Two-dimensional J-resolved proton MR spectroscopy and prior knowledge fitting (ProFit) in the frontal and parietal lobes of healthy volunteers: assessment of metabolite discrimination and general reproducibility.
OBJECTIVE
To investigate human brain metabolite discriminability and general measurement reproducibility of two-dimensional (2D) J-resolved (1)H MRS and Prior Knowledge Fitting (ProFit).


METHODS
2D J-resolved (1)H MRS spectra were acquired from the anterior cingulate cortex (ACC) and the parietal-occipital cortex (POC) of 10 healthy subjects at a magnetic field strength of 2.9 Tesla. Amplitude correlation matrices were constructed for each subject and brain region to assess metabolite discriminability. ProFit-estimated metabolite peak areas were normalized to a water reference signal, and intra- and inter-subject reproducibility was evaluated.


RESULTS
Favorable between-metabolite correlation coefficients (<20%) were observed for a range of metabolites. Lower correlation coefficients between a given pair of metabolite estimates were consistently observed for POC metabolites. The group mean correlation coefficient existing between glutamate and glutamine was calculated as -18% and -13% for ACC and POC, respectively. Most ACC and POC metabolites showed intra- and inter-subject CV values of <15% and <20%, respectively.


CONCLUSIONS
The observed Glu and Gln signal discrimination makes these techniques suitable for investigating a variety of psychiatric disorders. Intra- and inter-subject metabolite level reproducibility was comparable to the existing literature findings. These data serve as a valuable benchmark for assessing future modifications to 2D (1)H MRS data acquisition and ProFit analysis.
Brain Institute, Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA. andrew.prescot@utah.edu
Andrew P
AP
Prescot
Perry F
PF
Renshaw
D000328:Adult; D001921:Brain / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D004574:Electromagnetic Fields; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D010296:Parietal Lobe / Q000502:physiology*; D015203:Reproducibility of Results; D012984:Software; D055815:Young Adult
D005973:Glutamine; D018698:Glutamic Acid