Lead extensions, systems, and methods providing MRI compatible deep brain stimulation (DBS) and spinal cord stimulation (SCS) systems are described. Lead extensions are provided having band stop filters (BSFs) which resonate at a frequency expected from MRI systems to create a very high impedance which can effectively decouple the implanted lead from the lead extension proximal of the BSF and change the effective length. Changing the effective length can reduce the likelihood of undesirably heating tissue near the DBS/SCS electrodes during MRI. Some lead extensions include BSFs in a distal connector for coupling to the lead contacts. The BSFs can be included within a burr hole cap base which can also include a connector for connecting to the DBS lead. DBS and SCS leads having a sacrificial proximal portion and intermediate electrical contacts are also provided.