Kevin Fotso1,2, Stephen R Dager3, Alec Landow1,4, Elena Ackley1, Orrin Myers5, Mindy Dixon6, Dennis Shaw3,6, Neva M Corrigan3, Stefan Posse1,4,7. 1. Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA. 2. Department of Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico, USA. 3. Department of Radiology, University of Washington, Seattle, Washington, USA. 4. Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, USA. 5. Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, USA. 6. Seattle Children's Hospital, Seattle, Washington, USA. 7. Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico, USA.
Abstract
PURPOSE: We developed diffusion tensor spectroscopic imaging (DTSI), based on proton-echo-planar-spectroscopic imaging (PEPSI), and evaluated the feasibility of mapping brain metabolite diffusion in adults and children. METHODS: PRESS prelocalized DTSI at 3 Tesla (T) was performed using navigator-based correction of movement-related phase errors and cardiac gating with compensation for repetition time (TR) related variability in T1 saturation. Mean diffusivity (MD) and fractional anisotropy (FA) of total N-acetyl-aspartate (tNAA), total creatine (tCr), and total choline (tCho) were measured in eight adults (17-60 years) and 10 children (3-24 months) using bmax = 1734 s/mm2 , 1 cc and 4.5 cc voxel sizes, with nominal scan times of 17 min and 8:24 min. Residual movement-related phase encoding ghosting (PEG) was used as a regressor across scans to correct overestimation of MD. RESULTS: After correction for PEG, metabolite slice-averaged MD estimated at 20% PEG were lower (P < 0.042) for adults (0.17/0.20/0.18 × 10-3 mm2 /s) than for children (0.26/0.27/0.24 × 10-3 mm2 /s). Extrapolated to 0% PEG, the MD estimates decreased further (0.09/0.11/0.11 × 10-3 mm2 /s versus 0.15/0.16/0.15 × 10-3 mm2 /s). Slice-averaged FA of tNAA (P = 0.049), tCr (P = 0.067), and tCho (P = 0.003) were higher in children. CONCLUSION: This high-speed DTSI approach with PEG regression allows for estimation of metabolite MD and FA with improved tolerance to movement. Our preliminary data suggesting age-related changes support DTSI as a sensitive technique for investigating intracellular markers of biological processes. Magn Reson Med 78:1246-1256, 2017.
PURPOSE: We developed diffusion tensor spectroscopic imaging (DTSI), based on proton-echo-planar-spectroscopic imaging (PEPSI), and evaluated the feasibility of mapping brain metabolite diffusion in adults and children. METHODS: PRESS prelocalized DTSI at 3 Tesla (T) was performed using navigator-based correction of movement-related phase errors and cardiac gating with compensation for repetition time (TR) related variability in T1 saturation. Mean diffusivity (MD) and fractional anisotropy (FA) of total N-acetyl-aspartate (tNAA), total creatine (tCr), and total choline (tCho) were measured in eight adults (17-60 years) and 10 children (3-24 months) using bmax = 1734 s/mm2 , 1 cc and 4.5 cc voxel sizes, with nominal scan times of 17 min and 8:24 min. Residual movement-related phase encoding ghosting (PEG) was used as a regressor across scans to correct overestimation of MD. RESULTS: After correction for PEG, metabolite slice-averaged MD estimated at 20% PEG were lower (P < 0.042) for adults (0.17/0.20/0.18 × 10-3 mm2 /s) than for children (0.26/0.27/0.24 × 10-3 mm2 /s). Extrapolated to 0% PEG, the MD estimates decreased further (0.09/0.11/0.11 × 10-3 mm2 /s versus 0.15/0.16/0.15 × 10-3 mm2 /s). Slice-averaged FA of tNAA (P = 0.049), tCr (P = 0.067), and tCho (P = 0.003) were higher in children. CONCLUSION: This high-speed DTSI approach with PEG regression allows for estimation of metabolite MD and FA with improved tolerance to movement. Our preliminary data suggesting age-related changes support DTSI as a sensitive technique for investigating intracellular markers of biological processes. Magn Reson Med 78:1246-1256, 2017.
Authors: Stefan Posse; Bruno Sa De La Rocque Guimaraes; Troy Hutchins-Delgado; Kishore Vakamudi; Kevin Fotso Tagne; Steen Moeller; Stephen R Dager Journal: NMR Biomed Date: 2020-01-30 Impact factor: 4.044