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.
핵자기 공명 영상법에서의 핵자기 스핀의 확산현상은 영상의 Edge Enhancement를 불러 일으킨다. 이 Edge Enhancement는 스핀이 Bounded되어 있기 때문에 발생하는 Motion Narrowing 현상에 의해서 일어난다고 알려져 왔다. 또한 Diffusion 현상에 의한 Signal loss로 인하여 Signal이 지수적으로 감소한다. 이 감소 현상을 Monte Carlo Simulation과 Bloch equation Simulation을 통해서 분석해 보았다. 이 Simulation을 통해서 Edge Enhancement는 신호의 지수적 감소로 인한 High pass filtering 효과로 인해서도 발생한다는 것을 밝혔다.
