A formula based methodology for predicting Sacral Nerve Stimulation lead temperatures when undergoing MRI exposures is presented. A generalized lead pathway model having 4 primary factors is used to represent the clinical placement. Twelve experimental configurations are selected based on variation of these generalized factors. Heating data measured in an MRI phantom is used to formulate an analytical model. Predictions from the model are compared against the actual data measured in MRI testing. The mean squared error for the model against the 12 test cases is 0.112 °C.