Fast echo planar based correlation-peak imaging: Demonstration on the rat brain in vivo

Two-dimensional correlation spectroscopy (2D-COSY) was combined with a fast echo planar based spectroscopic imaging technique in a new sequence. It ca n be optimized according to the coupling patterns of particular metabolites by using a constant time (CT) variant of COSY with chemical shift selectiv e excitation and refocusing. Experiments were performed with an evolution t ime of 110 ms which was determined by simulating the CT-COSY experiment at several evolution times for the spin systems of myo-inositol (Ins) and taur ine (Tau). The sequence has a minimum total measurement time of 17 min and was tested on a spherical phantom filled with a solution of Ins. The in viv o application of this method on the healthy rat brain demonstrates its impr oved spectral resolution as cross-peak signals from both Ins and Tau can be separated clearly. (C) 2000 Wiley-Liss, Inc.