Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Oct 2007
Multiecho reconstruction for simultaneous water-fat decomposition and T2* estimation.
To describe and demonstrate the feasibility of a novel multiecho reconstruction technique that achieves simultaneous water-fat decomposition and T2* estimation. The method removes interference of water-fat separation with iron-induced T2* effects and therefore has potential for the simultaneous characterization of hepatic steatosis (fatty infiltration) and iron overload. ⋯ The T2*-IDEAL technique has potential applications in imaging of diffuse liver disease for evaluation of both hepatic steatosis and iron overload in a single breath-hold.
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J Magn Reson Imaging · Oct 2007
Interleaved water and fat imaging and applications to lipid quantitation using the gradient reversal technique.
To implement and evaluate the gradient reversal-based chemical shift imaging technique to obtain qualitative and quantitative spatially-registered fat and water images with high imaging efficiency at very high field. ⋯ The proposed MRI technique permits interleaved water and fat imaging, with which spectrally well-separated water and fat images at the identical slice locations could be obtained in a single acquisition without increasing scan time. The technique could be used for in vivo quantitative mapping of lipid content and applied to investigations using small animal experiment models.
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J Magn Reson Imaging · Oct 2007
Gadobenate dimeglumine-enhanced MR angiography: Diagnostic performance of four doses for detection and grading of carotid, renal, and aorto-iliac stenoses compared to digital subtraction angiography.
To determine the diagnostic performance of contrast-enhanced MR angiography (CE-MRA) with four doses of gadobenate dimeglumine for detection of significant steno-occlusive disease of the carotid, renal, and pelvic vasculature. ⋯ Significantly better diagnostic performance on CE-MRA of the renal, pelvic, and carotid arteries is achieved with a gadobenate dimeglumine dose of 0.1 mmol/kg bodyweight.
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J Magn Reson Imaging · Oct 2007
Range of ventricular dimensions and function by steady-state free precession cine MRI in repaired tetralogy of Fallot: right ventricular outflow tract patch vs. conduit repair.
To characterize the range of biventricular size and function evaluated by steady-state free precession (SSFP) cine magnetic resonance (MR) in a large cohort of patients with repaired tetralogy of Fallot (TOF), and to compare these measurements in those with a right ventricular outflow tract (RVOT) patch vs. a right ventricle-to-pulmonary artery (RV-PA) conduit. ⋯ This study provides the range and distribution of biventricular size and function, and PR measured by MRI in a large contemporary cohort of patients with repaired TOF, and demonstrates important variations in RV mechanics between patients repaired with a RVOT patch and those with an RV-PA conduit.
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The principles of contrast mechanisms and fast pulse sequences underlying neurological and neuroradiological application of MRI are introduced in this part of a two-part review. In particular, the relaxation time constants T(1), T(2), and T(2) (*) are introduced, along with pulse sequences harnessing their contrast, spin-echo, fast spin echo (FSE), inversion recovery (IR), gradient recalled echo (GRE), and echo planar imaging (EPI). The use of gadolinium (Gd)-based contrast is discussed in both T(1)- and T(2) (*)-weighted sequences. ⋯ T(2) (*) sensitivity is discussed as both a source of artifact as well as a contrast mechanism (perfusion imaging with contrast agents, susceptibility weighted imaging [SWI], and blood oxygenation level dependent [BOLD] imaging). Finally, the contrast mechanism of diffusion is introduced, as well as the concept of anisotropy. From these principles, the other part of this two-part review draws upon the pulse sequences and contrast mechanisms to design disease and indication-specific protocols for state-of-the-art clinical use.