Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Apr 2004
Comparative StudyComparison of TCA and ICA techniques in fMRI data processing.
To make a quantitative comparison of temporal cluster analysis (TCA) and independent component analysis (ICA) techniques in detecting brain activation by using simulated data and in vivo event-related functional MRI (fMRI) experiments. ⋯ TCA and ICA techniques are comparable in generating functional brain maps in event-related fMRI experiments. Although ICA has richer features in exploring the spatial and temporal information of the functional images, the TCA method has advantages in its computational efficiency, repeatability, and readiness to average data from group subjects
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J Magn Reson Imaging · Apr 2004
Parallel and nonparallel simultaneous multislice black-blood double inversion recovery techniques for vessel wall imaging.
To reduce long examination times of black-blood vessel wall imaging by acquiring multiple slices simultaneously and by using parallel acquisition techniques. ⋯ Future MRI atherosclerotic plaque studies can be performed in substantially shorter times using these methods.
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J Magn Reson Imaging · Apr 2004
In vivo measurement of T1rho dispersion in the human brain at 1.5 tesla.
To measure T1rho relaxation times and T1rho dispersion in the human brain in vivo. ⋯ T1rho-weighted MRI provides images of the brain with superb contrast and detail. T1rho values measured in the different brain tissues will serve as useful baseline values for analysis of T1rho changes associated with pathology.
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J Magn Reson Imaging · Apr 2004
Correction of spatial distortion in EPI due to inhomogeneous static magnetic fields using the reversed gradient method.
To derive and implement a method for correcting spatial distortion caused by in vivo inhomogeneous static magnetic fields in echo-planar imaging (EPI). ⋯ The correction was improved by the application of a nonlinear interpolation scheme. The correction requires that two EP images be acquired at each slice position. This increases the acquisition time, but an improved signal-to-noise ratio (SNR) is seen in the corrected image. The local SNR gain decreases with increasing distortion. In many EPI acquisition schemes, multiple images are averaged at each slice position to increase the SNR; in such cases the reversed gradient correction method can be applied with no increase in acquisition duration.
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J Magn Reson Imaging · Apr 2004
Comparative StudyMRI of bone tumors: Fast STIR imaging as a substitute for T1-weighted contrast-enhanced fat-suppressed spin-echo imaging.
To compare the usefulness of short inversion recovery (STIR) and T1-weighted, contrast-enhanced, fat-suppressed (T1W-CEFS) sequences for the evaluation of bone tumors. ⋯ The STIR sequence should be used instead of T1W-CEFS imaging for the evaluation of bone tumors.