Robotized Catheter With Enhanced Distal Targeting for Peripheral Pulmonary Biopsy
Takahisa Kato, Franklin King, Kiyoshi Takagi, Nobuhiko Hata
Abstract
Transbronchial biopsy with a lung catheter is more appealing with lower complication risks for peripheral pulmonary biopsy. The distal tips of the current lung catheters lack targeting capabilities, however, which prevents a physician from guiding the biopsy tools to lesions, especially those in a peribronchial location. In this study, we investigated if a robotized catheter could enhance distal targeting after passing through tortuous bronchi. We experimentally evaluated targeting accuracy and the spatial dispersion of targeting with attention to catheter shape constraints by utilizing the bronchi of a patient-derived lung phantom. This newly developed robotized catheter has an outer diameter of 3 mm and a total length of 800 mm and comprises two bending sections at the distal 30 mm length. With these two bending sections, the distal tip can be steered to peribronchial lesions followed by the targeting of multiple locations inside the lesion with controlled dispersion to improve opportunities for tissue sampling. In the experimental results, the targeting position error for a peribronchial lesion ranged from 4.6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 1.2 to 7.2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 3.3 mm (mean <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> STD) among the different shape constraints. As for the targeting dispersion, the shape constraints reduced dispersion ability by a maximum of 50% compared to straight reference constraints, while the dispersion was still larger than the expected minimum requirement of 1 mm. One-way analysis of variance concluded that targeting accuracy and targeting dispersion included a significant dependence on shape constraints (p <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$< $</tex-math></inline-formula> .05). This study demonstrates the feasibility of enhancing distal targeting with the proposed robotized catheter and found that bronchi shape constraints significantly affect targeting capability.