TE-dependent analysis of multi-echo fMRI with tedana
Elizabeth DuPré, Taylor Salo, Zaki Ahmed, Peter A. Bandettini, Katherine L. Bottenhorn, César Caballero‐Gaudes, Logan T. Dowdle, Javier González-Castillo, Stephan Heunis, Prantik Kundu, Angela R. Laird, Ross D. Markello, Christopher J. Markiewicz, Stefano Moia, Isla Staden, Joshua Teves, Eneko Uruñuela, Maryam Vaziri-Pashkam, Kirstie Whitaker, Daniel A. Handwerker
Abstract
Functional magnetic resonance imaging (fMRI) is a popular method for in vivo neuroimaging. Modern fMRI sequences are often weighted towards the blood oxygen level dependent (BOLD) signal, which is closely linked to neuronal activity This weighting is achieved by tuning several parameters to increase the BOLD-weighted signal contrast. One such parameter is "TE," or echo time. TE is the amount of time elapsed between when protons are excited (the MRI signal source) and measured. Although the total measured signal magnitude decays with echo time, BOLD sensitivity increases The optimal TE maximizes the BOLD signal weighting based on a number of factors, including several MRI scanner parameters (e.g., field strength), imaged tissue composition (e.g., grey vs. white matter), and proximity to air-tissue boundaries.