Free breathing cardiac MRI sequences

描述(申请人提供)：这项研究的目标是开发自由呼吸心脏磁共振成像，以准确和快速地评估心脏形态、心功能、血流动力学和心肌特征。目前临床心脏MRI采用屏气2D采集方法，通过多次重复屏气对心脏切片进行成像。这种屏气方法的局限性包括不适用于呼吸困难患者，屏气问题导致的图像质量差，切片配准错误，空间分辨率和体积覆盖不一致。我们和其他人使用铅笔梁横隔膜导航仪开发了解决这些屏气问题的自由呼吸方法。然而，在临床实践中，自由呼吸心脏MRI很少进行，部分原因是心脏导航仪序列没有得到充分的开发，横隔膜导航仪不直接测量心脏运动，以及当前导航仪扫描时间太长。我们建议扩展和优化自由呼吸导航仪心脏MRI序列。心脏脂肪导航仪将被用来直接监测心脏的运动。使用同时多体积方法将提高导航仪扫描效率。使用基于多线圈的并行成像将进一步缩短扫描时间。一旦成功完成，这项研究将带来快速而准确的自由呼吸心脏核磁共振。在这个五年的研究项目中，我们将重点开发两种类型的脉冲序列的导航仪并行成像，即心电触发的分段序列(黑血快速自旋回波和心肌延迟增强)和电影序列(电影相位对比和电影稳态自由进动)。这是我们实践中最常用的四种脉冲序列。因此，我们计划通过以下具体目标来实现快速、准确、自由呼吸的心脏MRI的目标：1.研制心脏脂肪导航仪和心电触发节段序列的综合导航仪并行成像。2.开发电影序列的导航仪并行成像。3.在一组心脏病患者中评估已开发的自由呼吸心脏MRI。这项研究拨款将开发使用导航仪方法和加速并行成像方法的快速自由呼吸心脏MRI序列。它将克服目前屏气心脏磁共振成像的局限性。它将把心脏MRI检查的好处扩大到屏气困难的患者。它将提高心脏MRI的空间分辨率、空间覆盖率、时间分辨率和扫描速度。

DESCRIPTION (provided by applicant): The objective of this research is to develop free breathing cardiac magnetic resonance imaging for accurate and fast assessment of cardiac morphology, ventricular function, flow dynamics and myocardial characterization. Currently clinical cardiac MRI is performed using the breath-holding 2D acquisition approach, imaging the heart slice by slice through many repetitive breath-holds. The limitations of this breath-hold approach include inapplicability in dyspneic patients, poor image quality with problematic breath-holding, slice misregistration, indequate spatial resolution and volume coverage. The free breathing approach to address these breath-hold problems have been developed by us and others using the pencil beam diaphragm navigator. However, free breathing cardiac MRI is rarely performed in clincal practice, partly because cardiac navigator sequences have not been adequately developed, the diaphragm navigator does not measure heart motion directly, and current navigator scan time is too long. We propose to expand and optimize free breathing navigator cardiac MRI sequences. The cardiac fat navigator will be used to directly monitor motion of the heart. Navigator scan efficiency will be increased using the simultaneous mulitple volume approach. The scan time will be further shortened using multiple coil based parallel imaging. Upon successful completion, this research will lead to a fast and accurate free breathing cardiac MRI. In this five year research project, we will focus on developing navigator parallel imaging for two types of pulse sequences, eletrocardiogram-triggered segmented sequences (black blood fast spin echo and myocardial delayed enhancement) and cine sequences (cine phase contrast, and cine steady state free precession). These are the four most commonly used pulse sequences in our practice. Accordingly we plan to achieve the goal of fast accurate free breathing cardiac MRI through the following specific aims: 1. Develop cardiac fat navigator and integrated navigator parallel imaging for ECG-triggered segmented sequences. 2. Develop navigator parallel imaging for cine sequences. 3. Evaluate developed free breathing cardiac MRI in a cohort of cardiac patients. This research grant will develop fast free breathing cardiac MRI sequences using the navigator method and the accelerated parallel imaging method. It will overcome the limitation of current breath hold cardiac MRI. It will extend the benefit of cardiac MRI examination to patients with difficulty holding breath. It will improve the spatial resolution, spatial coverage, temporal resolution, and scan speed of cardiac MRI.