Bonus Material-30_ACCP 2025 Shah Part I

Pdf Summary

This lecture on Thoracic Radiology, led by Dr. Rakesh Shah, focuses on interpreting thoracic imaging with an emphasis on idiopathic interstitial pneumonias (IIPs) and nodule evaluation in lung pathology. <br /><br />It begins with a review of key anatomical structures such as the secondary pulmonary lobule and pulmonary interstitium, essential for understanding radiologic patterns. Linear and reticular opacities are defined, including peribronchovascular interstitial thickening, interlobular and intralobular septal thickening, honeycomb cysts, traction bronchiectasis, and subpleural lines. Subpleural sparing and peribronchial opacities are also noted.<br /><br />The core content reviews IIPs, which are diffuse inflammatory/fibrotic lung disorders characterized by overlapping clinical, radiologic, and histopathologic features, and require exclusion of known causes for diagnosis. Major IIPs include idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), respiratory bronchiolitis-ILD, desquamative interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, lymphocytic interstitial pneumonia, and pleuroparenchymal fibroelastosis. Classification is based on categories such as chronic fibrosing, smoking-related, acute/subacute, and rare forms, with corresponding radiologic-pathologic patterns.<br /><br />Radiologists play a key role in pattern description on CT and providing differential diagnoses, while clinicians integrate clinical information for final diagnosis. The Fleischner Society criteria for diagnosing IPF based on CT patterns (definite UIP, probable UIP, indeterminate UIP, and alternative diagnosis) are detailed, highlighting features like peripheral-basal distribution, reticular opacities, honeycombing, and associated findings.<br /><br />The discussion then shifts to nodules: perilymphatic (near pleura, fissures; seen in sarcoidosis, lymphangitic carcinoma), random (diffuse, hematogenous spread in infections or metastases), and centrilobular (small airway-centered nodules seen in bronchiolitis and infections). Tree-in-bud pattern reflects endobronchial spread of infection. Interpretation emphasizes nodule type, distribution, size, and associated clinical data for diagnosis.<br /><br />Overall, the lecture integrates anatomy, radiologic patterns, and clinical correlation to guide diagnosis of thoracic diseases, particularly interstitial lung diseases and nodule assessment.

Meta Tag

Concept Secondary Pulmonary Lobule

Concept Honeycombing

Concept Idiopathic Interstitial Pneumonia

Concept Usual Interstitial Pneumonia

Concept Idiopathic Pulmonary Fibrosis

Concept Pulmonary Interstitium

Keywords

thoracic radiology

idiopathic interstitial pneumonias

interstitial lung disease

pulmonary lobule

reticular opacities

idiopathic pulmonary fibrosis

Fleischner criteria

lung nodules

tree-in-bud pattern

CT imaging

Secondary Pulmonary Lobule

Honeycombing

Idiopathic Interstitial Pneumonia

Usual Interstitial Pneumonia

Idiopathic Pulmonary Fibrosis

Pulmonary Interstitium