Localized proton MR spectroscopy of the human kidney in vivo by means of short echo time STEAM sequences.

abstract：PURPOSE:Balanced steady state free precession (bSSFP) imaging suffers from off-resonance artifacts such as signal modulation and banding. Solutions for removal of bSSFP off-resonance dependence are described and compared, and an optimal solution is proposed. THEORY AND METHODS:An Algebraic Solution (AS) that complemen...

journal_title：Magnetic resonance in medicine

authors： Hoff MN,Andre JB,Xiang QS

更新日期：2017-02-01 00:00:00

abstract：:The diffusional kurtosis is an indicator for diffusion restrictions in biological tissue. It is observed experimentally that the kurtosis is largest for directions perpendicular to the fiber direction in white matter. The directional dependence of the kurtosis can be described by the diffusion kurtosis tensor. Since t...

journal_title：Magnetic resonance in medicine

authors： Kuder TA,Stieltjes B,Bachert P,Semmler W,Laun FB

更新日期：2012-05-01 00:00:00

abstract：:Variations in T(1ρ) with locking-field strength (T(1ρ) dispersion) may be used to estimate proton exchange rates. We developed a novel approach utilizing the second derivative of the dispersion curve to measure exchange in a model system of cross-linked polyacrylamide gels. These gels were varied in relative compositi...

journal_title：Magnetic resonance in medicine

authors： Cobb JG,Xie J,Gore JC

更新日期：2011-12-01 00:00:00

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：PURPOSE:Gradient imperfections remain a challenge in MRI, especially for sequences relying on long imaging readouts. This work aims to explore image reconstruction based on k-space trajectories predicted by an impulse response model of the gradient system. THEORY AND METHODS:Gradient characterization was performed twi...

journal_title：Magnetic resonance in medicine

authors： Vannesjo SJ,Graedel NN,Kasper L,Gross S,Busch J,Haeberlin M,Barmet C,Pruessmann KP

更新日期：2016-07-01 00:00:00

abstract：PURPOSE:To determine whether neurochemical concentrations obtained at two MRI sites using clinical 3T scanners can be pooled when a highly optimized, nonvendor short-echo, single-voxel proton MRS pulse sequence is used in conjunction with identical calibration and quantification procedures. METHODS:A modified semi-LAS...

journal_title：Magnetic resonance in medicine

authors： Deelchand DK,Adanyeguh IM,Emir UE,Nguyen TM,Valabregue R,Henry PG,Mochel F,Öz G

更新日期：2015-05-01 00:00:00

abstract：:A type of local coil (or surface coil) for magnetic resonance imaging and spectroscopy is described in which two circular loops of the same diameter are disposed axially with respect to each other and in which counter rotating currents (CRC) are supported in the two loops. This type of coil has been used for localized...

journal_title：Magnetic resonance in medicine

authors： Froncisz W,Jesmanowicz A,Kneeland JB,Hyde JS

更新日期：1986-08-01 00:00:00

abstract：:A novel center-out 3D trajectory for sampling magnetic resonance data is presented. The trajectory set is based on a single Fermat spiral waveform, which is substantially undersampled in the center of k-space. Multiple trajectories are combined in a "stacked cone" configuration to give very uniform sampling throughout...

journal_title：Magnetic resonance in medicine

authors： Pipe JG,Zwart NR,Aboussouan EA,Robison RK,Devaraj A,Johnson KO

更新日期：2011-11-01 00:00:00

abstract：:MRI of hyperpolarized (129)Xe dissolved in pulmonary tissues, and blood has the potential to offer a new tool for regional evaluation of pulmonary gas exchange and perfusion; however, the extremely short T2* and low magnetization density make it difficult to acquire the image. In this study, an ultrashort echo-time se...

journal_title：Magnetic resonance in medicine

authors： Iguchi S,Imai H,Hori Y,Nakajima J,Kimura A,Fujiwara H

更新日期：2013-07-01 00:00:00

abstract：:A birdcage coil possesses various intrinsic resonant modes. One of the modes produces sinusoidal current distribution around the rung elements of the birdcage and generates a highly uniform B(1) field in the transverse plane. Another mode is the end-ring resonant mode, in which there are no currents in the rungs of th...

