Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Aug 2013
Effects of gadoxetic acid on quantitative diffusion-weighted imaging of the liver.
To prospectively evaluate the effect of gadoxetic acid (Gd-EOB-DTPA; Primovist, Bayer-Schering, Berlin, Germany) on quantitative diffusion-weighted imaging (DWI) using the Le Bihan IntraVoxel Incoherent Motion model and considering separately the following parameters: slow diffusion coefficient (D), fast diffusion coefficient (D*), perfusion fraction (PF), and apparent diffusion coefficient (ADC). ⋯ It is possible to perform DW acquisitions after gadoxetic acid administration without any significant variation of the values of DW-related parameters under consideration in this study.
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J Magn Reson Imaging · Aug 2013
Gadoxetic acid-enhanced fat suppressed three-dimensional T1-weighted MRI using a multiecho dixon technique at 3 tesla: emphasis on image quality and hepatocellular carcinoma detection.
To compare the image quality between T1 high-resolution isotropic volume examination using the multi-echo Dixon technique (mDixon-eTHRIVE) and that using spectrally adiabatic inversion recovery (SPAIR-eTHRIVE) in gadoxetic acid-enhanced liver MRI, and to evaluate the detectability of hepatocellular carcinoma (HCC) on mDixon-eTHRIVE. ⋯ For gadoxetic acid-enhanced liver MRI, mDixon-eTHRIVE showed improved homogeneity of fat suppression and overall image quality compared with SPAIR-eTHRIVE.
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J Magn Reson Imaging · Aug 2013
ReviewWhole body MRI: improved lesion detection and characterization with diffusion weighted techniques.
Diffusion-weighted imaging (DWI) is an established functional imaging technique that interrogates the delicate balance of water movement at the cellular level. Technological advances enable this technique to be applied to whole-body MRI. Theory, b-value selection, common artifacts and target to background for optimized viewing will be reviewed for applications in the neck, chest, abdomen, and pelvis. ⋯ Persisting signal at high b-values from restricted hypercellular tissue and viscous fluid also permits applications of DWI beyond oncologic imaging. DWI, when used in conjunction with routine imaging, can assist in detecting hemorrhagic degradation products, infection/abscess, and inflammation in colitis, while aiding with discrimination of free fluid and empyema, while limiting the need for intravenous contrast. DWI in conjunction with routine anatomic images provides a platform to improve lesion detection and characterization with findings rivaling other combined anatomic and functional imaging techniques, with the added benefit of no ionizing radiation.
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J Magn Reson Imaging · Jul 2013
Comparative StudyAssessment of left ventricular myocardial scar in coronary artery disease by a three-dimensional MR imaging technique.
To evaluate the feasibility of free-breathing three-dimensional (3D) phase sensitive inversion recovery (PSIR) Turbo FLASH late gadolinium enhancement (LGE) magnetic resonance images (MRI) on left ventricular scar in patients with coronary artery disease (CAD) compared with clinically established breathhold two-dimensional (2D) PSIR Turbo FLASH images. ⋯ Free-breathing 3D PSIR Turbo FLASH imaging is another feasible method to identify left ventricular myocardial scar in patients with CAD and detects more scar volume compared with breathhold 2D PSIR Turbo FLASH imaging.
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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.