Identification of signal bias in the variable flip angle method by linear display of the algebraic Ernst equation.

abstract：:Quantitative artificial neural network analysis for 1550 ex vivo 31P nuclear magnetic resonance spectra from hypothermically reperfused pig livers was assessed. These spectra show wide ranges of metabolite concentrations and have been analyzed using metabolite prior knowledge based lineshape fitting analysis which had...

journal_title：Magnetic resonance in medicine

authors： Ala-Korpela M,Changani KK,Hiltunen Y,Bell JD,Fuller BJ,Bryant DJ,Taylor-Robinson SD,Davidson BR

更新日期：1997-11-01 00:00:00

abstract：:Flow-independent angiography is a non-contrast-enhanced technique that can generate vessel contrast even with reduced blood flow in the lower extremities. A method is presented for producing these angiograms with magnetization-prepared balanced steady-state free precession (bSSFP). Because bSSFP yields bright fat sign...

journal_title：Magnetic resonance in medicine

authors： Cukur T,Lee JH,Bangerter NK,Hargreaves BA,Nishimura DG

更新日期：2009-06-01 00:00:00

abstract：:This contribution reports the first direct and noninvasive observation of cerebral glucose in normal anesthetized rats (n = 16) using short-echo-time localized proton NMR spectroscopy (2.35 T, STEAM, TR = 6000 ms, TE = 20 ms, 125 microliters). In addition to resonances from N-acetyl aspartate (NAA), glutamate, total c...

journal_title：Magnetic resonance in medicine

authors： Gyngell ML,Michaelis T,Hörstermann D,Bruhn H,Hänicke W,Merboldt KD,Frahm J

更新日期：1991-06-01 00:00:00

abstract：:Segmented interleaved echo planar imaging offers a fast and efficient approach to magnetic resonance angiography. Unfortunately, this technique is particularly sensitive to oblique flow in the imaging plane. In this work, a mathematical analysis of oblique flow effects for several types of k-space coverage is presente...

journal_title：Magnetic resonance in medicine

authors： Beck G,Li D,Haacke EM,Noll TG,Schad LR

更新日期：2001-04-01 00:00:00

abstract：:A method for volume selective proton spectroscopy is presented based on a multiecho sequence with short refocusing interval tcp. It is demonstrated, that by appropriate choice of tcp on the order of 4-6 ms, signals from overlapping multiplets like the glutamine and glutamate (Glu/Gln) resonances in spectra of the huma...

journal_title：Magnetic resonance in medicine

authors： Hennig J,Thiel T,Speck O

更新日期：1997-06-01 00:00:00

abstract：PURPOSE:To test and implement a motion-robust and respiratory-resolved 3D Radial Flow framework that addresses the need for rapid, high resolution imaging in neonatal patients with congenital heart disease. METHODS:A 4-point velocity encoding and 3D radial trajectory with double-golden angle ordering was combined with...

journal_title：Magnetic resonance in medicine

authors： Schrauben EM,Lim JM,Goolaub DS,Marini D,Seed M,Macgowan CK

更新日期：2020-02-01 00:00:00

abstract：PURPOSE:To accelerate whole-heart three-dimension MR angiography (MRA) by using a variable-density Poisson-disc undersampling pattern and a compressed sensing (CS) reconstruction algorithm, and compare the results with sensitivity encoding (SENSE). METHODS:For whole-heart MRA, a prospective variable-density Poisson-di...

journal_title：Magnetic resonance in medicine

authors： Moghari MH,Uecker M,Roujol S,Sabbagh M,Geva T,Powell AJ

更新日期：2018-02-01 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：:Myocardial tagging is a new noninvasive MRI method that allows the study of myocardial motion with high accuracy. However, with conventional tagging techniques tagging contrast is impaired at later heart phases due to longitudinal relaxation. An improved method, called Complementary SPAtial Modulation of Magnetization...

journal_title：Magnetic resonance in medicine

authors： Fischer SE,McKinnon GC,Maier SE,Boesiger P

更新日期：1993-08-01 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：:Sinusoidal capillarization induces microcirculatory changes in liver cirrhosis and fibrosis. The purpose of this study was to assess whether contrast-enhanced MRI can be used to demonstrate the effects of sinusoidal capillarization in liver fibrosis. Dynamic MRI after injection of a low-molecular-weight contrast agent...

