The invention is directed to a guidewire having a distal section with multiple distally tapered core segments with at least two contiguous distally tapering core segments in which the most distal tapered core segment preferably has a greater degree of taper than the proximally contiguous tapered core...http://www.google.com.au/patents/US20040059259?utm_source=gb-gplus-sharePatent US20040059259 - Guidewire having linear change in stiffness
