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An evaluation of prospective motion correction (PMC) for high resolution quantitative MRI.

Callaghan MF, Josephs O, Herbst M, Zaitsev M, Todd N, Weiskopf N - Front Neurosci (2015)

Bottom Line: In the presence of head motion, PMC-based motion correction considerably improved the quality of the maps as reflected by fewer visible artifacts and improved consistency.The precision of the maps, parameterized through the coefficient of variation in cortical sub-regions, showed improvements of 11-25% in the presence of deliberate head motion.Such a robust motion correction scheme is crucial in order to achieve the ultra-high resolution required of quantitative imaging for cutting edge in vivo histology applications.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK.

ABSTRACT
Quantitative imaging aims to provide in vivo neuroimaging biomarkers with high research and diagnostic value that are sensitive to underlying tissue microstructure. In order to use these data to examine intra-cortical differences or to define boundaries between different myelo-architectural areas, high resolution data are required. The quality of such measurements is degraded in the presence of motion hindering insight into brain microstructure. Correction schemes are therefore vital for high resolution, whole brain coverage approaches that have long acquisition times and greater sensitivity to motion. Here we evaluate the use of prospective motion correction (PMC) via an optical tracking system to counter intra-scan motion in a high resolution (800 μm isotropic) multi-parameter mapping (MPM) protocol. Data were acquired on six volunteers using a 2 × 2 factorial design permuting the following conditions: PMC on/off and motion/no motion. In the presence of head motion, PMC-based motion correction considerably improved the quality of the maps as reflected by fewer visible artifacts and improved consistency. The precision of the maps, parameterized through the coefficient of variation in cortical sub-regions, showed improvements of 11-25% in the presence of deliberate head motion. Importantly, in the absence of motion the PMC system did not introduce extraneous artifacts into the quantitative maps. The PMC system based on optical tracking offers a robust approach to minimizing motion artifacts in quantitative anatomical imaging without extending scan times. Such a robust motion correction scheme is crucial in order to achieve the ultra-high resolution required of quantitative imaging for cutting edge in vivo histology applications.

No MeSH data available.


Related in: MedlinePlus

A 1 min segment of the motion trace depicting (A) translation in the y-direction (posterior–anterior) from volunteer 6 under the no motion condition after linear detrending, along with (B) the extracted power spectrum. Peaks can be seen in the power spectrum at 0.34 and 0.94 Hz consistent with breathing and cardiac cycles, respectively.
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Figure 5: A 1 min segment of the motion trace depicting (A) translation in the y-direction (posterior–anterior) from volunteer 6 under the no motion condition after linear detrending, along with (B) the extracted power spectrum. Peaks can be seen in the power spectrum at 0.34 and 0.94 Hz consistent with breathing and cardiac cycles, respectively.

Mentions: Another important criterion for adopting a PMC system is that it does not in itself degrade the quality of the acquired imaging data. We assessed this via the data from the no motion factor, since it would most likely show any additional noise introduced by a PMC system. In this case, the peaks of the group histograms are sharpened when the PMC system is used. Five out of six volunteers showed reduced global CoV in all quantitative maps. Thus, the PMC system may also be used to reduce artifacts even in high quality datasets affected only by minimal motion, suggesting that the correction of artifacts introduced by physiological motion, e.g., due to breathing or the cardiac cycle, may be possible. Figure 5 shows a 1 minute long segment of the y-translation (posterior-anterior direction) motion trace for volunteer 6. The corresponding power spectrum (Figure 5B) identifies peaks in the spectrum at 0.34 Hz, consistent with breathing, and at 0.94 Hz, consistent with the cardiac cycle.


An evaluation of prospective motion correction (PMC) for high resolution quantitative MRI.

Callaghan MF, Josephs O, Herbst M, Zaitsev M, Todd N, Weiskopf N - Front Neurosci (2015)

A 1 min segment of the motion trace depicting (A) translation in the y-direction (posterior–anterior) from volunteer 6 under the no motion condition after linear detrending, along with (B) the extracted power spectrum. Peaks can be seen in the power spectrum at 0.34 and 0.94 Hz consistent with breathing and cardiac cycles, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373264&req=5

Figure 5: A 1 min segment of the motion trace depicting (A) translation in the y-direction (posterior–anterior) from volunteer 6 under the no motion condition after linear detrending, along with (B) the extracted power spectrum. Peaks can be seen in the power spectrum at 0.34 and 0.94 Hz consistent with breathing and cardiac cycles, respectively.
Mentions: Another important criterion for adopting a PMC system is that it does not in itself degrade the quality of the acquired imaging data. We assessed this via the data from the no motion factor, since it would most likely show any additional noise introduced by a PMC system. In this case, the peaks of the group histograms are sharpened when the PMC system is used. Five out of six volunteers showed reduced global CoV in all quantitative maps. Thus, the PMC system may also be used to reduce artifacts even in high quality datasets affected only by minimal motion, suggesting that the correction of artifacts introduced by physiological motion, e.g., due to breathing or the cardiac cycle, may be possible. Figure 5 shows a 1 minute long segment of the y-translation (posterior-anterior direction) motion trace for volunteer 6. The corresponding power spectrum (Figure 5B) identifies peaks in the spectrum at 0.34 Hz, consistent with breathing, and at 0.94 Hz, consistent with the cardiac cycle.

Bottom Line: In the presence of head motion, PMC-based motion correction considerably improved the quality of the maps as reflected by fewer visible artifacts and improved consistency.The precision of the maps, parameterized through the coefficient of variation in cortical sub-regions, showed improvements of 11-25% in the presence of deliberate head motion.Such a robust motion correction scheme is crucial in order to achieve the ultra-high resolution required of quantitative imaging for cutting edge in vivo histology applications.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK.

ABSTRACT
Quantitative imaging aims to provide in vivo neuroimaging biomarkers with high research and diagnostic value that are sensitive to underlying tissue microstructure. In order to use these data to examine intra-cortical differences or to define boundaries between different myelo-architectural areas, high resolution data are required. The quality of such measurements is degraded in the presence of motion hindering insight into brain microstructure. Correction schemes are therefore vital for high resolution, whole brain coverage approaches that have long acquisition times and greater sensitivity to motion. Here we evaluate the use of prospective motion correction (PMC) via an optical tracking system to counter intra-scan motion in a high resolution (800 μm isotropic) multi-parameter mapping (MPM) protocol. Data were acquired on six volunteers using a 2 × 2 factorial design permuting the following conditions: PMC on/off and motion/no motion. In the presence of head motion, PMC-based motion correction considerably improved the quality of the maps as reflected by fewer visible artifacts and improved consistency. The precision of the maps, parameterized through the coefficient of variation in cortical sub-regions, showed improvements of 11-25% in the presence of deliberate head motion. Importantly, in the absence of motion the PMC system did not introduce extraneous artifacts into the quantitative maps. The PMC system based on optical tracking offers a robust approach to minimizing motion artifacts in quantitative anatomical imaging without extending scan times. Such a robust motion correction scheme is crucial in order to achieve the ultra-high resolution required of quantitative imaging for cutting edge in vivo histology applications.

No MeSH data available.


Related in: MedlinePlus