Lung abscesses: US examination and US-guided transthoracic aspiration

Examinations with ultrasound (US) and US-guided transthoracic aspiration were conducted in 35 patients to enable diagnosis of lung abscesses. Thirty-three of the abscesses (94%) were demonstrated at US, while two lesions were not depicted. At US, lung abscesses were depicted as hypoechoic lesions with irregular outer margins and an abscess cavity that was manifested as a hyperechoic ring. Twenty-five abscesses (71%) had local adhesion to parietal pleura (lesion-pleura symphysis). US-guided transthoracic needle aspiration of fluid from the abscess cavity was performed successfully in 31 of 33 patients (94%). A total of 65 pathogens were isolated from 31 aspirates (41 anaerobes and 24 aerobes), not-withstanding the fact that 23 of the patients had been previously treated with antibiotics. Only two of 65 pathogens (3%) could be recovered from blood culture, seven (11%) from sputum culture, and two from bronchoalveolar lavage (3%). Two patients developed minimal pneumothorax. The authors conclude that US examination and US-guided transthoracic aspiration are useful and safe diagnostic methods of collecting specimens to enable accurate diagnosis of lung abscesses.