IMAGING FEATURES IN ASBESTOSIS

ASBESTOSIS

1. ASBESTOSIS Dr.I.Gurubharath MD PhD Dr.Pooja MD

2. ASBESTOSIS Chronic progressive diffuse interstitial pulmonary fibrosis due to inhalation of asbestos fibers 20-30years after start of exposure Frequency: in 49–52% of industrial asbestos exposure Related to length and Intensity of exposure

3. Diagnostic criteria: Reliable history of exposure Appropriate time interval between exposure & detection Radiographic opacities classified as ILO s,t,u Restrictive pattern of lung impairment Diffusing capacity below normal range Bilateral crackles at posterior lung bases NOT cleared by cough

4. D yspnea Restrictive pulmonary function tests: progressive reduction of vital capacity & diffusing capacity Location: lower posterior bases > apices Site Most severe in subpleural zones (asbestos fibers concentrate beneath visceral pleura)

5. Chest Xray : Small irregular linear opacities progressing from fine to coarse reticulations: Confined to lung bases, progressing superiorly S eptal lines (fibrous thickening around secondary lobules) Honeycombing (uncommon) “Shaggy” (obscured) heart border ( parenchymal + pleural changes) Ill-defined outline of diaphragm Rarely massive fibrosis, predominantly at lung bases without migration toward hilum ( ddx from silicosis / cwp ) Absence of hilar / mediastinal adenopathy

6. A: Chest radiograph shows irregular, geographic areas of calcification corresponding to pleura plaques seen en face. An increase in reticular opacities is visible at the lung bases. B: Lateral chest radiograph shows slight posterior displacement of the major fissures ( w hite arrow) resulting from fibrosis and volume loss in the posterior lung bases. An increase in retirular opacities is visible posteriorly

7. HRCT : Thickened intralobular lines as initial finding Multiple subpleural curvilinear branching lines (“ subpleural pulmonary arcades”) Dot like reticulonodularities connected to the most peripheral branch of pulmonary artery site: most prominent posteriorly parallel to and within 1 cm of pleura Thickened interlobular septal lines

8. Reticulations , network of linear densities, usually posteriorly at lung bases Architectural distortion of lobule Parenchymal band formation linear < 5 cm long & several mm wide opacity, often extending to pleura, which may be thickened & retracted at site of contact Patchy areas of ground-glass attenuation Honeycombing ( multiple cystic spaces < 1 cm in diameter with thickened walls)

9. HRCT features of early asbestosis include subpleural lines (arrowheads) and fine reticulation (arrows).

10. C. CT in soft tissuewindow shows calcified pleural plaques and areas of pleural thickening D. CT lung window shows fibrosis with honeycombing in the lung periphery

11. Complications : Pulmonary fibrosis, Pleuropulmonary malignancy (latency period of > 20 years) Differential Diagnosis Idiopathic pulmonary fibrosis (NO parietal pleural thickening

12. ATELECTATIC ASBESTOS PSEUDOTUMOR ROUND ATELECTASIS / “ FOLDED LUNG” / Blesovsky syndrome I nfolding of redundant pleura accompanied by segmental / subsegmental atelectasis Most common of benign masses caused by asbestos exposure Location : posteromedial / posterolateral basal region of lower lobes (most common); frequently bilateral - 2.5–8 cm focal subpleural mass abutting a region of thickened pleura size & shape show little progression, occasionally ↓ in size

13. CT : Rounded / lentiform / wedge-shaped peripheral mass Pleural thickening ± calcification always present and frequently greatest near mass “crow’s feet” linear bands radiating from mass into lung parenchyma (54%) “vacuum cleaner” / “comet” sign , bronchovascular markings emanating from nodular subpleural mass, coursing toward ipsilateral hilum “Swiss cheese” air bronchogram (18%) partial interposition of lung between pleura + mass volume loss of affected lobe ± hyperlucency of adjacent lung

14. A.Chest Xray PA view Shows Peripheral Well definrd opacity B.Contrast CT axial view a.Soft tissue density in both lower lobes.lesions adhere to the pleura forming acute angles.

15. REFERENCES: Webb WR, Higgins CB. Thoracic imaging: pulmonary and cardiovascular radiology. Lippincott Williams & Wilkins; 2010. Adam A, Dixon AK, Gillard JH, Schaefer- Prokop C, Grainger RG, Allison DJ. Grainger & Allison's Diagnostic Radiology E-Book. Elsevier Health Sciences; 2014 Jun 16. Dahnert WF. Radiology review manual. Lippincott Williams & Wilkins; 2017 Mar 9. www.Radiopedia.org

16. THANK YOU