FREE BREATHING 3D CARDIAC MRI

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。在心脏MRI应用中，需要冻结或解决心脏和呼吸运动提出了一个困难的挑战。我们提出了一种新的方法来检测和纠正复杂的呼吸引起的心脏运动，同时捕捉其跳动运动。与我们目前的临床壁运动方案相比，我们将开发一种呼吸补偿的3D心脏成像方法，并测试其评估心肌运动的能力。具体目标是：1。开发和实施一个非常快速的3D成像策略。并行成像算法、我们的展开方法和部分傅立叶成像算法将被融合在一起，得到的混合方法将在三维稳态自由进动（SSFP）成像序列上实现。2. 开发，实施和评估在具体目标1中开发的快速成像方法的进一步补充。将研究新的策略来抑制脂肪信号，进一步抑制潜在的伪影，提高空间/时间分辨率。由此产生的快速成像方法将用于生成时间序列的三维心脏图像，其时间分辨率足以分辨呼吸周期（每1至1.5秒一帧）。开发一种第一步检测/校正呼吸运动，第二步生成心相图像的方法。心脏呼吸运动将以两种互补的方式检测：传统的呼吸监测可拉伸带将提供具有非常高时间分辨率的（非定量）信息，而具体目标1和2中开发的3D成像方案将提供丰富的空间/几何定量运动相关信息。结合这两种来源的知识将允许检测和纠正心脏在空间/时间上复杂的呼吸运动。在第二步中，呼吸校正数据将从时间序列转换为高质量的心脏期3D图像序列。4. 为了评估该方法在捕获心肌运动任务中的性能，并将其与我们机构目前使用的方案进行比较，这是当前最先进技术的一个代表性例子。目标是验证我们的方法提供信噪比，空间分辨率（包括空间模糊）和诊断价值优于当前协议的假设。将对志愿者和患者进行幻影实验、模拟和成像。对这些结果的评估将涉及客观标准（定量测量）和主观标准（临床医生对图像质量的印象）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In cardiac MRI applications, the need to freeze or resolve both cardiac and respiratory motion poses a difficult challenge. We propose a novel approach to detect and correct for the complex respiration-induced motion of the heart, while capturing its beating motion. A respiration compensated, 3D cardiac imaging method will be developed and tested in its ability to evaluate myocardium motion, as compared to our current clinical wall-motion protocol. The specific aims are: 1. To develop and implement a very fast 3D imaging strategy. The algorithms for parallel imaging, for our UNFOLD method and for partial-Fourier imaging will be fused, and the resulting hybrid method will be implemented on a 3D steady-state free-precession (SSFP) imaging sequence. 2. To develop, implement and evaluate further additions to the fast imaging approach developed in Specific Aim 1. Novel strategies will be investigated to suppress fat signal, further suppress potential artifacts and improve spatial/temporal resolution. The resulting fast imaging method will be used to generate time series of 3D cardiac images with temporal resolution sufficient to resolve the respiratory cycle (one frame every 1 to 1.5 s). 3. To develop a method for detecting/correcting respiratory motion in a first step, and generating cardiac-phase images in a second step. The heart respiratory motion will be detected in two complementary ways: A conventional respiration monitoring stretchable belt will provide (non-quantitative) information with very high temporal resolution, while the 3D imaging scheme developed in Specific Aims 1 and 2 will provide a wealth of spatial/geometrical quantitative motionrelated information. Combining the knowledge from these two sources will allow the spatially/temporally complex respiratory-motion of the heart to be detected and correct for. In a second step, the respiration-corrected data will be converted from a time series to a cardiac-phase series of high quality 3D images. 4. To evaluate the method's performance in the task of capturing myocardium motion as compared to the protocol currently in use at our institution, a representative example of the current state-of-the-art. The goal is to verify the hypothesis that our method provides SNR, spatial resolution (which includes spatial blurring) and diagnostic value superior to those of the current protocol. Phantom experiments, simulations and imaging of volunteers and patients will be performed. The evaluation of these results will involve both objective criteria (quantitative measurements) as well as subjective criteria (clinicians' impressions on image quality).