Mri conditionally safe lead with low-profile multi-layer conductor for longitudinal expansion

An implantable electrical lead, comprising:

• a lead body having a longitudinal body lumen;
• an electrode coupled to the flexible body in the distal region;
• and
• a multi-layer coil conductor extending within the longitudinal body lumen and coupled to the electrode, the multi-layer coil conductor including a first coil layer and a second coil layer disposed about the first coil layer, wherein at least one parameter of the first and the second coil layer is configured such that the lead exhibits a predetermined axial stiffness or bending stiffness, wherein the at least one parameter of the first and second coil layers is at least one of a coil filar thickness, a number of filars, a filar material, a coil winding direction, or a coil diameter, and wherein the first and second coil layers are configured such that the multi-layer coil conductor has an axial stiffness substantially equal to an axial stiffness of the lead body adjacent to the multi-layer coil conductor.