journal_title：Magnetic resonance in medicine

authors： Fujita H,Braum WO,Morich MA

更新日期：2000-10-01 00:00:00

abstract：PURPOSE:To enable fast and flexible high-resolution four-dimensional (4D) MRI of periodic thoracic/abdominal motion for motion visualization or motion-corrected imaging. METHODS:We proposed a Cartesian three-dimensional k-space sampling scheme that acquires a random combination of k-space lines in the ky/kz plane. A p...

journal_title：Magnetic resonance in medicine

authors： Küstner T,Würslin C,Schwartz M,Martirosian P,Gatidis S,Brendle C,Seith F,Schick F,Schwenzer NF,Yang B,Schmidt H

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:Oscillating gradient (OG) enables the access of short diffusion times for time-dependent diffusion MRI (dMRI); however, it poses several technical challenges for clinical use. This study proposes a 3D oscillating gradient-prepared gradient spin-echo (OGprep-GRASE) sequence to improve SNR and shorten acquisition...

journal_title：Magnetic resonance in medicine

authors： Wu D,Liu D,Hsu YC,Li H,Sun Y,Qin Q,Zhang Y

更新日期：2021-01-01 00:00:00

abstract：:MRI evaluations of intramyocardial hemorrhage in acute infarction have relied on T(2) and T(2)(*) shortening only. We propose a more comprehensive evaluation of hemorrhagic infarction based on the concept that fluctuations in T(2) and T(1) relaxation in acute reperfused infarction will reflect transient edema and hemo...

journal_title：Magnetic resonance in medicine

authors： Foltz WD,Yang Y,Graham JJ,Detsky JS,Wright GA,Dick AJ

更新日期：2006-12-01 00:00:00

abstract：:The feasibility of reconstructing three-dimensional (3D) MRI data sets from limited-view projections is investigated in phantom and in vivo animal studies to improve the temporal resolution of magnetic resonance angiography without sacrificing spatial resolution. Thirty-two pairs of orthogonal biplane projections are ...

journal_title：Magnetic resonance in medicine

authors： Huang Y,Gurr D,Wright GA

更新日期：2006-01-01 00:00:00

abstract：:The resolution and homogeneity limitations of echo-planar imaging (EPI) are overcome by zoom imaging of an easily shimmed localized volume. Use of the stimulated echo enables single-shot localization. In vivo 0.5-mm resolution EPI images of selected regions of a cat brain at 4.7 T are presented. ...

journal_title：Magnetic resonance in medicine

authors： Turner R,von Kienlin M,Moonen CT,van Zijl PC

更新日期：1990-05-01 00:00:00

abstract：:Two-dimensional intersecting k-space trajectories have previously been demonstrated to allow fast multispectral imaging. Repeated sampling of k-space points leads to destructive interference of the signal coming from the off-resonance spectral peaks; on-resonance data reconstruction yields images of the on-resonance p...

journal_title：Magnetic resonance in medicine

authors： Bucholz EK,Song J,Johnson GA,Hancu I

更新日期：2008-03-01 00:00:00

abstract：PURPOSE:Develop and test an analytic correction method to correct the signal intensity variation caused by the inhomogeneous reception profile of an eight-channel phased array for hyperpolarized (13) C imaging. THEORY AND METHODS:Fiducial markers visible in anatomical images were attached to the individual coils to pr...

journal_title：Magnetic resonance in medicine

authors： Dominguez-Viqueira W,Geraghty BJ,Lau JY,Robb FJ,Chen AP,Cunningham CH

更新日期：2016-02-01 00:00:00

abstract：:Magnetization exchange effects between the matrix macromolecules (e. g., collagen and proteoglycan) and water were examined in normal, deuterated, and proteoglycan-depleted articular cartilage. Relaxation results (T(2), T(1rho), and T(1)) suggested that a four-site exchange scheme provided an accurate model for articu...

journal_title：Magnetic resonance in medicine

authors： Lattanzio PJ,Marshall KW,Damyanovich AZ,Peemoeller H

更新日期：2000-12-01 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：PURPOSE:A ghost correction strategy for Simultaneous Multi-Slice (SMS) EPI methods that provides improved ghosting artifact reduction compared to conventional methods is presented. Conventional Nyquist ghost correction methods for SMS-EPI rely on navigator data that contain phase errors from all slices in the simultane...

journal_title：Magnetic resonance in medicine

authors： Hoge WS,Setsompop K,Polimeni JR

更新日期：2018-10-01 00:00:00

abstract：:The objective of this study is to evaluate the effect of MR image resolution on trabecular bone parameters and to determine the acceptable resolution that can be accurately analyzed to assess structural parameters. Ten distal femoral condyle specimens of 1 × 1 × 1 cm(3) were scanned with a 4.7-T Bruker BioSpec MRI sca...

