B0 concomitant field compensation for MRI systems employing asymmetric transverse gradient coils.

abstract：:Tumor pH is physiologically important since it influences a number of processes relevant to tumorigenesis and therapy. Hence, knowledge of localized pH within tumors would contribute to understanding these processes. The destructiveness, poor spatial resolution, and poor signal-to-noise ratio (SNR) of current technolo...

journal_title：Magnetic resonance in medicine

authors： van Sluis R,Bhujwalla ZM,Raghunand N,Ballesteros P,Alvarez J,Cerdán S,Galons JP,Gillies RJ

更新日期：1999-04-01 00:00:00

abstract：PURPOSE:The goal of this study is to characterize and improve the accuracy of 2D magnetic resonance fingerprinting (MRF) scans in the presence of slice profile (SP) and B1 imperfections, which are two main factors that affect quantitative results in MRF. METHODS:The SP and B1 imperfections are characterized and correc...

journal_title：Magnetic resonance in medicine

authors： Ma D,Coppo S,Chen Y,McGivney DF,Jiang Y,Pahwa S,Gulani V,Griswold MA

更新日期：2017-11-01 00:00:00

abstract：PURPOSE:To develop a method based on fat-water transition region extraction (TREE) for robust fat-water separation and quantification in challenging scenarios, including low signal-to-noise ratio (SNR), fast changing B0 field, and disjointed anatomies. THEORY AND METHODS:In TREE method, the phasor solutions of each pi...

journal_title：Magnetic resonance in medicine

authors： Peng H,Zou C,Cheng C,Tie C,Qiao Y,Wan Q,Lv J,He Q,Liang D,Liu X,Liu W,Zheng H

更新日期：2019-07-01 00:00:00

abstract：PURPOSE:Quantitative mapping of the native T1 of the heart using the modified look-locker inversion recovery (MOLLI) technique provides high quality diagnostic information without requiring contrast agents. Previous work has considered the effects of T2 relaxation on MOLLI T1 measurements, finding that the T1 measured ...

journal_title：Magnetic resonance in medicine

authors： Robson MD,Piechnik SK,Tunnicliffe EM,Neubauer S

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:To characterize the fundamental limits of MRI near metallic implants on RF excitation, frequency encoding, and chemical shift-encoding water-fat separation. METHODS:Multicomponent three-dimensional (3D) digital models of a total hip and a total knee replacement were used to construct material-specific suscepti...

journal_title：Magnetic resonance in medicine

authors： Smith MR,Artz NS,Wiens C,Hernando D,Reeder SB

更新日期：2015-12-01 00:00:00

abstract：:In past decades, much effort has been invested in developing therapies for spinal injuries. Lack of standardization of clinical read-out measures, however, makes direct comparison of experimental therapies difficult. Damage and therapeutic effects in vivo are routinely evaluated using rather subjective behavioral test...

journal_title：Magnetic resonance in medicine

authors： Stieltjes B,Klussmann S,Bock M,Umathum R,Mangalathu J,Letellier E,Rittgen W,Edler L,Krammer PH,Kauczor HU,Martin-Villalba A,Essig M

更新日期：2006-05-01 00:00:00

abstract：:High-field MRI scanners are, in principle, well suited for mouse studies; however, many high-field magnets employ a vertical design that may influence the physiological state of the rodent. The purpose of this study was to investigate the orthostatic response of cerebral blood flow (CBF) in mice during a prolonged MR ...

journal_title：Magnetic resonance in medicine

authors： Foley LM,Hitchens TK,Kochanek PM,Melick JA,Jackson EK,Ho C

更新日期：2005-10-01 00:00:00

abstract：PURPOSE:Vulnerable atherosclerotic plaques are structurally weak and prone to rupture, presumably due to local oxidative stress. Redox active iron is linked to oxidative stress and the aim of this study was to investigate the distribution of Fe(III) in carotid plaques and its relation to vulnerability for rupture. MET...

journal_title：Magnetic resonance in medicine

authors： Gustafsson H,Hallbeck M,Norell M,Lindgren M,Engström M,Rosén A,Zachrisson H

更新日期：2014-02-01 00:00:00

abstract：:Three-dimensional magnetization-prepared (MP) MR angiography (MRA) was applied to the carotid and vertebral arteries by using ECG triggering, a slab selective RF inversion pulse, centric phase encoding and acquisition during diastole. Both theoretically and experimentally, the MP MRA sequence was shown to perform well...

