A pitfall associated with lactate detection using stimulated-echo proton spectroscopy.
At TE values of 136 ms, it has recently been shown that the lactate methyl signal, when obtained with a stimulated-echo (STE) sequence, is modulated at the zero-quantum (ZQ) frequency when TM is varied. Here we describe an additional modulation of the ZQ lactate signal, due to spin-spin coupling, that results in a 10-fold reduction in the lactate signal for TM intervals ranging between 48 and 84 ms (and at multiples of 136 ms thereof). Because of this J-modulation, improper choice of TE and TM intervals may give false negative results for lactate detection by STE spectroscopy.
Sotak
C H
CH
Department of Biomedical Engineering, Worcester Polytechnic Institute, Massachusetts 01609.
Alger
J R
JR
D000409:Alanine / Q000031:analogs & derivatives / Q000032:analysis; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000737:chemistry; D005583:Fourier Analysis; D006801:Humans; D006859:Hydrogen; D007773:Lactates / Q000032:analysis*; D019344:Lactic Acid; D008055:Lipids / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008961:Models, Structural; D013997:Time Factors
D007773:Lactates; D008055:Lipids; C028444:methyl lactate; C010530:N-acetylalanine; D019344:Lactic Acid; D006859:Hydrogen; D000409:Alanine