压缩感知理论为快速磁共振成像提供了一种系统的理论框架，即通过少量非相干的采样数据便可实现精确的图像重建。然而，在高度欠采样的情况下，混叠伪影依然很严重。目前，已有大量的研究工作探讨了利用来自参考图像的先验信息来提高重建质量的方法。文章提出基于参考图像梯度方向先验的压缩感知磁共振成像方法。该方法通过约束目标图像中结构边缘的切向量与参考图像中对应位置的法向量相垂直，以使目标图像中结构边缘的方向和参考图像保持一致。最后，运用多对比度扫描的实验数据，通过与传统的压缩感知磁共振成像方法相比较，验证了该方法能够实现快速且高质量的磁共振成像。%The theory of compressed sensing (CS) provides a systematic framework for magnetic resonance (MR) image reconstruction from incoherently under-sampledk-space data. However, severe aliasing artifacts may still occur in cases of high acceleration and noisy measurements. Thereupon, an extensive body of work investigates exploiting additional prior information extracted from a reference image which can be acquired with relative ease in many MR applications. In this work, a CS-based MR image reconstruction method using reference gradient orientation priors was proposed. Specifically, the tangent vector in the target image was regularized to be perpendicular to the corresponding normal vector in the reference image over all spatial locations to make the gradient orientations in the reference and the target image consistent. The proposed method is validated using multi-scan experiment data and is shown to provide high speed and high quality imaging.
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