journal_title：Magnetic resonance in medicine

authors： Wilman AH,Huston J 3rd,Riederer SJ

更新日期：1997-02-01 00:00:00

abstract：PURPOSE:Over the last two decades, extended criteria have promoted an increased number of donor livers available for liver transplantation. But posttransplant graft loss is still a major concern. Macrovesicular hepatic steatosis (MHS) is recognized as the most significant prognostic histologic parameter in predicting p...

journal_title：Magnetic resonance in medicine

authors： Chen G,Jiang J,Wang X,Yang M,Xie Y,Guo H,Tang H,Zhou L,Hu D,Kamel IR,Chen Z,Li Z

更新日期：2020-11-16 00:00:00

abstract：:A 3D sequence for dynamic susceptibility imaging is proposed which combines echo-shifting principles (such as PRESTO), sensitivity encoding (SENSE), and partial-Fourier acquisition. The method uses a moderate SENSE factor of 2 and takes advantage of an alternating partial k-space acquisition in the "slow" phase encode...

journal_title：Magnetic resonance in medicine

authors： Klarhöfer M,Dilharreguy B,van Gelderen P,Moonen CT

更新日期：2003-10-01 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:To develop a novel technique for voxel-based mapping of lung microstructural parameters using hyperpolarized 129 Xe dissolved-phase MR imaging during saturation recovery. METHODS:A pulse sequence using a highly undersampled stack-of-stars trajectory was developed, and low-rank plus sparse matrix decomposition ...

journal_title：Magnetic resonance in medicine

authors： Kern AL,Gutberlet M,Voskrebenzev A,Klimeš F,Rotärmel A,Wacker F,Hohlfeld JM,Vogel-Claussen J

更新日期：2019-04-01 00:00:00

abstract：:Patient motion and image distortion induced by eddy currents cause artifacts in maps of diffusion parameters computed from diffusion-weighted (DW) images. A novel and comprehensive approach to correct for spatial misalignment of DW imaging (DWI) volumes acquired with different strengths and orientations of the diffusi...

journal_title：Magnetic resonance in medicine

authors： Rohde GK,Barnett AS,Basser PJ,Marenco S,Pierpaoli C

更新日期：2004-01-01 00:00:00

abstract：:A new volume selection/spectral editing pulse sequence (VOSING) is presented. The features specific to the technique are that the volume selection and the editing intervals coincide and that no decoupling is necessary. The pulse sequence can be applied under both homo- and heteronuclear conditions. Phantom experiments...

journal_title：Magnetic resonance in medicine

authors： Knüttel A,Rommel E,Clausen M,Kimmich R

更新日期：1988-09-01 00:00:00

abstract：PURPOSE:Dipole antennas in ultrahigh field MRI have demonstrated advantages over more conventional designs. In this study, the fractionated dipole antenna is presented: a dipole where the legs are split into segments that are interconnected by capacitors or inductors. METHODS:A parameter study has been performed on di...

journal_title：Magnetic resonance in medicine

authors： Raaijmakers AJ,Italiaander M,Voogt IJ,Luijten PR,Hoogduin JM,Klomp DW,van den Berg CA

更新日期：2016-03-01 00:00:00

abstract：:We have noninvasively produced low-resolution, quantitative nuclear magnetic resonance images of cerebral blood flow in 2-ml voxels in eight cats. Typical signal-to-noise of 4 to 1 was obtained in cerebral voxels in 16.5-s epochs. Mean flow during normocapnia (paCO2 = 39 +/- 4 mm Hg) and hypercapnia (paCO2 = 62 +/- 4 ...

journal_title：Magnetic resonance in medicine

authors： Branch CA,Ewing JR,Helpern JA,Ordidge RJ,Butt S,Welch KM

更新日期：1992-11-01 00:00:00

abstract：:Three-dimensional spatial-spectral radiofrequency pulses using a stack-of-spirals trajectory can achieve two-dimensional spatial localization and one-dimensional spectral selection simultaneously. These pulses are useful, for example, in reduced field-of-view applications that also require frequency specificity such a...

journal_title：Magnetic resonance in medicine

authors： Deng W,Stenger VA

更新日期：2010-03-01 00:00:00

abstract：:Baseline distortion in NMR spectroscopy, caused by the "dead time" between signal excitation and detection, makes quantitative interpretation difficult and is aesthetically displeasing. Here the use of the CLEAN algorithm for deconvolving the effect of signal dead time to produce a distortionless baseline is discussed...

