Homonuclear uncoupled H-1-spectroscopy of the human brain using weighted accumulation schemes

Homonuclear uncoupled H-1-spectroscopy based on 2-dimensional (2D) J-resolv ed spectroscopy is a well suited technique for the assessment of J-coupled metabolite resonances. In comparison with 1-dimensional H-1-spectroscopy th is technique largely reduces problems due to spectral overlap between low m olecular weight metabolite resonances and superimposed broad macromolecule resonances, as well as overlap between adjacent multiplets, Usually, 2D J-r esolved spectroscopic data were acquired using a constant number of accumul ations for each of the various echo times. In contrast to this, a weighted accumulation scheme has been applied in this study, using an echo time depe ndent number of accumulations. The aims of this modification were to reduce the acquisition time and to improve the signal-to-noise ratio per unit acq uisition time (SNRt), Four different sine-bell like accumulation schemes an d a reference scheme using a constant number of accumulations have been app lied on five normal volunteers. Localized spectra obtained from the parieto -occipital white matter were compared with regard to SNRt and linewidth, A reduction in acquisition time of 45%, related to the reference scheme, and an increase in SNRt of 25-30% were achieved using a sine-bell accumulation scheme in combination with a quarter sine-wave apodization of the short ech o time data. Down to an acquisition time of 122 s no significant line broad ening has been observed in comparison with the reference scheme. (C) 1999 E lsevier Science Inc.