3D Slicer-based preprocedural trajectory planning for transvenous mediastinal biopsy using automated segmentation: a technical note.

Histological diagnosis of mediastinal tumors can be challenging when safe puncture access is limited by adjacent airway and vascular structures. This technical note describes a 3D Slicer software-based preprocedural planning workflow for transvenous mediastinal biopsy using automated segmentation of normal anatomical structures. In a woman in her 60s with a large mediastinal tumor and superior vena cava (SVC) syndrome, a transpulmonary approach was considered undesirable because of the risk of pneumothorax and hemorrhage, and a transvenous approach was advantageous because biopsy and subsequent endovascular management of SVC syndrome could be incorporated into the same strategy. Contrast-enhanced computed tomography data were imported into 3D Slicer, and critical organs were segmented using artificial intelligence-based tools, and the tumor was manually segmented. With a fixed entry point in the SVC, six candidate puncture trajectories were generated and compared using three-dimensional distance-based metrics. A composite risk score was used to rank the trajectories as a heuristic within-case decision-support tool rather than a validated predictor. The workflow did not automatically determine the puncture direction but provided practical decision support by visualizing and avoiding high-risk trajectories. Transvenous biopsy was successfully performed under biplane fluoroscopic guidance using a transjugular liver biopsy kit without procedural complications.