Continuous wave MRI of heterogeneous materials.

A prototype continuous wave MRI system operating at 7T has been used successfully to study a variety of heterogeneous materials exhibiting T2 relaxation values ranging from 10 micros to 50 ms. Two-dimensional images of a poly(methly methacrylate) (PMMA) resolution phantom (T2=38 micros) exhibited a spatial resolution of approximately 1mm at a magnetic field gradient strength of 200 mT/m. The technique was used to study the hydration, drying, and subsequent water penetration properties of cement samples made from ordinary Portland cement, and revealed inhomogeneities arising from the cure conditions. Sandstone samples from an oil reservoir in the North Sea were also studied; structure within these materials, arising from the sedimentary bed layering in the reservoir, was found to have an effect on their water transport properties. A section from a confectionery bar (T2* approximately 50-60 ms) was also imaged, and its internal structure could be clearly discerned.

[1]  M. R. Halse,et al.  Two-dimensional fourier transform NMR imaging of solids using large oscillating field gradients , 1992 .

[2]  M J Mallett,et al.  A three-dimensional NMR imaging scheme utilizing doubly resonant gradient coils. , 1996, Journal of magnetic resonance. Series B.

[3]  B. Blümich,et al.  NMR Imaging of Solids , 1994 .

[4]  The Modified Stretched-Exponential Model for Characterization of NMR Relaxation in Porous Media , 1996 .

[5]  J M Hutchison,et al.  Continuous-wave magnetic resonance imaging of short T(2) materials. , 2001, Journal of magnetic resonance.

[6]  E. Chaniotakis,et al.  ANALYSIS OF COMPLEX 1H NUCLEAR MAGNETIC RESONANCE RELAXATION MEASUREMENTS IN DEVELOPING POROUS STRUCTURES : A STUDY IN HYDRATING CEMENT , 1995 .

[7]  J. Godward,et al.  Multidimensional imaging using combined stray field and pulsed gradients. , 2002, Journal of magnetic resonance.

[8]  P. McDonald.  The application of broad line MRI to the study of porous media. , 1996, Magnetic resonance imaging.

[9]  Solid state NMR imaging of irreducible water in reservoir cores for spatially resolved pore surface relaxation estimation. , 1994, Magnetic resonance imaging.

[10]  Peter J. McDonald,et al.  Stray field magnetic resonance imaging , 1997 .

[11]  P Szomolanyi,et al.  SPIRAL-SPRITE: a rapid single point MRI technique for application to porous media. , 2001, Magnetic resonance imaging.

[12]  S. Cottrell,et al.  NMR imaging of solids using large oscillating field gradients , 1990 .

[13]  U. Goerke,et al.  A broad line NMR and MRI study of water and water transport in Portland cement pastes. , 1998, Magnetic resonance imaging.

[14]  Bruce J. Balcom,et al.  Three-dimensional magnetic resonance imaging of rigid polymeric materials using single-point ramped imaging with T 1 enhancement (SPRITE) , 1998 .

[15]  C. Ramanathan,et al.  Direct measurement of porous media local hydrodynamical permeability using gas MRI. , 2001, Magnetic resonance imaging.

[16]  T W Bremner,et al.  Imaging of heterogeneous materials with a turbo spin echo single-point imaging technique. , 2000, Journal of magnetic resonance.

[17]  L. Hall,et al.  A General Survey of Chocolate Confectionery by Magnetic Resonance Imaging , 1998 .

[18]  E. R. Andrew,et al.  A historical account of NMR in the solid state , 1995 .

[19]  B. Balcom,et al.  Using Magnetic Resonance Imaging and Petrographic Techniques to Understand the Textural Attributes and Porosity Distribution in Macaronichnus-Burrowed Sandstone , 2002 .

[20]  P. McDonald.  Stray field magnetic resonance imaging , 1997 .

[21]  Theodore W. Bremner,et al.  Magnetic resonance imaging of 1H, 23Na, and 35Cl penetration in Portland cement mortar , 2002 .

[22]  S. Emid.  Ultra high resolution multiple quantum spectroscopy in solids , 1985 .

[23]  Peter Jezzard,et al.  Nuclear magnetic resonance imaging in the solid state , 1991 .

[24]  B. Balcom,et al.  Single-Point Ramped Imaging with T1 Enhancement (SPRITE) , 1996, Journal of magnetic resonance. Series A.

[25]  J. Howard.  Quantitative estimates of porous media wettability from proton NMR measurements. , 1998, Magnetic resonance imaging.

[26]  J. Tritt-Goc,et al.  Proton magnetic resonance microimaging of human trabecular bone. , 1999, Solid state nuclear magnetic resonance.

[27]  Vapour phase application of hydrophobic coatings to cement-based materials , 2001 .

[28]  B. Blümich,et al.  Solid-state NMR imaging methods. part I: strong field gradients , 2000 .

[29]  B J Balcom,et al.  Water content profiles with a 1D centric SPRITE acquisition. , 2002, Journal of magnetic resonance.

[30]  Prado,et al.  SPRITE MRI with prepared magnetization and centric k-space sampling , 1999, Journal of magnetic resonance.