Real-time dynamic frequency and shim correction for single-voxel magnetic resonance spectroscopy.

abstract：PURPOSE:Sensitivity encoding (SENSE) reconstruction of multiband echo planar imaging (EPI) may cause artifacts when simultaneously excited slices require different phase correction to remove the EPI-specific ghost shifted by half of the matrix size (N). We propose a simplified solution of this problem that combines SEN...

journal_title：Magnetic resonance in medicine

authors： Hennel F,Buehrer M,von Deuster C,Seuven A,Pruessmann KP

更新日期：2016-09-01 00:00:00

abstract：:Transmit and receive RF coil arrays have proven to be particularly beneficial for ultra-high-field MR. Transmit coil arrays enable such techniques as B(1) (+) shimming to substantially improve transmit B(1) homogeneity compared to conventional volume coil designs, and receive coil arrays offer enhanced parallel imagin...

journal_title：Magnetic resonance in medicine

authors： Adriany G,Auerbach EJ,Snyder CJ,Gözübüyük A,Moeller S,Ritter J,Van de Moortele PF,Vaughan T,Uğurbil K

更新日期：2010-06-01 00:00:00

abstract：:The relaxation of (1)H nuclei due to their interaction with quadrupolar (14)N nuclei in gel structures is measured using fast field-cycling NMR. This phenomenon called quadrupolar dips has been reported in different (1)H-(14)N bond-rich species. In this study, we have studied quadrupolar dips in fibrin, an insoluble p...

journal_title：Magnetic resonance in medicine

authors： Broche LM,Ismail SR,Booth NA,Lurie DJ

更新日期：2012-05-01 00:00:00

abstract：:Comparative NMR studies of normal and pathologically altered human stomach tissues were performed on the basis of proton T1 relaxation time measurements in the presence of high external concentrations of relaxation (contrast) agents manganese ethylenediaminetetraacetic acid (Mn-EDTA) and gadolinium diethylenetriaminep...

journal_title：Magnetic resonance in medicine

authors： Srejić R,Popov DV,Boricić I,Zuvela M

更新日期：1990-09-01 00:00:00

abstract：PURPOSE:Parameter mapping in sodium MRI data is challenging due to inherently low SNR and spatial resolution, prompting the need to employ robust models and estimation techniques. This work aims to develop a continuum model of sodium T 2 ...

journal_title：Magnetic resonance in medicine

authors： Syeda W,Blunck Y,Kolbe S,Cleary JO,Johnston LA

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:The oxygen extraction fraction (OEF) is an important biomarker for tissue-viability. MRI enables noninvasive estimation of the OEF based on the blood-oxygenation-level-dependent (BOLD) effect. Quantitative OEF-mapping is commonly applied using least-squares regression (LSR) to an analytical tissue model. Howeve...

journal_title：Magnetic resonance in medicine

authors： Domsch S,Mürle B,Weingärtner S,Zapp J,Wenz F,Schad LR

更新日期：2018-02-01 00:00:00

abstract：PURPOSE:T2 -relaxation-under-spin-tagging (TRUST) is an MR technique for the non-invasive assessment of whole-brain cerebral oxygen extraction fraction (OEF), through measurement of the venous blood T2 relaxation time in the sagittal sinus. A key limitation of TRUST, however, is the lack of spatial specificity of the m...

journal_title：Magnetic resonance in medicine

authors： O'Brien C,Okell TW,Chiew M,Jezzard P

更新日期：2019-10-01 00:00:00

abstract：:Intra-plaque hemorrhage (IPH) and lipid core, characteristics of rupture prone carotid plaques, are often visualized in vivo with MRI using T1 weighted gradient and spin echo, respectively. Increasing magnetic field strength may help to identify IPH and lipid core better. As a proof of concept, automatic segmentation ...

journal_title：Magnetic resonance in medicine

authors： te Boekhorst BC,van 't Klooster R,Bovens SM,van de Kolk KW,Cramer MJ,van Oosterhout MF,Doevendans PA,van der Geest RJ,Pasterkamp G,van Echteld CJ

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To measure the apparent diffusion coefficients (ADC) of five main metabolites in the human brain at 3T with PRESS and STEAM, avoiding measurement biases because of cross-terms. Cross-terms arise from interactions between slice-selection and spoiler gradients in the localized spectroscopy sequence and the diffus...

journal_title：Magnetic resonance in medicine

authors： Deelchand DK,Auerbach EJ,Marjańska M

更新日期：2018-06-01 00:00:00

abstract：:Healthy human brain diffusion anisotropy maps derived from standard spin echo diffusion tensor imaging (DTI) were compared with those using fluid-attenuated inversion recovery (FLAIR) preparation prior to DTI to null the signal from cerebrospinal fluid (CSF). Consistent comparisons entailed development of DTI postproc...

