Lactate is one of the more important compounds assessed on MR spectroscopy, and resonates at 1.3 ppm chemical shift, with a characteristic double peak at long TEs. It is however superimposed on the lipid band, and using an intermediate TE (e.g. 144ms) will invert only lactate allowing it to be distinguished.
It is a marker of anaerobic metabolism with no peak seen in normal spectra. It is therefore elevated in necrotic areas (e.g. higher grade tumours) and infections (cerebral abscess). An elevated lactate peak may also be seen in the setting of diffuse axonal injury. In which case, it is associated with a worse prognosis 1.
- 1. Hesselink, JR. Fundamentals of MR Spectroscopy. Available online: http://spinwarp.ucsd.edu/NeuroWeb/Text/mrs-TXT.htm
- 2. Al-Okaili RN, Krejza J, Wang S et-al. Advanced MR imaging techniques in the diagnosis of intraaxial brain tumors in adults. Radiographics. 2006;26 Suppl 1 (suppl_1): S173-89. doi:10.1148/rg.26si065513 - Pubmed citation
MR spectroscopy (MRS)
- Hunter's angle
- lactate peak: resonates at 1.3 ppm
- lipids peak: resonate at 1.3 ppm
- alanine peak: resonates at 1.48 ppm
- N-acetylaspartate (NAA) peak: resonates at 2.0
- glutamine-glutamate peak: resonate at 2.2-2.4 ppm
- gamma-aminobutyric acid (GABA) peak: resonate at 2.2-2.4 ppm
- citrate peak: resonates at 2.6 ppm
- creatine peak: resonates at 3.0 ppm
- choline peak: resonates at 3.2 ppm
- myo-inositol peak: resonates at 3.5 ppm