Cone-beam computed tomography-guided endobronchial ultrasound using an ultrathin bronchoscope for diagnosis of peripheral pulmonary lesions: a prospective pilot study.

Background: Multimodal transbronchial biopsy (TBB) may have improved diagnostic yield for peripheral pulmonary lesions suspected as lung cancer. Radial endobronchial ultrasound (R-EBUS) provides real-time imaging and confirmation of the location of the lesions. Cone-beam computed tomography (CBCT) can confirm that the forceps tip has reached the lesion before biopsy. Methods: Patients with peripheral pulmonary lesions and a positive computed tomography (CT) bronchus sign (based on slice thickness of 1 mm) were prospectively enrolled. An ultrathin bronchoscope (UTB) and R-EBUS probe were advanced to the target bronchus. Thereafter, forceps were advanced, and CBCT was performed. R-EBUS was performed for re-navigation, if possible. The obtained EBUS and CBCT images were classified into "within" (type 1), "adjacent to" (type 2), or "far from" (type 3), based on the probe or forceps tip. Results: For 20 lesions, the diagnostic yield was 85%. The primary EBUS images were of types 1, 2, and 3 in 12, 6, and 2 cases, respectively. The primary CBCT images were of types 1, 2, and 3 in 12, 6, and 2 cases, respectively. Primary EBUS and CBCT image types were equivalent in 14 cases. Of the 12 cases with type 1 primary EBUS image, 9 cases had a type 1 primary CBCT image, while 3 cases exhibited positional misalignment of the forceps tip. Re-navigation was required in 8 cases with types 2 and 3 primary CBCT images. Conclusions: CBCT-guided TBB using an UTB and EBUS may enable real-time positioning guidance and better re-navigation in the diagnosis of peripheral pulmonary lesions.