Quantitative NumART2* mapping in functional MRI studies at 1.5 T

Gisela E. Hagberg, Marta Bianciardi, Fabiana Patria, Iole Indovina

Research output: Contribution to journalArticlepeer-review

Abstract

Quantitative mapping of the effective transverse relaxation time, T 2* and proton density was performed in a motor activation functional MRI (fMRI) study using multi-echo, echo planar imaging (EPI) and NumART2* (Numerical Algorithm for Real time T 2*). Comparisons between NumART2* and conventional single echo EPI with an echo time of 64 ms were performed for five healthy participants examined twice. Simulations were also performed to address specific issues associated with the two techniques, such as echo time-dependent signal variation. While the single echo contrast varied with the baseline T 2* value, relative changes in T2* remained unaffected. Statistical analysis of the T2* maps yielded fMRI activation patterns with an improved statistical detection relative to conventional EPI but with less activated voxels, suggesting that NumART 2* has superior spatial specificity. Two effects, inflow and dephasing, that may explain this finding were investigated. Particularly, a statistically significant increase in proton density was found in a brain area that was detected as activated by conventional EPI but not by NumART 2* while no such changes were observed in brain areas that showed stimulus correlated signal changes on T2* maps.

Original languageEnglish
Pages (from-to)1241-1249
Number of pages9
JournalMagnetic Resonance Imaging
Volume21
Issue number10
DOIs
Publication statusPublished - Dec 2003

Keywords

  • Effective transverse relaxation
  • Functional MRI (fMRI)
  • Quantitative
  • T *

ASJC Scopus subject areas

  • Biophysics
  • Clinical Biochemistry
  • Structural Biology
  • Radiology Nuclear Medicine and imaging
  • Condensed Matter Physics

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