Smartphone Augmented Reality CT-Based Platform for Needle Insertion Guidance: A Phantom Study

Objective: To develop and assess the accuracy of an augmented reality (AR) needle guidance smartphone application.

Methods: A needle guidance AR smartphone application was developed using Unity and Vuforia SDK platforms, enabling real-time displays of planned and actual needle trajectories. To assess the application's accuracy in a phantom, eleven operators (including interventional radiologists, non-interventional radiology physicians, and non-physicians) performed single-pass needle insertions using AR guidance (n = 8) and CT-guided freehand (n = 8). Placement errors were measured on post-placement CT scans. Two interventional radiologists then used AR guidance (n = 3) and CT-guided freehand (n = 3) to navigate needles to within 5 mm of targets with intermediate CT scans permitted to mimic clinical use. The total time and number of intermediate CT scans required for successful navigation were recorded.

Results: In the first experiment, the average operator insertion error for AR-guided needles was 78% less than that for CT-guided freehand (2.69 ± 2.61 mm vs. 12.51 ± 8.39 mm, respectively, p < 0.001). In the task-based experiment, interventional radiologists achieved successful needle insertions on each first attempt when using AR guidance, thereby eliminating the need for intraoperative CT scans. This contrasted with 2 ± 0.9 intermediate CT scans when using CT-guided freehand. Additionally, average procedural times were reduced from 13.1 ± 6.6 min with CT-guided freehand to 4.5 ± 1.3 min with AR guidance, reflecting a 66% reduction.

Conclusions: All operators exhibited superior needle insertion accuracy when using the smartphone-based AR guidance application compared to CT-guided freehand. This AR platform can potentially facilitate percutaneous biopsies and ablations by improving needle insertion accuracy, expediting procedural times, and reducing radiation exposures.