HIGH FIELD MRI: LIMITATIONS AND SOLUTIONS

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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.