Quantitative magnetic resonance flow and diffusion imaging in porous media

Autor: James M. Pope, Vasanthan Rajanayagam, Shenggen Yao
Rok vydání: 1995
Předmět:
Zdroj: Magnetic Resonance Imaging. 13:729-738
ISSN: 0730-725X
DOI: 10.1016/0730-725x(95)00022-9
Popis: Quantitative flow and diffusion measurements have been made for water in model porous media, using magnetic resonance micro-imaging methods. The samples consisted of compacted glass beads of various sizes down to 1 mm diameter. Typical flow and diffusion images exhibited a spatial resolution of 117 μm × 117 μm and velocities in the range 1–2 mm/s. Comparison of volume flow rates calculated from the flow velocity maps with values measured directly yielded good agreement in all cases. There was also good agreement between the mean diffusion coefficient of water calculated from the diffusion maps and the bulk diffusion coefficient for pure water at the same temperature. In addition, the mean diffusion coefficient did not depend on the pore sizes in the bead diameter range of 1–3 mm. Our results also show that partial volume effects can be compensated by appropriate thresholding of the images prior to the final Fourier transformation in the flow-encoding dimension.
Databáze: OpenAIRE