Partial field-of-view spiral phase-contrast imaging using complex difference processing.

abstract：PURPOSE:To develop methods for characterizing materials used in screen-printed MRI coils and improve signal-to-noise ratio (SNR) with new lower-loss materials. METHODS:An experimental apparatus was created to characterize dielectric properties of plastic substrates used in receive coils. Coils were fabricated by scree...

journal_title：Magnetic resonance in medicine

authors： Corea JR,Lechene PB,Lustig M,Arias AC

更新日期：2017-08-01 00:00:00

abstract：:Nuclear Overhauser effect (NOE) enhancements and relaxation times of 31P metabolites in human calf were measured in 12 volunteers (4 men and 8 women) at 1.5 T using a dual tuned four-ring birdcage. The NOE enhancements of inorganic phosphate (Pi), phosphocreatine (PCr), gamma-, alpha-, and beta-nucleoside triphosphate...

journal_title：Magnetic resonance in medicine

authors： Brown TR,Stoyanova R,Greenberg T,Srinivasan R,Murphy-Boesch J

更新日期：1995-03-01 00:00:00

abstract：PURPOSE:Going to ultrahigh field MRI (e.g., 7 Tesla [T]), the nonuniformity of the B1+ field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B1+, its field remains nonuniform. In this work, an RF pulse was designed that uses the slab selecti...

journal_title：Magnetic resonance in medicine

authors： van Kalleveen IM,Boer VO,Luijten PR,Klomp DW

更新日期：2015-08-01 00:00:00

abstract：:Cirrhosis is an important and growing public health problem, affecting millions of Americans and many more people internationally. A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide thera...

journal_title：Magnetic resonance in medicine

authors： Chung S,Breton E,Mannelli L,Axel L

更新日期：2011-04-01 00:00:00

abstract：:A technique using hyperpolarized (HP) 3He to image the small airways of the lung by using moderate flip angles and a short scanning period during early inspiration is demonstrated. Flip angles (alpha) ranging from 10-90 degrees were used in guinea pig experiments with scanning during the entire inspiration period. A s...

journal_title：Magnetic resonance in medicine

authors： Chen XJ,Chawla MS,Hedlund LW,Möller HE,MacFall JR,Johnson GA

更新日期：1998-01-01 00:00:00

abstract：PURPOSE:To accelerate dynamic MR applications using infimal convolution of total generalized variation functionals (ICTGV) as spatio-temporal regularization for image reconstruction. THEORY AND METHODS:ICTGV comprises a new image prior tailored to dynamic data that achieves regularization via optimal local balancing b...

journal_title：Magnetic resonance in medicine

authors： Schloegl M,Holler M,Schwarzl A,Bredies K,Stollberger R

更新日期：2017-07-01 00:00:00

abstract：:The combination of an in-plane B(1) sensitivity encoding (SENSE) technique with a simultaneous multiple-slice B(0) field step technique (multiple-acquisition micro B(0) array (MAMBA)) has produced high scan time reduction factors (R < or = 8). In this study, two slices were acquired simultaneously in combination with ...

journal_title：Magnetic resonance in medicine

authors： Paley MN,Lee KJ,Wild JM,Fichele S,Whitby EH,Wilkinson ID,Van Beek EJ,Griffiths PD

更新日期：2003-06-01 00:00:00

abstract：PURPOSE:To illustrate the potential bias caused by imaging gradients in correlation MRI sequences using longitudinal magnetization storage (LS) and examine the case of filter exchange imaging (FEXI) yielding maps of the apparent exchange rate (AXR). METHODS:The effects of imaging gradients in FEXI were observed on yea...

journal_title：Magnetic resonance in medicine

authors： Lasič S,Lundell H,Topgaard D,Dyrby TB

更新日期：2018-04-01 00:00:00

abstract：:With the advent of breath-hold MR cardiac imaging techniques, the minimization of TR and TE for oblique planes has become a critical issue. The slew rates and maximum currents of gradient amplifiers limit the minimum possible TR and TE by adding dead-periods to the pulse sequences. We propose a method of designing gra...

