Accelerated Neuro-MRA Using Compressed Sensing and Constrained Reconstruction

描述（由申请人提供）：磁共振成像（MRI）是大多数诊断性神经成像的标准护理，但有某些明显的缺点。脑动脉瘤，通常首先诊断为猝死或大出血，最好通过计算机断层扫描或数字减影血管造影（DSA）来观察。MRI的速度往往不足以显示动静脉畸形（AVM）的动脉输入和静脉引流。缺血性脑卒中是世界范围内最常见的神经系统疾病，颅内动脉狭窄是缺血性脑卒中的主要危险因素。为了提高诊断的可信度并提供脑血管系统病理变化的早期检测，即使是最先进的MRA技术也无法实现空间和时间分辨率，因此应该在空间和时间分辨率方面取得重大进展。我们一直在开发采集和重建方法，以克服MRI在速度和分辨率方面的缺点，为神经血管成像提供多维生理和解剖信息。我们已经认识到，为了实现所需的时空分辨率和信噪比的组合，我们需要利用互补的先进图像采集和重建技术的协同作用。我们实验室开发的图像估计方法将约束重建算法与非笛卡尔径向轨迹相结合，其可变采样密度允许高质量的扩展扫描和时间分辨成像。我们已经成功开发了第一代该技术，称为HYPR（高度约束反向投影）成像技术家族，为串行采集图像提供了实质性的加速。该建议提出了下一代加速成像技术，用于血管狭窄，动脉瘤和avm的综合评估，通过开发新的图像采集和重建方法，将与CT竞争并超越CT。这些方法将利用优化的径向轨迹、并行成像和约束重建的独立和共生加速机制，包括HYPR和先进的压缩感知算法。这些算法还将提供来自新型高加速采集方法的数据：1)无对比度流入技术，消除对比度增强丸的分散，提供极好的动脉隔离，高分辨率和覆盖范围；2)高质量的时间平均血管图像体积，以约束时间分辨对比度增强数据的重建。这些方法将在动静脉畸形的治疗和跟踪、血管狭窄的评估和脑动脉瘤的评估中得到评价。成功的完井也将补充中风管理中使用的工具库。

DESCRIPTION (provided by applicant): Magnetic resonance imaging (MRI) is the standard of care for most diagnostic neurological imaging, but with certain notable shortcomings. Cerebral aneurysms, still first often diagnosed either by sudden death or catastrophic hemorrhage, are best visualized with the resolution provided by computed tomography or digital subtraction angiography (DSA). The speed of MRI is often not enough to visualize the arterial inputs and venous drainage of arterial-venous malformations (AVM). Ischemic stroke is the most common neurological disorder worldwide and intracranial arterial stenosis is a major risk factor for ischemic stroke. In order to improve confidence of diagnosis and provide early detection of the pathological changes in the cerebrovascular system, significant advances should be made towards spatial and temporal resolutions currently unavailable even with state-of-art MRA techniques. We have been developing acquisition and reconstruction methods that circumvent MRI shortcomings in speed and resolution to provide multi-dimensional physiological and anatomical information for neurovascular imaging. We have recognized that in order to achieve the required combinations of spatial and temporal resolution and signal-to-noise ratio we need to exploit the synergy of complementary advanced image acquisition and reconstruction techniques. Image estimation methods developed in our labs combine constrained reconstruction algorithms with non-Cartesian radial trajectories whose variable sampling density allows for both high quality extended scans and time-resolved imaging. We have already successfully developed the first generation of this technology known as the HYPR (HighlY constrained back Projection) family of imaging techniques, delivering substantial acceleration to the acquisition of serially acquired images. This proposal suggests a next generation of accelerated imaging technology for the comprehensive evaluation of vessel stenoses, aneurysms, and AVMs that will rival and surpass CT through the development of new image acquisition and reconstruction methods. These methods will utilize independent and symbiotic acceleration mechanisms of optimized radial trajectories, parallel imaging, and constrained reconstruction, including HYPR and advanced compressed sensing algorithms. These algorithms will also be supplied with data from novel highly accelerated acquisition methods: 1) a contrast-free inflow technique that eliminates the dispersion of contrast-enhanced bolus to provide superb arterial isolation, high resolution, and coverage; and 2) high quality time-averaged vascular image volumes to constrain reconstruction of time-resolved contrast- enhanced data. These methods will be evaluated in the treatment and tracking of AVMs, the evaluation of vascular stenoses and the evaluation of cerebral aneurysms. Successful completion would supplement the arsenal of tools used in stroke management as well. PUBLIC HEALTH RELEVANCE: The enormous economic and social burden of stroke demands better imaging tools to assess the cerebrovascular system. Our proposal entitled "Accelerated Neuro MRA using Compressed Sensing and Constrained Reconstruction" introduces innovative methods to safely visualize the vascular structures of the brain. Our proposed techniques have benefits over current MRA methods in that they provides greater temporal information, high spatial resolution and flow information. The techniques are of minimal risk compared to conventional catheter based X-ray angiography and are thus better suited for the evaluation of atherosclerotic disease in elderly patients. The MRA methods described in this proposal are major advances in the evaluation of patients with atherosclerotic disease, brain aneurysms and vascular malformations, which are the leading causes of stoke in the US.