Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Dec 2006
Dual-bolus approach to quantitative measurement of pulmonary perfusion by contrast-enhanced MRI.
To evaluate a dual-bolus approach to pulmonary perfusion MRI. ⋯ A dual-bolus approach to pulmonary perfusion MRI is feasible and may reduce the problem of lacking linear relationship between the contrast-agent concentration and signal intensity.
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J Magn Reson Imaging · Dec 2006
Mapping activation levels of skeletal muscle in healthy volunteers: an MRI study.
To use muscle functional MRI (mfMRI) to compare activation levels within and among triceps surae (TS) muscles. ⋯ There is substantial variation in the level of activation within and among the TS muscles; however, the activation level is mainly in the moderate to low range in all three muscles.
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J Magn Reson Imaging · Nov 2006
Correction of eddy-current distortions in diffusion tensor images using the known directions and strengths of diffusion gradients.
To correct eddy-current artifacts in diffusion tensor (DT) images without the need to obtain auxiliary scans for the sole purpose of correction. ⋯ The proposed algorithm can accurately correct eddy-current artifacts in DT images. Its principal advantages are that only images with comparable signals and contrasts are cross-correlated, and no additional scans are required.
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J Magn Reson Imaging · Nov 2006
Automated perfusion-weighted MRI using localized arterial input functions.
To investigate the utility of an automated perfusion-weighted MRI (PWI) method for estimating cerebral blood flow (CBF) based on localized arterial input functions (AIFs) as compared to the standard method of manual global AIF selection, which is prone to deconvolution errors due to the effects of delay and dispersion of the contrast bolus. ⋯ Automated CBF calculation using local AIFs is feasible and appears to produce more useful CBF maps.
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To improve the tag persistence throughout the whole cardiac cycle by providing a constant tag-contrast throughout all the cardiac phases when using balanced steady-state free precession (bSSFP) imaging. ⋯ The tag persistence was significantly improved when the proposed method was applied, with better Tag-CNR during the diastolic cardiac phase. The improved Tag-CNR will support automated tagging analysis and quantification methods.