Fig. 6.

H¹MRS spectra acquired at intermediate TE (135ms) in a suspected metastasis (a case of lung cancer) shows a non-specific spectra with an elevated choline at 3.2 and a decreased NAA peak at 2.02, presence of an inverted lactate peak at 1.3 indicating anaerobic metabolism. Significant choline elevation indicates a high cell membrane turn over while reduced NAA in an intra-axial tumor raises a suspicion of non-neurological origin of the lesion. A situation where an intra-axial lesion also behaves like being ‘extra-axial’, as the NAA seen is due to voxel contamination from adjacent brain rather than intra-tumoral signal, this can be noted while evaluating the voxel. This correlates with a possibility of secondary deposit, especially so if a primary is known.