Detecting in vivo changes of electrical properties of Cerebral Spinal Fluid using microwave signals from small coil antennas - numerical simulation

Dielectric properties of Cerebral Spinal Fluid (CSF) at microwave frequencies correlate with a higher level of glucose or protein observed at certain diseases, including early stages of Alzheimer's disease. In this study, a simulation of in vivo monitoring dielectric properties of Cerebral Spinal Fluid (CSF) using small antennas precisely positioned around the human head is made. We use a realistic mesh model of the head and head organs obtained by fine segmentation of the Visible Human Project® data. An accurate source model with coincident phase centers is employed in the underlying Finite Difference Time-Domain (FDTD) algorithm. Simulation result strongly depends on the type and positioning of small antennas around the head, and on the mechanical accuracy. Once these factors are properly optimized, the changes in the relative dielectric constant on the order of 10-15% may be recorded using the phase shift of a second received pulse.

[1]  Ari Sihvola,et al.  Confinement and propagation relations for Zenneck surface waves , 2010, Proceedings of the Fourth European Conference on Antennas and Propagation.

[2]  Trey Sunderland,et al.  Decreased beta-amyloid1-42 and increased tau levels in cerebrospinal fluid of patients with Alzheimer disease. , 2003, JAMA.

[3]  W. Lukosz,et al.  Light emission by magnetic and electric dipoles close to a plane interface. I. Total radiated power , 1977 .

[4]  W. Lukosz.  Light emission by magnetic and electric dipoles close to a plane dielectric interface. III. Radiation patterns of dipoles with arbitrary orientation , 1979 .

[5]  J. Ollikainen,et al.  Propagation Between On-Body Antennas , 2009, IEEE Transactions on Antennas and Propagation.

[6]  P. L. Overfelt,et al.  Review of Electromagnetic Surface Waves - 1960 Through 1987 , 1988 .

[7]  Trey Sunderland,et al.  Decreased-Amyloid 1-42 and Increased Tau Levels in Cerebrospinal Fluid of Patients With Alzheimer Disease , 2003 .

[8]  J. Zenneck.  Über die Fortpflanzung ebener elektromagnetischer Wellen längs einer ebenen Leiterfläche und ihre Beziehung zur drahtlosen Telegraphie , 1907 .

[9]  J. Kaye,et al.  High cerebrospinal fluid tau and low amyloid beta42 levels in the clinical diagnosis of Alzheimer disease and relation to apolipoprotein E genotype. , 1998, Archives of neurology.

[10]  Jonathan Neil Bringuier.  MULTI-SCALE TECHNIQUES IN COMPUTATIONAL ELECTROMAGNETICS , 2010 .

[11]  Y. Rahmat-Samii,et al.  Implanted antennas inside a human body: simulations, designs, and characterizations , 2004, IEEE Transactions on Microwave Theory and Techniques.

[12]  Vinu Thomas,et al.  Analysis of Human Cerebro Spinal Fluid at the ISM Band of Frequencies , 2006 .

[13]  W. Lukosz,et al.  Light emission by magnetic and electric dipoles close to a plane dielectric interface. II. Radiation patterns of perpendicular oriented dipoles , 1977 .

[14]  S. N. Makarov,et al.  Directional in-quadrature orthogonal-coil antenna and an array thereof for localization within a human body in a Fresnel region , 2012, Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation.

[15]  Glenn S. Smith.  Directive properties of antennas for transmission into a material half-space , 1984 .

[16]  J. Trojanowski,et al.  Diagnosis-independent Alzheimer disease biomarker signature in cognitively normal elderly people. , 2010, Archives of neurology.

[17]  Gregory M. Noetscher,et al.  Accuracy of point source models with coincident phase centers in a cubic FDTD grid for arbitrary source orientation , 2012, Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation.

[18]  Heinrich Müller,et al.  Improved Laplacian Smoothing of Noisy Surface Meshes , 1999, Comput. Graph. Forum.

[19]  R. W. Lau,et al.  The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues. , 1996, Physics in medicine and biology.