Projection reconstruction MR imaging using FOCUSS.

abstract：PURPOSE:Spectrally selective "prewinding" radiofrequency pulses can counteract B0 inhomogeneity in steady-state sequences, but can only prephase a limited range of off-resonance. We propose spectral-spatial small-tip angle prewinding pulses that increase the off-resonance bandwidth that can be successfully prephased by...

journal_title：Magnetic resonance in medicine

authors： Williams SN,Nielsen JF,Fessler JA,Noll DC

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:This study aims to identify work-related and personal factors associated with workers' exposure to static magnetic fields (SMF) and motion-induced time-varying magnetic fields (TVMF) from MRI scanners. METHODS:Measurements of personal exposure to SMF and TVMF were performed among MRI staff during 439 work shif...

journal_title：Magnetic resonance in medicine

authors： Schaap K,Christopher-De Vries Y,Cambron-Goulet É,Kromhout H

更新日期：2016-05-01 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：:The resolution in conventional BOLD FMRI is considerably lower than can be achieved with other MRI methods, and is insufficient for many important applications. One major difficulty in robustly improving spatial resolution is the poor image quality in BOLD FMRI, which suffers from distortions, blurring, and signal dro...

journal_title：Magnetic resonance in medicine

authors： Miller KL,Smith SM,Jezzard P,Pauly JM

更新日期：2006-01-01 00:00:00

abstract：PURPOSE:Compare the transmural distribution of forward creatine kinase reaction (kf,CK ) and ATP hydrolysis rate (kr,ATPase ) in the myocardium of normal porcine heart. Rate constants were extracted from partially relaxed spectra by applying the T1nom method, effectively reducing data acquisition time by up to an order...

journal_title：Magnetic resonance in medicine

authors： Jang A,Xiong Q,Zhang P,Zhang J

更新日期：2016-05-01 00:00:00

abstract：:A new decoupling sequence, PBAR, is described for broadband heteronuclear decoupling in vivo in humans at 1.5T. The sequence uses non-adiabatic, frequency- and amplitude-modulated inversion pulses designed to minimize decoupling sidebands at low applied gammaB(2) RF field levels and to cover only the narrow range of r...

journal_title：Magnetic resonance in medicine

authors： Barker PB,Golay X,Artemov D,Ouwerkerk R,Smith MA,Shaka AJ

更新日期：2001-02-01 00:00:00

abstract：PURPOSE:Imaging gradients result in the generation of concomitant fields, or Maxwell fields, which are of increasing importance at higher gradient amplitudes. These time-varying fields cause additional phase accumulation, which must be compensated for to avoid image artifacts. In the case of gradient systems employing ...

journal_title：Magnetic resonance in medicine

authors： Weavers PT,Tao S,Trzasko JD,Frigo LM,Shu Y,Frick MA,Lee SK,Foo TK,Bernstein MA

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:To assess the performance, in the presence of scanner instabilities, of three dynamic correction methods which integrate ∆B0 mapping into the chemical exchange saturation transfer (CEST) measurement and three established static ∆B0 -correction approaches. METHODS:A homogeneous phantom and five healthy voluntee...

journal_title：Magnetic resonance in medicine

authors： Poblador Rodriguez E,Moser P,Dymerska B,Robinson S,Schmitt B,van der Kouwe A,Gruber S,Trattnig S,Bogner W

更新日期：2019-08-01 00:00:00

abstract：:Functional MR imaging (fMRI) of activation in the brain is one of the more demanding applications required of an NMR imaging instrument. Since the signal changes in activation imaging are quite small, any instrumental variations can easily compromise the fMRI contrast. The authors describe a simple method for measurin...

journal_title：Magnetic resonance in medicine

authors： Weisskoff RM

更新日期：1996-10-01 00:00:00

abstract：PURPOSE:We propose a new acquisition to minimize the per-excitation encoding duration and improve the imaging capability for short T2 * species. METHODS:In the proposed ramped hybrid encoding (RHE) technique, gradients are applied before the radiofrequency (RF) pulse as in pointwise encoding time reduction with radial...

journal_title：Magnetic resonance in medicine

authors： Jang H,Wiens CN,McMillan AB

更新日期：2016-09-01 00:00:00

abstract：:It has been suggested that orientational changes in the collagen network of articular cartilage account for the depthwise T2 anisotropy of MRI through the magic angle effect. To investigate the relationship between laminar T2 appearance and collagen organization (anisotropy), bovine osteochondral plugs (N = 9) were T2...

