NMR microimaging

I. V. Koptyug, S.A. Altobelli, E. Fu-kushima, A.V. Matveev, R.Z. Sagdeev 2000, (Thermally polarized H NMR microimaging studies of liquid and gas flow in monolithic catalysts), J. Magn. Reson. 147, 36. 

Most NMR studies of potato have focused on understanding the effects of processes such as boiling, frying, freezing and drying. Exceptions are the NMR microimaging of healthy and diseased potato tubers reported by Goodman and co-workers, and relaxometry responses in healthy tubers... 

FIGURE 3.31 NMR microimages of methane hydrate formation as a function of time. Left Images for two slices right difference images in both, white represents hydrates. (Reproduced from Moudrakovski, I.L., McLaurin, G.E., Ratcliffe, C.I., Ripmeester, J.A., J. Phys. Chem. B, 108, 17591 (2004). With permission from the American Chemical Society.)... 

Instead of polarized noble gases, thermally polarized NMR microimaging was used to study of liquid and gas flow in monolithic catalysts. Two-dimensional spatial maps of flow velocity distributions for acetylene, propane, and butane flowing along the transport channels of shaped monolithic alumina catalysts were obtained at 7 T by NMR, with true in-plane resolution of 400 xm and reasonable detection times. The flow maps reveal the highly nonuniform spatial distribution of shear rates within the monolith channels of square cross-section, the kind of information essential for evaluation and improvement of the efficiency of mass transfer in shaped catalysts. The water flow imaging, for comparison, demonstrates the transformation of a transient flow pattern observed closer to the inflow edge of a monolith into a fully developed one further downstream. 

Some applications of NMR microimaging and EPR spectroscopy to the study of disease and senescence processes in plant organs are presented, with emphasis on the non-invasive nature of the techniques. A particular strength of the use of NMR microimaging in research on live specimens is its ability to perform repeated measurements on the same specimen. From EPR spectroscopy information specifically on free radicals and paramagnetic metal-containing species was produced. Techniques to avoid the production of artifacts from sample preparation was described in both methods. 

The presence of hollows in cooked rice grains was additionally confirmed for four more cultivars Koshihikari with various amylose contents."" The size, shape and total volume of hollows differed between cultivars. The hypothetical model for the formation of hollows has not been proved experimentally. NMR microimaging was used to determine moisture distribution in boiled Japanese noodles (udon) made from different varieties of wheat.The T2 profile of a piece of boiled udon was monitored in time course measurements during and after boiling. Water permeation from the surface to the core was evaluated by the T2 profile. Effect of moisture distribution on texture of boiled Japanese noodles was discussed. 

The structure of a CH4 hydrate layer from ice was argued by Moudrakovski et al. and L. A. Stem et al. A polemic is given answering the publication by Moudrakovski (Letter, Hydrate layers on ice particles and superheated ice A NMR microimaging study in J. Phys. Chem. 1999, 103, 4969) by L. A. Stem et al The experimental conditions in both groups are completely different for the formation of CH4 hydrate from ice and CH4 gas, i.e. under high pressure (27-33 MPa) by Stern et al and at lower pressures (5.7-11.9 MPa) by Moudrakovski s NMR microimaging experiments. 

Dahlberg C, Fureby A, Schuleit M, et al. Polymer mobilization and drug release during tablet swelling. A H-1 NMR and NMR microimaging study. J Control Release 2007 122(2) 199-205. 

Abrahmsen-Alami S, Komer A, Nilsson I, et al. New release cell for NMR microimaging of tablets swelling and erosion of poly(ethylene oxide), bit J Pharm 2007 342(1-2) 105-114. 

The in situ 3D-SPI sequence was applied in order to observe the spatial change of the specimen at various temperatures (25, 300, 350, 375, 400, 425, 450, 475 °C). The experimental sample scheme is shown in Fig. 24. The rate of heating was 3°Cmin l which is the same as that of the industrial coking process.93 This means that the sample temperature was increased by about 24 °C (8 min x 3 °Cmin ) during the NMR microimaging measurements. 

This review covers the progress in the field of NMRI, NMR microimaging, NMR microscopy, MR tomography as well as MRI over a period from June 2008 to May 2009. Medical or clinical use of the NMR imaging technique has increasingly expanded. In this review, however, we will stay mainly on the papers rather in non-clinical research field and the both words, NMRI and MRI, will be used as it was in the original literature. 

Based on the examinations of sensitivity, precision, accuracy and valid range, they concluded that this is a promising technique to measure cake thickness of biological particles. This method has the benefits of low cost, easy installation and accuracy compared to gamma-ray absorption, NMR microimaging and computerized axial tomographic scans (CATSCAN) techniques. The fact that this method can only be applied to a flat plate membrane module is its major limitation. 

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