journal_title：Magnetic resonance in medicine

authors： Van Beers BE,Materne R,Annet L,Hermoye L,Sempoux C,Peeters F,Smith AM,Jamart J,Horsmans Y

更新日期：2003-04-01 00:00:00

abstract：:19F NMR imaging of the perfluorocarbon emulsion Fluosol has been used to study regional variations in oxygen tension in rat liver and spleen. We have used the linear dependence of spin lattice relaxation rate (1/T1) on the partial oxygen pressure (pO2) of Fluosol to determine the oxygen tension in the reticuloendothel...

journal_title：Magnetic resonance in medicine

authors： Holland SK,Kennan RP,Schaub MM,D'Angelo MJ,Gore JC

更新日期：1993-04-01 00:00:00

abstract：:Applications of fMRI in functional brain imaging are mainly confined to single subject designs, prohibiting the assessment of subject or group by condition interactions (i.e., differential activations) or areas of conjoint activation. In this paper a framework for fMRI group designs, using statistical parametric mappi...

journal_title：Magnetic resonance in medicine

authors： Büchel C,Turner R,Friston K

更新日期：1997-11-01 00:00:00

abstract：:We report the synthesis and characterization of polyvinyl alcohol (PVA) embolic particles modified with a clinically approved magnetic resonance (MR) contrast agent. PVA particles are used during transcatheter arterial embolization (TAE) procedures and this minimally invasive technique is a widely employed treatment f...

journal_title：Magnetic resonance in medicine

authors： Cilliers R,Song Y,Kohlmeir EK,Larson AC,Omary RA,Meade TJ

更新日期：2008-04-01 00:00:00

abstract：:This report describes a noninvasive 1H-NMR method for measuring absolute temperatures (+/- 0.2 degrees C) in biological samples and, in particular, in cell culture perfusion systems, utilizing the linear temperature dependence of the water chemical shift relative to the temperature-independent shift of one of the comp...

journal_title：Magnetic resonance in medicine

authors： Lutz NW,Kuesel AC,Hull WE

更新日期：1993-01-01 00:00:00

abstract：PURPOSE:We incorporate simultaneous multislice (SMS) acquisition into MR fingerprinting (MRF) to accelerate the MRF acquisition. METHODS:The t-Blipped SMS-MRF method is achieved by adding a Gz blip before each data acquisition window and balancing it with a Gz blip of opposing polarity at the end of each TR. Thus the ...

journal_title：Magnetic resonance in medicine

authors： Ye H,Ma D,Jiang Y,Cauley SF,Du Y,Wald LL,Griswold MA,Setsompop K

更新日期：2016-05-01 00:00:00

abstract：:The theoretical description of steady state free precession (SSFP) sequences is generally well accepted and unquestioned, although it is based on instantaneously acting radiofrequency (RF) pulses. In practice, however, all excitation processes are finite, thereby questioning the overall validity of the common SSFP sig...

journal_title：Magnetic resonance in medicine

authors： Bieri O,Scheffler K

更新日期：2009-11-01 00:00:00

abstract：:A novel iterative k-space data-driven technique, namely parallel reconstruction using null operations (PRUNO), is presented for parallel imaging reconstruction. In PRUNO, both data calibration and image reconstruction are formulated into linear algebra problems based on a generalized system model. An optimal data cali...

journal_title：Magnetic resonance in medicine

authors： Zhang J,Liu C,Moseley ME

更新日期：2011-11-01 00:00:00

abstract：:Formation of ternary complexes between Gd-DTPA, Gd-DTPA-BMA, and Gd-DOTA, used as contrast enhancement agents in MRI and the endogenously available carbonate and phosphate ions, has been demonstrated. The extent of ternary complex formation and its effect on the proton relaxation, measured at 9 MHz, rates is negligibl...

journal_title：Magnetic resonance in medicine

authors： Burai L,Hietapelto V,Király R,Tóth E,Brücher E

更新日期：1997-07-01 00:00:00

abstract：:Human intervertebral discs were investigated by 1H NMR in vitro. The measured parameters of samples differently located in discs give the "maps" of discs. The spin-lattice relaxation-time maps show similar structure to dry matter and bound water maps, which might mean the future possibility to detect certain disc proc...

journal_title：Magnetic resonance in medicine

authors： Furó I,Bobest M,Pócsik I,Tompa K

更新日期：1986-02-01 00:00:00

abstract：:Sensitivity encoding is used to improve the performance of real-time MRI. The encoding efficiency of single-shot and segmented echo-planar imaging is tripled by means of a 6-element receiver coil array. The feasibility of this approach is verified for double oblique cardiac real-time imaging of human subjects at rest ...

