Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine
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Comparative Study
Renal perfusion imaging with two-dimensional navigator gated arterial spin labeling.
To develop a navigator technique enabling free-breathing acquisition to afford sufficient signal averaging for quantitative renal perfusion measurement using arterial spin labeling MRI. ⋯ 2D navigator-gated free breathing arterial spin labeling is feasible and is a noninvasive method to evaluate renal perfusion both in healthy subjects and those with chronic kidney disease.
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Arranging transmit array elements in multiple rows provides an additional degree of freedom to correct B1 (+) field inhomogeneities and to achieve whole-brain excitation at ultrahigh field strengths. Receive arrays shaped to the contours of the anatomy increase the signal-to-noise ratio of the image. In this work, the advantages offered by the transmit and receive array techniques are combined for human brain imaging at 9.4 T. ⋯ The dual-row transmit array provides whole-brain coverage at 9.4 T, which, in combination with the helmet-shaped receive array, is a valuable radio frequency configuration for ultra-high field magnetic resonance imaging of the human brain.
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Comparative Study
High-resolution multishot spiral diffusion tensor imaging with inherent correction of motion-induced phase errors.
To develop and compare three novel reconstruction methods designed to inherently correct for motion-induced phase errors in multishot spiral diffusion tensor imaging without requiring a variable-density spiral trajectory or a navigator echo. ⋯ The proposed sensitivity encoding + conjugate gradient method can inherently and effectively correct for phase errors, signal loss, and aliasing artifacts caused by both rigid and nonrigid motion in multishot spiral diffusion tensor imaging, without increasing the scan time or reducing the signal-to-noise ratio.
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Myocardial T1 mapping is an emerging technique that could improve cardiovascular magnetic resonance diagnostic accuracy. In this study, a variable flip angle approach with B1 correction is proposed at 3T on the myocardium, employing standard 3D spoiled fast gradient echo and echo planar imaging sequences. ⋯ Myocardial 3D T1 mapping using the variable flip angle approach can potentially be useful for evaluating fibrosis on the entire myocardium using a standard clinical sequence.
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To assess the feasibility of high resolution knee cartilage MRI with in situ mechanical loading using optical tracking to compensate for motion. ⋯ The proposed technique enables knee cartilage imaging under in situ mechanical loading with submillimeter spatial resolution devoid of significant motion artifacts and thus appropriate for cartilage volumetry. It has the potential to provide new insight into the biomechanics of the knee and might complement the panoply of diagnostic MR methods for osteoarthritis.