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Fig 1. Hybrid hydrogel-platinum coil device. Left, Bare platinum coil. Middle, Prehydration image shows initial profile of the device. Highly compact hydrogel material is wrapped around a platinum coil. An outer "overcoil" is wrapped around the hydrogel-covered coil. The outer diameter of the coil is 0.008 inch. The thickness of the hydrogel is approximately 0.0005 inch, such that the outer diameter of the gel covering is 0.009 inch. With the "overcoil," the outer diameter is 0.013 inch. Right, Posthydration image of the device shows marked expansion of the hydrogel material, which has become translucent. The radial thickness of the expanded hydrogel is approximately 0.009 inch, such that the total outer diameter of the hydrated device is 0.027 inch.