journal_title：Magnetic resonance in medicine

authors： McKinnon GC,Burger C,Boesiger P

更新日期：1990-01-01 00:00:00

abstract：:Keyhole acquisition techniques have been used to reduce image acquisition times primarily in contrast agent studies and via simulation in interventional MRI procedures. More recent simulations have suggested that improved definition of an interventional device [e.g., biopsy needles, radio frequency (RF) electrodes] co...

journal_title：Magnetic resonance in medicine

authors： Hwang KP,Lim J,Wendt M,Merkle E,Lewin JS,Duerk JL

更新日期：1999-09-01 00:00:00

abstract：:A transrectal probe for 1H imaging and 31P MR spectroscopy of the prostate gland is described. The probe is covered with plastic and consists of an insectional portion containing an rf coil and a handle containing a tuning and matching circuit. Using this transrectal probe, 1H MR images and the first 31P MR spectra of...

journal_title：Magnetic resonance in medicine

authors： Narayan P,Vigneron DB,Jajodia P,Anderson CM,Hedgcock MW,Tanagho EA,James TL

更新日期：1989-08-01 00:00:00

abstract：:In this article, we determined the relative accuracy of semiautomated spleen volumetry with diffusion-weighted (DW) MR images compared to standard manual volumetry with DW-MR or CT images. Semiautomated spleen volumetry using simple thresholding followed by 3D and 2D connected component analysis was performed with DW-...

journal_title：Magnetic resonance in medicine

authors： Lee J,Kim KW,Lee H,Lee SJ,Choi S,Jeong WK,Kye H,Song GW,Hwang S,Lee SG

更新日期：2012-07-01 00:00:00

abstract：:To quantify the extraction fraction, E, for gadopentetate across tumor capillaries, R3230 adenocarcinomas were implanted in the mammary fat pads of seven rats. The value of E was determined by using a two-compartment tissue model in which the endothelial transfer coefficient, K(PS) (ml x min(-1) x cc(-1) of tissue), w...

journal_title：Magnetic resonance in medicine

authors： Daldrup HE,Shames DM,Husseini W,Wendland MF,Okuhata Y,Brasch RC

更新日期：1998-10-01 00:00:00

abstract：:MnCl(2) was injected intrathecally through the cisterna magna in rats, allowing infusion of divalent manganese ions (Mn(++)) into the CSF space and thence into the brain, without breaking the blood-brain barrier (BBB). Mn(++) uptake and washout dynamics in the brain were measured by serial T(1)-weighted MRI and EPI T(...

journal_title：Magnetic resonance in medicine

authors： Liu CH,D'Arceuil HE,de Crespigny AJ

更新日期：2004-05-01 00:00:00

abstract：PURPOSE:To obtain three-dimensional (3D) MR angiography having high contrast between vessel and stationary background tissue, a novel technique called sliding time of flight (TOF) is proposed. METHODS:The proposed method relies on the property that flow-related enhancement (FRE) is maximized at the blood-entering slic...

journal_title：Magnetic resonance in medicine

authors： Choi J,Seo H,Lim Y,Han Y,Park H

更新日期：2015-03-01 00:00:00

abstract：:The most widely-used functional magnetic resonance imaging (fMRI) technique is based on the blood oxygenation level dependent (BOLD) effect, which requires at least partial uncoupling between cerebral blood flow (CBF) and oxygen consumption changes during increased mental activity. To compare BOLD and CBF effects duri...

journal_title：Magnetic resonance in medicine

authors： Kim SG,Uğurbil K

更新日期：1997-07-01 00:00:00

abstract：PURPOSE:To improve the quality and speed of electron paramagnetic resonance imaging (EPRI) acquisition by combining a uniform sampling distribution with spinning gradient acquisition. THEORY AND METHODS:A uniform sampling distribution was derived for spinning gradient EPRI acquisition (uniform spinning sampling, USS) ...

journal_title：Magnetic resonance in medicine

authors： Johnson DH,Ahmad R,Liu Y,Chen Z,Samouilov A,Zweier JL

更新日期：2014-02-01 00:00:00

abstract：:Saline solutions of manganese ions (Mn2+) were used as articular contrast agents in magnetic resonance microscopy (9.4 T) of cartilage of chicken femoral condyles and pig temporomandibular joints. The diffusion of Mn2+ from the articular surface into the cartilage matrix led to a strong contrast enhancement in the car...

journal_title：Magnetic resonance in medicine

authors： Kusaka Y,Gründer W,Rumpel H,Dannhauer KH,Gersonde K

更新日期：1992-03-01 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: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