Evaluation of Technical Performance of Ultrasound-Guided Procedures through Hand Motion Analysis: An Exploration of Motion Metrics.

PURPOSE: To evaluate the ability of hand motion analysis using conventional and new motion metrics to differentiate between operators of varying levels of experience for central venous access (CVA) and liver biopsy (LB). MATERIALS AND METHODS: In the CVA task, 7 interventional radiologists (experts), 10 senior trainees, and 5 junior trainees performed ultrasound-guided CVA on a standardized manikin; 5 trainees were retested after 1 year. In the LB task, 4 radiologists (experts) and 7 trainees biopsied a lesion on a manikin. Conventional motion metrics (path length and task time), a refined metric (translational movements), and new metrics (rotational sum and rotational movements) were calculated. RESULTS: In the CVA task, experts outperformed trainees on all metrics (P < .02). Senior trainees required fewer rotational movements (P = .02), translational movements (P = .045), and time (P = .001) than junior trainees. Similarly, on 1-year follow-up, trainees had fewer translational (P = .02) and rotational (P = .003) movements with less task time (P = .003). The path length and rotational sum were not different between junior and senior trainees or for trainees on follow-up. Rotational and translational movements had greater area under the curve values (0.91 and 0.86, respectively) than the rotational sum (0.73) and path length (0.61). In the LB task, experts performed the task with a shorter path length (P = .04), fewer translational (P = .04) and rotational (P = .02) movements, and less time (P < .001) relative to the trainees. CONCLUSIONS: Hand motion analysis using translational and rotational movements was better at differentiating levels of experience and improvement with training than the conventional metric of path length.