Evaluation of the performance of robot assisted CT-guided percutaneous needle insertion: Comparison with freehand insertion in a phantom

Purpose: To evaluate the performance of a novel robot for CT-guided needle positioning procedures and compare it to the freehand technique in an abdominal phantom.Methods: One interventional radiology fellow and one experienced interventional radiologist (IR) performed twelve robot-assisted and twelve freehand needle positionings in a phantom over predetermined trajectories. The robot automatically aimed a needle-guide according to the planned trajectories, after which the clinician manually inserted the needle. Using repeated CT scans, the needle position was assessed and adjusted if the clinician deemed it necessary. Technical success, accuracy, number of position adjustments, and procedure time were measured. All outcomes were analyzed using descriptive statistics and were compared between the robot-assisted and freehand procedures using the paired t-test and Wilcoxon signed rank test.Results: Compared with the freehand technique, the robot system improved the number of technically success-fully needle targeting (20/24 vs 14/24), with higher accuracy (mean Euclidean deviation from target center: 3.5 symbolscript 1.8 mm vs 4.6 symbolscript 2.1 mm, p symbolscript 0.02) and required fewer needle position adjustments (0.0 symbolscript 0.2 steps vs 1.7 symbolscript 0.9 steps, p < 0.001), respectively. The robot improved the needle positioning for both, the fellow and the expert IR, compared to their freehand performances, with more improvement for the fellow than for the expert IR. The procedure time was similar for the robot-assisted and freehand procedures (19.5 symbolscript 9.2 min. vs 21.0 symbolscript 6.9 min., p symbolscript 0.777).Conclusions: CT-guided needle positioning with the robot was more successful and accurate than freehand needle positioning and required fewer needle position adjustments without prolonging the procedure.