journal_title：Magnetic resonance in medicine

authors： Kim N,Lee JG,Song Y,Kim HJ,S Yeom J,Cho G

更新日期：2012-01-01 00:00:00

abstract：:In a research environment, a magnetic resonance imaging system's manufacturer-supplied protection against excessive rf power deposition in the sample is often compromised. This paper presents a widely applicable scheme, based on a commonly available fuse, that simply and effectively limits the average rf power into a ...

journal_title：Magnetic resonance in medicine

authors： Hedges LK

更新日期：1989-02-01 00:00:00

abstract：PURPOSE:Real-time assessment of ventricular volumes requires high acceleration factors. Residual convolutional neural networks (CNN) have shown potential for removing artifacts caused by data undersampling. In this study, we investigated the ability of CNNs to reconstruct highly accelerated radial real-time data in pat...

journal_title：Magnetic resonance in medicine

authors： Hauptmann A,Arridge S,Lucka F,Muthurangu V,Steeden JA

更新日期：2019-02-01 00:00:00

abstract：PURPOSE:Golden-angle radial sparse parallel (GRASP) MRI reconstruction requires gridding and regridding to transform data between radial and Cartesian k-space. These operations are repeatedly performed in each iteration, which makes the reconstruction computationally demanding. This work aimed to accelerate GRASP recon...

journal_title：Magnetic resonance in medicine

authors： Benkert T,Tian Y,Huang C,DiBella EVR,Chandarana H,Feng L

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Magnetic resonance elastography (MRE) measures stiffness of soft tissues by analyzing their spatial harmonic response to externally induced shear vibrations. Many MRE methods use inversion-based reconstruction approaches, which invoke first- or second-order derivatives by finite difference operators (first- and...

journal_title：Magnetic resonance in medicine

authors： Mura J,Schrank F,Sack I

更新日期：2020-07-01 00:00:00

abstract：:In this work a model-free arterial spin labeling (ASL) quantification approach for measuring cerebral blood flow (CBF) and arterial blood volume (aBV) is proposed. The method is based on the acquisition of a train of multiple images following the labeling scheme. Perfusion is obtained using deconvolution in a manner s...

journal_title：Magnetic resonance in medicine

authors： Petersen ET,Lim T,Golay X

更新日期：2006-02-01 00:00:00

abstract：:Paramagnetic ions complexed to proteins may lose, retain, or enhance solvent paramagnetic relaxation (SPR) relative to free solution. We measured T1 and T2 of three mouse cancers, their normal counterparts, and six additional tissues. Long T1 of cancers was not caused by necrosis or by different contents of water, fat...

journal_title：Magnetic resonance in medicine

authors： Negendank W,Corbett T,Crowley M,Kellogg C

更新日期：1991-04-01 00:00:00

abstract：PURPOSE:Banding artifacts in images acquired by balanced steady-state free precession (bSSFP) remain a challenge in MRI as they considerably reduce image quality, and diagnostic value deteriorates accordingly. As the steady-state tolerates small shifts in frequency, it is possible to acquire frequency-modulated bSSFP. ...

journal_title：Magnetic resonance in medicine

authors： Slawig A,Wech T,Ratz V,Tran-Gia J,Neubauer H,Bley T,Köstler H

更新日期：2017-12-01 00:00:00

abstract：:A new approach to spin-echo imaging is presented in which the 180 degrees RF pulse refocuses two or more spin-echoes at different positions in the readout period. When simultaneous echo refocusing (SER) is implemented using multiple 180 degrees pulses, an undesirable mixing of stimulated echoes and primary echoes from...

journal_title：Magnetic resonance in medicine

authors： Günther M,Feinberg DA

更新日期：2005-09-01 00:00:00

abstract：PURPOSE:We propose a constrained optimization approach for designing parallel transmit (pTx) pulses satisfying all regulatory and hardware limits. We study the trade-offs between excitation accuracy, local and global specific absorption rate (SAR), and maximum and average power for small flip-angle pTx (eight channels)...

journal_title：Magnetic resonance in medicine

authors： Guérin B,Gebhardt M,Cauley S,Adalsteinsson E,Wald LL

更新日期：2014-04-01 00:00:00