IMPROVED CINE MRI BY DIRECT-INVERSION RECONSTRUCTION

在电影磁共振成像（MRI）中，采集速度仍然是一个关键问题。结构和 功能性心脏成像以及越来越多的冠状动脉和血流成像正变得越来越重要。 是评估多种心血管疾病的重要工具。所有这些扫描通常涉及 受心脏和呼吸运动影响的解剖结构。多相位心电门控成像是当今 常规在屏气模式下进行，但屏气采集的持续时间和次数 是图像质量和分辨率的主要限制因素。这些 许多心脏病的特殊症状加重了这种限制。 更快的MRI数据采集正在以多种方式进行：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更高的信噪比（SNR）;新的稳定- 状态自由进动获取技术有助于在这两个方面的改进; 部分傅立叶成像、平行成像或缩小视场（rFOV）方法等创新探索了 成像速度的进一步提高，通常通过交易一些SNR，通过利用各种类型的先验 成像模型中的知识。提高信噪比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局限性。然而，并不是所有的技术都是 兼容，从所有个别技术的收益是有限的，所以额外的发展 这一领域的技术仍然是需要的和高度相关的。 该提案将研究一种新型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了优于可比方法的重要优势。项目 建立在回顾性实施的令人鼓舞的初步结果的基础上， 常规采集的MRI数据以获得全分辨率电影重建。建议开发一种 在临床设备上全面实施采集方法。优化将是 研究了SNR、伪影和数值效率。定性和定量评价 将使用该方法执行图像质量和流量计算。最后，可行性 研究了将该方法与并行成像方法相结合。

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 performedin breath-hold mode, but both the duration and number of breath-hold acquisitions that can be tolerated by the patient are dominant limiting factorsfor 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.