DEVELOPMENT OF ADVANCED CHEMICAL SHIFT IMAGING (CSI) TECHNIQUES

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Chemical Shift Imaging (CSI) is the method of choice for in vivo localized spectroscopy. However, several persistent obstacles still remain in its application to nuclei other than protons, specifically 31P and 19F CSI proposed in projects of this application. First, the sensitivity is low. Second and several consequents, the measurements are long, thus, only one nucleus can be observed in a clinical session, even if information from another is significant and sought. Third, the current Fourier reconstruction methods, widely used because of their computational convenience and simplicity, result in an artifact that intermixes signal from one voxel, with its its neighbors. This artifact, known as A voxel bleed, leads to spectral-contamination and impacts CSI in general. We propose to address these difficulties from three angles. First, to use polarization transfer techniques from 1H to the less sensitive 31P to increase the signal of the latter and to be used in project II. Second, to develop simultaneous acquisition techniques that will allow 1H decoupled 31P and 19F CSI acquisition during a single clinical examination. Third, to develop non-Fourier transform techniques that, using prior knowledge from the proton images, will improve the accuracy of CSI reconstruction.