Proton‐decoupled 31P chemical shift imaging of the human brain in normal volunteers

Abstract

Proton‐decoupled, ³¹P three‐dimensional (3‐D) chemical shift imaging (CSI) spectra have been acquired from the entire human brain using a new dual tuned resonator. The resonator operates in quadrature mode to provide improved sensitivity, excellent B₁ homogeneity, and reduced power deposition at both frequencies. Proton‐decoupled and fully NOE enhanced, ³¹P spectra were acquired from normal volunteers using Waltz‐4 proton decoupling with continuous wave bi‐level excitation applied through a second radio frequency channel. Well resolved peaks in the phosphomonoester (PME) and phosphodiester regions were obtained from non‐localized FIDs and spectra localized with 3‐D CSI without processing for resolution enhancement. pH measurements made over large regions of the brain using the P_i resonance show no significant variations (6.9±0.02) for a single individual. The improved spectral resolution and sensitivity of the PME resonances results in more well defined metabolite images of the PME peak region.