Multi-echo (ME) fMRI has several advantages with respect to standard single-echo (SE) acquisition. In particular, ME fMRI is used to optimize the BOLD contrast using a weighted combination of the signals obtained from acquisition at different echo times (TEs), with improved SNR, recovery of fMRI signal from regions affected by signal dropout and a better separation of BOLD and non-BOLD components. A much less explored approach offered by ME fMRI is the possibility to derive time series of T2∗ by modeling the data acquired at different TEs with the exponential decay function S=S0exp(-TE/T2∗). >T2∗ time series are expected to be more specific to BOLD activation effects, whereas the acquired signal intensity S can be also affected by scanner drift, motion and inflow effects. In this study we investigated the sensitivity of fMRI based on T2∗ time series for the evaluation of functional connectivity in the default mode network during resting state, and showed that it retains a statistical significance comparable to that of standard SE acquisition.
Dynamic T2* Mapping of Resting State Functional Connectivity: A Multi-Echo fMRI Approach
Ponetti, G.
Primo
;Bosello, G.Secondo
;Dono, F.;Chiacchiaretta, P.;Sensi, S.;Caulo, M.;Perrucci, M. G.Penultimo
;Ferretti, A.Ultimo
2025-01-01
Abstract
Multi-echo (ME) fMRI has several advantages with respect to standard single-echo (SE) acquisition. In particular, ME fMRI is used to optimize the BOLD contrast using a weighted combination of the signals obtained from acquisition at different echo times (TEs), with improved SNR, recovery of fMRI signal from regions affected by signal dropout and a better separation of BOLD and non-BOLD components. A much less explored approach offered by ME fMRI is the possibility to derive time series of T2∗ by modeling the data acquired at different TEs with the exponential decay function S=S0exp(-TE/T2∗). >T2∗ time series are expected to be more specific to BOLD activation effects, whereas the acquired signal intensity S can be also affected by scanner drift, motion and inflow effects. In this study we investigated the sensitivity of fMRI based on T2∗ time series for the evaluation of functional connectivity in the default mode network during resting state, and showed that it retains a statistical significance comparable to that of standard SE acquisition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
