Experimental confirmation of phase encoding of instantaneous derivatives of position.

abstract：:Designing multidimensional radiofrequency pulses for clinical application must take into account the local specific absorption rate (SAR) as controlling the global SAR does not guarantee suppression of hot spots. The maximum peak SAR, averaged over an N grams cube (local NgSAR), must be kept under certain safety limit...

journal_title：Magnetic resonance in medicine

authors： Sbrizzi A,Hoogduin H,Lagendijk JJ,Luijten P,Sleijpen GL,van den Berg CA

更新日期：2012-03-01 00:00:00

abstract：:High-signal artifacts produced by cerebrospinal fluid (CSF) flow can adversely affect fluid-attenuated inversion recovery (FLAIR) imaging of the brain and spinal cord. This study explores the use of a nonslice-selective inversion pulse to eliminate CSF flow artifacts together with a technique called "K-space Reordered...

journal_title：Magnetic resonance in medicine

authors： Herlihy AH,Oatridge A,Curati WL,Puri BK,Bydder GM,Hajnal JV

更新日期：2001-08-01 00:00:00

abstract：:The time evolution of water diffusion, perfusion, T1, and T2 is investigated at high magnetic field (8.5 T) following permanent middle cerebral artery occlusion in the rat. Cerebral blood flow maps were obtained using arterial spin tagging. Although the quantitative perfusion measurements in ischemic tissue still pose...

journal_title：Magnetic resonance in medicine

authors： Calamante F,Lythgoe MF,Pell GS,Thomas DL,King MD,Busza AL,Sotak CH,Williams SR,Ordidge RJ,Gadian DG

更新日期：1999-03-01 00:00:00

abstract：PURPOSE:To develop and demonstrate the feasibility of a new technique for respiratory-gated, fat-suppressed, three-dimensional spoiled gradient-recalled echo (3D-SPGR) with navigator gating for more accurate and robust motion detection. METHODS:A navigator-gated 3D-SPGR technique was modified to include a wait period ...

journal_title：Magnetic resonance in medicine

authors： Iwadate Y,Brau AC,Vasanawala SS,Kabasawa H

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:A target-pattern-driven (TD) trajectory design is introduced in combination with parallel transmit (pTX) radiofrequency (RF) pulses to provide localized suppression of unwanted signals. The design incorporates target-pattern and B1+ information to adjust denser sampling and coverage in k-space regions where the...

journal_title：Magnetic resonance in medicine

authors： Schneider R,Haueisen J,Pfeuffer J

更新日期：2014-10-01 00:00:00

abstract：:Parameter-selective imaging for tissue characterization is performed at low magnetic fields (0.24-0.28 T) employing echo trains with a large number of echoes (less than or equal to 50), high-power pulses, and the projection reconstruction method. Preprocessing of the raw echoes is important for the quality of the echo...

journal_title：Magnetic resonance in medicine

authors： Staemmler M,Gersonde K

更新日期：1986-06-01 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：:Kinetic analysis with mathematical models has become increasingly important to quantify physiological parameters in computed tomography (CT), positron emission tomography (PET), and dynamic contrast-enhanced MRI (DCE-MRI). The modified Kety/Tofts model and the graphical (Patlak) model have been widely applied to DCE-M...

journal_title：Magnetic resonance in medicine

authors： Chen H,Li F,Zhao X,Yuan C,Rutt B,Kerwin WS

更新日期：2011-09-01 00:00:00

abstract：:The manufacturing of intravascular imaging coils poses several challenges. Due to their size, it can be difficult to incorporate local matching networks and signal amplifiers. The goal of this study is to investigate tuning and amplification strategies for intravascular coils and to assess the signal-to-noise benefits...

journal_title：Magnetic resonance in medicine

authors： Yak N,Anderson KJ,Wright GA

更新日期：2012-11-01 00:00:00

abstract：:Flow-sensitive dephasing (FSD) magnetization preparation has been developed for black-blood vessel wall MRI and noncontrast MR angiography. The first-order gradient moment, m(1) , is a measure of the flow-sensitization imparted by an FSD preparative module. Determination of the optimal m(1) for each individual is high...

