4cms - is most commonly due to - Bronchial adenoma* HoneyComb appearance - -Sarcoidosis -Histiocytosis X -Interstitial lung disease -Tuberculosis -Collagen disorders -Pneumoconiosis -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 pneumoconiosis, Lymphoma following radiotherapyQ* Pop-corn calcification / Craggy pop-corn calcification - Pulmonary Hamaoma* Pleural calcification - the commonest cause is - Tuberculosis (Asbestosis)* Diaphragmatic Pleura calcification - is due to - Asbestosis* Calcification of a pulmonary metastasis - is most commonly due to - Osteosarcoma* Coin shadow in the lung (single), with calcification in the center - 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 atresia, Stenosis; Ebstein&;s anomaly* Perihilar fluffy opacities - seen in - Pulmonary venous hypeensionRibs* Superior surface notch of ribs - seen in - Hyperparathyroidism, Neurofibromatosis, Connective tissue disorders* Inferior surface notch of ribs - seen in - Coarctation of Aoa, SVC obstruction, Chest wall AV fistula, Aoic Thrombosis,* Unilateral notching of ribs - Coarctation of Left subclan aery, Subclan aery block, Blalock-Taussig OperationOthers* Displacement of tracheal shadow - most common cause is - Thyroid swelling* Water Lily sign - Ruptured hydatid cyst(Ref: David Sutton; Textbook of radiology and imaging, 7th edition, page no.552-3, 866; Grainger&;s diagnostic radiology, 4th ed,. 874)">