journal_title：Magnetic resonance in medicine

authors： Nieminen MT,Rieppo J,Töyräs J,Hakumäki JM,Silvennoinen J,Hyttinen MM,Helminen HJ,Jurvelin JS

更新日期：2001-09-01 00:00:00

abstract：:Experiments were performed to determine whether changes in T2*-weighted MR images during and after hyperoxia differentiate tumors from normal tissue. Mammary adenocarcinomas implanted in the right hind limbs of rats were studied. Gradient echo images were obtained at 2 Tesla with an evolution time of 20 ms and a recyc...

journal_title：Magnetic resonance in medicine

authors： Kuperman VYu,River JN,Lewis MZ,Lubich LM,Karczmar GS

更新日期：1995-03-01 00:00:00

abstract：:Diffusion tensor imaging (DTI) is a new imaging modality that can provide unique information on brain white matter anatomy. Measurements of water diffusion constant along multiple axes are fitted to a tensor model, from which the diffusion anisotropy and dominant fiber orientation can be estimated. Even though the ten...

journal_title：Magnetic resonance in medicine

authors： Zhang J,van Zijl PC,Mori S

更新日期：2006-02-01 00:00:00

abstract：PURPOSE:MR-based quantification of liver magnetic susceptibility may enable field strength-independent measurement of liver iron concentration (LIC). However, susceptibility quantification is challenging, due to nonlocal effects of susceptibility on the B0 field. The purpose of this work is to demonstrate feasibility o...

journal_title：Magnetic resonance in medicine

authors： Hernando D,Cook RJ,Diamond C,Reeder SB

更新日期：2013-09-01 00:00:00

abstract：:In vivo 1H MRS can be used to detect and quantify the lactate resonance at 1.3 ppm provided that overlapping lipid resonances are eliminated. A homonuclear spectral editing method was developed to acquire uncontaminated 1H spectra of lactate with adiabatic pulses. An advantage of the adiabatic pulse sequence is the ab...

journal_title：Magnetic resonance in medicine

authors： Schupp DG,Merkle H,Ellermann JM,Ke Y,Garwood M

更新日期：1993-07-01 00:00:00

abstract：PURPOSE:To develop and evaluate a technique for accelerating phase contrast MRI (PC-MRI) acquisitions without significant compromise in flow quantification accuracy. METHODS:PC-MRI is commonly acquired using interleaved flow-compensated (FC) and flow-encoded (FE) echoes. We hypothesized that FC data, which represent b...

journal_title：Magnetic resonance in medicine

authors： Wang D,Shao J,Rapacchi S,Middione MJ,Ennis DB,Hu P

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:To develop a deep learning-based Bayesian estimation for MRI reconstruction. METHODS:We modeled the MRI reconstruction problem with Bayes's theorem, following the recently proposed PixelCNN++ method. The image reconstruction from incomplete k-space measurement was obtained by maximizing the posterior possibili...

journal_title：Magnetic resonance in medicine

authors： Luo G,Zhao N,Jiang W,Hui ES,Cao P

更新日期：2020-10-01 00:00:00

abstract：:A novel linear parameterization for the variable flip angle method for longitudinal relaxation time T(1) quantification from spoiled steady state MRI is derived from the half angle tangent transform, τ, of the flip angle. Plotting the signal S at coordinates x=Sτ and y=S/τ, respectively, establishes a line that render...

journal_title：Magnetic resonance in medicine

authors： Helms G,Dathe H,Weiskopf N,Dechent P

更新日期：2011-09-01 00:00:00

abstract：PURPOSE:All methods presented to date to map both conductivity and permittivity rely on multiple acquisitions to compute quantitatively the magnitude of radiofrequency transmit fields, B1+. In this work, we propose a method to compute both conductivity and permittivity based solely on relative receive coil sensitivitie...

journal_title：Magnetic resonance in medicine

authors： Marques JP,Sodickson DK,Ipek O,Collins CM,Gruetter R

更新日期：2015-07-01 00:00:00

abstract：PURPOSE:To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. METHODS:A T1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and...

journal_title：Magnetic resonance in medicine

authors： Bane O,Hectors SJ,Wagner M,Arlinghaus LL,Aryal MP,Cao Y,Chenevert TL,Fennessy F,Huang W,Hylton NM,Kalpathy-Cramer J,Keenan KE,Malyarenko DI,Mulkern RV,Newitt DC,Russek SE,Stupic KF,Tudorica A,Wilmes LJ,Yankeelov TE

