Effects of lobar atelectasis on the distribution of pleural effusion and pneumothorax.

Atelectasis is known to change the retractility of the involved part of the lung and the pleural pressure adjacent to it. Consequently, pleural effusions or pneumothoraxes will change their distribution and preferentially migrate toward the site of atelectasis. This alteration will often result in an atypical distribution of pleural liquid or gas. The radiological implications of this phenomenon are discussed herein.