Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jun 2005
Comparative StudyNavigator-gated three-dimensional MR angiography of the pulmonary arteries using steady-state free precession.
To assess the quality of a navigator-gated, free breathing, steady-state free precession (SSFP) technique in comparison to a single breathhold for pulmonary artery imaging in normal volunteers. ⋯ The navigator-gated SSFP sequence is able to acquire images equal in quality to the breathhold sequence. This may be of clinical importance for pulmonary imaging in patients who are unable to sustain a long breathhold.
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J Magn Reson Imaging · Jun 2005
Quantitative perfusion measurements using pulsed arterial spin labeling: effects of large region-of-interest analysis.
To study arterial spin labeling (ASL) MRI techniques and to investigate various problematic issues that still hinder the accurate and robust quantitative analysis of ASL data. ⋯ Analysis of ASL data based on a large ROI may suffer from inaccuracies arising from a distribution of transit times, implying that averaging of ASL kinetic data over such regions should therefore be avoided. When possible, a PBP fit should be performed.
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J Magn Reson Imaging · Jun 2005
Diffusion-weighted MRI of the lung with hyperpolarized helium-3: a study of reproducibility.
To determine the reproducibility of several parameters of the ADC measurement by calculating the scan-to-scan intrasubject variability. ⋯ Diffusion-weighted imaging (DWI) is a well-reproducible method for assessing the lung microstructure.
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J Magn Reson Imaging · Jun 2005
Relationship between contrast enhancement on fluid-attenuated inversion recovery MR sequences and signal intensity on T2-weighted MR images: visual evaluation of brain tumors.
To investigate the relationship between the degree of contrast enhancement in fluid-attenuated inversion recovery (FLAIR) sequences and tumor signal intensity on T2-weighted images. ⋯ The signal intensity in FLAIR sequences is largely influenced by both T1 and T2 relaxation time; there is a close relationship between the signal intensity of brain tumors on T2-weighted images and the degree of contrast enhancement on FLAIR sequences. When tumors have higher signal intensity than normal cortex on T2-weighted images, additional postcontrast FLAIR imaging may improve their depiction.