The effect of magnetic interference by magnetic resonance imaging on programmable shunt valves in patients with normal pressure hydrocephalus: a systematic review and pooled analysis.

INTRODUCTION: Normal pressure hydrocephalus (NPH) is a cause of neurological impairment, with programmable shunt valves serving as the standard treatment. However, magnetic interference can result in altered pressure settings, affecting valve functionality. RESEARCH QUESTION: This systematic review investigates the effects of magnetic resonance imaging (MRI) on programmable shunt valves in NPH patients. MATERIAL AND METHODS: Conducted in adherence to PRISMA guidelines, an extensive literature search across PubMed and Embase databases from January 2000 to January 2025, was performed. Studies evaluating the impact of MRI at 1.5T and 3T field strengths on valve settings were included. Valve reprogrammability and outcomes were analysed, with statistical comparisons across MRI strengths and valve types using Mann-Whitney U and ANOVA tests. RESULTS: The pooled analysis included 475 NPH patients across 11 studies. Valve setting alteration was required in 44.2% of cases following 1.5T exposure and 55.2% after 3T exposure, with no statistically significant difference between field strengths (p > 0.05). Valve type analysis revealed that the Codman Hakim valve exhibited the highest incidence of setting changes (37.05% at 3T). However, differences in valve setting changes between manufacturers were not statistically significant (p > 0.05). DISCUSSION AND CONCLUSION: Magnetic interference from MRI can disrupt programmable shunt valves in NPH patients. While 3T MRI shows a slightly higher incidence of valve setting changes than 1.5T, the difference is not significant. Further research is required to assess long- term clinical implications and standardize MRI protocols to mitigate variability in outcomes. CLINICAL TRIAL NUMBER: Not applicable.