4cms - is most commonly due to - Bronchial adenoma * Honey Comb appearance - o SarcoidosisQ o Histiocytosis XQ o Interstitial lung diseaseQ o TuberculosisQ o Collagen disordersQ o PneumoconiosisQ o Drugs - bleomycin, busulphan, melphalan, cyclophosphamide * Meniscus sign / Crescent sign (mobile mass in pulmonary cavity) is most commonly seen in - Aspergilloma (fungal ball lesion) * Egg-Shell calcification - SilicosisQ , SarcoidosisQ , Coal miner's pneumoconiosisQ, Lymphoma following radiotherapyQ * Pop-corn calcification / Craggy pop-corn calcification - Pulmonary Hamartoma * Pleural calcification - commonest cause is - Tuberculosis (Asbestosis) * Diaphragmatic Pleura calcification - is due to - Asbestosis * Calcification in a pulmonary metastasis - is most commomly due to - Osteosarcoma * Coin shadow in the lung (single), with calcification in the centre - Epidermoid carcinoma * For radiologically evident pleural effusion - the minimal amount of pleural fluid that should be present is - 250 ml * Plethoric lung fields - seen in - L-R shunts ( VSD, PDA, ASD) * Oligemic lung fields - Pulmonary atreisa, Stenosis; Ebstein's anomaly * Perihilar fluffy opacities - seen in - Pulmonary venous hypertension Ribs * Superior surface notch of ribs - seen in - Hyperparathyroidsm, Neurofibromatosis, Connective tissue disorders * Inferior surface notch of ribs - seen in - Coarctation of Aorta, SVC obstruction, Chest wall AV fistula, Aortic Thrombosis, * Unilateral notching of ribs - Coarctation of Left subclavian artery, Subclavian artery block, Blalock-Taussig Operation Others * Displacement of tracheal shadow - most common cause is - Thyroid swelling * Water Lily sign - Ruptured hydatid cyst">