journal_title：Magnetic resonance in medicine

authors： Weiger M,Pruessmann KP,Boesiger P

更新日期：2000-02-01 00:00:00

abstract：:At TE values of 136 ms, it has recently been shown that the lactate methyl signal, when obtained with a stimulated-echo (STE) sequence, is modulated at the zero-quantum (ZQ) frequency when TM is varied. Here we describe an additional modulation of the ZQ lactate signal, due to spin-spin coupling, that results in a 10-...

journal_title：Magnetic resonance in medicine

authors： Sotak CH,Alger JR

更新日期：1991-02-01 00:00:00

abstract：:Parallel transmission has emerged as an efficient means for implementing multidimensional spatially selective radiofrequency excitation pulses. To date, most theoretical and experimental work on parallel transmission radiofrequency (RF) pulse design is based on the small-tip-angle approximation to the Bloch equation. ...

journal_title：Magnetic resonance in medicine

authors： Zheng H,Zhao T,Qian Y,Ibrahim TS,Boada FE

更新日期：2011-09-01 00:00:00

abstract：PURPOSE:To develop and evaluate a method for volumetric contrast-enhanced MRI of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography (MRA) using a single injection of contrast agent. METHODS:An interleaved variable density (IVD) undersampling pattern was implemented i...

journal_title：Magnetic resonance in medicine

authors： Salmani Rahimi M,Korosec FR,Wang K,Holmes JH,Motosugi U,Bannas P,Reeder SB

更新日期：2015-03-01 00:00:00

abstract：PURPOSE:Cardiac stimulation (CS) limits to gradient coil switching speed are difficult to measure in humans; instead, current regulatory guidelines (IEC 60601-2-33) are based on animal experiments and electric field-to-dB/dt conversion factors computed for a simple, homogeneous body model. We propose improvement to thi...

journal_title：Magnetic resonance in medicine

authors： Klein V,Davids M,Schad LR,Wald LL,Guérin B

更新日期：2021-02-01 00:00:00

abstract：PURPOSE:To improve imaging performance for body MRI with a local transmit array at 10.5T, the geometry of a dipole antenna was optimized to achieve lower peak specific absorption rate (SAR) levels and a more uniform transmit profile. METHODS:Electromagnetic simulations on a phantom were used to evaluate the SAR and ...

journal_title：Magnetic resonance in medicine

authors： Steensma B,van de Moortele PF,Ertürk A,Grant A,Adriany G,Luijten P,Klomp D,van den Berg N,Metzger G,Raaijmakers A

更新日期：2020-11-01 00:00:00

abstract：:Calibration of the spatial sensitivity functions of coil arrays is a crucial element in parallel magnetic resonance imaging (PMRI). The most common approach has been to measure coil sensitivities directly using one or more low-resolution images acquired before or after accelerated data acquisition. However, since it i...

journal_title：Magnetic resonance in medicine

authors： McKenzie CA,Yeh EN,Ohliger MA,Price MD,Sodickson DK

更新日期：2002-03-01 00:00:00

abstract：:An optimized multislice data acquisition scheme for phase acquisition of composite echoes (PACE) imaging is presented. This new scheme uses a repetition time equal to the mixing time and an appropriate phase cycling scheme, which allows for more efficient exploitation of all composite echoes. These modifications provi...

journal_title：Magnetic resonance in medicine

authors： Ropele S,Stollberger R,Kapeller P,Hartung HP,Fazekas F

更新日期：1999-12-01 00:00:00

abstract：:Spiral k-space magnetic resonance spectroscopic imaging (MRSI) requires high performance from gradient hardware systems. During the readout phase, oscillating gradients are continuously played out, which can cause undesired effects. These effects on the quality of SI data are non-intuitive because of their time-varyin...

journal_title：Magnetic resonance in medicine

authors： Kim DH,Spielman DM

更新日期：2006-07-01 00:00:00

abstract：PURPOSE:In contrast to conventional linear gradients, gradient coil arrays with arbitrary spatial dependency might experience strong mutual coupling. Although conventional gradient power amplifiers with feedback loop might compensate the effect of coupling, required voltages for the compensation are generally unknown a...

journal_title：Magnetic resonance in medicine

authors： Ertan K,Taraghinia S,Atalar E

更新日期：2019-09-01 00:00:00