Lipid elimination with an echo‐shifting N/2‐ghost acquisition (LEENA) MRI

Purpose The Dixon techniques provide uniform water‐fat separation but require multiple image sets, which extend the overall acquisition time. Here, an alternative rapid single acquisition method, lipid elimination with an echo‐shifting N/2‐ghost acquisition (LEENA), was introduced. Methods The LEENA method utilized a fast imaging with steady‐state free precession sequence to obtain a single k‐space dataset in which successive k‐space lines are acquired to allow the fat magnetization to precess 180°. The LEENA data were then unghosted using either image‐domain (LEENA‐S) or k‐space domain (LEENA‐G) parallel imaging techniques to reconstruct water‐only and fat‐only images. An off‐resonance correction technique was incorporated to improve the uniformity of the water‐fat separation. Results Uniform water‐fat separation was achieved for both the LEENA‐S and LEENA‐G methods for phantom and human body and leg imaging applications at 1.5T and 3T. The resultant water and fat images were qualitatively similar to conventional 2‐point Dixon and fat‐suppressed images. Conclusion The LEENA‐S and LEENA‐G methods provide uniform water and fat images from a single MRI acquisition. These straightforward methods can be adapted to 1.5T and 3T clinical MRI scanners and provide comparable fat/water separation with conventional 2‐point Dixon and fat‐suppression techniques. Magn Reson Med 73:711–717, 2015. © 2014 Wiley Periodicals, Inc