Optimal endobronchial tool sizes for targeting lung lesions based on 3D modeling

Area of Science:

• Pulmonary Medicine
• Medical Imaging
• Interventional Pulmonology

Background:

• Lung biopsies are crucial for diagnosing suspicious lesions found on imaging.
• Increased lung cancer screening leads to more small, peripheral lesions requiring biopsy.
• Optimal endobronchial tool size for accessing these lesions remains unclear.

Purpose of the Study:

• To determine the percentage of lung lesions reachable by endobronchial tools of varying diameters.
• To assess the 'off-road' distance tools need to travel outside airways to reach all lesions.
• To inform the development of improved diagnostic and therapeutic tools for lung lesions.

Main Methods:

• Generated six 3D lung models with airways simulated during inspiration and expiration.
• Randomly distributed three sets of 1,000 lesions within the models for each respiratory phase.
• Validated simulation findings with CT scans from 21 patient lesions.

Main Results:

• Reachable lesion percentage decreases as tool diameter increases and lesion diameter decreases.
• A 1mm tool reaches <25% of 1cm lesions when confined to airways.
• To reach all 1cm lesions, a 1mm tool requires up to 8.5mm of parenchymal navigation.

Conclusions:

• Smaller tool diameters enhance the likelihood of reaching lung lesions for biopsy, ablation, or resection.
• Even 1mm tools are insufficient for accessing the majority of small (1-2cm) lesions.
• Endobronchial tools require parenchymal navigation capabilities to reach most lung lesions effectively.