Structured phantom-assisted simulation for early abdominal ultrasound skill training in ultrasound medicine residents: a quasi-experimental study

BACKGROUND: Abdominal ultrasound is a core component of residency training in ultrasound medicine, yet opportunities for repetitive and standardized bedside practice are often limited in routine clinical settings. Although simulation-based teaching may help address this gap, evidence remains limited regarding the role of abdominal ultrasound phantom training in standardized residency curricula. This study evaluated whether integrating structured phantom-assisted simulation into routine residency teaching was associated with improved early abdominal ultrasound skill acquisition and clinically oriented performance among novice residents. METHODS: We conducted a quasi-experimental study with a historical comparison cohort at a tertiary teaching hospital. Consecutive postgraduate year 2 residents in ultrasound medicine were included. The intervention cohort (2023-2025) received the routine curriculum supplemented with a 4-week structured phantom-assisted training module, whereas the historical comparison cohort (2020-2022) underwent the conventional bedside apprenticeship-based curriculum alone. The primary outcome was total score on a standardized patient-based abdominal ultrasound objective structured clinical examination (OSCE). The secondary outcome was learner-reported self-assessment measured using a 6-item questionnaire. Standard-view acquisition and embedded-lesion recognition were assessed as intervention-process measures within the intervention cohort. RESULTS: A total of 58 residents were included (intervention, n = 32; historical comparison, n = 26). Baseline characteristics were comparable between cohorts. The intervention cohort achieved significantly higher OSCE scores than the historical comparison cohort (87.16 ± 3.81 vs. 84.04 ± 4.00), with a mean difference of 3.12 points (95% CI 1.06-5.18; P = 0.004; Cohen's d = 0.80). Inter-rater reliability for OSCE scores was good (ICC[2,1] = 0.746). Among residents in the intervention cohort, 71.9% completed all required standard views, and lesion-recognition task performance ranged from 78.6% to 86.5% across assessed domains. Compared with the historical comparison cohort, the intervention cohort also reported higher learner-reported scores in understanding of ultrasound anatomy, perceived skill mastery, and clinical readiness (all P < 0.05). CONCLUSIONS: Integration of a structured phantom-assisted simulation module into residency teaching was associated with improved abdominal ultrasound OSCE performance and better learner-reported outcomes in selected domains. Structured phantom-assisted training may serve as a useful supplementary approach for early abdominal ultrasound skill development, although its long-term transfer value requires further study.