Journal of magnetic resonance imaging : JMRI
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The radiofrequency (RF) receive array coil is a complicated device with many inductors and capacitors and serves as one of the most critical magnetic resonance imaging (MRI) electronic devices. It directly determines the achievable level of signal-to-noise ratio (SNR). Simply put, however, the RF coil is nothing but an LC circuit. ⋯ This article summarizes the basic concepts pertaining to RF receive coil arrays and their associated SNR and reviews the theories behind the major components of such arrays. This includes discussions of the intrinsic SNR of a receive coil, the matching circuits, low-noise preamplifiers, coupling/decoupling amongst coils, the coupling between receive and transmit coils, decoupling via preamplifiers, and baluns. An 8-channel receive array coil on a cylindrical former serves as a useful example for demonstrating various points in the review.
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J Magn Reson Imaging · Jul 2013
Diffusion tensor tractography of the uncinate fasciculus: pitfalls in quantitative analysis due to traumatic volume changes.
To demonstrate the sensitivity of quantitative diffusion tensor tractography to traumatic injury of the uncinate fasciculus (UF), and to evaluate the effect of volume changes on the accuracy of quantitative analysis. ⋯ Posttraumatic FA and MD changes and volume reductions are common in the tractography of UF. Trauma-induced volume changes can cause misleading whole-tract mean FA values. Therefore, additional volume-based analysis of the central part is beneficial for clinical assessment.
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To acquire more detailed information noninvasively through on diffusion and perfusion in normal and cirrhotic livers, we analyzed three diffusion components using triexponential function. ⋯ Triexponential analysis makes it possible to noninvasively obtain more detailed tissue diffusion and perfusion information and to assist in the diagnosis of liver cirrhosis.
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J Magn Reson Imaging · Jul 2013
Use of 3T MRI and an unspoiled 3D fast gradient echo sequence for porcine knee cartilage volumetry: preliminary findings.
To assess the utility of knee cartilage volumetry using an unspoiled fat-suppressed 3D fast gradient echo (FGRE) sequence at 3T. ⋯ Interscan reproducibility of quantification of total cartilage volume and reproducibility of the manual segmentation technique were both high (>95%). Accurate and reproducible cartilage volumetry can be obtained by using a clinical unspoiled fat-suppressed 3D FGRE acquired at 3T MRI.