Accelerated Neuro-MRA Using Compressed Sensing and Constrained Reconstruction

摘要 磁共振成像（MRI）是大多数诊断性神经成像的护理标准，但 一些明显的缺点。脑动脉瘤，仍然首先经常被诊断为猝死或 灾难性出血，最好通过计算机断层扫描或数字成像提供分辨率 减影血管造影（DSA）。MRI的速度通常不足以可视化动脉输入， 动静脉畸形（AVM）的静脉引流。缺血性中风是最常见的神经系统疾病 颅内动脉狭窄是缺血性卒中的主要危险因素。为了 提高诊断的信心，并提供早期发现的病理变化， 脑血管系统，应朝着空间和时间分辨率取得重大进展 目前即使使用最先进的MRA技术也无法获得。 我们一直在开发采集和重建方法，以规避MRI在速度方面的缺点 为神经血管提供多维生理和解剖信息 显像我们认识到，为了实现所需的空间和时间组合， 分辨率和信噪比，我们需要利用互补的先进图像的协同作用， 采集和重建技术。我们实验室开发的图像估计方法联合收割机 具有可变采样密度的非笛卡尔径向轨迹的约束重建算法 允许高质量的扩展扫描和时间分辨成像。我们已经成功地 开发了第一代这种技术，称为HYPR（HighlY约束反投影） 系列成像技术，为连续采集的图像的采集提供实质性加速。 这一建议提出了下一代加速成像技术的全面评估 血管狭窄，动脉瘤和AVM，将通过开发新的 图像采集和重建方法。这些方法将利用独立和共生 优化径向轨迹、并行成像和约束重建的加速机制， 包括HYPR和高级压缩感知算法。这些算法还将提供 来自新型高加速采集方法的数据：1）无造影剂流入技术， 分散对比增强的团注，以提供极好的动脉隔离、高分辨率和覆盖范围;以及 2)高质量时间平均血管成像体积以约束时间分辨对比度的重建， 增强数据。这些方法将在AVM的治疗和跟踪中进行评价， 血管狭窄和脑动脉瘤的评估。成功完成将补充 也有很多用于中风管理的工具。

Abstract 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 substraction 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.