RF resonator array device for use in magnetic resonance imaging and methods of use thereof

Inventors

ALIPOUR, Akbar • Balchandani, Priti • SEIFERT, Alan C.

Assignees

Icahn School of Medicine at Mount Sinai

Abstract

A radiofrequency (RF) resonator array device for use in magnetic resonance imaging (MRT), The RF resonator array device includes a substrate. An array of coupled split ring resonators are located on the substrate. Each of the coupled split ring resonators includes a first split ring resonator positioned on a first side of the substrate and a second split ring resonator positioned on a second side of the substrate located opposite the first side. The second split ring resonator is inductively coupled to the first split ring resonator. Methods of making and using the RF resonator device are also disclosed.

Core Innovation

The invention relates to a radiofrequency (RF) resonator array device for use in magnetic resonance imaging (MRI). The device includes a substrate bearing an array of coupled split ring resonators (CSSRs), where each resonator consists of a first split ring resonator on one side of the substrate and a second split ring resonator on the opposite side. The second is inductively coupled to the first and oriented rotated 180 degrees relative to it. The resonators are designed to inductively couple with the MRI’s RF coil to augment local magnetic fields and improve MRI performance.

The RF resonator array can be used as a wireless, passive device that enhances transmission efficiency and signal sensitivity, particularly focused on the cerebellum and inferior brain regions. It can be placed near the patient's anatomy during MRI, such as the brain, to increase local signal intensity via additional flux during RF transmit and amplification during receive phases. The substrate is flexible and thin to conform to anatomy, and the device is tuned to the Larmor frequency corresponding to MRI field strengths, such as 7 T (approximately 297 MHz). This configuration improves transmit efficiency, signal-to-noise ratio (SNR), and coverage in MRI imaging, addressing challenges in ultra-high field MRI.

The problem addressed arises from limitations in current ultra-high field (UHF) MRI systems, where radiofrequency inhomogeneity and limited sensitivity, especially in challenging brain regions such as the cerebellum and skull base, reduce image quality. Commercial 7 T head coils have limited field-of-view and transmit/receive inefficiencies attributed to wavelength effects and inhomogeneous RF fields. Passive methods like dielectric pads have been used but cause RF field gradients and occupy significant space. Active RF shimming like parallel transmission improves homogeneity but increases SAR and complexity. New methods to improve RF field uniformity and sensitivity without compromising safety and coverage are needed, and this invention provides an inductively coupled RF resonator array device to overcome these deficiencies.

Claims Coverage

The patent contains three independent claims directed toward an RF resonator array device, a method of making the device, and a method of generating an MRI using the device. The inventive features focus on the physical structure and operational coupling aspects of the coupled split ring resonators (CSSRs) on a substrate, their configuration, and their functional coupling during MRI.

The claims cover the structure of a coupled split ring resonator array device mounted on a substrate, methods of making this array, and employing the array during MRI to enhance local signal intensity by inductive coupling with the MRI coil during both transmission and reception.

Stated Advantages

Documented Applications