Meta Quest Store: https://www.meta.com/experiences/stanford-mri-simulator/8205539289482347/ Magnetic Resonance Imaging (MRI) can be a stressful experience for pediatric patients due to the loud acoustic environment, enclosed scanner bore, and a prolonged requirement to remain still. While sedation is commonly used to manage anxiety and motion, it carries clinical risks and logistical burdens. Traditional preparatory approaches, such as instructional videos and mock scans, often lack engagement for older children and adolescents. In this study, we present a comparative evaluation of four MRI preparation modalities: (1) a gamified virtual reality (VR) simulation that trains stillness through real-time feedback; (2) a passive VR experience replicating the MRI environment without interactivity; (3) a 360° first-person video of a real MRI procedure; and (4) a standard 2D educational video. Using a within-subjects design (N = 11, ages 10-16), we assess each method's impact on head motion data, anxiety reduction, procedural preparedness, usability, cognitive workload, and subjective preference. Results show that the gamified VR condition has significantly lower head motion (p < 0.001) and yielded the highest preparedness scores (p < 0.05). Head motion data were significantly correlated with learning outcomes (p < 0.01), suggesting that behavioral performance in VR strongly indicates procedural readiness. While all modalities reduced anxiety and were rated usable, interactive VR was preferred by most participants and demonstrated unique advantages in promoting engagement and behavioral rehearsal. We conclude with design recommendations for designing immersive simulations and integrating VR training into pediatric imaging workflows.