đ¤ AI Summary
To address the challenge of simultaneously modeling low-frequency structural information and preserving high-frequency details in undersampled k-space MRI reconstruction, this paper proposes a dual-stream Mamba architecture enhanced with a W-Laplacian module. The method introduces: (1) a W-Laplacian module that enables fidelity-driven spectral decoupling, explicitly separating low-frequency semantics from high-frequency textures; (2) a dual-stream Mamba design with an adaptive state-space modulation mechanism to jointly capture long-range dependencies and local fine-grained details; and (3) a unidirectional sequence scanning strategy that maintains modeling capacity while reducing computational redundancy. With linear time complexity, the proposed approach significantly outperforms mainstream CNNs, Transformers, and existing Mamba variants. It achieves state-of-the-art reconstruction accuracy on multiple standard MRI benchmarks using a substantially more lightweight architecture.
đ Abstract
Reconstructing high-fidelity MR images from undersampled k-space data remains a challenging problem in MRI. While Mamba variants for vision tasks offer promising long-range modeling capabilities with linear-time complexity, their direct application to MRI reconstruction inherits two key limitations: (1) insensitivity to high-frequency anatomical details; and (2) reliance on redundant multi-directional scanning. To address these limitations, we introduce High-Fidelity Mamba (HiFi-Mamba), a novel dual-stream Mamba-based architecture comprising stacked W-Laplacian (WL) and HiFi-Mamba blocks. Specifically, the WL block performs fidelity-preserving spectral decoupling, producing complementary low- and high-frequency streams. This separation enables the HiFi-Mamba block to focus on low-frequency structures, enhancing global feature modeling. Concurrently, the HiFi-Mamba block selectively integrates high-frequency features through adaptive state-space modulation, preserving comprehensive spectral details. To eliminate the scanning redundancy, the HiFi-Mamba block adopts a streamlined unidirectional traversal strategy that preserves long-range modeling capability with improved computational efficiency. Extensive experiments on standard MRI reconstruction benchmarks demonstrate that HiFi-Mamba consistently outperforms state-of-the-art CNN-based, Transformer-based, and other Mamba-based models in reconstruction accuracy while maintaining a compact and efficient model design.