Sui Yao, Afacan Onur, Gholipour Ali, Warfield Simon K
Harvard Medical School, Boston, MA, USA.
Boston Children's Hospital, Boston, MA, USA.
Med Image Comput Comput Assist Interv. 2019 Oct;11766:3-11. doi: 10.1007/978-3-030-32248-9_1. Epub 2019 Oct 10.
In this work, we proposed a novel image-based MRI super-resolution reconstruction (SRR) approach based on anisotropic acquisition schemes. We achieved superior reconstruction to state-of-the-art work by introducing a new multi-scale gradient field prior that guides the reconstruction of the high-resolution (HR) image. The prior improves both spatial smoothness and edge preservation. The inverse of the forward model of image formation is used to propagate the gradient guidance from the low-resolution (LR) images to the HR image space. The gradient fields over multiple scales were exploited for more accurate edge localization in the reconstruction. The proposed SRR allows inter-volume motion during the MRI scans and can incorporate with the LR images with arbitrary orientations and displacements in the frequency space, such as orthogonal and origin-shifted scans. The proposed approach was evaluated on the synthetic data as well as the data acquired on a Siemens 3T MRI scanner containing 45 MRI scans from 14 subjects. The evaluation results demonstrate that our proposed prior leads to improved SRR as compared to state-of-the-art priors, and that the proposed SRR obtains better results at lower or the same cost in scan time than direct HR acquisition. In particular, the anatomical structures of hippocampus can be clearly shown in our reconstructed images. This is a significant improvement for the in vivo studies of the hippocampus.
在这项工作中，我们提出了一种基于各向异性采集方案的新型基于图像的磁共振成像超分辨率重建（SRR）方法。通过引入一种新的多尺度梯度场先验来指导高分辨率（HR）图像的重建，我们实现了比现有技术更优的重建效果。该先验提高了空间平滑度和边缘保留能力。利用图像形成正向模型的逆过程将梯度引导从低分辨率（LR）图像传播到HR图像空间。利用多尺度的梯度场在重建中进行更精确的边缘定位。所提出的SRR允许在磁共振成像扫描期间进行体间运动，并且可以与频率空间中具有任意方向和位移的LR图像相结合，例如正交和原点偏移扫描。所提出的方法在合成数据以及在西门子3T磁共振成像扫描仪上采集的数据上进行了评估，该数据包含来自14名受试者的45次磁共振成像扫描。评估结果表明，与现有技术的先验相比，我们提出的先验导致了改进的SRR，并且所提出的SRR在扫描时间成本更低或相同的情况下比直接采集HR获得了更好的结果。特别是，海马体的解剖结构在我们重建的图像中可以清晰显示。这对于海马体的体内研究是一个显著的改进。