journal_title：Magnetic resonance in medicine

authors： Papadakis NG,Martin KM,Mustafa MH,Wilkinson ID,Griffiths PD,Huang CL,Woodruff PW

更新日期：2002-08-01 00:00:00

abstract：PURPOSE:Structure-guided total variation is a recently introduced prior that allows reconstruction of images using knowledge of the location and orientation of edges in a reference image. In this work, we demonstrate the advantages of a variant of structure-guided total variation known as directional total variation (D...

journal_title：Magnetic resonance in medicine

authors： Teh I,McClymont D,Carruth E,Omens J,McCulloch A,Schneider JE

更新日期：2020-10-01 00:00:00

abstract：:A demonstration of MR guided thermal surgery involved experiments with imaging of focused ultrasound in an MRI system, measurements of the thermal transients and a thermal analysis of the resulting images. Both the heat distribution and the creation of focused ultrasound lesions in gel phantoms, in vitro bovine muscle...

journal_title：Magnetic resonance in medicine

authors： Cline HE,Schenck JF,Watkins RD,Hynynen K,Jolesz FA

更新日期：1993-07-01 00:00:00

abstract：:We have obtained high-field (11.7 Tesla), high-resolution carbon-13 solid-state "magic-angle" sample-spinning nuclear magnetic resonance (NMR) spectra of a variety of phospholipids, sphingolipids, myelin and white matter samples, resolving and assigning over 40 resonances in the spectra of human and bovine myelin. The...

journal_title：Magnetic resonance in medicine

authors： Husted C,Montez B,Le C,Moscarello MA,Oldfield E

更新日期：1993-02-01 00:00:00

abstract：:In this study, a spin- and gradient-echo echo-planar imaging (SAGE EPI) MRI pulse sequence is presented that allows simultaneous measurements of gradient-echo and spin-echo dynamic susceptibility-contrast perfusion-weighted imaging data. Following signal excitation, five readout trains were acquired using spin- and gr...

journal_title：Magnetic resonance in medicine

authors： Schmiedeskamp H,Straka M,Newbould RD,Zaharchuk G,Andre JB,Olivot JM,Moseley ME,Albers GW,Bammer R

更新日期：2012-07-01 00:00:00

abstract：:The eigenimage filter was used to evaluate the results of a MRI study of cerebral ischemia in a rat model. This linear filter segments a desired feature in an image sequence from other features which may interfere with its observation. The animals were imaged temporally, after occlusion of the middle cerebral artery, ...

journal_title：Magnetic resonance in medicine

authors： Peck DJ,Spickler EM,Knight RA,Hearshen DO,Windham JP

更新日期：1992-08-01 00:00:00

abstract：PURPOSE:To develop a method to correct for geometric distortions in non-Cartesian echo planar imaging using data acquired in a fast prescan. METHODS:Echo planar images were obtained using a non-Cartesian density weighted k-space trajectory. In contrast to linear Cartesian acquisition, distortions arising in non-Cartes...

journal_title：Magnetic resonance in medicine

authors： Zeller M,Müller A,Hahn D,Köstler H

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:To develop and validate a method for acquiring helium-3 ((3) He) and proton ((1) H) three-dimensional (3D) image sets of the human lung with isotropic spatial resolution within a 10-s breath-hold by using compressed sensing (CS) acceleration, and to assess the fidelity of undersampled images compared with fully...

journal_title：Magnetic resonance in medicine

authors： Qing K,Altes TA,Tustison NJ,Feng X,Chen X,Mata JF,Miller GW,de Lange EE,Tobias WA,Cates GD Jr,Brookeman JR,Mugler JP 3rd

更新日期：2015-10-01 00:00:00

abstract：:Mathematical models are required to estimate kinetic parameters of [1-(13)C] pyruvate-lactate interconversion from magnetic resonance spectroscopy data. One- or two-way exchange models utilizing a hypothetical approximation to the true arterial input function (AIF), (e.g. an ideal 'box-car' function) have been used pr...

journal_title：Magnetic resonance in medicine

authors： Kazan SM,Reynolds S,Kennerley A,Wholey E,Bluff JE,Berwick J,Cunningham VJ,Paley MN,Tozer GM

更新日期：2013-10-01 00:00:00

abstract：:1H MR spectra were recorded from human gastrocnemius muscle at 63.86 MHz using the body coil of the Signa scanner as transmitter and a 3-in. surface coil as receiver. The fat content of the muscle was quantified relative to that of water in a selected volume or slice. The fat/water ratio was 0.05-0.07 for normal muscl...

journal_title：Magnetic resonance in medicine

authors： Bárány M,Venkatasubramanian PN,Mok E,Siegel IM,Abraham E,Wycliffe ND,Mafee MF

更新日期：1989-05-01 00:00:00

abstract：:Experiments have been performed to demonstrate and quantify cross-relaxation between water and methylene resonances in a simple model system. Inversion recovery experiments on aqueous solutions of polyethylene glycol produce a transient nuclear Overhauser effect that alters the recovery of the methylene resonance. The...

