Efficient diffeomorphic metric image registration via stationary velocity.

•A simplified Euler-Lagrange equation for diffeomorphic metric image registration via stationary velocity is proposed.•This model keeps the same accuracy as the non-simplified integral model but reduces time cost significantly.•It shows clear advantage on large deformation mapping compared to previous 1st-order approximation model.•It achieves whole brain mapping accuracy comparable to time-varying velocity approach with much faster speed.