Patients diagnosed with CRPS-I and CLBP will participate in a Magnetic Resonance Imaging (MRI) experiment. In this observational study, we examine the effects of GEXP treatment that all patients receive as part of usual care. Anatomical as well as diffusion-weighted and T2*-weighted (Blood oxygenation level dependent) MR images will be acquired. The study has a 3x4 split plot design with group (CRPS-I patients and CLBP receiving GEXP treatment / healthy controls) as between-subjects variable and time (pre-, during, post-treatment and follow-up) as within-subject variable.