Light Coils: MRI with Modular RF Coils Using Optical Power and Data Transmission

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The design of dense receive coil arrays for magnetic resonance imaging (MRI) is challenging due to electromagnetic interference and crosstalk in the electrically conducting cables which lead to signal-to-noise ratio (SNR) losses during signal transmission. This limits the maximum number of channels. By combining innovative radio frequency (RF) antenna architectures, low-noise-low-power front end electronics and state-of-the-art silicon photonics technology, the Light Coil approach in this work will overcome the problems of conventional receive coil arrays offering a robust and scalable solution for MRI coil arrays that are optically powered and use modular broadcasting technologies. There are major draw-backs associated with the current RF coil arrays: 1. Fixed and limited number of coil elements; 2. cannot adapt to various sizes; 3. conducting cables are required to transfer MR signal to the receiver and to deliver power for driving the amplifiers and active detuning. Electrically conducting cables present a potential safety hazard in MRI, and crosstalk between them impairs the imaging performance. 4. The dense cable bundles and circuitry around the coil affects the RF transmission performance. A modular RF coil technology with fully optical signal and power transmission can overcome these problems and enable design of so-far-not-attainable number of channels to improve acquisition speed and SNR. The modular design will also facilitate optimal fit and performance for different patient sizes enabling new findings in human brain research. In this proposal, we combine the state-of-the-art RF electronics and optics to realize the Light Coil technology. Each Light Coil element is associated with a specific wavelength for optical power and signal transmission. Signal and power transmission waves will be multiplexed and demultiplexed separately using on-coil photonic ICs. Optical connectors between the Light Coil elements are used both for distributing the signal and power waves and for mechanical attachment. Only the main Light Coil element is connected to the control system via fibers. All the attached elements have only internal fiber connections and optical connectors to get attached to the next Light Coil element. We will investigate and optimize power requirements on an RF coil element using novel amplifier and active detuning networks, and assess feasibility of implementing Light Coil technology on two 16-channel flexible Light Coil module prototypes which can be attached to form an array of 32, and compare it to the state-of-the-art signal transmission systems and commercially available coils. We will also ensure that the developed solutions and techniques are upscalable to higher channel count RF coil arrays in the second phase of the project where functional MRI and MREG with 256-channel Light Coils with unprecedented temporal and spatial resolution will be demonstrated.