journal_title：Magnetic resonance in medicine

authors： Fan Z,Zhou X,Bi X,Dharmakumar R,Carr JC,Li D

更新日期：2011-04-01 00:00:00

abstract：PURPOSE:The aim of this study was to compare prospective head motion correction and motion tracking abilities of two tracking systems: Active NMR field probes and a Moiré phase tracking camera system using an optical marker. METHODS:Both tracking systems were used simultaneously on human subjects. The prospective head...

journal_title：Magnetic resonance in medicine

authors： Eschelbach M,Aghaeifar A,Bause J,Handwerker J,Anders J,Engel EM,Thielscher A,Scheffler K

更新日期：2019-01-01 00:00:00

abstract：:The properties of the image noise for selective averaging of phase-encoding lines have been investigated. For a given acquisition time, selective averaging results in a signal-to-noise ratio penalty compared to averaging all lines equally. In addition, selective averaging yields a non uniform distribution of noise cha...

journal_title：Magnetic resonance in medicine

authors： Mugler JP 3rd

更新日期：1991-05-01 00:00:00

abstract：PURPOSE:To enable accurate magnetic resonance (MR) parameter mapping with accelerated data acquisition, utilizing recent advances in constrained imaging with sparse sampling. THEORY AND METHODS:A new constrained reconstruction method based on low-rank and sparsity constraints is proposed to accelerate MR parameter map...

journal_title：Magnetic resonance in medicine

authors： Zhao B,Lu W,Hitchens TK,Lam F,Ho C,Liang ZP

更新日期：2015-08-01 00:00:00

abstract：:We exploit the intrinsic difference in magnetic resonance spin-spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue in order to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain. In normal vo...

journal_title：Magnetic resonance in medicine

authors： MacKay A,Whittall K,Adler J,Li D,Paty D,Graeb D

更新日期：1994-06-01 00:00:00

abstract：PURPOSE:Blood flow causes induced voltages via the magnetohydrodynamic (MHD) effect distorting electrograms (EGMs) made during magnetic resonance imaging. To investigate the MHD effect in this context MHD voltages occurring inside the human heart were simulated in an in vitro model system inside a 1.5 T MR system. MET...

journal_title：Magnetic resonance in medicine

authors： Buchenberg WB,Mader W,Hoppe G,Lorenz R,Menza M,Büchert M,Timmer J,Jung B

更新日期：2015-09-01 00:00:00

abstract：PURPOSE:To investigate the influence of transcytolemmal water exchange on estimates of tissue microstructural parameters derived from diffusion MRI using conventional PGSE and IMPULSED methods. METHODS:Computer simulations were performed to incorporate a broad range of intracellular water life times τin (50-∞ ms), cel...

journal_title：Magnetic resonance in medicine

authors： Li H,Jiang X,Xie J,Gore JC,Xu J

更新日期：2017-06-01 00:00:00

abstract：:Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a ...

journal_title：Magnetic resonance in medicine

authors： Weber OM,Martin AJ,Higgins CB

更新日期：2003-12-01 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：PURPOSE:Multiple nonlinear gradient fields offer many potential benefits for spatial encoding including reduced acquisition time, fewer artefacts and region-specific imaging, although designing a suitable trajectory for such a setup is difficult. This work aims to optimize encoding trajectories for multiple nonlinear g...

journal_title：Magnetic resonance in medicine

authors： Layton KJ,Kroboth S,Jia F,Littin S,Yu H,Zaitsev M

更新日期：2016-07-01 00:00:00

abstract：:The concept of temporal echo multiplexing is defined and used to develop rapid biphasic spin-echo sequences for imaging the heart. Three imaging sequences, based on four-echo and two-echo multiplexing and rapid single echo (i.e., conventional spin-echo imaging), are compared. Preliminary results indicate that two-echo...

journal_title：Magnetic resonance in medicine

authors： Parker DL,Caputo GR,Frederick PR

更新日期：1989-07-01 00:00:00

abstract：:The feasibility of MR subtraction imaging of lung ventilation using air against oxygen using a multiple inversion recovery half-Fourier single-shot turbo spin echo (MIR-HASTE) sequence was investigated. Eight healthy, nonsmoking volunteers (3 males, 5 females; from 27 to 48 years of age) were studied on a 1.5 T MR uni...

