Analysis of SNR Enhancement in 1.5T MRI by using Metasurfaces

Magnetic Resonance Imaging (MRI) is a clinical diagnostic tool for detection of malfunctional tissues and organs in a human body. The image resolution and scanning efficiency of MRI are directly dependent on signal-to-noise ratio (SNR). A higher SNR can be obtained by increasing the RF magnetic field which is accomplished by using metamaterials or metasurfaces. Here we present a thin metasurface which can be used as an 'add-on' in clinical 1.5T MRI for its SNR enhancement. A convoluted cross-type structure has been employed for increasing the magnetic flux density in the region of interest (ROI) by local confinement of electromagnetic fields in the near field region. A dielectric phantom made up of saline solution is integrated with the metasurface to demonstrate the enhancement of magnetic flux density up to a depth of 105 mm. The metasurface placed behind a human head bio-model, to emulate virtual brain-scan, results in SNR enhancement by a factor of 400 on the surface of the phantom.