The document discusses the imaging findings of miliary tuberculosis. Miliary tuberculosis typically appears as discrete, spherical nodules 1-2mm in diameter, distributed bilaterally and evenly throughout the lungs in a millet seed pattern. The nodules are well-circumscribed, homogeneous with no or rare calcifications. Radiological signs may not appear for several weeks. Differential diagnoses include other infectious diseases like histoplasmosis as well as metastatic lung cancers and sarcoidosis. HRCT imaging is more sensitive than plain radiography for detecting miliary tuberculosis.

1. Dr. Prof. TITO’s Unit Dr. Pandichelvan R .

6. Most commonly manifest as post primary TB rather than Primary TB in older patients Purely Nodular Pattern in febrile patient with acute presentation suggestive of hematogenous infection, particularly miliary TB. Radiological evidence usually takes several weeks to appear. MILIARY TUBERCULOSIS

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