Radiologic Patterns

1. Radiologic Patterns Lungs are too white (consolidation) Lungs are too black (oligemia, air-trapping) Pulmonary nodule or mass Cystic and cavitary disease Pleural effusion Lymphadenopathy Mediastinal widening

3. Air Space Definition Gas-containing portion lung parenchyma, to include acini Excludes the interstitium & purely conductive portion of lung

4. Air Space Consolidation: Definition Air in alveoli is replaced by water, blood, pus, or tumor; results in confluent opacity which obscures broncho-vascular margins May be focal, patchy, or diffuse Air-bronchogram: radiologic appearance of an air-containing bronchus, surrounded by consolidated lung

5. Airspace Consolidation: Differential Edema - fluid overload (heart, renal failure) Infectious - pneumonia Inhalation - aspiration, toxic gases, drowning Pulmonary hemorrhage Neoplasm - adeno CA, lymphoma, mets Adult respiratory distress syndrome (ARDS) Metabolic - alveolar proteinosis

6. Ground Glass Opacity: Definition Hazy increased lung attenuation, with preservation of broncho-vascular margins Partial filling of the alveoli, interstitial thickening, or ? capillary blood flow Individual deposits not detectable “Smeared chalk” appearance

7. Ectasia Dilatation, expansion Ectatic aorta - mildly aneursymal Bronchiectasis - bronchial dilatation Atelectasis - collapse of lung, volume loss Gr. ateles imperfect + ektasis expansion

8. Atelectasis ? inflation of a segment, lobe, or lung Results in reabsorption of air Involved lung has decreased volume, increased opacity Due to mucous plug, stricture, tumor, or extrinsic compression of bronchus Non-involved lung responds with over-inflation

9. The Interstitium Continuum of loose supporting connective tissue in the lung Broncho-arterial Acinar - between alveoli and capillaries Subpleural - continuous with interlobar septa When diseased, tissues surrounding the air spaces & airways are thickened, with preservation of alveolar air

10. Secondary Pulmonary Lobule Building block of the lung Unit of lung structure, consists of < 12 acini Irregular polyhedral, ~ 1.23 cm Marginated by interlobular septa - pulmonary veins & lymphatics Lobular core - pulmonary arteriole & bronchiole

11. Reticular - Nodular Pattern Reticular: interlacing network of fine linear markings that form a mesh & contain air Nodular: discrete, punctate, round 1 - 5 mm deposits Reticulo-nodular: mixture of interstitial linear thickening & nodular deposits Honeycomb: air-containing cystic spaces (5-10 mm) surrounded by thick fibrous walls

12. Reticular Pattern: Differential Infectious - viruses, PCP Immune - scleroderma, hypersensitivity Edema Inhalational - asbestosis Airways - COPD with increased markings, cystic fibrosis (bronchiectasis) Drug-induced lung disease Pulmonary fibrosis

13. Nodular Pattern: Differential Infectious - miliary TB, fungi, CMV Non-infectious granulomatous - sarcoid Neoplastic - lymphangetic mets, lymphoma Inhalational - silicosis

14. Lungs Are Too Black Oligemia - reduced pulmonary blood flow cardiac: pulmonic stenosis or atresia pulmonary artery hypertension large pulmonary embolism Over-inflation, air-trapping emphysema central airway obstruction small airways disease

15. Air Trapping Retention of excess gas in all or part of lung, especially during expiration Due to partial airway obstruction or abnormal pulmonary compliance Emphysema: abnormally expanded air spaces distal to terminal bronchiole, with destruction of walls of involved air spaces

16. Nodule Sharply marginated, discrete, circular opacity, measuring 2 - 30 mm in diameter (T1), arising in lung or pleura Mass: > 3 cm (T2 - lung cancer staging)

17. Pulmonary Nodule or Mass Developmental - AVM, bronchial cyst Infectious - TB, fungal (granuloma) Neoplastic benign: hamartoma malignant: lung CA, lymphoma, met Traumatic - hematoma Immunologic - rheumatoid, Wegener’s

18. Cystic & Cavitary Disease: Definition Cystic: circumscribed air-containing spaces with distinct walls Cavity: focus of opacity whose central portion has been replaced by air Bulla: dilated > 1cm air space with thin epithelial wall Bronchiectasis: irreversible dilation of bronchi with wall thickening

19. Cystic & Cavitary Disease: Differential Developmental - bronchial cyst, sequestration Infection - bacteria, TB, fungi, PCP, parasites Thromboembolic - septic Neoplasm - lung CA, mets, lymphoma Immunologic - Wegener’s, rheumatoid nodule Trauma - pulmonary laceration Airways - blebs, bullae, cystic bronchiectasis

20. Pleural Effusion: Differential Infectious, inflammatory Neoplastic - primary or metastatic Cardiac decompensation Thromboembolic Trauma - blood, chyle, food (rupture esoph) Inhalational - asbestosis Immunologic (SLE, RA) Drugs - bromocriptine, methylsergide

21. Lymph Node Enlargement Infectious - TB, fungal Non-infectious granulomatous - sarcoid Neoplasm - lung CA, lymphoma, mets Inhalational - silicosis, berylliosis Metabolic - amyloidosis Reactive

22. Mediastinal Widening Developmental - bronchial, pericardial cyst Infectious - mediastinitis Neoplastic - thymus, lymphoma, esophagus, mets, lymphadenopathy Vascular - aneurysm, cardiac enlargement Trauma - blood Other - hernias, mega-esophagus, fat