Implementation of two-dimensional L-COSY at 7 Tesla: An investigation of reproducibility in human brain

Gaurav Verma, Hari Hariharan, Rajakumar Nagarajan, Ravi P.R. Nanga, Edward J. Delikatny, M. Albert Thomas, Harish Poptani

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Materials and Methods: The 2D L-COSY sequence was implemented at 7T and its reliability was assessed by test-retest studies of a metabolite phantom and a healthy volunteer. L-COSY data were acquired from the occipital lobe of healthy subjects (n=6; all male; age, 30-72 years) to assess intersubject variability. Additionally, two subjects underwent scans from the parieto-occipital region, basal ganglia, frontal lobe or dorsolateral prefrontal cortex to test the versatility of L-COSY in studying differing anatomy. Integral/volume measurements of L-COSY spectra were used to estimate normalized metabolite-to-creatine concentrations.

Purpose: To evaluate the utility of two-dimensional (2D) Localized Correlated Spectroscopy (L-COSY) in metabolic profiling of the human brain at 7 Tesla (T).

Results: Phantom test-retest studies revealed coefficients of variation (CVs) of 3-20% for most metabolites. Human 2D L-COSY spectra permitted detection of several metabolite resonances from multiple locations and intersubject variation studies demonstrated CVs of 4-26%. Cross-peaks from gamma-aminobutyric acid (GABA), isoleucine (Ile), lysine (Lys) and Ethanolamine (Eth) were quantified, which are not readily resolvable with conventional one-dimensional (1D) MR spectroscopy.

Conclusion: 2D L-COSY at 7T demonstrated improved sensitivity in detecting additional metabolites with reliability comparable to established techniques at lower fields, which may aid in the metabolic assessment of diseased states.

Original languageEnglish
Pages (from-to)1319-1327
Number of pages9
JournalJournal of Magnetic Resonance Imaging
Volume40
Issue number6
DOIs
StatePublished - 1 Dec 2014
Externally publishedYes

Keywords

  • 7T
  • Isoleucine
  • L-COSY
  • Localized Correlated Spectroscopy
  • Lysine
  • Magnetic resonance spectroscopy

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