Association of caregiver presence with MRI quality in preschool children: an observational study

Non-sedated brain MRI in preschool children is frequently limited by anxiety-related motion artifacts. This study examined whether caregiver presence was associated with brain MRI image quality and explored whether autonomic regulation and anxiety-related measures were statistically associated with this relationship. This prospective, controlled, non-randomized two-center study included 259 children aged 3-6 years undergoing non-contrast brain MRI. Children received either caregiver presence or routine digital distraction according to institutional workflow and caregiver availability. Pre-MRI heart rate variability (HRV), behavioral responses, image quality and diagnostic confidence were assessed. The primary outcome was suboptimal-quality MRI, defined as an image-quality score ≤3. Sensitivity analyses, propensity score adjustment and exploratory bootstrap mediation analysis were performed. Caregiver presence was associated with lower anxiety, fear, crying and repeat-scan risk, better cooperation, lower heart rate, higher RMSSD, more favorable autonomic balance and higher image quality. Suboptimal-quality MRI was less frequent in the caregiver-presence group than in the digital-distraction group (64/129 [49.6%] vs 83/130 [63.8%]; P = 0.029). The stricter poor-quality threshold of score ≤2 showed a similar association (8.5% vs 22.3%; P = 0.004). After propensity score adjustment, caregiver presence remained associated with lower odds of suboptimal-quality MRI. The integrated HRV-behavioral model showed strong discrimination for suboptimal-quality MRI. Exploratory mediation analysis suggested that anxiety-related measures and RMSSD-related measures were statistically associated with the observed relationship between caregiver presence and image quality. Caregiver presence was associated with better non-contrast brain MRI image quality in preschool children.This association may involve differences in autonomic regulation and anxiety-related responses; however, causal interpretation is limited by the observational design. External validation and randomized studies are warranted before implementation of HRV-informed individualized MRI preparation.