Experimental demonstration of a μ=−1 metamaterial lens for magnetic resonance imaging

Abstract

In this work a μ=-1 metamaterial (MM) lens for magnetic resonance imaging (MRI) is demonstrated. MRI uses surface coils to detect the radiofrequency (RF) energy absorbed and emitted by the nuclear spins in the imaged object. The proposed MM lens manipulates the RF field detected by these surface coils, so that the coil sensitivity and spatial localization is substantially improved. Beyond this specific application, we feel that the reported results are the experimental confirmation of a new concept for the manipulation of RF field in MRI, which paves the way to many other interesting applications.After the demonstration of the ability of a slab of an ideal negative refractive index metamaterial (MM) with ε=-1 and μ=-1 to obtain sub-diffraction images 1 , the

0 μ Magnetic Polarizer for 1.5-T MRI

“…This property was absent in previous work of negative permeability -μ metamaterial lenses [26]. Polarizer with compact thickness of only 5 mm and novel combination of parametric elements (capacitors, inductors), exhibited resonance at very low working frequency of 63.85 MHz, which was the frequency of operation for 1.5-T MRI systems.…”

“…Theoretically and experimentally proved that metamaterials when used with MRI systems has improved image resolution, image acquisition time and image quality inside the human body [23][24][25][26][27][28][29][30][31]. We still believe that metamaterials for MRI systems contain much hidden potential which should be expose in future research.…”

Bandwidth Tuning in Transistor Embedded Metamaterials Using Variable Resistance

“…Examples of these properties are negative permeability [1,2], negative permittivity [3], and negative index of refraction [4,5]. Correctly engineering and controlling these properties has yielded advances in cloaking [6], lensing [7,8], and antenna design [9][10][11]. However, for all of these properties to be expressed in the manner required for the aforementioned applications, metamaterials need to be composed of resonant inclusions.…”

Realistic metamaterial lenses: Limitations imposed by discrete structure

“…In particular, metamaterials based on split-ring resonators were put forward for various superlenses. 10,11 Practical solutions are so far available at microwave and radio frequencies, with the key goal to aid at magnetic resonance imaging ͑MRI͒. A metamaterial superlens suggested 11 for MRI applications employs an idea of imaging with a sufficiently subwavelength slab having negative permeability or permittivity.…”

“…10,11 Practical solutions are so far available at microwave and radio frequencies, with the key goal to aid at magnetic resonance imaging ͑MRI͒. A metamaterial superlens suggested 11 for MRI applications employs an idea of imaging with a sufficiently subwavelength slab having negative permeability or permittivity. 5 This must be distinguished from another approach, based on a multiple point-to-point channelling ͑ca-nalization͒, as can be achieved with wires 12 or "Swiss rolls," 13 although such method is also applicable for MRI.…”