In general, the disclosure is related to characterization of implanted electrical stimulation electrode arrays using post-implant imaging. The electrode arrays may be carried by implanted leads. Characterization of implanted electrode arrays may include identification of the type or types of leads implanted within a patient and/or determination of positions of the implanted leads or electrodes carried by the leads relative to one another or relative to anatomical structures within the patient. In addition, the disclosure relates to techniques for specifying or modifying patient therapy parameters based on the characterization of the implanted electrode arrays.