Feasibility studies have been completed on design and evaluation of a new class of local (or surface) coils for magnetic resonance imaging and 31P spectroscopy at 1.5T. Strategies have been found to obtain localized depth sensitivity using pairs and also twin-pairs of coils (or quads); strategies have been found to provide geometrical isolation of coils when used as receivers from quadrature whole body excitation fields; and strategies have been found to reduce and perhaps eliminate need for adjustments of tuning or matching. High resolution images are shown of the cervical and lumbar spine, of the neck, and of the shoulder obtained with the coils. The coils are loop-gap resonators based on microwave electron spin resonance designs that have been scaled to NMR frequencies. Funds are requested to permit aggressive development optimization, engineering characterization, and clinical evaluation of a variety of coil structures based on our newly discovered principles. Computer simulations of coil performance will be further developed. Coils of lower symmetry (and therefore more difficult to construct) will first be modeled theoretically. The coils will be tested with new (and more powerful) gradient coils yielding improved resolution because of the higher intrinsic signal-to-noise ratio. Local coils will also be evaluated for combined excitation and reception. Proposed clinical studies include in-vivo 31P adult human liver and renal transplants, and proton imaging studies of the orbits, temporomandibular joints, parathyroid glands, laryngeal tumors, spinal disk herniation, and knee and shoulder joints. In other proposed studies, local gradient coils will be inserted into the 1.5T magnet, yielding three times higher gradients for MRI of the limbs. Local transmission and receiving coils will yield sufficiently high signal-to-noise that very high resolution images of the extremities can be obtained. This geometry will be evaluated postoperatively on patients who have had microsurgery of the wrist on patients with carpal tunnel syndrome, and on patients with trauma to the ligaments and tendons of the hand.
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