Low-Cost homemade Agar-Based phantoms for Ultrasound-Guided procedure Training: A randomized educational trial

To assess the non-inferiority of low-cost homemade agar-based phantoms compared to commercial models regarding students' self-reported confidence and performance in basic ultrasound-guided procedures.

This randomized controlled study was conducted at a single university in June 2025, during interventional radiology (IR) resident training sessions. Participants were all consecutive students randomized 2:1 to either agar-based or commercial phantoms. Phantoms were designed to simulate deep collection puncture and vascular access. Participants completed technical assessments and questionnaires before and after the training.

Twenty-three residents (8 male [35%]; median residency semester [IQR], 2 [2-4]) were included and randomized to the agar-based group (n = 15) or the commercial phantom group (n = 8). Students increased their self-reported confidence in basic procedures from 3.7 ± 2.4 to 6.2 ± 1.7 out of 10 (+ 2.5 points; p < 0.01), with non-inferiority of agar-based models confirmed (p = 0.04). Procedure time improved by 135 ± 174 s (p < 0.01), with non-inferiority demonstrated for deep collection puncture test (p = 0.04). The number of punctures decreased by 0.6 ± 0.7 (p = 0.04) for this test, again with non-inferiority confirmed for agar phantoms (p = 0.02). Overall interest in IR was high (7.1 ± 2.2 /10), particularly for Level-1 procedures (8.6 ± 1.3/10). Students trained with agar models expressed high satisfaction, rating their support for using such models in educational settings at 8.9 ± 1.3/10.

Low-cost homemade agar-based phantoms appeared to be non-inferior to commercial models for confidence improvement, but not for all performance outcomes in this small sample. However, they significantly improved trainees' performance during ultrasound-guided intervention training.