I ran three consecutive MEGA-PRESS scans using the following parameter at Siemens 3T Skyra.
TR/TE=2000/ 68 ms, Average=96, voxel =3x3x3 and one non-water scan.
I processed the data using Gannet software. The stability between the second and third scans is less than 5%, and the first and second scans are around 15%, even though I used four preparation scans. Is it acceptable?
Why are there more fluctuations between the 1st and second scan compared to 2nd and third scan? Is there any reason for this?
Also, could you please tell me how to calculate the absolute concentration of GABA and Glx using Gannet?