IPBronch.com | Interventional Pulmonology

🎯 Background & Rationale

Cone-beam computed tomography (CBCT)-guided bronchoscopy is an established technique for accessing peripheral pulmonary lesions, offering 3-dimensional imaging for navigation and tool-in-lesion confirmation. However, its widespread adoption as a stand-alone modality is limited by a steep learning curve and a lack of integrated planning and real-time guidance tools, forcing endoscopists to mentally translate 2D augmented fluoroscopy into 3D endobronchial anatomy. This study evaluates the clinical feasibility and performance of dedicated navigation bronchoscopy-specific CBCT software (AirWaze) designed to integrate preprocedural CT planning, automated image fusion, and intraprocedural directional guidance.

👥 Study Design & Population

Study Type: Prospective, single-center clinical feasibility study.
Population: 34 patients with 37 peripheral pulmonary lesions evaluated at a single center by experienced interventional pulmonologists (>200 cases of CBCT-NB experience).
Intervention: Use of the Philips AirWaze v1.1 investigational software combining preprocedural CT planning, automated CT-to-CBCT and CBCT-to-CBCT image fusion, automated device-detection guidance, and an ultralow-dose (ULD) CBCT scanning protocol during standard CBCT-guided navigation bronchoscopy with a passive extended working channel.

📈 Methodology & Rigor

As a feasibility study, no formal comparative hypothesis-testing sample size calculations or comparative efficacy statistics were performed; results rely on descriptive statistics, success counts, and subjective scoring. Usability was rigorously assessed via the standardized System Usability Score (SUS; threshold $\ge 70$ for good usability) administered every 4 procedures, alongside 5-point Likert scale evaluations for individual software components (planning, image fusion, guidance) and an evaluation of ULD-CBCT accuracy versus conventional CBCT radiation dose (dose-area product).

🔬 Key Findings [or Planned Endpoints]

Usability & Overall Performance: The investigational software yielded an overall SUS of 45, failing to meet the predefined threshold of 70. The navigation success rate was 92% (34/37 lesions), and the strict diagnostic yield was 65%. Total median procedure time was 72 minutes (25 min navigation, 26 min biopsy).
Planning Component: Unanimously rated as accurate and intuitive (median Likert score of 5 for airway segmentation branching near the pleura). Planning time averaged 4 minutes.
Image Fusion: Preprocedural CT to intraprocedural CBCT image fusion was fully automated in 25% (9/36) of cases, manually correctable in 22% (8/36), and failed in 53% (19/36), requiring manual intraprocedural planning. Subsequent intra-to-intraprocedural CBCT fusions performed better, with 84% achieving automation.
Guidance Component: Automated device-detection and directional guidance (distance and angle to the lesion center) succeeded in 61% of conventional CBCTs and 50% of ULD-CBCTs, with failures primarily driven by misidentification of ribs or ECG leads as tool tips.
Ultralow-Dose Imaging: ULD-CBCT achieved 84% clinical accuracy compared to standard CBCT (yielding the same clinical conclusion) while reducing the radiation dose by 94% (mean dose-area product of $0.58\text{ Gy}\cdot\text{cm}^2$ vs. $9.3\text{ Gy}\cdot\text{cm}^2$).

⚖️ Critical Appraisal

The study provides a transparent, rigorous assessment of a novel integrated software suite, highlighting a critical chasm between endoscopist appreciation for preprocedural planning tools and the current technical limitations of automated image registration and instrument tracking. Limitations include its single-center design performed exclusively by high-volume experts (limiting generalizability to novice operators) and a relatively low patient BMI cohort, which may overestimate ULD-CBCT image quality. Furthermore, software failures in non-supine patient positions or complex non-solid lesions underscore that current algorithms cannot yet fully replace manual operator adaptation.

💡 The Clinical Bottom Line

While dedicated planning algorithms and ultralow-dose CBCT protocols ($>90%$ radiation reduction) show immense clinical promise for streamlining the workflow and minimizing radiation exposure in the bronchoscopy suite, the tested software’s image fusion and intraprocedural guidance components require significant algorithmic refinement before they can reliably serve as a seamless stand-alone guidance platform. Interventional pulmonologists should recognize that while automated planning is ready for prime time, real-time intraprocedural tracking and registration still demand rigorous operator oversight.

Background: Cone-beam computed tomography (CBCT)- guided bronchoscopy is an established technique for diagnosing peripheral pulmonary lesions, offering 3-dimensional imaging for both navigation and confirmation. However, its usability as a stand-alone modality is limited by a substantial learning curve and a lack of integrated planning tools. This study evaluates the feasibility and performance of navigation bronchoscopy-specific CBCT software that enables preprocedural CT-planning fusion with intraprocedural CBCT imaging and provides intraprocedural support algorithms. Methods: This prospective, single-center clinical feasibility study exploratively assessed the usability of the AirWaze investigational software. Usability was measured using a standardized system usability score, with scores of 70 or higher considered indicative of good usability (range, 0-100). The performance of the individual software components (‘planning,’ ‘image fusion,’ and ‘guidance’) was evaluated. An ultralow-dose CBCT protocol was compared with conventional CBCT scans for accuracy and radiation exposure. Results: The study enrolled 34 patients with 37 lesions. The investigational software achieved a system usability score of 45. The planning component was available in all cases and was unanimously rated by the endoscopists as accurate and intuitive. In contrast, the image fusion and guidance components were rated as insufficient. The ultralow-dose CBCT protocol provided clinically accurate imaging in 84% of cases and reduced the radiation dose by 94%. Conclusion: Integrating planning and procedural guidance within stand-alone CBCT-guided navigation bronchoscopy procedures has great potential. Although several components of the investigational software were considered valuable, further development is required to ensure comprehensive procedural guidance.