title: Computerized MRS voxel registration and partial volume effects in single voxel 1H-MRS.
abstract: Partial volume effects in proton magnetic resonance spectroscopy in the brain have been studied previously in terms of proper water concentration calculations, but there is a lack of disclosure in terms of voxel placement techniques that would affect the calculations. The purpose of this study is to facilitate a fully automated MRS voxel registration method which is time efficient, accurate, and can be extended to all imaging modalities. A total of thirteen healthy adults underwent single voxel 1H-MRS scans in 3.0T MRI scanners. Transposition of a MRS voxel onto an anatomical scan is derived along with a full calculation of water concentration with a correction term to account for the partial volume effects. Five metabolites (tNAA, Glx, tCr, mI, and tCho) known to yield high reliability are studied. Pearson's correlation analyses between tissue volume fractions and metabolite concentrations were statistically significant in parietal (tCr, Glx, and tNAA) lobe and occipital lobe (tNAA). MRS voxel overlaps quantified by dice metric over repeated visits yielded 60%~70% and coefficients of variance in metabolites concentration were 4%~10%. These findings reiterate an importance of considering the partial volume effects when tissue water is used as an internal concentration reference so as to avoid misinterpreting a morphometric difference as a metabolic difference.
authors: Department of Anesthesiology, State University of New York at Stony Brook, Stony Brook, NY 11794, USA. hedoklee@gmail.com
authors: Hedok
authors: H
authors: Lee
authors: Elisabeth
authors: E
authors: Caparelli
authors: Haifang
authors: H
authors: Li
authors: Amit
authors: A
authors: Mandal
authors: S David
authors: SD
authors: Smith
authors: Shaonan
authors: S
authors: Zhang
authors: Thomas V
authors: TV
authors: Bilfinger
authors: Helene
authors: H
authors: Benveniste
mesh_terms: D000368:Aged; D000465:Algorithms; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000473:pathology; D010296:Parietal Lobe / Q000473:pathology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012984:Software
keywords: (1)HMRS; Image reconstruction; Partial volume effects