Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jul 2005
Apparent diffusion coefficient and fractional anisotropy in spinal cord: age and cervical spondylosis-related changes.
To present the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) change with age in the normal spinal cord and in cervical spondylosis. ⋯ ADC increases and FA decreases with age in the normal spinal cord. Elevated ADC and reduced FA were measured in the spinal cord of spondylosis cases with clinical symptoms of myelopathy.
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J Magn Reson Imaging · Jul 2005
Cardiac CINE imaging with IDEAL water-fat separation and steady-state free precession.
To decompose multicoil CINE steady-state free precession (SSFP) cardiac images acquired at short echo time (TE) increments into separate water and fat images, using an iterative least-squares "Dixon" (IDEAL) method. ⋯ Multicoil IDEAL-SSFP imaging can produce high quality CINE cardiac images with uniform water-fat separation, insensitive to Bo inhomogeneities. This approach provides a new method for reliable fat-suppression in cardiac imaging.
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To establish image parameters for some routine clinical brain MRI pulse sequences at 3.0 T with the goal of maintaining, as much as possible, the well-characterized 1.5-T image contrast characteristics for daily clinical diagnosis, while benefiting from the increased signal to noise at higher field. ⋯ When parameters are adjusted for changes in relaxation rates, routine clinical scans at 3.0 T can provide similar image appearance as 1.5 T, but with superior image quality and/or increased speed.
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In view of recent applications in cardiovascular and functional brain imaging, this work revisits the basic performance characteristics of spiral imaging in direct comparison to echo-planar imaging (EPI) and conventional rapid gradient-echo imaging. Using both computer simulations and experiments on phantoms and human subjects at 2.9 T, the study emphasizes single-shot applications and addresses the design of a suitable trajectory, the choice of a gridding algorithm, and the sensitivity to experimental inadequacies. ⋯ Moreover, when ignoring parallel imaging strategies that are also applicable to EPI, improvements of image quality via reduced acquisition periods are only achievable by interleaved multishot spirals because partial Fourier sampling and rectangular fields of view (FOVs) cannot be exploited for non-Cartesian trajectories. Taken together, while spiral imaging may find its niche applications, most high-speed imaging needs are more easily served by EPI.
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J Magn Reson Imaging · Jun 2005
Dynamic susceptibility contrast perfusion imaging of radiation effects in normal-appearing brain tissue: changes in the first-pass and recirculation phases.
To identify radiation-induced changes in the cerebral vasculature of healthy tissue in the first four months following radiotherapy through the analysis of dynamic-susceptibility contrast perfusion imaging. ⋯ The observed results suggest a dose-dependent decline in vessel density and increase in vascular permeability and/or tortuosity in irradiated normal-appearing brain tissue at two months following radiotherapy.