Theory and validation of a novel image reconstruction method applied to a rotating radiofrequency coil

• Calibration-free, radial image reconstruction method. • Hankel transform image reconstruction without gridding operations. • Improved image quality without incurring scan time penalty. A novel calibration-free image reconstruction method is presented; the suggested technique is independent of sensitivity profiles or gridding operations for a rotating radiofrequency coil. Recently, an eight-element rotating radiofrequency coil array has been designed and numerically evaluated. This coil improves image quality compared to a static coil array. This enhancement can be ascribed to an increase in the number of pseudo-coils in a parallel array, which is achieved by avoiding the adverse effects of mutual coupling or a scan time penalty. Current image reconstruction methods for the rotating coil either rely on gridding, on restricting the rotational speed of the RRFCA, or requiring the accurate measurement of rotated sensitivity maps. These are difficult to obtain accurately in practice and can potentially prolong scan time. The proposed method uses subsets of the radial k-space grid to perform calibration-free image reconstruction without explicit dependence on sensitivity maps or gridding operations. Our algorithm has been validated using both numerical phantom images and retrospectively using brain images from two volunteers. The method demonstrates enhanced performance when compared to the results that can be obtained using a conventional stationary eight loop-coil array. This method may improve the practicality of rotating radiofrequency technology and pave the way for further clinical applications.