A fast algorithm for phased array image reconstruction in Magnetic Resonance Imaging

Radiofrequency receiver coils in magnetic resonance imaging systems are used to pick up the signals emitted by the nuclei. Surface coils provide a high signal-to-noise ratio because of their small sensitive region but the usable field of view is also limited to the size of the sensitive region. Using coil array permits to obtain high SNR and a large region of sensitivity: the outputs from the receiver channels are combined in order to construct a single composite image from the data of many coils. For the image construction, usually sum-of-squares (SoS) method is used, which combines data without the knowledge of the coils sensitivity but it is known to provide low contrast images. In this work we investigate and test on MR images a simple method (SUPER algorithm) which uses an estimation of coils field maps to combine the data from the phased array elements to yield an image with higher contrast respect to the usual SoS.