MRI image enhancement using Biot Savart law at 3 tesla

Coil sensitivity is considered as the most valuable data in the parallel reconstruction of magnetic resonance imaging (MRI). In this study, a novel coil sensitivity map extraction method is introduced for spatially fixed phased array coils. The proposed technique uses the Biot Savart law with coil internal shape information and low-resolution phase image data to form sensitivity maps. The performance of this method is tested in a parallel image reconstruction task, using the sensitivity-encoding (SENSE) technique. Under the quasi-static assumption and using the duality principle, we computed the sensitivity maps of a phased-array head coil and reconstructed full FOV images. The experiments show that the resulting image quality is higher in terms of sharpness, artifact level, homogeneity, etc. than existing methods that use sensitivity maps calculated only from low-resolution image data. Moreover, several simulations were conducted using an electromagnetic simulation software tool to theoretically prove the success of the proposed technique. Our simulation results indicate that the success of the method depends heavily on the size of the coil elements. A new method for calculation of sensitivity maps is briefly introduced, which increases image quality and homogeneity while reducing the artifacts.

PDF

___

[1] Blaimer M, Breuer F, Mueller M, Griswold M A, Jakob P M. SMASH, SENSE, PILS, GRAPPA: how to choose the optimal method. Top Magn Reson Imag 2004; 15: 223-236.
[2] Pruessmann, KP, Weiger M, Scheidegger MB, Boesiger P. SENSE: sensitivity encoding for fast MRI. Magn Reson Med 1999; 42: 952-962.
[3] Griswold MA, Jakob PM, Wang J, Kiefer B, Haase A. Generalized autocalibrating partially parallel acquisitions (grappa). Magn Reson Med 2002; 47: 1202-1210.
[4] Heidemann RM, Ozsarlak ¨ O, Parizel PM, Michiels J, Kiefer B, Jellus V, M¨uller M, Breuer F, Blaimer M, Griswold ¨ MA et al. A brief review of parallel magnetic resonance imaging. Eur Radiol 2003; 13: 2323-2337.
[5] Griswold MA, Breuer F, Nittka M, Jellus V, Kiefer B, Jakob PM. Autocalibrated coil sensitivity estimation for parallel imaging. NMR Biomed 2006; 19: 316-324.
[6] Bradley WG, Brant-Zawadski M, Cambray-Forker J. MRI of the Brain. Vol. 1. Philadelphia, PA, USA: Lippincott Williams & Wilkins, 2001.
[7] Baert AL, Prayer D. Fetal MRI. Berlin, Germany: Springer, 2011.
[8] Pruessmann KP. Encoding and reconstruction in parallel MRI. NMR Biomed 2006; 19: 288-299.
[9] Jin J, Liu F, Crozier S. An electromagnetic reverse method of coil sensitivity mapping for parallel MRItheoretical framework, J Magn Reson 2010; 207: 59-68.
[10] Hoult D. The principle of reciprocity in signal strength calculationsa mathematical guide. Concept Magnetic Res 2000; 12: 173-187.
[11] Wiesinger F, de Moortele V, Adriany G, Ugurbil K, Pruessmann KP. Potential and feasibility of parallel MRI at high field. NMR Biomed 2006; 19: 368-378.
[12] Poston A. Human Engineering Design Data Digest: Human Factors Standardization Systems. Washington, DC, USA: Federal Aviation Administration, 2000.
[13] Gabriel S, Lau R, Gabriel C. The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues. Phys Med Biol 1996; 41: 2271-2293.
[14] Cherry SR, Badawi RD, Qi J. Essentials of In Vivo Biomedical Imaging. Boca Raton, FL, USA: CRC Press, 2015.
[15] Lerner LS. Physics for Scientists and Engineers. Burlington, MA, USA: Jones & Bartlett Learning, 1997.
[16] Bankson JA, Wright SM. Simulation-based investigation of partially parallel imaging with a linear array at high accelerations. Magn Reson Med 2002; 47: 777-786.
[17] Kamel IR, Elmar MM. Body MR Imaging at 3 Tesla. Cambridge, UK: Cambridge University Press, 2011.
[18] Wang J, Kluge T, Nittka M, Jellus V, Kiefer B. Parallel acquisition techniques with modified SENSE reconstruction (mSENSE). In: Proceedings of the First W¨urzburg Workshop on Parallel Imaging Basics and Clinical Applications; 2001; W¨urzburg, Germany. p. 89.
[19] Zhang Y, Peterson BS, Dong Z, A support-based reconstruction for SENSE MRI. Sensors 2013; 13: 4029-4040.
[20] Ibrahim TS, Mitchell C, Schmalbrock P, Lee R, Chakeres DW. Electromagnetic perspective on the operation of RF coils at 1.511.7 Tesla. Magn Reson Med 2005; 54: 683-690.
[21] Xu B, Li BK, Crozier S, Liu F. Model implementation and case study for the lossy, multilayered spherical head phantom in MRI application. In: IEEEEMBS 2005 Engineering in Medicine and Biology Society Conference; 14 September 2005; Shanghai, China. New York, NY, USA: IEEE. pp. 1400-1403.