ABSTRACT
I. Introduction The pleura, a relatively superficial structure, is easily accessible to ultrasonography (US) and has gained its recognition as a highly useful tool in the evaluation of pleural lesions (1-7). Pathological processes that involve the pleura, either directly from isolated pleural disease or indirectly from neighboring pulmonary lesions, manifest as pleural effusion, which is one of the main causes of increased opacity in the hemithorax seen on chest radiography. US easily identifies the cause of the opaque chest on radiography by their acoustic properties and avoids unnecessary diagnostic procedures.