journal_title：Magnetic resonance in medicine

authors： Gore JC,Brown MS,Armitage IM

更新日期：1989-03-01 00:00:00

abstract：:Experimental procedures for obtaining localized 31P NMR spectra of humans by means of the ISIS sequence are discussed in detail. The technique is optimized for use with volume coils and with surface coils in order to measure localized 31P NMR spectra of different tissues and organs. Selective frequency-modulated (FM) ...

journal_title：Magnetic resonance in medicine

authors： Luyten PR,Groen JP,Vermeulen JW,den Hollander JA

更新日期：1989-07-01 00:00:00

abstract：PURPOSE:Fourier decomposition (FD) is a noninvasive method for assessing ventilation and perfusion-related information in the lungs. However, the technique has a low signal-to-noise ratio (SNR) in the lung parenchyma. We present an approach to increase the SNR in both morphological and functional images. METHODS:The d...

journal_title：Magnetic resonance in medicine

authors： Corteville DM,Kjïrstad Å,Henzler T,Zöllner FG,Schad LR

更新日期：2015-05-01 00:00:00

abstract：PURPOSE:To develop an MRI acquisition and reconstruction framework for volumetric cine visualization of the fetal heart and great vessels in the presence of maternal and fetal motion. METHODS:Four-dimensional (4D) depiction was achieved using a highly-accelerated multi-planar real-time balanced steady-state free prece...

journal_title：Magnetic resonance in medicine

authors： van Amerom JFP,Lloyd DFA,Deprez M,Price AN,Malik SJ,Pushparajah K,van Poppel MPM,Rutherford MA,Razavi R,Hajnal JV

更新日期：2019-09-01 00:00:00

abstract：PURPOSE:To develop a novel, simultaneous multislice reconstruction method that exploits Hankel subspace learning (SMS-HSL) for aliasing separation in the slice direction. METHODS:An SMS signal model with the Hankel-structured matrix was proposed. To efficiently suppress interslice leakage artifacts from a signal subsp...

journal_title：Magnetic resonance in medicine

authors： Park S,Park J

更新日期：2017-10-01 00:00:00

abstract：:The ability to directly detect neuronal magnetic fields by MRI would help investigators achieve the "holy grail" of neuroimaging, namely both high spatial and temporal resolution. Both positive and negative findings have been reported in the literature, with no clear consensus as to the feasibility of direct detection...

journal_title：Magnetic resonance in medicine

authors： Parkes LM,de Lange FP,Fries P,Toni I,Norris DG

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:To analyze the effect of B0 field drift on multivoxel MR spectroscopic imaging and to propose an approach for its correction. THEORY AND METHODS:It is shown, both theoretically and in a phantom, that for ∼30 min acquisitions a linear B0 drift (∼0.1 ppm/h) will cause localization errors that can reach several v...

journal_title：Magnetic resonance in medicine

authors： Tal A,Gonen O

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:To assess the risk of radiofrequency (RF)-induced heating in patients with MR-conditional pacemaker (PM) systems, in the presence of another lead abandoned from a previous implant. METHODS:Four commercial pacemaker leads were placed beside a MR-conditional PM system, inside a human trunk simulator. The phantom...

journal_title：Magnetic resonance in medicine

authors： Mattei E,Gentili G,Censi F,Triventi M,Calcagnini G

更新日期：2015-01-01 00:00:00

abstract：:NMRD profiles, the magnetic field dependence of the water proton longitudinal relaxation rates, have been acquired for two new diphosphonate-modified GdDTPA complexes currently under evaluation as relaxation agents for the MRI detection of soft-tissue calcifications. Fresh dilute solutions show profiles identical to t...

journal_title：Magnetic resonance in medicine

authors： Adzamli IK,Blau M

更新日期：1991-01-01 00:00:00

abstract：PURPOSE:The purpose of this study is to increase the robustness of MR fingerprinting (MRF) toward subject motion. METHODS:A novel reconstruction algorithm, MOtion insensitive MRF (MORF), was developed, which uses an iterative reconstruction based retrospective motion correction approach. Each iteration loops through t...

journal_title：Magnetic resonance in medicine

authors： Mehta BB,Ma D,Pierre EY,Jiang Y,Coppo S,Griswold MA

更新日期：2018-12-01 00:00:00

abstract：:Perfusion imaging with pulsed arterial spin labeling techniques, like flow-sensitive alternating inversion recovery (FAIR), may suffer from inflow of fresh, i.e., unlabeled, spins. Inflow of fresh spins is caused by the arrival of unlabeled spins in the image slice and can lead to underestimation of the perfusion if n...

journal_title：Magnetic resonance in medicine

authors： Schepers J,van Osch MJ,Bartels LW,Heukels SN,Viergever MA,Nicolay K

更新日期：2005-06-01 00:00:00