Changho Choi1, Ivan Dimitrov1,2, Deborah Douglas1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Philips Medical Systems, Cleveland, OH, USA
Measurement of serine (Ser) in human brain has been pursued with constant-echo time PRESS difference editing at 7T. Subecho time dependence of the Ser multiplet was investigated for TE1 and TE2 between 20 200 ms, using density-matrix simulation incorporating the slice-selective shaped RF and gradient pulses. The simulation indicated that the Ser ~3.96 ppm resonances can be edited by means of difference between PRESS spectra at (TE1, TE2) = (108, 80) and (49, 139) ms, canceling the creatine (Cr) 3.92 ppm signal. An in vivo spectrum obtained from the frontal cortex showed a Ser edited signal clearly. The area of this peak was estimated to be 1.5% with respect to a Cr 3.03-ppm signal, giving 0.4 mM with reference to Cr at 8 mM.