Virtual airways heatmaps to optimize point of entry location in lung biopsy planning systems

TL;DR

This paper introduces a virtual airway heatmap model to optimize biopsy entry points in lung procedures, accounting for orientation errors and lesion characteristics to improve planning accuracy.

Contribution

The study presents a novel 3D heatmap approach that visualizes optimal biopsy points considering navigation errors and lesion shape, enhancing lung biopsy planning.

Findings

Heatmaps reveal lesion orientation significantly affects biopsy success.

Distance from airways impacts tissue extraction potential.

Multiple optimal entry zones can be identified for flexible planning.

Abstract

Purpose: We present a virtual model to optimize point of entry (POE) in lung biopsy planning systems. Our model allows to compute the quality of a biopsy sample taken from potential POE, taking into account the margin of error that arises from discrepancies between the orientation in the planning simulation and the actual orientation during the operation. Additionally, the study examines the impact of the characteristics of the lesion. Methods: The quality of the biopsy is given by a heatmap projected onto the skeleton of a patient-specific model of airways. The skeleton provides a 3D representation of airways structure, while the heatmap intensity represents the potential amount of tissue that it could be extracted from each POE. This amount of tissue is determined by the intersection of the lesion with a cone that represents the uncertainty area in the introduction of biopsy instruments. The cone, lesion, and skeleton are modelled as graphical objects that define a 3D scene of the intervention. Results: We have simulated different settings of the intervention scene from a single anatomy extracted from a CT scan and two lesions with regular and irregular shapes. The different scenarios are simulated by systematic rotation of each lesion placed at different distances from airways. Analysis of the heatmaps for the different settings show a strong impact of lesion orientation for irregular shape and the distance for both shapes. Conclusion: The proposed heatmaps help to visually assess the optimal POE and identify whether multiple optimal POEs exist in different zones of the bronchi. They also allow us to model the maximum allowable error in navigation systems and study which variables have the greatest influence on the success of the operation. Additionally, they help determine at what point this influence could potentially jeopardize the operation.