Minimum fluid collection required for radiological detection of pleural effusion in lateral decubitus view is: September 2009

Ans. Amount of pleural fluid required to cause a blunted costophrenic angle discernible on chest radiography is more than 300 ml. A chest computerized tomography scan is more sensitive than a simple chest x-ray and is often used for assessment of loculated effusions because, in some instances, up to 500 cc of loculated fluid can be obscured behind the dome of the diaphragm