Partially parallel imaging with localized sensitivities (PILS)

In this study a novel partially parallel acquisition method is presented, w hich can be used to accelerate image acquisition using an RF coil array for spatial encoding. In this technique, Parallel Imaging with Localized Sensi tivities (PILS), it is assumed that the individual coils in the array have localized sensitivity patterns, in that their sensitivity is restricted to a finite region of space. Within the PILS model, a detailed, highly accurat e RF field map is not needed prior to reconstruction. In PILS, each coil in the array is fully characterized by only two parameters: the center of coi l's sensitive region in the FOV and the width of the sensitive region aroun d this center. In this study, it is demonstrated that the incorporation of these coil parameters into a localized Fourier transform allows reconstruct ion of full FOV images in each of the component coils from data sets acquir ed with a reduced number of phase encoding steps compared to conventional i maging techniques. After the introduction of the PILS technique, primary fo cus is given to issues related to the practical implementation of PILS, inc luding coil parameter determination and the SNR and artifact power in the r esulting images. Finally, in vivo PILS images are shown which demonstrate t he utility of the technique. (C) 2000 Wiley-Liss, Inc.