It is found that the decay rate of the quantum fidelity is suppressed when the periodic orbit scars in the accumulation of the time-evolving wavefunction become obvious in two-dimensional (2D) nanostructure The fidelity is numerically evaluated by the time-evolution of the wavepacket inside a 2D chaotic nanostructure the stadium which is the typical chaotic system The suppression is apparent in the Lyapunov regime where the decay rate does not depend on the strength of the perturbation (C) 2010 Elsevier BV All rights reserved