| In vivo mapping of brain myo-inositol. | |
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MedLine Citation:
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PMID: 20951217 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Myo-Inositol (MI) is one of the most abundant metabolites in the human brain located mainly in glial cells and functions as an osmolyte. The concentration of MI is altered in many brain disorders including Alzheimer's disease and brain tumors. Currently available magnetic resonance spectroscopy (MRS) methods for measuring MI are limited to low spatial resolution. Here, we demonstrate that the hydroxyl protons on MI exhibit chemical exchange with bulk water and saturation of these protons leads to reduction in bulk water signal through a mechanism known as chemical exchange saturation transfer (CEST). The hydroxyl proton exchange rate (k=600 s(-1)) is determined to be in the slow to intermediate exchange regime on the NMR time scale (chemical shift (∆ω)>k), suggesting that the CEST effect of MI (MICEST) can be imaged at high fields such as 7 T (∆ω=1.2×10(3)rad/s) and 9.4 T (∆ω=1.6×10(3) rad/s). Using optimized imaging parameters, concentration dependent broad CEST asymmetry between ~0.2 and 1.5 ppm with a peak at ~0.6 ppm from bulk water was observed. Further, it is demonstrated that MICEST detection is feasible in the human brain at ultra high fields (7 T) without exceeding the allowed limits on radiofrequency specific absorption rate. Results from healthy human volunteers (N=5) showed significantly higher (p=0.03) MICEST effect from white matter (5.2±0.5%) compared to gray matter (4.3±0.5%). The mean coefficient of variations for intra-subject MICEST contrast in WM and GM were 0.49 and 0.58 respectively. Potential overlap of CEST signals from other brain metabolites with the observed MICEST map is discussed. This noninvasive approach potentially opens the way to image MI in vivo and to monitor its alteration in many disease conditions. |
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Authors:
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Mohammad Haris; Kejia Cai; Anup Singh; Hari Hariharan; Ravinder Reddy |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2010-10-14 |
Journal Detail:
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Title: NeuroImage Volume: 54 ISSN: 1095-9572 ISO Abbreviation: Neuroimage Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2010-12-21 Completed Date: 2011-03-31 Revised Date: 2012-02-02 |
Medline Journal Info:
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Nlm Unique ID: 9215515 Medline TA: Neuroimage Country: United States |
Other Details:
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Languages: eng Pagination: 2079-85 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Elsevier Inc. All rights reserved. |
Affiliation:
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Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Algorithms Body Water Brain / anatomy & histology* Brain Chemistry / physiology* Brain Mapping / methods* Electromagnetic Fields Humans Hydrogen-Ion Concentration Image Processing, Computer-Assisted Inositol / metabolism* Magnetic Resonance Imaging / methods* Magnetic Resonance Spectroscopy Protons |
| Grant Support | |
ID/Acronym/Agency:
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P41 RR002305-26/RR/NCRR NIH HHS; P41RR0230/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Protons; 6917-35-7/Inositol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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