Bonus Material-30_ACCP 2025 Shah Part I

Pdf Summary

This lecture by Dr. Rakesh Shah provides an overview of thoracic radiology focused on interstitial lung diseases (ILDs), with emphasis on idiopathic interstitial pneumonias (IIPs) and CT imaging patterns.<br /><br />Key topics include the anatomy of the secondary pulmonary lobule and pulmonary interstitium, essential for interpreting thoracic imaging. The presentation reviews various CT patterns such as linear and reticular opacities, nodules and nodular opacities, and altered lung attenuation.<br /><br />Linear and reticular opacities represent thickening of interstitial structures like peribronchovascular bundles, interlobular septa, and intralobular septa, and include features like honeycomb cysts and traction bronchiectasis. Distinguishing between subpleural sparing and peribronchial opacities aids diagnosis.<br /><br />The idiopathic interstitial pneumonias (IIPs) group includes chronic fibrosing (usual interstitial pneumonia [UIP], nonspecific interstitial pneumonia [NSIP]), smoking-related (respiratory bronchiolitis-ILD, desquamative interstitial pneumonia), acute/subacute (cryptogenic organizing pneumonia, acute interstitial pneumonia), and rare entities like lymphocytic interstitial pneumonia and pleuroparenchymal fibroelastosis. Diagnosis hinges on exclusion of known causes; identifying etiology guides treatment and prognosis.<br /><br />Radiologists play a key role in describing CT patterns and providing differential diagnoses, while clinicians correlate with clinical syndromes.<br /><br />The Fleischner Society criteria categorize UIP patterns into definite UIP, probable UIP, indeterminate UIP, and alternative diagnoses based on distribution (typically peripheral and basal), presence of reticular opacities, honeycombing, traction bronchiectasis, ground-glass opacities, nodules, and other features.<br /><br />Nodular patterns are classified by distribution as perilymphatic (close to pleura and lymphatics, seen in sarcoidosis, lymphangitic carcinoma), random (evenly distributed, e.g. miliary infections, metastases), and centrilobular (around secondary pulmonary lobule centers, sparing pleura—linked to bronchiolitis and airway diseases). Tree-in-bud appearance typically indicates endobronchial infection.<br /><br />The lecture emphasizes integrating imaging features with clinical and histopathologic data to reach accurate diagnoses in ILDs and other thoracic pathologies.<br /><br />In summary, thoracic radiology involves recognizing specific CT patterns and distributions to differentiate types of ILDs, diagnose idiopathic pulmonary fibrosis confidently when possible, and identify alternative conditions, thereby guiding patient management effectively.

Meta Tag

Concept Secondary Pulmonary Lobule

Concept Interstitial Lung Disease

Concept Honeycombing

Concept Reticular Opacity

Concept Traction Bronchiectasis

Concept Fleischner Society UIP/IPF CT Classification

Keywords

thoracic radiology

interstitial lung disease

idiopathic interstitial pneumonias

CT imaging patterns

usual interstitial pneumonia

nonspecific interstitial pneumonia

honeycombing

traction bronchiectasis

perilymphatic nodules

tree-in-bud appearance

Secondary Pulmonary Lobule

Interstitial Lung Disease

Honeycombing

Reticular Opacity

Traction Bronchiectasis

Fleischner Society UIP/IPF CT Classification