After local anesthesia with lidocaine and moderate sedation with intravenous midazolam, a UTB (BF-MP290F; Olympus Medical Systems, Tokyo, Japan: distal-end diameter, 3.0 mm and working channel diameter, 1.7 mm) was advanced to engage the target bronchus using VBN (SYNAPSE VINCENT; Fujifilm Medical, Tokyo, Japan) and conventional fluoroscopy (Artis Zeego, Siemens Healthcare, Forchheim, Germany). After reaching the target bronchus, a 1.4-mm R-EBUS probe (UM-S20-17S; Olympus Medical Systems) was advanced toward the lesion through the working channel under the guidance of conventional fluoroscopy. The obtained EBUS images were classified into three types based on the classification by Kurimoto
et al. (17 (
link)) (primary EBUS image). Type 1 EBUS images indicated “within”, type 2 indicated “adjacent to”, and type 3 indicated “invisible”. The type with a smaller image number was considered a better EBUS and CBCT image (
Figures 1,2). After the EBUS image was obtained, a 1.5-mm biopsy forceps (FB-433D; Olympus Medical Systems) was introduced through the working channel of the UTB directly into the target bronchus under the guidance of conventional fluoroscopy without augmented fluoroscopy.
After the biopsy forceps engaged the target bronchus, CBCT was performed during breath-holding using a 6-s acquisition protocol with 400 projection images acquired over a 200-degree rotation (Artis Zeego, Siemens Healthcare). Multi-planar reconstruction images were generated automatically on a dedicated workstation (Syngo X Workplace, Siemens Healthcare). Based on the relationship between the lesion and the forceps position, we classified the obtained images into three groups, as described in our previous report (primary CBCT image) (14 (
link)). Type 1 CBCT image indicated that the forceps clearly reached the inside of the target lesion, type 2 indicated that the forceps reached adjacent to the lesion, and type 3 indicated that the forceps did not reach the lesion. Type 1 EBUS and CBCT, type 2 EBUS and CBCT, and type 3 EBUS and CBCT were recognized as equivalent images. If the primary CBCT image was type 1, a biopsy was performed. If it was type 2 or 3, the three-dimensional re-navigation toward the lesion was determined on the CBCT image and re-navigation was performed using R-EBUS. In the re-navigation procedure, first, based on the multi-planar reconstruction image obtained from the CBCT image, it was determined whether the target bronchus was ventral or dorsal and lateral or medial to the current forceps tip position. It was also determined if the position of the bronchoscope tip needed to be adjusted. Next, while viewing the two-dimensional fluoroscopic image of the front or side, the position and direction of the tip of the bronchoscope were adjusted, and the R-EBUS probe was advanced in the direction of the target bronchus. This EBUS image was defined as the secondary EBUS image. Thereafter, CBCT was performed if required and defined as the secondary CBCT image. Subsequently, tertiary or more EBUS or CBCT images were obtained and defined as required. The best image obtained during the examination (smaller numbers in each image type) was defined as the best EBUS/CBCT image. We obtained six biopsy samples and two brushing samples and performed bronchial alveolar lavage with 20 mL saline. If the tip of the forceps did not reach the lesion, only bronchial alveolar lavage with 20 mL saline was performed.
Kawakita N., Toba H., Sakamoto S., Miyamoto N., Takashima M., Kawakami Y., Kondo K, & Takizawa H. (2023). Cone-beam computed tomography-guided endobronchial ultrasound using an ultrathin bronchoscope for diagnosis of peripheral pulmonary lesions: a prospective pilot study. Journal of Thoracic Disease, 15(2), 579-588.