7. Imaging Findings Discrete Distinctive Pin-point opacities WHY NODULARITY? Nodule size 1 – 2 mm in diameter - SPHERICAL LESION IN Miliary ( millet seed ) Pattern INTERSTITIUM B/L even distribution - WELL CIRCUMSCRIBED Basal Predominance HOMOGENOUS PATTERN Rare or non-existent calcifications Upto 30 % no radiological signs Thickening of intralobar fissure / interlobular septa Nodular irregularity of vessels HRCT – more sensitive

8. Differential diagnosis PNEUMOCONIOSIS - Coal Workers Pneumoconiosis - Silicosis - Siderosis - Stannosis SARCOIDOSIS METASTATIC LUNG DISEASES NON TB INFECTIONS - Histoplasmosis - Blastomycosis - Cryptococcosis - Nocardiosis - Coccidiodomycosis BRONCHIOLITIS OBLITERANS

9. SILICOSIS : Multiple well circumscribed nodules Uniform density Upper lobe predominance Mainly posterior lobe Nodular Calcification seen in 10 – 20 % cases Hilar lymphadenopathy Egg Shell Calcification :

10. COAL WORKERS PNEUMOCONIOSIS: Simple Pneumoconiosis small round nodule 1 – 5mm granular densities calcifications begin as central dot Complicated Pneumoconiosis large opacities > 1cm upper lung zones start peripherally

11. Metastatic Lung Disease 75% -multiple pulmonary nodules B/L with basal predominance peripheral lesions ( subpleural ) cavitatory lesions squamous carcinomas sarcomas calcification rare ,except in osteogenic sarcoma chondrosarcoma mucinous adenocarcinoma

12. SARCOIDOSIS B/L symmetrical diffuse pulmonary disease B/L Hilar lymphadenopathy Upper zone mainly Imaging Patterns : m/c nodular reticulo-nodular reticular pattern (rare) air space consolidaton ground glass opacification