CALCULATIONS AND EXPERIMENTAL STUDIES OF THE LINESHAPE OF THE LACTATEDOUBLET IN PRESS-LOCALIZED H-1 MRS

Accurate quantification of NMR metabolites by spectral modeling requir es assumed lineshape functions. For singlet resonances, a combination of Lorentzian and Gaussian lineshapes is sufficient, but for weakly J- coupled resonances such as lactate, more complex lineshapes are necess ary. In this work, the lactate lineshape is calculated for the PRESS s equence using standard RF pulses, and compared with experimental measu rements. A similar comparison is made for PRESS-localized spectroscopi c imaging, in which the lineshape varies from voxel to voxel across th e field of view. These observations have important implications for th e quantification of lactate in experimental and human studies.