Due to the self-diffusion of nuclear spins, the edge of phantoms is enhanced in the magnetic resonance imaging(MRI), especially in the case of microscopy. According to several published works, theory has been established that the edge enhancement is cause by the motion narrowing around bounded resions due to diffusions of nuclear spins during data acquisition. It is found, however, that the signal decreases due to the diffusion attenuation, image is distorted as edge of the image is sharpened. In this paper, we will investigate this signal loss during data acquisition and its effects on image, i.e., image edge enhancement due to the diffusion phenomenon. This result is new and different from the previously discussed edge enhancement due to the diffusion, namely, by motion narrowing effect or spin bounching effect at the boundary.