Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine
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To introduce a new method for removing background artifacts in field maps and apply it to enhance the accuracy of susceptibility mapping. ⋯ Compared with SHARP, RESHARP removes background field artifact more effectively, leading to more accurate susceptibility measurements in iron-rich deep gray matter.
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Cardiac cine balanced steady-state free precession (bSSFP) imaging uses a high flip angle (FA) to obtain high blood-myocardium signal-to-noise and contrast-to-noise ratios (CNR). Use of high FAs, however, results in substantially increased SAR. Our objective was to develop a variable FA bSSFP cardiac cine imaging technique with: (1) low SAR and blood-myocardium CNR similar to conventional constant FA bSSFP (CFA-bSSFP) or (2) increased blood-myocardium CNR compared to CFA-bSSFP with similar SAR. ⋯ aVFA-bSSFP can be used for lower SAR or higher contrast cardiac cine imaging compared to the conventional segmented CFA-bSSFP imaging.
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To develop a method to correct for geometric distortions in non-Cartesian echo planar imaging using data acquired in a fast prescan. ⋯ The method presented allows correcting non-Cartesian EPI from a reference scan consisting of only two phase-labeled echo planar images.
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Quantitative measure of blood flow provides important information regarding renal function, nephropathies and viability of kidney transplantation. Therefore, a method that would allow quantitative and reliable assessment of the renal microvascular perfusion would be very valuable. Arterial spin labeling Magnetic Resonance Imaging has started to be widely used for human studies. For rodents though, despite the increasing number of transgenic mouse models, renal perfusion Magnetic Resonance Imaging has been only sparsely reported. This study investigated the use of FAIR (flow-sensitive alternating inversion recovery) and pseudo-continuous arterial spin labeling (pCASL) for mouse renal blood flow measurements. ⋯ pCASL was successfully applied at very high field for mouse renal blood flow measurements, demonstrating high sensitivity, flexibility and multislice imaging capability. pCASL may be considered as a method of choice for mouse kidney perfusion studies.
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Comparative Study
Comparison of hyperpolarized (3)He and (129)Xe MRI for the measurement of absolute ventilated lung volume in rats.
MRI using hyperpolarized noble gases, (3)He and (129)Xe, provides noninvasive assessments of lung structure and function. Previous work demonstrated that absolute ventilated lung volumes (aVLV) measured in rats using hyperpolarized (3)He agree well with micro-CT. ⋯ (129)Xe offers an important alternative to (3)He for hyperpolarized gas MRI of aVLV in rats.