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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

Quantitative maps across conditions focussing on spatial regions in which features are obscured due to volunteer motion during the acquisition of the constituent weighted volumes. The manifestation of the motion in the maps was dependent on the coherence of the artifact in the component volumes. Each set of a particular parameter map was acquired from a different volunteer within the cohort (Volunteers 1, 3, 4, and 6 are shown, respectively in descending rows).
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Figure 1: Quantitative maps across conditions focussing on spatial regions in which features are obscured due to volunteer motion during the acquisition of the constituent weighted volumes. The manifestation of the motion in the maps was dependent on the coherence of the artifact in the component volumes. Each set of a particular parameter map was acquired from a different volunteer within the cohort (Volunteers 1, 3, 4, and 6 are shown, respectively in descending rows).

Mentions: Figure 1 shows exemplar quantitative maps across the four experimental conditions, zoomed in to highlight the effects of motion on the quantitative maps. To provide a comprehensive illustration, each set of a given parameter map was derived from a different volunteer. Figure 2 shows histograms of the quantitative parameters. The shaded area of each curve demarks one standard deviation across volunteers. In the presence of motion, the width of the histograms broadened and the gray and white matter peaks converged (red). Under comparable motion conditions, the PMC system sharpened the histogram peaks (yellow), such that they approached the level of the no motion, PMC Off case (black). The histograms were further sharpened when PMC was used with no deliberate motion (green). These characteristics were common to all maps and volunteers.


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)

Quantitative maps across conditions focussing on spatial regions in which features are obscured due to volunteer motion during the acquisition of the constituent weighted volumes. The manifestation of the motion in the maps was dependent on the coherence of the artifact in the component volumes. Each set of a particular parameter map was acquired from a different volunteer within the cohort (Volunteers 1, 3, 4, and 6 are shown, respectively in descending rows).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Quantitative maps across conditions focussing on spatial regions in which features are obscured due to volunteer motion during the acquisition of the constituent weighted volumes. The manifestation of the motion in the maps was dependent on the coherence of the artifact in the component volumes. Each set of a particular parameter map was acquired from a different volunteer within the cohort (Volunteers 1, 3, 4, and 6 are shown, respectively in descending rows).
Mentions: Figure 1 shows exemplar quantitative maps across the four experimental conditions, zoomed in to highlight the effects of motion on the quantitative maps. To provide a comprehensive illustration, each set of a given parameter map was derived from a different volunteer. Figure 2 shows histograms of the quantitative parameters. The shaded area of each curve demarks one standard deviation across volunteers. In the presence of motion, the width of the histograms broadened and the gray and white matter peaks converged (red). Under comparable motion conditions, the PMC system sharpened the histogram peaks (yellow), such that they approached the level of the no motion, PMC Off case (black). The histograms were further sharpened when PMC was used with no deliberate motion (green). These characteristics were common to all maps and volunteers.

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