constrictive bronchiolitis. The coronal view shows the extent of disease to better advantage. CHEST 2010 137, 938-951DOI: (10.1378/chest.09-0800) Copyright © 2010 The American College of Chest Physicians Terms and Conditions