Integrated Needle Guide on Smartphone for Percutaneous Interventions Using Augmented Reality.

Purpose: This study aimed to describe the workflow and evaluate the accuracy of a novel smartphone augmented reality (AR) application that includes an integrated needle guide, in a phantom.

Materials and methods: A smartphone cover with an integrated needle guide was designed and 3D-printed. An AR application for percutaneous application was developed, which integrated a projected needle path based on the rigid needle guide. After planning the needle path using this novel tool, the operator could place the needle through the guide to reach the target. Six lesions with out-of-plane entry points were targeted on an abdominal phantom. Timing and accuracy of needle placements were measured on post-procedural CT both using smartphone AR guidance and with a freehand approach. Results were compared using Wilcoxon rank sum and Pearson's chi-squared tests.

Results: A total of 108 needle placements were performed by 9 physicians with widely varying experience. The median accuracy was 4 mm (IQR 3-6 mm) using the smartphone versus 18 mm (IQR 9-27 mm) for freehand (P < 0.001). Using the smartphone AR application, planning time was 91 s (IQR 71-151 s), and puncture time was 68 s (IQR 57-77 s). There was no difference in accuracy, planning, or puncture times according to experience level when using the AR tool.

Conclusion: This smartphone application with an integrated needle guide allows path planning and accurate needle placement on phantoms with real-time angular feedback in less than 3 min. This technology could promote standardization, reduce experience requirements, or provide accurate low-cost guidance in environments without procedural imaging for percutaneous interventions.