Quantification of Cerebral Glucose Concentrations via Detection of the H1‐α‐Glucose Peak in 1H MRS at 7 T

Abstract

BackgroundSensitive detection and quantification of cerebral glucose is desired.PurposeTo quantify cerebral glucose by detecting the H1‐α‐glucose peak at 5.23 ppm in 1H magnetic resonance spectroscopy at 7 T.Study TypeProspective.SubjectsTwenty‐eight non‐fasted healthy subjects (aged 20–28 years).Field Strength/SequenceShort echo time stimulated echo acquisition mode (short‐TE STEAM) and semi‐localized by adiabatic selective refocusing (semi‐LASER) at 7 T.AssessmentSingle voxel spectra were obtained from the posterior cingulate cortex (27‐mL) using a 32‐channel head coil. The H1‐α‐glucose peak in the spectrum with retrospective removal of the residual water peak was fitted using LCModel with a glucose basis set of only the H1‐α‐glucose peak. Conventional spectral analysis was performed with a glucose basis set of a full spectral pattern of glucose, also. Fitting precision was evaluated with Cramér‐Rao lower bounds (CRLBs). The repeatability of glucose quantification via the semi‐LASER sequence was tested.Statistical TestsPaired or Welch's t‐test were used for normally distributed values. A P value of <0.05 was considered significant. The repeatability of measures was analyzed using coefficient of variation (CV).ResultsRemoval of the residual water peak improved the flatness and stability of baselines around the H1‐α‐glucose peak and reduced CRLBs for fitting the H1‐α‐glucose peak. The semi‐LASER sequence was superior to the short‐TE STEAM in the higher signal‐to‐noise ratio of the H1‐α‐glucose peak (mean ± SD 7.9 ± 2.5, P < 0.001). The conventional analysis overfitted the H1‐α‐glucose peak. The individual CVs of glucose quantification by detecting the H1‐α‐glucose peak were smaller than the corresponding CRLBs.Data ConclusionCerebral glucose concentration is quantitated to be 1.07 mM by detecting the H1‐α‐glucose peak in the semi‐LASER spectra. Despite requiring long scan times, detecting the H1‐α‐glucose peak allows true glucose quantification free from the influence of overlapping taurine and macromolecule signals.Evidence Level2Technical Efficacy Stage1