Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Aug 2010
Noise analysis for 3-point chemical shift-based water-fat separation with spectral modeling of fat.
To model the theoretical signal-to-noise ratio (SNR) behavior of 3-point chemical shift-based water-fat separation, using spectral modeling of fat, with experimental validation for spin-echo and gradient-echo imaging. The echo combination that achieves the best SNR performance for a given spectral model of fat was also investigated. ⋯ The optimal echo combination that provides the best SNR performance for water using spectral modeling of fat is very similar to previous optimizations that modeled fat as a single peak. Therefore, the optimal echo spacing commonly used for single fat peak models is adequate for most applications that use spectral modeling of fat.
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J Magn Reson Imaging · Aug 2010
Effects of gradient non-linearity correction and intensity non-uniformity correction in longitudinal studies using structural image evaluation using normalization of atrophy (SIENA).
To evaluate the effects of gradient nonlinearity correction and intensity nonuniformity correction on longitudinal (two-year) changes in global and regional brain volumes. ⋯ Correction for gradient nonlinearity and intensity nonuniformity reduces the variance of measured longitudinal changes in brain volumes and will improve accuracy for detecting subtle brain changes.
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J Magn Reson Imaging · Jul 2010
Visualization of cerebral microbleeds with dual-echo T2*-weighted magnetic resonance imaging at 7.0 T.
To assess the visualization of cerebral microbleeds with dual echo T2*-weighted imaging at 7.0 T magnetic resonance imaging (MRI). ⋯ T2*-weighted imaging at two echo times at 7.0 T combines the advantages of the first and second echo. Microbleeds visible on the first echo show large contrast with the surrounding tissue, even in the presence of paramagnetic ferritin. The second echo enables visualization of smaller microbleeds than the first echo.
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J Magn Reson Imaging · Jul 2010
Reproducibility of in vivo magnetic resonance imaging-based measurement of myelin water.
To evaluate the reproducibility of multicomponent quantitative T(2) (QT2) measurements, in particular the myelin water fraction (MWF), to determine the sensitivity of this method for monitoring myelin changes in longitudinal studies and to provide a basis for correctly powering such studies. ⋯ The reproducibility of QT2 measurements using existing methods is moderate and the method can be used in longitudinal studies, with careful consideration of the methodologic variability and an appropriate group size.
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J Magn Reson Imaging · Jul 2010
Comparative StudyComparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery disease.
To investigate the incremental diagnostic value of dual-bolus over single-contrast-bolus first pass magnetic resonance myocardial perfusion imaging (MR-MPI) for detection of significant coronary artery disease (CAD). ⋯ In this study the dual-bolus technique had no incremental diagnostic value over single-bolus technique for detection of significant CAD with the used contrast concentrations.