journal_title：Magnetic resonance in medicine

authors： Mai VM,Chen Q,Bankier AA,Edelman RR

更新日期：2000-06-01 00:00:00

abstract：:A novel ultra-rapid gradient echo (URGE) NMR imaging technique is introduced, which is capable of continuous high resolution 3D scanning while neither subject to fast gradient switching nor excessive RF power deposition. Sampling free induction decays instead of creating spin echoes enables maintaining a workable stea...

journal_title：Magnetic resonance in medicine

authors： Heid O,Deimling M,Huk WJ

更新日期：1995-01-01 00:00:00

abstract：:Parallel magnetic resonance imaging (pMRI) using multichannel receiver coils has emerged as an effective tool to reduce imaging time in various applications. However, the issue of accurate estimation of coil sensitivities has not been fully addressed, which limits the level of speed enhancement achievable with the tec...

journal_title：Magnetic resonance in medicine

authors： Ying L,Sheng J

更新日期：2007-06-01 00:00:00

abstract：:To increase image acquisition efficiency, we develop alternative gradient encoding strategies designed to provide spatial encoding complementary to the spatial encoding provided by the multiple receiver coil elements in parallel image acquisitions. Intuitively, complementary encoding is achieved when the magnetic fiel...

journal_title：Magnetic resonance in medicine

authors： Tam LK,Stockmann JP,Galiana G,Constable RT

更新日期：2012-10-01 00:00:00

abstract：:Quantitative diffusion measurements were performed in tumors arising from inoculation of nude mice with two human breast cancer cell lines (MCF7 and T47D) to evaluate the specificity of this technique for characterizing solid tumors. ADC maps were compared to histology and correlated well with gross tumor morphology. ...

journal_title：Magnetic resonance in medicine

authors： Maier CF,Paran Y,Bendel P,Rutt BK,Degani H

更新日期：1997-04-01 00:00:00

abstract：:Fast proton magnetic resonance spectroscopic imaging (MRSI) using a multi-element head-coil array is examined with respect to three aspects: the coil design, the use of an appropriate signal combination method, and the design of the MRSI pulse sequence itself. An eight-element head-coil array has been developed to inc...

journal_title：Magnetic resonance in medicine

authors： Schäffter T,Börnert P,Leussler C,Carlsen IC,Leibfritz D

更新日期：1998-08-01 00:00:00

abstract：:Single-slab 3D turbo/fast spin echo (SE) imaging with very long echo trains was recently introduced with slab selection using a highly selective excitation pulse and short, nonselective refocusing pulses with variable flip angles for high imaging efficiency. This technique, however, is vulnerable to image degradation ...

journal_title：Magnetic resonance in medicine

authors： Park J,Mugler JP 3rd,Hughes T

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:To assess the use of image registration for correcting respiratory motion in free breathing lung T1 mapping acquisition in patients with idiopathic pulmonary fibrosis (IPF). THEORY AND METHODS:The method presented used image registration to synthetic images during postprocessing to remove respiratory motion. S...

journal_title：Magnetic resonance in medicine

authors： Saunders LC,Eaden JA,Bianchi SM,Swift AJ,Wild JM

更新日期：2020-12-01 00:00:00

abstract：:A novel method based on selective detection of rapidly changing DeltaB(0) magnetic fields and suppression of slowly changing DeltaB(0) fields is presented. The ultimate goal of this work is to present a method that may allow detection of transient and subtle changes in B(0) in cortical tissue associated with electrica...

journal_title：Magnetic resonance in medicine

authors： Bodurka J,Bandettini PA

更新日期：2002-06-01 00:00:00

abstract：PURPOSE:The aim of the study was to investigate whether incorrectly compensated eddy currents are the source of persistent X-nuclear spectroscopy and imaging artifacts, as well as methods to correct this. METHODS:Pulse-acquire spectra were collected for 1 H and X-nuclei (23 Na or 31 P) using the minimum TR permitted o...

journal_title：Magnetic resonance in medicine

authors： McLean MA,Hinks RS,Kaggie JD,Woitek R,Riemer F,Graves MJ,McIntyre DJO,Gallagher FA,Schulte RF

更新日期：2020-12-04 00:00:00