Abstract：
:In independent component analysis (ICA), principal component analysis (PCA) is generally used to reduce the raw data to a few principal components (PCs) through eigenvector decomposition (EVD) on the data covariance matrix. Although this works for spatial ICA (sICA) on moderately sized fMRI data, it is intractable for temporal ICA (tICA), since typical fMRI data have a high spatial dimension, resulting in an unmanageable data covariance matrix. To solve this problem, two practical data reduction methods are presented in this paper. The first solution is to calculate the PCs of tICA from the PCs of sICA. This approach works well for moderately sized fMRI data; however, it is highly computationally intensive, even intractable, when the number of scans increases. The second solution proposed is to perform PCA decomposition via a cascade recursive least squared (CRLS) network, which provides a uniform data reduction solution for both sICA and tICA. Without the need to calculate the covariance matrix, CRLS extracts PCs directly from the raw data, and the PC extraction can be terminated after computing an arbitrary number of PCs without the need to estimate the whole set of PCs. Moreover, when the whole data set becomes too large to be loaded into the machine memory, CRLS-PCA can save data retrieval time by reading the data once, while the conventional PCA requires numerous data retrieval steps for both covariance matrix calculation and PC extractions. Real fMRI data were used to evaluate the PC extraction precision, computational expense, and memory usage of the presented methods.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Wang Z,Wang J,Calhoun V,Rao H,Detre JA,Childress ARdoi
10.1016/j.mri.2005.12.013subject
Has Abstractpub_date
2006-06-01 00:00:00pages
591-6issue
5eissn
0730-725Xissn
1873-5894pii
S0730-725X(05)00410-8journal_volume
24pub_type
杂志文章abstract：:3D (kx, ky, t)-space analysis is invoked to provide insights into dynamic magnetic resonance imaging (DMRI) with arbitrary k-space sampling trajectories. The effects of 3D sampling in (kx, ky, t) are analyzed theoretically and verified with computer simulation. The analyses show that a 3D sampling pattern that is more...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2006.04.009
更新日期：2006-10-01 00:00:00
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journal_title：Magnetic resonance imaging
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更新日期：2014-04-01 00:00:00
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更新日期：2000-12-01 00:00:00
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journal_title：Magnetic resonance imaging
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doi：10.1016/j.mri.2009.12.016
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更新日期：1993-01-01 00:00:00
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pub_type： 杂志文章
doi：10.1016/j.mri.2018.12.003
更新日期：2019-04-01 00:00:00
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journal_title：Magnetic resonance imaging
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doi：10.1016/0730-725x(89)90325-1
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pub_type： 杂志文章
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更新日期：1998-06-01 00:00:00
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更新日期：2020-02-01 00:00:00
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doi：10.1016/s0730-725x(01)00267-3
更新日期：2001-04-01 00:00:00
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更新日期：2020-02-01 00:00:00
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pub_type： 杂志文章
doi：10.1016/j.mri.2011.10.005
更新日期：2012-04-01 00:00:00
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journal_title：Magnetic resonance imaging
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doi：10.1016/j.mri.2016.03.016
更新日期：2016-09-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(89)90706-6
更新日期：1989-03-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2007.03.002
更新日期：2007-07-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章,评审
doi：10.1016/j.mri.2010.03.036
更新日期：2010-07-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.02.002
更新日期：2018-06-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(88)90473-0
更新日期：1988-07-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2003.09.006
更新日期：2004-02-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(01)00396-4
更新日期：2001-07-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.11.001
更新日期：2006-06-01 00:00:00
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journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.01.002
更新日期：2005-02-01 00:00:00
abstract：:Magnetic resonance imaging (MRI) is a completely noninvasive modality that has shown significant promise for the evaluation of the cardiovascular system. Our imaging technique employed electrocardiographic (ECG) gating, which resulted in well-resolved images of the cardiac structures. Patients and animals with a varie...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(84)90002-x
更新日期：1984-01-01 00:00:00
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journal_title：Magnetic resonance imaging
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doi：10.1016/j.mri.2007.08.010
更新日期：2008-04-01 00:00:00
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journal_title：Magnetic resonance imaging
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更新日期：2017-06-01 00:00:00
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journal_title：Magnetic resonance imaging
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doi：10.1016/j.mri.2013.03.024
更新日期：2013-09-01 00:00:00
abstract：:We have applied diffusion and relaxation Nuclear Magnetic Resonance experiments to investigate the translational and rotational mobility of adsorbents on quartz and calcite mineral surfaces. On both surfaces it was found that water is the dominant molecule. On the quartz surface the majority of water molecules have a ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.10.002
更新日期：2019-02-01 00:00:00
abstract：PURPOSE:To evaluate the performance of combined integrated slice-by-slice shimming and readout-segmented EPI (irsEPI) for diffusion-weighted MR imaging (DWI) of the neck at 3Tesla. METHODS:This study was approved by the local ethics committee. An anthropometric phantom of the head/neck region incorporating compartment...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.05.004
更新日期：2017-10-01 00:00:00
abstract：:Acrylamide gel loaded with phosphate has been used in two compartment phantoms designed to assess localized spectroscopy techniques. A chemical shift difference of 2.3 ppm was produced by changing the pH from 6 to 8.9. The 31P relaxation times were modified by doping the gels with paramagnetic ions. For a T1 of approx...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(92)90381-9
更新日期：1992-01-01 00:00:00
