In vivo T2 relaxation time measurement with echo-time averaging

Andrew P. Prescot, Xianfeng Shi, Changho Choi, Perry F. Renshaw

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

The accuracy of metabolite concentrations measured using in vivo proton (1H) MRS is enhanced following correction for spin-spin (T2) relaxation effects. In addition, metabolite proton T2 relaxation times provide unique information regarding cellular environment and molecular mobility. Echo-time (TE) averaging 1H MRS involves the collection and averaging of multiple TE steps, which greatly simplifies resulting spectra due to the attenuation of spin-coupled and macromolecule resonances. Given the simplified spectral appearance and inherent metabolite T2 relaxation information, the aim of the present proof-of-concept study was to develop a novel data processing scheme to estimate metabolite T2 relaxation times from TE-averaged 1H MRS data. Spectral simulations are used to validate the proposed TE-averaging methods for estimating methyl proton T2 relaxation times for N-acetyl aspartate, total creatine, and choline-containing compounds. The utility of the technique and its reproducibility are demonstrated using data obtained in vivo from the posterior-occipital cortex of 10 healthy control subjects. Compared with standard methods, distinct advantages of this approach include built-in macromolecule resonance attenuation, in vivo T2 estimates closer to reported values when maximum TE≈T2, and the potential for T2 calculation of metabolite resonances otherwise inseparable in standard 1H MRS spectra recorded in vivo.

Original languageEnglish (US)
Pages (from-to)863-869
Number of pages7
JournalNMR in biomedicine
Volume27
Issue number8
DOIs
StatePublished - Aug 2014

Keywords

  • Echo-time averaging
  • Proton MRS

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy

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