Peripheral pulmonary lesions: ultrasonography and ultrasonically guided aspiration biopsy.

Twenty-five patients, each of whom had peripheral intrathoracic lesions that were smaller than 5.0 X 5.0 cm in size and not diagnosed by conventional methods, underwent real-time sonography and ultrasonically guided aspiration biopsy. The lesions included 18 nodules, two infiltrates, and five cavitary lesions. Sonography showed homogeneous hypoechoic or isoechoic density with well-defined margins in 16 of the nodules, and heterogeneous echogenicity with irregular margins in infiltrates. The cavitary lesions showed a hyperechoic ring with a central sonolucent area. Biopsy specimens were successfully obtained by percutaneous aspiration under ultrasound guidance in 24 (96%) of the patients, and a positive diagnosis was established in 21 (84%) by cytology and/or histology. All 17 malignant lesions were diagnosed by aspiration biopsy, while only four of seven benign lesions were diagnosed by this method. Two patients (8%) experienced minimal pneumothorax after aspiration biopsy. We conclude that real-time sonography, including ultrasonically guided aspiration biopsy, is a useful and safe method for examination of peripheral intrathoracic lesions and has a high diagnostic yield.