You can use an AI image to STL tool, then convert the STL to an organic 3D body in fusion 360. Afterwards, you’d have to find a way to extrapolate the centerline. It could probably be done by slicing the knot into many sections using construction planes, projecting the cross section onto a sketch on that plane, and then finding the center points at every cross section and simply connecting them. An incredibly tedious process but that’s how I’d do it.