Edge enhancement by diffusion: microscopic magnetic resonance imaging of an ultrathin glass capillary

Abstract

Diffusion can improve magnetic resonance imaging (MRI) on a microscopic length scale by edge enhancement which acts against diffusional blurring. We demonstrate the edge-enhancement effect and we provide an appropriate mathematical description using Kubo's line shape function formalism. We apply the theory to make specific predictions for edge enhancement in a two-dimensional phantom system. In particular, we determine the corresponding line shape function and use it to reconstruct an MRI image of water in an ultrathin (50 μm) capillary tube. We explain how a corresponding experiment can be realized with microcoils capable of receiving adequate free induction decay signals from microscopically small sample volumes.