Article

Volumetric navigators for prospective motion correction and selective reacquisition in neuroanatomical MRI

Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
Magnetic Resonance in Medicine (Impact Factor: 3.57). 12/2011; 68(2):389-99. DOI: 10.1002/mrm.23228
Source: PubMed

ABSTRACT

We introduce a novel method of prospectively compensating for subject motion in neuroanatomical imaging. Short three-dimensional echo-planar imaging volumetric navigators are embedded in a long three-dimensional sequence, and the resulting image volumes are registered to provide an estimate of the subject's location in the scanner at a cost of less than 500 ms, ~ 1% change in contrast, and ~3% change in intensity. This time fits well into the existing gaps in sequences routinely used for neuroimaging, thus giving a motion-corrected sequence with no extra time required. We also demonstrate motion-driven selective reacquisition of k-space to further compensate for subject motion. We perform multiple validation experiments to evaluate accuracy, navigator impact on tissue intensity/contrast, and the improvement in final output. The complete system operates without adding additional hardware to the scanner and requires no external calibration, making it suitable for high-throughput environments.

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    • "However, it is likely that individuals with ASD who exhibit more severe symptoms would also find it harder to remain still in the MRI scanner for a long period of time and thus there may be a selection bias in our data. Future research should employ real-time prospective motion correction (PMC) techniques (e.g.,888990) during the sMRI scan. The use of PMC techniques can also prevent the risk of using sedation, is more likely to be approved by most IRB for research purpose, and may be a better option than sedation for future sMRI research that aims at minimizing head motion confounds[91]. "
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    • "i - shot , segmented EPI to motion and B 0 changes across segments include direct alignment of phase between segments in post - processing , although typically these methods require extra information or additional scans [ Hoge et al . , 2010 ; Chen et al . , 2013 ] . Bulk , rigid head motion could potentially be addressed by either image - based [ Tisdall et al . , 2012 ] or external sensor - based [ Zaitsev et al . , 2006 ; Schulz et al . , 2012 ] motion tracking along with either real - time feedback to the gradient system or a model for how the motion impacts the information acquired across the multiple , interleaved segments . However , independent motion ( e . g . , of the eyes ) during ACS acquis"
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    Full-text · Article · Mar 2015 · Magnetic Resonance in Medicine
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    • "A Multi-Echo MPRAGE (MEMPR) with motion correction, developed at the Massachusetts General Hospital (MGH, Boston), was employed [70,71]. This sequence has the advantage of combining the properties of the classical MPRAGE sequence, which has high contrast aiding cortical segmentation, with Multi-Echo FLASH, which improves segmentation of subcortical regions. "
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