Magnetic resonance imaging in patients with spinal neurostimulation systems

Background: The safety of performing magnetic resonance imaging (MRI) in patients with spinal cord stimulation (SCS) systems needs to be documented. A prospective in vivo study in patients with SCS, exploring the changes produced by MRI and the associated side effects, was performed. Methods: After ethics committee approval and patient consent, 31 consecutive patients with SCS at different spinal levels requiring a scheduled MRI evaluation were studied during an 18-month period. All MRIs were performed with a 1.5-T clinical use magnet and a specific absorption rate of no more than 0.9 W/kg. Frequency tables were used for the descriptive study, whereas comparative evaluations were made with the chisquare test for qualitative variables and single-factor analysis of variance for quantitative variables. Results: The mean patient age was 49 +/- 9.5 yr; 67.7% were women (n = 21), and 32.3% were men (n = 10). None of the patients experienced hemodynamic, respiratory, or neurologic alterations. Reported changes were as follows: increased temperature in the generator's area (n = 2, 6.5%); increased in the intensity of the stimulation (n = 1, 3.2%); impedance greater than 4,000 Omega on several of the electrodes in the leads (n = 1, 3.2%); telemetry not possible (n = 2, 6.5%). Radiologic evaluation after MRI revealed no spatial displacements of the SCS leads in any case. Conclusion: Under the conditions of the described protocol, MRI in patients with SCS systems resulted in few complications. None of the recorded problems were serious, and in no case were patients harmed or the systems reprogrammed. Maximum patient satisfaction was reported in all cases.