Enabling Metabolic Imaging Using Feedback Driven Magnetic Resonance Spectroscopy

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DESCRIPTION (provided by applicant): Elevated levels of glycolysis are known to correlate with the presence and disease stage of various cancers. This phenomenon, known as the Warburg effect, provides the biological basis of Fluoro-Deoxyglucose Positron Emission Tomography (FDG PET) studies. FDG is taken up by the cell in a manner similar to glucose but then remains trapped in the cell for times exceeding an hour. If the 19F atom in the FDG molecule has been irradiated to 18F it can then detected and spatially located using the tomography device. Radioactive 18FDG PET has been shown to be able to spatially locate tumors on length scales down to approximately 8 mm in clinically available devices and has been widely used in the detection and staging of tumors for more than 30 years. However, it imposes a non-trivial radioactive burden on the patient; for this reason, 18FDG FDG PET scans for humans are typically limited to not more than once per 12 months per patient and only after a tissue diagnosis has already been made. The need to manufacture radioactive FDG in a cyclotron, as well as provide for safe handling/disposal of radioactive materials adds greatly to its intrinsic costs. Magnetic Resonance Spectroscopy Imaging (MRSI) techniques have been also used to detect and locate 19FDG in in vivo research experiments. This approach does not require the FDG be made radioactive; however, because of the much lower signal in an MRSI study this approach has not translated to the clinic. MKT is developing a method of improving the signal to noise per unit time in an MRSI study. The MKT technique leverages the well-known phenomenon of "super-radiance" (SR), also known as radiation damping, to rapidly restore magnetic equilibrium following an MRSI pulse sequence. This allows imaging sequences to be rapidly repeated so that the average signal over time can be increased. The MKT approach is to produce SR conditions in a standard clinical MR imaging device using a feedback enabled circuit (FEC) and a volume situated within the resonant coil containing a quantity of the target molecule, known as a Supplementary Spin Reservoir (SSR), to create SR conditions for a molecule of interest such as FDG. By increasing the signal averaging rate we improve detection of a target molecule and make it possible to use MRSI to enhance detection of fluorinated molecules such as FDG.