Dymerska, Barbara;
Poser, Benedikt;
Bogner, Wolfgang;
Visser, Elke;
Eckstein, Korbinian;
Cardoso, Pedro;
Barth, Markus;
... Robinson, Simon Daniel; + view all
(2015)
Single echo EPI sequence with dynamic distortion correction: minimization of errors due to motion and breathing.
Presented at: ISMRM 23rd Annual Meeting & Exhibition, Toronto, ON, Canada.
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Abstract
The geometric distortions encountered in EPI can be corrected using field maps (FMs) calculated from a reference measurement, usually a dual echo Gradient Echo scan (GEFM)[1]. This “static” approach does not account for temporal B0 changes over the course of an fMRI experiment. An alternative “dynamic” approach is to use a dual echo EPI for fMRI measurements and calculate FMs for each time point, a method known as DOCMA[2]. Dual echo EPI limits the achievable spatial and/or temporal resolution, however. A new, single-echo dynamic method called CURED was recently proposed to overcome this limitation[3]. In CURED, the echo time (TE) is “jittered” between two values; one for the odd, another for the even time points, and FMs are calculated between adjacent volumes. These FMs are subject to errors, however, where there are substantial field changes between adjacent volumes, e.g. due to motion and breathing. In this study, the errors encountered in CURED are analysed and reduced via parameter optimization, and residual errors in both CURED and static FMs are quantified with respect to DOCMA (taken to be the gold standard). The effect of jittering the TE on the BOLD sensitivity (BS) of CURED is investigated by comparison with standard EPI in two motor tasks.
| Type: | Conference item (Presentation) |
|---|---|
| Title: | Single echo EPI sequence with dynamic distortion correction: minimization of errors due to motion and breathing |
| Event: | ISMRM 23rd Annual Meeting & Exhibition |
| Location: | Toronto, ON, Canada |
| Dates: | 30 May - 05 June 2015 |
| Open access status: | An open access version is available from UCL Discovery |
| Publisher version: | https://cds.ismrm.org/protected/15MProceedings/PDF... |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10190751 |
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