FREE BREATHING 3D CARDIAC MRI

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 在心脏MRI应用中，需要冻结或解析心脏和呼吸运动，这是一个困难的挑战。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，同时捕捉其跳动的运动。将开发一种呼吸补偿的3D心脏成像方法，并与我们目前的临床室壁运动方案相比，测试其评价心肌运动的能力。具体目标是： 1.开发和实施一个非常快速的3D成像策略。并行成像的算法，为我们的展开方法和部分傅立叶成像将被融合，所得到的混合方法将在3D稳态自由进动（SSFP）成像序列上实现。 2.开发、实施和评价对具体目标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并提高空间/时间分辨率。所得到的快速成像方法将用于生成3D心脏图像的时间序列，其时间分辨率足以解析呼吸周期（每1至1.5秒一帧）。 3.开发一种方法，用于在第一步骤中检测/校正呼吸运动，并且在第二步骤中生成心脏相位图像。将以两种互补的方式检测心脏呼吸运动：传统的呼吸监测可拉伸带将提供具有非常高的时间分辨率的（非定量）信息，而特定目标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。组合来自这两个源的知识将允许检测和校正心脏的空间/时间复杂的重复运动。在第二步中，呼吸校正数据将从时间序列转换为高质量3D图像的心脏相位序列。 4.为了评估该方法在捕获心肌运动的任务中的性能相比，目前在我们的机构中使用的协议，当前国家的最先进的一个代表性的例子。我们的目标是验证假设，我们的方法提供的SNR，空间分辨率（包括空间模糊）和诊断价值优于当前协议的上级。将对志愿者和患者进行体模实验、模拟和成像。这些结果的评价将涉及客观标准（定量测量）和主观标准（临床医生对图像质量的印象）。 未来计划 尽管已经获得了显示自由呼吸志愿者的3D跳动心脏的初步结果，但伪影仍然限制了相应结果的有用性。我们将追踪，并希望解决，这些文物的来源。空间分辨率的提高也将纳入实施工作。与儿童医院的合作已经建立，以调查该方法是否可以用于防止年龄足够大的儿童在扫描过程中保持静止，但无法可靠地遵循呼吸指令时需要镇静和机械通气。这项工作的2D成像方面现在似乎已准备好进行临床验证。 合作对NCIGT的好处 该项目提供了一个应用程序，其中开发的快速成像方法作为NCIGT成像核心的一部分，可以应用。更具体地说，它是第一个被考虑的3D应用程序，并提供了一个实际的环境，在这个环境中，我们正在编写的软件的3D兼容性可以被测试和改进。 对项目的好处 NCIGT正在提供并行成像软件，以更快的代码取代目前缓慢的重建程序（典型的3D时间序列需要几个小时），这可以使该方法从概念验证阶段进行到临床环境中的实际测试。 确认R 01和U41赠款的出版物 -B. Madore，W.S.霍格河阿广展开方法的扩展，包括自由呼吸。Magn Reson Med 55：352-362（2006）。 -B.马多雷湾Farneb ck，C.- F. M.威斯汀A.在门迪库蒂。一种新的呼吸补偿策略，适用于3D自由呼吸心脏MR成像。Magn Reson Imag 24：727-737（2006）。

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). Plans going forward Although preliminary results showing the beating heart in 3D in free-breathing volunteers have been obtained, artifacts still limit the usefulness of the corresponding results. We will track down, and hopefully address, the sources of these artifacts. Increases in spatial resolution will also be incorporated into the implementation. Collaboration with the Children's hospital has been established to investigate whether the approach can be used to prevent the need for sedation and mechanical ventilation in children old enough to remain mostly still during a scan, but yet unable to reliably follow breathing instructions. The 2D imaging aspect of this work now seems ready for clinical validation. Benefits of the Collaboration to the NCIGT This project provides one of the applications where the fast-imaging approaches developed as part of the NCIGT Imaging core can be applied. More specifically, it is the first 3D application to be considered, and provides a practical context in which the 3D compatibility of the software we are writing can be tested and improved. Benefits to the Project The NCIGT is providing parallel-imaging software to replace the slow reconstruction programs currently in place (a few hours for a typical 3D time series) by much faster code, which can allow the method to proceed from a proof-of-concept stage to actual tests in a clinical setting. Publications Acknowledging both the R01 and the U41 Grants -B. Madore, W.S. Hoge, R. Kwong. An extension to the UNFOLD method to include free-breathing. Magn Reson Med 55:352-362 (2006). -B. Madore, G. Farneb¿ck, C.-F. Westin, M. A. Dur¿n Mendicuti. A new strategy for respiration compensation, applied toward 3D free-breathing cardiac MR imaging. Magn Reson Imag 24:727-737 (2006).