MRI Parallel Excitation for Neuroimaging Applications

描述（由申请人提供）：生物工程研究合作伙伴关系（PAR-06-459）被提议用于开发并行激励技术，以改善下额叶皮层的功能性磁共振成像（fMRI）研究。这个项目的动机是需要消除大的信号空洞和图像失真所造成的大脑组织和空气之间的磁化率差异在鼻窦。这些伪影在功能磁共振成像中普遍存在，尤其是对于许多下脑结构，包括眶额皮质（OFC）、下颞叶和内侧颞叶以及脑干结构。大脑的这些部分与神经退行性疾病、癫痫、精神疾病和酒精/药物滥用疾病有关。许多去除这些失真的当前技术在用于检测激活的时间分辨率或灵敏度方面具有很大的成本。我们的小组开创了减少这些文物的方法，包括多维选择性激发，一种有前途的技术，但目前在校正程度和激发脉冲的持续时间长的限制。并行激励是一种新技术，通过使用多个独立的激励通道，可以更灵活地激励MRI中的特定模式或更均匀的模式。对于多维激励模式，例如用于消除功能磁共振成像中大脑下部区域信号丢失伪影的模式，平行激励应该允许更短的脉冲，并提供更完整的校正。该项目是独特的多学科，因为它涉及并行激励脉冲设计，并行激励硬件，系统集成和应用于患者的研究的进展。该项目将由多学科研究人员小组领导：该项目的首席研究员是道格拉斯·诺尔（PI;系统集成和软件，验证）、杰弗里·费斯勒（脉冲优化）和斯蒂芬·泰勒（患者研究）;所有人都来自密歇根大学和来自德克萨斯农工大学的史蒂文·赖特（联合PI;硬件，系统集成）。该项目为并行激励脉冲设计提供了新颖的优化策略、用于驱动并行发射阵列的独特电流源技术以及对OFC功能的重要科学研究。总之，这些方法导致有价值的新方法的功能性磁共振成像，能够探测大脑下部结构的敏感性等于其他结构，这将有助于研究各种神经精神疾病。这里开发的并行激励技术也将推进MRI技术的总体状态，用于校正高磁场下的激励不均匀性以及MRI中多维激励的许多其他应用。

DESCRIPTION (provided by applicant): A Bioengineering Research Partnership (PAR-06-459) is proposed for the development of parallel excitation technology to improve functional magnetic resonance imaging (fMRI) studies in the inferior frontal cortex. This project is motivated by the need to eliminate large signal voids and image distortions caused by magnetic susceptibility differences between brain tissue and air in the nasal sinuses. These artifacts are ubiquitous in fMRI, especially for many inferior brain structures including the orbitofrontal cortex (OFC), inferior and medial temporal lobes, and brain stem structures. These parts of the brain have been implicated in neurodegenerative disorders, epilepsy, psychiatric conditions and alcohol/substance abuse disorders. Many current techniques to remove these distortions have a large cost in terms of temporal resolution or sensitivity for detection of activation. Our group has pioneered methods for reducing these artifacts, including multidimensional selective excitation, a technique that is promising, but is currently limited in the degree of correction and by the long duration of the excitation pulses. Parallel excitation is a new technology that will allow for greater flexibility in exciting specific patterns or more uniform patterns in MRI through the use of multiple independent excitation channels. For multidimensional excitation patterns, such as those used to eliminate the signal-loss artifacts in inferior brain regions in fMRI, parallel excitation should allow shorter pulses and offer more complete correction. This project is uniquely multidisciplinary in that it involves advances in parallel excitation pulse design, parallel excitation hardware, system integration, and application to studies of patients. This project will be lead by a multidisciplinary group of investigators: the Lead Investigators for this project are Douglas Noll (PI; System Integration and Software, Validation), Jeffrey Fessler (Pulse Optimization), and Stephen Taylor (Patient Studies); all from Univ. of Michigan and Steven Wright (Co-PI; Hardware, System Integration) from Texas A&M University. This project offers novel optimization strategies to parallel excitation pulse design, unique current source technologies for driving the parallel transmit array, and important scientific investigation into the functioning of the OFC. Together, these approaches lead to valuable new methods for functional MRI that are capable of probing inferior brain structures with sensitivity equal to other structures, which will aid in the study of a variety of neuropsychiatric disorders. The parallel excitation technology developed here will also advance the general state of MRI technology for correction of excitation inhomogeneity at high magnetic fields and for many other application of multidimensional excitation in MRI.