MRI of the denture foundation -Development of a new contrast enhancement for MRI-

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To diagnose the denture foundation under function, magnetic resonance imaging(MRI)was employed as a noninvasive, highly sensitive diagnostic imaging procedure. MR images of two edentulous patients were obtained with the 0.5T resistive MR unit. However, the denture foundation was not distinguished clearly from acrylic resin dentures because of their low sensitivity.The purpose of this study was to develop a new contrast enhancement for MR imaging which can be used in oral cavity like impression materials, and the following results were obtained.1. The contrast agent for enhancement consists of hydrocolloid 92% water, 5% agar, 2%, -PVA(polyvinyl-alcohol)1% silicone), and Gd-DTPA(gadolinium-diethylenetriaminepentaacetic-acid)was mixed.2. GD-DTPA was dispersed in the hydrocolloid equally, and it's complex was stable in the thermal cycling test.3. In a preliminary MR imaging experiment, plaster models and acrylic resin dentures were distinguished clearly using the contrast enhancer between them.4. It was suggested that the proper contrast enhancement was achieved using Tl(spin-lattice-relaxation time)-weighted techniques with more than 1.6mmol/kg GD-DTPA in hydrocolloid, and the density and the proper parameters of MRI instruments must be examined still more to use MRI for living bodies.