Palestrante
Descrição
Classical Magnetic Resonance (MR) applications for material sciences and medical diagnostics have been extended to study porous media, mainly due to the applications for the oil industry. However, MR imaging in porous media is challenging due to short relaxation times and different magnetic susceptibility between rock walls and pores, which compromise the image quality. (1-2) In a previous work, we have introduced a model system developed to mimic real rocks in order to study the morphology in porous media under precisely controlled conditions. The proposed rock model was used to compare different imaging techniques and acquisition protocols, which allowed us to evaluate the applicability of conventional MR imaging techniques for porous media. Our results showed that, despite the susceptibility variations on the medium and short relaxation times, the uncertainties on the final evaluation were below the spatial resolution threshold, therefore not representing a limiting factor. This suggests that MR imaging techniques can indeed be used to study of porous media. Now our challenge is to study the behaviour of water and oil within these rocks by simulating the accuracy of low-angle multi-touch inverted angle gradient (GRE) fat quantification methods using MR spectroscopy as the reference. (3) The fat fraction (FF) will be calculated from T2-corrected fat and water spectral peak areas. Signals involving a low flip angle (to suppress the effects of T1) and multiple echo times (to estimate the effects of T2 *) will be simulated. To correct the effects of T2 * a multi-sequence sequencing analysis method will be assumed. The fat percentage will be compared with the FF spectroscopic values by means of a linear regression. This will evaluate the accuracy of the fat quantification methods that will be used for oil and water analysis on rocks.
Referências
1 GALLEGOS, D. P. A NMR technique for the analysis of pore structure: application to materials with well-defined pore structure. Journal of Colloid and Interface Science, v. 119, n. 1, p. 127-140, Sept. 1987.
2 HAACKE, E. M. et al. Magnetic resonance imaging: physical principles and sequence design. New York: Wiley, 1999.
3 YOKOO, T. et al. Nonalcoholic fatty liver disease: diagnostic and fat-grading accuracy of low-flip-angle multiecho gradient-recalled-echo MR imaging at 1.5 T. Radiology, v. 251, n. 1, p. 67-76, Apr. 2009.
| Apresentação do trabalho acadêmico para o público geral | Não |
|---|---|
| Subárea | Ressonância Magnética e Caos |
