Asynchronous Timing Error Offset Identification and Deskews (ASTEROIDS) for wireless MRI

A wireless mode for the radiofrequency (RF) subsystem in Magnetic Resonance Imaging (MRI) is highly desirable owing to several challenges associated with wired connections utilizing coaxial cables. These issues include cable management for larger arrays, wear and tear and depreciating signal-to-noise ratio due to increases in external noise. Nonetheless, a primary constraint in implementing wireless RF coil solutions is synchronization between the transmit (Tx) and receive (Rx) signals. Poor synchronization arising from frequency mismatch between separate Tx and Rx clocks from one data readout line or repetition time (TR) to the next, or from one image (a set of TRs) to the next in an acquisition can induce phase rotations and degrade image quality. In this work, we propose an innovative error correction method that can effectively address image artifacts from timing offsets between the Tx and Rx clocks in wireless RF coil setups. Our method, Asynchronous Timing Error Offset Identification and Deskews (ASTEROIDS), utilizes navigator echo acquisitions as extra data within conventional MRI scans without significantly lengthening scan time. These echoes can then be used to identify linear phase shifts in k-space and the overall skew which occurs due to the TR mismatch between the Tx and Rx clocks. Based on this, a correction of every k-space line or the overall k-space skew (for all lines) can be performed to yield undistorted artifact-free wireless MR images.