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:Subendocardial dark-rim artifacts (DRAs) remain a major concern in first-pass perfusion (FPP) myocardial MRI and may lower the diagnostic accuracy for detection of ischemia. A major source of DRAs is the "Gibbs ringing" effect. We propose an optimized radial acquisition strategy aimed at eliminating ringing-ind...

journal_title：Magnetic resonance in medicine

authors： Sharif B,Dharmakumar R,LaBounty T,Arsanjani R,Shufelt C,Thomson L,Merz CN,Berman DS,Li D

更新日期：2014-07-01 00:00:00

abstract：:The hypothesis was tested that the intravoxel distribution of water diffusion rates, as measured with a stretched-exponential model of diffusion-weighted imaging (DWI), is a marker of brain tumor invasion. Eight rats underwent intracerebral inoculation of C6 glioma cells. In three rats, cells were labeled with a fluor...

journal_title：Magnetic resonance in medicine

authors： Bennett KM,Hyde JS,Rand SD,Bennett R,Krouwer HG,Rebro KJ,Schmainda KM

更新日期：2004-11-01 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：:A method is presented that employs the inherent spectral selectivity of the Steady-State Free Precession (SSFP) pulse sequence to provide a spectral band of suppression. At TE = TR/2, SSFP partitions the magnetization into two phase-opposed spectral components. Z-storing one of these components simultaneously further ...

journal_title：Magnetic resonance in medicine

authors： Derbyshire JA,Herzka DA,McVeigh ER

更新日期：2005-10-01 00:00:00

abstract：:The concentration of oxygen within cells is important in many physiological and pathological processes, but such oxygen-dependent phenomena are generally studied as a function of the concentration of extracellular oxygen, due to a lack of suitable methods. Electron parmamagnetic resonance (EPR) oximetric techniques of...

journal_title：Magnetic resonance in medicine

authors： Glockner JF,Norby SW,Swartz HM

更新日期：1993-01-01 00:00:00

abstract：PURPOSE:Irreversible electroporation (IRE) is a nonthermal tissue ablation technique that represents a promising treatment option for unresectable liver tumors, but the effectively treated zone cannot be reliably predicted. We investigate the potential benefit of transcatheter intra-arterial perfusion (TRIP) -MRI for t...

journal_title：Magnetic resonance in medicine

authors： Figini M,Zhou K,Pan L,Sun C,Wang B,Hu S,Yang J,Shangguan J,Eresen A,Velichko Y,Yaghmai V,Zhang Z

更新日期：2020-07-01 00:00:00

abstract：:The shells trajectory is a 3D data acquisition method with improved efficiency compared to Cartesian sampling. It is a true center-out trajectory that does not repeatedly resample the center of k-space, and also offers advantages for motion correction. This work demonstrates that k-space undersampling can be combined ...

journal_title：Magnetic resonance in medicine

authors： Shu Y,Riederer SJ,Bernstein MA

更新日期：2006-09-01 00:00:00

abstract：:The image intensity in magnetic resonance magnitude images in the presence of noise is shown to be governed by a Rician distribution. Low signal intensities (SNR < 2) are therefore biased due to the noise. It is shown how the underlying noise can be estimated from the images and a simple correction scheme is provided ...

journal_title：Magnetic resonance in medicine

authors： Gudbjartsson H,Patz S

更新日期：1995-12-01 00:00:00

abstract：:Manganese-enhanced MRI has previously been used for visualization of brain architecture and functional mapping of neural pathways. The present work investigated the potential of manganese-enhanced MRI for noninvasive imaging of salivary glands in living subjects. Marked shortening of T(1) was observed in salivary glan...

journal_title：Magnetic resonance in medicine

authors： Seshadri M,Hoy A

更新日期：2010-09-01 00:00:00

abstract：PURPOSE:To investigate the relative gain in sensitivity of five histology coils designed in-house to accommodate tissue sections of various sizes and compare with commercial mouse head coils. METHODS:The coil set was tailored to house tissue sections ranging from 5 to1000 µm encased in either glass slides or coverslip...

journal_title：Magnetic resonance in medicine

authors： Hoang DM,Voura EB,Zhang C,Fakri-Bouchet L,Wadghiri YZ

更新日期：2014-05-01 00:00:00