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Deelchand DK, Iltis I, Henry PG. Improved quantification precision of human brain short echo-time (1) H magnetic resonance spectroscopy at high magnetic field: a simulation study. Magn Reson Med 2014; 72:20-5. [PMID: 23900976 PMCID: PMC3907456 DOI: 10.1002/mrm.24892] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/24/2013] [Accepted: 06/27/2013] [Indexed: 11/10/2022]
Abstract
PURPOSE The gain in quantification precision that can be expected in human brain (1) H MRS at very high field remains a matter of debate. Here, we investigate this issue using Monte-Carlo simulations. METHODS Simulated human brain-like (1) H spectra were fitted repeatedly with different noise realizations using LCModel at B0 ranging from 1.5T to 11.7T, assuming a linear increase in signal-to-noise ratio with B0 in the time domain, and assuming a linear increase in linewidth with B0 based on experimental measurements. Average quantification precision (Cramér-Rao lower bound) was then determined for each metabolite as a function of B0 . RESULTS For singlets, Cramér-Rao lower bounds improved (decreased) by a factor of ∼ B0 as B0 increased, as predicted by theory. For most J-coupled metabolites, Cramér-Rao lower bounds decreased by a factor ranging from B0 to B0 as B0 increased, reflecting additional gains in quantification precision compared to singlets owing to simplification of spectral pattern and reduced overlap. CONCLUSIONS Quantification precision of (1) H magnetic resonance spectroscopy in human brain continues to improve with B0 up to 11.7T although peak signal-to-noise ratio in the frequency domain levels off above 3T. In most cases, the gain in quantification precision is higher for J-coupled metabolites than for singlets.
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Affiliation(s)
- Dinesh Kumar Deelchand
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Marjańska M, Weigand SD, Preboske G, Wengenack TM, Chamberlain R, Curran GL, Poduslo JF, Garwood M, Kobayashi D, Lin JC, Jack CR. Treatment effects in a transgenic mouse model of Alzheimer's disease: a magnetic resonance spectroscopy study after passive immunization. Neuroscience 2013; 259:94-100. [PMID: 24316473 DOI: 10.1016/j.neuroscience.2013.11.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 11/08/2013] [Accepted: 11/25/2013] [Indexed: 12/14/2022]
Abstract
Despite the enormous public health impact of Alzheimer's disease (AD), no disease-modifying treatment has yet been proven to be efficacious in humans. A rate-limiting step in the discovery of potential therapies for humans is the absence of efficient non-invasive methods of evaluating drugs in animal models of disease. Magnetic resonance spectroscopy (MRS) provides a non-invasive way to evaluate the animals at baseline, at the end of treatment, and serially to better understand treatment effects. In this study, MRS was assessed as potential outcome measure for detecting disease modification in a transgenic mouse model of AD. Passive immunization with two different antibodies, which have been previously shown to reduce plaque accumulation in transgenic AD mice, was used as intervention. Treatment effects were detected by MRS, and the most striking finding was attenuation of myo-inositol (mIns) increases in APP-PS1 mice with both treatments. Additionally, a dose-dependent effect was observed with one of the treatments for mIns. MRS appears to be a valid in vivo measure of anti-Aβ therapeutic efficacy in pre-clinical studies. Because it is noninvasive, and can detect treatment effects, use of MRS-based endpoints could substantially accelerate drug discovery.
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Affiliation(s)
- M Marjańska
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA.
| | - S D Weigand
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55902, USA
| | - G Preboske
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - T M Wengenack
- Departments of Neurology, Neuroscience, and Biochemistry/Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - R Chamberlain
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - G L Curran
- Departments of Neurology, Neuroscience, and Biochemistry/Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - J F Poduslo
- Departments of Neurology, Neuroscience, and Biochemistry/Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - M Garwood
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - D Kobayashi
- Rinat, Pfizer Inc., South San Francisco, CA 94080, USA
| | - J C Lin
- Rinat, Pfizer Inc., South San Francisco, CA 94080, USA
| | - C R Jack
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
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