A new publication for the PiPA Group!
Goksan S, Hartley C, Hurley SA, Winkler AM, Duff EP, Jenkinson M, Rogers R, Clare S, Slater R (2016) Optimal echo time for functional MRI of the infant brain identified in response to noxious stimulation. Magnetic Resonance in Medicine. [epub ahead of print
Purpose: Blood oxygen level dependent (BOLD) brain activity, measured using functional MRI (fMRI), is dependent on the echo time (TE) and the reversible spin-spin relaxation time constant ( T2*) that describes the decay of transverse magnetization. Use of the optimal TE during fMRI experiments allows maximal sensitivity to BOLD to be achieved. Reports that T2* values are longer in infants (due to higher water concentrations and lower lipid content) have led to the use of longer TEs during infant fMRI experiments; however, the optimal TE has not been established.
Methods: In this study, acute experimental mildly noxious stimuli were applied to the heel in 12 term infants (mean gestational age = 40 weeks, mean postnatal age = 3 days); and the percentage change in BOLD activity was calculated across a range of TEs, from 30 to 70 ms, at 3 Tesla. In addition, T2* maps of the whole brain were collected in seven infants.
Results: The maximal change in BOLD occurred at a TE of 52 ms, and the average T2* across the whole brain was 99 ms.
Conclusion: A TE of approximately 50 ms is recommended for use in 3T fMRI investigations in term infants.
For the whole paper please click the link above.