US Patent 9757018 Medical guidewire with integral light transmission

A guidewire comprises an elongate metal core, an inner layer, an optical core, and an outer layer. The metal core is configured to communicate torsional motion from a proximal end of the metal core to the distal end of the metal core. The inner layer extends about the metal core and has a first index of refraction. The optical core is disposed about the inner layer, wherein the optical core is configured to transmit light along the length of the guidewire. The optical core has a second index of refraction, which is greater than the first index of refraction. The outer layer is disposed about the optical core and has a third index of refraction. The third index of refraction is less than the second index of refraction.