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In vivo characterization of brain ultrashort-T2 components.

ABSTRACT: PURPOSE:Recent nuclear magnetic resonance and MRI studies have measured a fast-relaxing signal component with T2?<1 ms in white matter and myelin extracts. In ex vivo studies, evidence suggests that a large fraction of this component directly arises from bound protons in the myelin phospholipid membranes. Based on these results, this ultrashort-T2 component in nervous tissue is a new potential imaging biomarker of myelination, which plays a critical role in neuronal signal conduction across the brain and loss or degradation of myelin is a key feature of many neurological disorders. The goal of this work was to characterize the relaxation times and frequency shifts of ultrashort-T2 components in the human brain. METHODS:This required development of an ultrashort echo time relaxometry acquisition strategy and fitting procedure for robust measurements in the presence of ultrashort T2? relaxation times and large frequency shifts. RESULTS:We measured an ultrashort-T2 component in healthy volunteers with a median T2? between 0.5-0.7 ms at 3T and 0.2-0.3 ms at 7T as well as an approximately -3 ppm frequency shift from water. CONCLUSION:To our knowledge, this is the first time a chemical shift of the ultrashort-T2 brain component has been measured in vivo. This chemical shift, at around 1.7 ppm, is similar to the primary resonance of most lipids, indicating that much of the ultrashort-T2 component observed in vivo arises from bound protons in the myelin phospholipid membranes. Magn Reson Med 80:726-735, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

SUBMITTER: Boucneau T

PROVIDER: S-EPMC5910201 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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In vivo characterization of brain ultrashort-T<sub>2</sub> components.

Boucneau Tanguy T Cao Peng P Tang Shuyu S Han Misung M Xu Duan D Henry Roland G RG Larson Peder E Z PEZ

Magnetic resonance in medicine 20171201 2

<h4>Purpose</h4>Recent nuclear magnetic resonance and MRI studies have measured a fast-relaxing signal component with T2∗<1 ms in white matter and myelin extracts. In ex vivo studies, evidence suggests that a large fraction of this component directly arises from bound protons in the myelin phospholipid membranes. Based on these results, this ultrashort-T<sub>2</sub> component in nervous tissue is a new potential imaging biomarker of myelination, which plays a critical role in neuronal signal con ...[more]

PMID: 29194734

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In vivo characterization of brain ultrashort-T2 components.

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In vivo characterization of brain ultrashort-T<sub>2</sub> components.

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