Percutaneous needle washing for the diagnosis of pulmonary thin-walled cavitary lesions filled with air.

Objective: It is difficult to obtain sufficient material from pulmonary thin-walled cavitary lesions filled with air by conventional percutaneous aspiration biopsy in order to make a diagnosis. In these cases, we performed percutaneous needle washing (PNW) and ascertained the diagnostic significance of this method.

Materials And Methods: PNW was performed on 27 patients with a pulmonary thin-walled cavitary lesion whose diagnosis could not be made by sputum and bronchoscopic examinations. Before centesis, the depth of the lesion was measured on CT scan. After the 22-gauge needle was inserted under X-ray fluoroscopic guidance, normal saline was injected into the cavity and aspirated. The aspirated material was examined cytologically and microbiologically. The procedure was carried out during one 30-second breath-holding.

Results: Upon performing PNW on 27 patients, malignant cells were detected in 10 patients and a bacterial or fungal pathogen was detected in 9 other patients [Aspergillus (4), Mycobacterium (3), Staphylococcus (1), Streptococcus (1)]. The diagnoses of 16 of the 17 patients who were negative for malignant cells on PNW, were ascertained as benign disease during their clinical course including 3 patients who were diagnosed as (or suspected of) having infectious disease clinically, while the diagnosis of one case was unknown. Therefore, the diagnostic sensitivity of PNW for malignant diseases was 91% (10/11), while that for infectious diseases was 69% (9/13). Mild pneumothorax was the only complication of PNW (2 cases).

Conclusion: PNW may be an appropriate diagnostic procedure for pulmonary thin-walled cavitary lesions whose diagnosis can not be established by other techniques.