The secondary objective is to estimate a) preparation and b) procedure time, c) injection site and d) depth, e) discomfort, f) change in MAP, g) plasma lidocaine pharmacokinetics, h) motor and i) sensory block, j) perineural and k) epidural spread of lidocaine-epinephrine added gadotorate meglumine on MRI, and l) cost-effectiveness of SSPS guided by ultrasound/MR image fusion vs. SSPS guided by ultrasound.