Usefulness of endobronchial ultrasonography with a guide sheath for diagnosing ground glass opacity lesions

Background and purpose: It is often hard to diagnose ground glass opacity (GGO) lesions by transbronchial biopsy (TBB), because of difficulty in detecting the site of the lesions under X-ray fluoroscopy. We have reported the usefulness of TBB using endobronchial ultrasonography with a guide sheath (EBUS-GS) for small peripheral pulmonary lesions (PPLs). EBUS-GS has an advantage to detect the location of PPLs. In this study, we retrospectively analyzed the diagnostic yield of GGO lesions by EBUS-GS and examined of lesions which might influence the diagnostic yield. Patients and methods: Between August 2003 and December 2007, we performed EBUS-GS for a total of 67 GGO lesions in Hokkaido University Hospital and Hokkaido Cancer Center. Results: Of the 67 lesions (11 pure GGO lesions and 56 mixed GGO lesions, which consist of GGO components more than 50%), 43 (64%) were not visible by conventional X-ray fluoroscopy. Thirty-eight lesions were diagnosed by TBB with EBUS-GS (36 adenocarcinoma, 1 lymphoma and 1 inflammation). The average size of lesions with diagnosis was significantly larger than that of lesions without definitive diagnosis. (23.9mm vs. 16.7mm; P<0.01) For lesions with bronchus leading directly to the center of the lesions on high-resolution computed tomography images (positive CT sign), the diagnostic yield was significantly higher than lesions with negative CT sign. (31% vs. 66%; P < 0.01) Conclusion: EBUS-GS is a useful method for diagnosing GGO lesions. However, failure of diagnosis is associated with the lesions in smaller size and/or with negative CT sign.