Proton MR Spectroscopy - ppm of Minor Metabolites

Metabolite                PPM

Valine
Leucine                         --->      0.9 ppm
Isoleucine

Alanine                          --->     1.48 ppm

Acetate                          --->     1.9 ppm

Succinate                      ---->     2.4 ppm

Lipid / Lactate              ---->     0.8 to 1.3 ppm


PS: To differentiate Lipids vs Lactate which occur at the 1.3ppm in the short TE acquisition, and additional TE = 135ms imaging is done in which the lipids do not invert.

       Pic F - Short TE                                           Pic G - Intermediate TE

Distinguishing the Amino acid peaks of Valine, Leucine and Isoleucine at the 0.9ppm and the lactate/lipid at 0.8-1.3ppm is important in distinguishing between Cystic Tumors (Both primary and mets) from Brain Abscesses - by doing the Intermediate TE (135ms) Spectroscopy, which causes the inversion of Aminoacids and lactate peak, but not of lipid.

Image showing the inversion of lipid in intermediate TE..