HIGH FIELD MRI: LIMITATIONS AND SOLUTIONS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 本研究的目的是理解和开发工程解决方案，以解决高磁场强度下磁共振成像（MRI）的困难。 最近在明尼苏达大学（1999年）举办的关于高场MRI的研讨会将磁化率引起的信号损失、射频磁场失真和信噪比确定为高场实施面临的三个最紧迫的问题。 我们的伙伴关系将直接解决其中两个重要问题。 具体目标1：开发并验证方法，以分析、量化并最终消除因磁化率区域差异而在高场MR图像中产生的静磁场失真。 这些解决方案将用于开发高速功能性MRI和人类、动物和细胞解剖学的无失真MRI的无失真校正技术。 具体目标二：开发和验证模型和方法，以分析和量化发生在人体头部和身体的射频（rf）磁场失真。 这些解决方案将用于评估吸收射频能量的患者安全性，并评估射频场均匀性的失真和限制及其潜在校正。 本着生物工程研究合作伙伴关系的精神，该提案将借鉴明尼苏达大学磁共振研究中心（首个7.0特斯拉全身MRI国家研究资源中心），REMCOM（磁场建模软件公司）和国家高场磁体实验室（国家研究实验室，包括14特斯拉MRI显微镜）的专业知识和合作伙伴关系。 这些研究的结果将有助于广泛的研究人员在高速无失真功能磁共振成像，解剖研究在低和高场强，磁共振显微镜在动物和完整的细胞，评估病人的安全性，并在许多情况下回收技术已被证明是有问题的高场强。

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. he objective of this research is to understand and develop engineering solutions to the difficulties presented to magnetic resonance imaging (MRI) at high magnetic field strength. A recent workshop at the University of Minnesota (1999) on high field MRI recently identified magnetic susceptibility induced signal loss, radio frequency magnetic field distortion, and signal-to-noise as the three most pressing issues facing high field implementation. Our partnership will directly address two of these important issues. Specific Aim 1: Develop and validate methodology to analyze, quantify, and ultimately elimiate static magnetic field distortion produced in high field MR images by regional differences in magnetic susceptibility. These solutions will be used to develop distortion-free correction techniques for high-speed functional MRI and distortion-free MRI of human, animal, and cellular anatomy. Specific Aim 2: Develop and validate models and methodology to analyze, and quantify radio frequency (rf) magnetic field distortion occurring in the human head and body. These solutions will be used to evaluate patient safety from absorbed rf energy and to evaluate distortion and limitations of rf field homogeneity and its potential correction. In the spirit of the Bioengineering Research Partnership this proposal will draw expertise and partnership from the Center for Magnetic Resonance Research at the University of Minnesota (a premiere 7.0 Tesla whole body MRI National Research Resource Center), REMCOM (a magnetiac field modeling software company), and the National High FIeld Magnet Laboratory (a National Research Laboratory incorporating 14 Tesla MRI microscopy). The results of these studies will aid a wide array of researchers in high speed distortion-free functional MRI, aanatomical studies at both low and high field strengths, MR microscopy in animals and intact cells, evaluation of patient safety, and in many cases reclaiming techniques which have proven problematic at high field strengths.