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Prospective motion correction of 3D echo-planar imaging data for functional MRI using optical tracking.

Todd N, Josephs O, Callaghan MF, Lutti A, Weiskopf N - Neuroimage (2015)

Bottom Line: Metrics were developed to quantify the amount of motion as it occurred relative to k-space data acquisition.The PMC system did not introduce extraneous artifacts for the no motion conditions and improved the time series temporal signal-to-noise by 30% to 40% for all combinations of low/high resolution and slow/fast head movement relative to the standard acquisition with no prospective correction.The numbers of activated voxels (p<0.001, uncorrected) in both task-based experiments were comparable for the no motion cases and increased by 78% and 330%, respectively, for PMC on versus PMC off in the slow motion cases.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, UK. Electronic address: nicholas.todd@ucl.ac.uk.

No MeSH data available.


tSNR histograms for 1.5 mm data comparing PMC on vs PMC off for cases of no, slow, and fast motion. The tSNR values have been pooled from all five volunteers into one histogram for each condition. The inset image in each histogram shows one slice through the tSNR map from Volunteer #3. Note that the scales are different on both the histogram axes and tSNR maps from Fig. 4.
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f0025: tSNR histograms for 1.5 mm data comparing PMC on vs PMC off for cases of no, slow, and fast motion. The tSNR values have been pooled from all five volunteers into one histogram for each condition. The inset image in each histogram shows one slice through the tSNR map from Volunteer #3. Note that the scales are different on both the histogram axes and tSNR maps from Fig. 4.

Mentions: Similar results are shown in Fig. 5 for the tSNR distributions from the 1.5 mm resolution runs, where the inset image of the tSNR map is also from Volunteer #3. Note that the scales on both the histogram axes and the tSNR maps are different from those in Fig. 4. The same effects as seen in the 3.0 mm resolution data were seen here as well: the no motion distributions of tSNR were very similar between PMC on and PMC off, the effect of decreasing tSNR with increasing motion was seen, and the runs with PMC on had clearly higher overall tSNR values for comparable levels of motion (43% improvement for the slow motion case, 32% improvement for the fast motion case). One slight anomaly is seen in the double-peaked distribution of the PMC on, fast motion case. This is due to the fact that Volunteer #5's movements during the fast motion cases were significantly greater than all of the other volunteer's movements, which created a subset of the pooled data that had significantly lower tSNR values. Volunteer #5 had consistently higher motion metrics for all fast motion cases, but the effect on the total distribution of tSNR values was not as obvious for the PMC off case or the 3.0 mm resolution cases.


Prospective motion correction of 3D echo-planar imaging data for functional MRI using optical tracking.

Todd N, Josephs O, Callaghan MF, Lutti A, Weiskopf N - Neuroimage (2015)

tSNR histograms for 1.5 mm data comparing PMC on vs PMC off for cases of no, slow, and fast motion. The tSNR values have been pooled from all five volunteers into one histogram for each condition. The inset image in each histogram shows one slice through the tSNR map from Volunteer #3. Note that the scales are different on both the histogram axes and tSNR maps from Fig. 4.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4441089&req=5

f0025: tSNR histograms for 1.5 mm data comparing PMC on vs PMC off for cases of no, slow, and fast motion. The tSNR values have been pooled from all five volunteers into one histogram for each condition. The inset image in each histogram shows one slice through the tSNR map from Volunteer #3. Note that the scales are different on both the histogram axes and tSNR maps from Fig. 4.
Mentions: Similar results are shown in Fig. 5 for the tSNR distributions from the 1.5 mm resolution runs, where the inset image of the tSNR map is also from Volunteer #3. Note that the scales on both the histogram axes and the tSNR maps are different from those in Fig. 4. The same effects as seen in the 3.0 mm resolution data were seen here as well: the no motion distributions of tSNR were very similar between PMC on and PMC off, the effect of decreasing tSNR with increasing motion was seen, and the runs with PMC on had clearly higher overall tSNR values for comparable levels of motion (43% improvement for the slow motion case, 32% improvement for the fast motion case). One slight anomaly is seen in the double-peaked distribution of the PMC on, fast motion case. This is due to the fact that Volunteer #5's movements during the fast motion cases were significantly greater than all of the other volunteer's movements, which created a subset of the pooled data that had significantly lower tSNR values. Volunteer #5 had consistently higher motion metrics for all fast motion cases, but the effect on the total distribution of tSNR values was not as obvious for the PMC off case or the 3.0 mm resolution cases.

Bottom Line: Metrics were developed to quantify the amount of motion as it occurred relative to k-space data acquisition.The PMC system did not introduce extraneous artifacts for the no motion conditions and improved the time series temporal signal-to-noise by 30% to 40% for all combinations of low/high resolution and slow/fast head movement relative to the standard acquisition with no prospective correction.The numbers of activated voxels (p<0.001, uncorrected) in both task-based experiments were comparable for the no motion cases and increased by 78% and 330%, respectively, for PMC on versus PMC off in the slow motion cases.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, UK. Electronic address: nicholas.todd@ucl.ac.uk.

No MeSH data available.