岡地 祥太郎

Introduction: Accurate diagnosis of peripheral pulmonary lesions is crucial in respiratory medicine. Radial endobronchial ultrasound (R-EBUS), navigation technologies, and ultrathin bronchoscopes have progressively enhanced distal airway access. Mixed reality (MR) offers a hands-free method for visualizing and manipulating CT-derived three-dimensional (3D) anatomy within the operator’s field of view. This retrospective study aimed to describe the technical feasibility and safety of intraprocedural MR-based holographic virtual bronchoscopy (VB) use. Methods: This study included patients who underwent bronchoscopy for peripheral pulmonary lesions using an MR-based 3D holographic VB system. CT datasets were converted into 3D polygon models and displayed on a HoloLens 2 headset. Operators/assistants intraprocedurally referenced and manipulated the hologram while advancing the bronchoscope. Procedural variables, R-EBUS findings, biopsy techniques, diagnostic yield, and complications were evaluated. Results: Eighteen patients were included. A direct bronchus sign was present in 12 lesions. The median bronchial generation that could be visualized on CT and 3D-VB was six, whereas bronchoscopy enabled advancement to a median of five generations. Radial EBUS demonstrated a within-lesion position in 13 cases. Biopsy techniques included forceps biopsy, cryobiopsy, and TBNA. The overall diagnostic yield was 72.2% (13/18), with malignant disease accounting for the majority of diagnoses. One patient developed mild pneumothorax, which resolved without drainage. Conclusion: MR-based holographic VB enabled real-time, hands-free 3D anatomical referencing without interrupting the procedure. Further prospective studies are warranted to assess procedural benefits and potential integration with other bronchoscopic modalities and devices.

BACKGROUND: Data regarding the diagnostic efficacy of radial endobronchial ultrasound (R-EBUS) findings obtained via transbronchial needle aspiration (TBNA)/biopsy (TBB) with endobronchial ultrasonography with a guide sheath (EBUS-GS) for peripheral pulmonary lesions (PPLs) are lacking. We evaluated whether intraoperative probe repositioning improves R-EBUS imaging and affects diagnostic yield and safety of EBUS-guided sampling for PPLs. METHODS: We retrospectively studied 363 patients with PPLs who underwent TBNA/TBB (83 lesions) or TBB (280 lesions) using EBUS-GS. Based on the R-EBUS findings before and after these procedures, patients were categorized into three groups: the improved R-EBUS image (n = 52), unimproved R-EBUS image (n = 69), and initial within-lesion groups (n = 242). The impact of improved R-EBUS findings on diagnostic yield and complications was assessed using multivariable logistic regression, adjusting for lesion size, lesion location, and the presence of a bronchus leading to the lesion on CT. A separate exploratory random-forest model with SHAP analysis was used to explore factors associated with successful repositioning in lesions not initially "within." RESULTS: The diagnostic yield in the improved R-EBUS group was significantly higher than that in the unimproved R-EBUS group (76.9% vs. 46.4%, p = 0.001). The regression model revealed that the improvement in intraoperative R-EBUS findings was associated with a high diagnostic yield (odds ratio: 3.55, 95% confidence interval, 1.57-8.06, p = 0.002). Machine learning analysis indicated that inner lesion location and radiographic visibility were the most influential predictors of successful repositioning. The complication rates were similar across all groups (total complications: 5.8% vs. 4.3% vs. 6.2%, p = 0.943). CONCLUSIONS: Improved R-EBUS findings during TBNA/TBB or TBB with EBUS-GS were associated with a high diagnostic yield without an increase in complications, even when the initial R-EBUS findings were inadequate. This suggests that repeated intraoperative probe repositioning can safely boost outcomes.

Bronchoscopic lung volume reduction (BLVR) with endobronchial valves is an established treatment for selected patients with advanced emphysema. A 74-year-old male patient with chronic obstructive pulmonary disease and severe dyspnea was scheduled to undergo BLVR targeting the right middle lobe bronchus based on high-resolution CT findings, which showed severe emphysematous changes with hyperinflation and fissure completeness of 98% in the right middle lobe. The physician conducted preoperative virtual reality (VR)-assisted planning using the patient's imaging data, enabling comprehensive visualisation of the bronchial tree, airway measurements, and procedural simulation. The Chartis system confirmed a 'no flow' pattern, supporting the absence of collateral ventilation. During the procedure, a size 5.5 valve was placed in the right B4/5 bronchus following VR and intraoperative assessments. The patient remained stable postoperatively without complications. VR enhanced procedural planning by improving airway assessment, optimising valve sizing, and reducing cognitive load, leading to increased efficiency and operator confidence. Further research is warranted to validate the utility of VR in bronchoscopic interventions.