IMPROVED CINE MRI BY DIRECT-INVERSION RECONSTRUCTION

描述（由申请人提供）：采集速度仍然是电影磁共振成像（MRI）中的关键问题。结构和功能心脏成像，以及越来越多的冠状动脉和血流成像，正在成为越来越重要的工具，在评价范围广泛的心血管疾病。所有这些扫描通常涉及到受心脏和呼吸运动影响的解剖结构。目前，多相ECG门控成像通常在屏气模式下进行，但患者可耐受的屏气采集的持续时间和数量是图像质量和分辨率的主要限制因素。许多心脏疾病的特殊症状加重了这些限制。正在以多种方式追求更快的MRI数据采集：改进的梯度硬件允许更快的空间编码;相控阵射频线圈提供增加的信噪比（SNR）;新的稳态自由进动采集技术有助于在这两个方面的改进;其它创新，如部分傅立叶成像、并行成像或缩小视场（rFOV）方法，探索成像速度的进一步改进，通常通过利用成像模型中的各种类型的先验知识来交换一些SNR。提高SNR或速度的技术的组合使用不断推动电影成像的临床可行应用的极限。然而，并非所有技术都总是兼容的，并且所有单个技术的收益都是有限的，因此在这一领域中开发其他技术仍然是期望的，并且具有高度相关性。该提案将研究一种新的rFOV技术的开发和评估，该技术有望在空间和时间分辨率方面提供优于可比方法的重要优势。该项目建立在回顾性实施的令人鼓舞的初步结果的基础上，使用常规采集的MRI数据的减少子集来获得全分辨率电影重建。开发提出了一个完整的前瞻性实施的采集方法的临床设备。优化将调查方面的SNR，文物，和数值效率。将使用该方法对图像质量和流量计算进行定性和定量评价。最后，将研究该方法与并行成像方法相结合的可行性。

DESCRIPTION (provided by applicant): Acquisition speed remains a critical issue in cine magnetic resonance imaging (MRI). Structural and functional cardiac imaging, and increasingly also coronary artery and flow imaging, are becoming ever-more important tools in evaluation of a wide range of cardiovascular diseases. All of these scans often involve anatomy that is subject to both cardiac and respiratory motion. Multi-phase ECG-gated imaging is nowadays routinely performed in breath-hold mode, but both the duration and number of breath-hold acquisitions that can be tolerated by the patient are dominant limiting factors for image quality and resolution. These limitations are aggravated by the particular symptoms of many cardiac diseases. Faster MRI data acquisition is being pursued in multiple ways: improved gradient hardware allows faster spatial encoding; phased-array radiofrequency coils offer increased signal-to-noise ratio (SNR); new steady- state free precession acquisition techniques contribute improvements on both these fronts; other innovations, like partial-Fourier imaging, parallel imaging, or reduced field of view (rFOV) methods explore further improvements in imaging speed, often by trading some SNR, by exploiting various types of prior knowledge in the imaging model. Combined use of technologies that improve SNR or speed keeps pushing the limits of clinically feasible applications of cine imaging. However, not all techniques are always compatible, and the gains from all individual techniques are bounded, so the development of additional technologies in this realm is still desired and highly relevant. This proposal will investigate development and evaluation of a novel rFOV technique that promises to offer important advantages over comparable methods in terms of spatial and temporal resolution. The project builds on encouraging preliminary results from a retrospective implementation, using reduced subsets from conventionally acquired MRI data to obtain full-resolution cine reconstructions. Development is proposed of a full prospective implementation of the acquisition method on clinical equipment. Optimization will be investigated with respect to SNR, artifacts, and numerical efficiency. Qualitative and quantitative evaluations will be performed of image quality and flow calculations using the method. Finally, feasibility will be investigated of combining this method and parallel imaging methods.