Sparse sampling and constrained reconstruction for accelerated contrast enhanced magnetic resonance imaging

加速对比增强磁共振成像的稀疏采样和约束重建

• 批准号: RGPIN-2014-04730
• 负责人: Lebel, Robert
• 金额: $ 1.82万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587982
• 关键词: Sparse; sampling; constrained; reconstruction; accelerated

Magnetic resonance imaging (MRI) is a powerful modality but remains limited. Time-resolved scans, which aim to capture changing physiology, are severely hindered by long scan times. This is particularly true for dynamic contrast enhanced (DCE) MRI, which aims to visualize the flow of an injected contrast agent as it passes through the vasculature. This technique has significant clinical value yet is rarely performed due solely to acquisition limitations. Hardware advances continue to reduce scan times, but with diminishing returns. New methods for accelerated imaging are urgently needed. My research program established by this Discovery Grant will develop, validate, and translate novel methods for highly accelerated dynamic MRI. My research program will explore sparse sampling and constrained reconstruction—together termed compressed sensing (CS)—for faster MRI. These techniques exploit what is well known from the JPEG file format: images can be stored using a fraction of their original data. CS posits that since images can effectively stored, there is no need to acquire all of the original data. This enables image formation from fewer samples than are typically required—thus faster imaging. Compression becomes more effective as dimensions are added, making 4D imaging (i.e., dynamic 3D) a strong candidate for acceleration. My preliminary work has demonstrated that DCE MRI is amenable to extreme speed-ups: acceleration an order of magnitude beyond conventional methods is feasible. Despite its potential, optimal methods for CS are poorly established. Furthermore, the utility of high-resolution dynamic scans has not been explored: the same source data will allow extraction of multiple pieces of physiological information. Currently, no MRI vendor has productized CS—this is due to technological barriers, not utility. It is clear that CS will play a vital role in medical imaging but effective techniques currently preclude widespread adoption. The projects detailed in this application will form the basis of a trainee focused research program with a long-term goal to develop, implement, and commercialize advanced data sampling and reconstruction technologies for MRI. Specific aims of this proposal are: Aim 1: design novel acquisition and reconstruction algorithms for accelerated 4D imaging. Aim 2: develop a comprehensive DCE exam. Aim 3: implement on-line reconstruction of these techniques. The first aim of this project will focus on optimizing data acquisition methods that are amenable to both conventional image reconstruction (albeit with low temporal resolution) and to constrained reconstruction (for high fidelity images). The second aim of this project will exploit the vastly improved image quality available from Aim 1 to extract multiple pieces of clinical data. This is not possible from current DCE scans and has the potential to revolutionize how contrast enhanced imaging is performed clinically. The third aim will strive to tightly integrate the techniques defined by Aims 1 and 2 with the MRI scanner to enable rapid image reconstruction. This objective is often overlooked yet is crucial to facilitate clinical validation and to expedite commercialization. In summary, this application proposes technological innovations to accelerate MRI. Applications of the proposed inventions reach far beyond our initial clinical application (DCE). Trainee involvement, industrial and clinical collaborations, and commercialization will be central themes in my research program.

磁共振成像（MRI）是一种强大的方式，但仍然有限。时间分辨扫描的目的是捕捉不断变化的生理机能，但由于扫描时间长而受到严重阻碍。这对于动态对比增强（DCE）MRI尤其如此，动态对比增强（DCE）MRI旨在使注射的造影剂在其穿过脉管系统时的流动可视化。该技术具有重要的临床价值，但仅由于采集限制而很少执行。硬件的进步继续减少扫描时间，但回报越来越少。迫切需要加速成像的新方法。我的研究计划建立了这个发现补助金将开发，验证和翻译的新方法，高度加速动态MRI。 我的研究计划将探索稀疏采样和约束重建-一起称为压缩感知（CS）-更快的MRI。这些技术利用了众所周知的JPEG文件格式：可以使用原始数据的一小部分存储图像。CS假定，由于图像可以有效地存储，因此不需要采集所有原始数据。这使得成像所需的样本比通常所需的样本少，因此成像速度更快。随着尺寸的增加，压缩变得更加有效，使得4D成像（即，动态3D）是加速的强有力的候选者。我的初步工作已经证明，DCE MRI可以承受极端的加速：超过传统方法一个数量级的加速是可行的。尽管它的潜力，CS的最佳方法建立得很差。此外，高分辨率动态扫描的实用性还没有被探索：相同的源数据将允许提取多条生理信息。目前，还没有MRI供应商将CS产品化-这是由于技术障碍，而不是实用性。很明显，CS将在医学成像中发挥至关重要的作用，但目前有效的技术排除了广泛采用。 本申请中详细介绍的项目将构成以培训生为中心的研究计划的基础，其长期目标是开发，实施和商业化MRI的先进数据采样和重建技术。这项建议的具体目标是： 目标1：设计新的采集和重建算法，用于加速4D成像。 目标2：制定全面的DCE考试。 目标3：实现这些技术的在线重建。 该项目的第一个目标将集中在优化数据采集方法，既适合传统的图像重建（虽然时间分辨率低）和约束重建（高保真图像）。该项目的第二个目标是利用目标1中大幅提高的图像质量来提取多个临床数据。这是不可能从目前的DCE扫描，并有可能彻底改变如何对比增强成像在临床上进行。第三个目标将努力将目标1和2定义的技术与MRI扫描仪紧密结合，以实现快速图像重建。这一目标经常被忽视，但对于促进临床验证和加速商业化至关重要。 总之，本申请提出了加速MRI的技术创新。所提出的发明的应用远远超出了我们的初始临床应用（DCE）。实习生参与，工业和临床合作，以及商业化将是我的研究计划的中心主题。