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arXiv · 2509.05955

Active noise cancellation in ultra-low field MRI: distinct strategies for different channels

Jiali He·Sheng Shen·Jiamin Wu·Xiaohan Kong·Yamei Dai·Liang Tan·Zheng Xu
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Abstract

Ultra-low field magnetic resonance imaging(ULF-MRI) systems operating in open environments are highly susceptible to composite electromagnetic interference(EMI). Different imaging channels respond non-uniformly to EMI owing to their distinct coupling characteristics. Here, we investigate channel-specific interference pathways in a permanent-magnet-based low-field MRI system and show that saddle coils are intrinsically more vulnerable to transverse EMI components than solenoidal coils. To mitigate these heterogeneous coupling effects, we propose a dual-stage suppression strategy that combines front-end spatial-domain inverse field reconstruction with back-end channel-adaptive active noise cancellation. Experiments demonstrate that this approach suppresses EMI by more than 80%, substantially improves inter-channel signal-to-noise ratio(SNR) consistency, and enhances the fused-image SNR by 24%. These findings elucidate the channel-dependent nature of EMI coupling and establish targeted mitigation strategies, providing both a theoretical basis and practical guidance for noise suppression in future array-coil ULF-MRI systems.

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Jiali He, Sheng Shen, Jiamin Wu, Xiaohan Kong, Yamei Dai, Liang Tan, Zheng Xu. 2025-09-07. Active noise cancellation in ultra-low field MRI: distinct strategies for different channels. https://arxiv.org/abs/2509.05955

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