Said Boujraf talk abstract
June 1st, 2007
Said Boujraf, Fez, Morocco.
Ultra fast BOLD fMRI Using Single Shot Spin-Echo EPI With SENSE at 3 Tesla
The choice of imaging parameters for functional MRI can have an impact upon the accuracy of functional localization by affecting image quality and the degree of blood oxygenation dependent (BOLD) contrast achieved. By improving sampling efficiency, parallel acquisition techniques such as sensitivity encoding (SENSE) have been used to shorten readout trains in single-shot (SS) echo planar imaging (EPI). This has been applied to susceptibility artifact reduction and improving spatial resolution. SENSE together with single-shot spin-echo (SE) imaging may also reduce off-resonance artifacts. The goal of this work was to investigate the BOLD response of a SENSE adapted SE-EPI on 3 Tesla scanner.
Whole brain fMRI studies of 7 healthy right hand dominant volunteers were carried out in 3 Tesla scanner. fMRI was performed using a SS-SE EPI sequence with SENSE. The subjects performed a self-paced, simple motor task with the dominant hand alternating with rest in a block design. The data was processed using statistical parametric mapping. Both, group analysis and individual subject data analysis were performed. Individual average percentage and maximal percentage signal changes attributed to BOLD effect in M1 for all the subjects as function of echo time was done. Corresponding activation maps and the size of the activated clusters were calculated.
Our results show that susceptibility artifacts were reduced by use of SENSE; and the acquired BOLD images were free of the typical quadrature artifacts of the SS-EPI. At high field strengths, such measures are crucial. SS SE-EPI with SENSE offer further benefits in this regard as well as being more specific to oxygenation changes in the microvasculature bed.
Single shot spin echo EPI using SENSE at high magnetic fields can be used to investigate functional brain activity.