Bonus Material-32_ACCP 2025 Shah Part II

Pdf Summary

This presentation by Dr. Rakesh Shah focuses on Thoracic Radiology II, emphasizing the anatomy and radiologic interpretation of pulmonary disease patterns, particularly altered lung attenuation and its diagnostic implications.<br /><br />Key topics include the secondary pulmonary lobule, pulmonary interstitium, and radiological patterns such as linear/reticular opacities, nodules, and altered attenuation classified as increased, decreased, or mosaic.<br /><br />Increased pulmonary attenuation primarily involves ground glass opacity (GGO) and consolidation. GGO appears as a hazy increase in lung density with preserved vascular markings, caused by partial alveolar filling, seen in conditions like pulmonary hemorrhage, COVID-19 infection, alveolar proteinosis, and bacterial pneumonia. Consolidation indicates complete alveolar filling, obscuring vessels, and occurs in infections (e.g., Legionella pneumonia), chronic eosinophilic pneumonia, and malignancies like adenocarcinoma. The "crazy-paving" pattern—a combination of GGO and interlobular septal thickening—is discussed with differential diagnoses including alveolar proteinosis, COVID pneumonia, and pulmonary hemorrhage. The "reverse halo" or "atoll sign," central GGO surrounded by consolidation, is noted in organizing pneumonia, infections, infarcts, and certain vasculitides.<br /><br />Decreased attenuation relates to air-filled abnormalities such as honeycomb cysts, cavitary nodules, emphysema (centrilobular and panlobular), lung cysts, and bronchiectasis. Bronchiectasis involves irreversible bronchial dilatation and thickening, with etiologies ranging from infections, immune deficiencies, to systemic diseases, and specific patterns connected to cystic fibrosis, ABPA, and MAC infection.<br /><br />Mosaic attenuation features alternating areas of increased and decreased lung density and may stem from small airway disease (reversible asthma, obliterative bronchiolitis) or vascular disease (pulmonary arterial hypertension, chronic thromboembolic disease). Differentiation employs paired inspiratory-expiratory CT imaging; small airway disease lucent areas persist/enlarge upon expiration, whereas vascular disease areas decrease.<br /><br />Several clinical examples and imaging findings illustrate these principles, including constrictive bronchiolitis after lung transplant, smoke inhalation injury, pulmonary hypertension, and chronic thromboembolic disease.<br /><br />The review reinforces systematic assessment of pattern, distribution, and clinical context for accurate thoracic imaging interpretation.

Meta Tag

Concept Secondary Pulmonary Lobule

Concept Mosaic Attenuation

Concept Ground-Glass Opacity

Concept Consolidation

Concept Thoracic CT Pattern Recognition

Keywords

Thoracic Radiology

Pulmonary Attenuation

Ground Glass Opacity

Consolidation

Crazy-Paving Pattern

Reverse Halo Sign

Bronchiectasis

Emphysema

Mosaic Attenuation

Pulmonary Interstitium

Secondary Pulmonary Lobule

Mosaic Attenuation

Ground-Glass Opacity

Consolidation

Thoracic CT Pattern Recognition