journal_title：Magnetic resonance in medicine

authors： Atalar E,McVeigh ER

更新日期：1994-12-01 00:00:00

abstract：PURPOSE:High field T2* -weighted MR images of the cerebral cortex are increasingly used to study tissue susceptibility changes related to aging or pathologies. This paper presents a novel automated method for the computation of quantitative cortical measures and group-wise comparison using 7 Tesla T2* -weighted magnitu...

journal_title：Magnetic resonance in medicine

authors： Doan NT,van Rooden S,Versluis MJ,Buijs M,Webb AG,van der Grond J,van Buchem MA,Reiber JHC,Milles J

更新日期：2015-07-01 00:00:00

abstract：:Coronary artery data acquisition with steady-state free precession (SSFP) is typically performed in a single frame in mid-diastole with a spectrally selective pulse to suppress epicardial fat signal. Data are acquired while the signal approaches steady state, which may lead to artifacts from the SSFP transient respons...

journal_title：Magnetic resonance in medicine

authors： Park J,Larson AC,Zhang Q,Simonetti O,Li D

更新日期：2005-10-01 00:00:00

abstract：:A single-shot, two-echo method for the simultaneous detection of multiple-quantum (MQ)-filtered gamma-aminobutyric acid (GABA) and creatine (Cr) was developed and demonstrated in the human brain in vivo at 3 Tesla. The simultaneously measured Cr singlet served as a navigator for the spectral phase of GABA and any freq...

journal_title：Magnetic resonance in medicine

authors： Choi IY,Lee SP,Merkle H,Shen J

更新日期：2004-06-01 00:00:00

abstract：:Hydrogen, sodium, and fluorine (added F-) NMR spectra of venous and oxygenated blood were measured. The fluorine resonance was seen as a single peak in both samples, and all three resonances exhibited the same deoxy-oxy shift. Because F- exchanges slowly across the red cell membrane, and because sodium is 95% extracel...

journal_title：Magnetic resonance in medicine

authors： Brooks RA,Brunetti A,Alger JR,Di Chiro G

更新日期：1989-11-01 00:00:00

abstract：:When using tracer kinetic modeling to analyze dynamic contrast-enhanced MRI (DCE-MRI) it is necessary to identify an appropriate arterial input function (AIF). The measured AIF is often poorly sampled in both clinical and preclinical MR systems due to the initial rapid increase in contrast agent concentration and the ...

journal_title：Magnetic resonance in medicine

authors： McGrath DM,Bradley DP,Tessier JL,Lacey T,Taylor CJ,Parker GJ

更新日期：2009-05-01 00:00:00

abstract：:A new NMR imaging technique, aiming at a reduction of the data acquisition time, is described in detail. The method is applicable in all multidimensional imaging situations where at least one spatial coordinate is resolved. Discussed at some length are the point-spread function, the required bandwidth of the NMR spect...

journal_title：Magnetic resonance in medicine

authors： van Uijen CM,den Boef JH,Verschuren FJ

更新日期：1985-06-01 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 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：:An automatic fMRI protocol for the investigation of the human auditory cortex has been developed. For the activation of the auditory system, the scanner noise itself is the source of sound. Rapid switching of B0 gradients allows the generation of tones of defined frequencies and amplitude on a conventional scanner wit...

journal_title：Magnetic resonance in medicine

authors： Bilecen D,Radü EW,Scheffler K

更新日期：1998-12-01 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：:The chemical shift of water and fat resonances in proton MRI allows separation of water and fat signal from chemical shift encoded data. This work describes an automatic method that produces separate water and fat images as well as quantitative maps of fat signal fraction and T2* from complex multiecho gradient-recall...

journal_title：Magnetic resonance in medicine

authors： Berglund J,Kullberg J

更新日期：2012-06-01 00:00:00

abstract：:The purpose of this study was to evaluate an optimized multislice acquisition technique for oxygen-enhanced MRI of the lung using slice-selective inversion and refocusing pulses in combination with parallel imaging. An inversion recovery HASTE sequence was implemented with respiratory triggering to perform imaging in ...

journal_title：Magnetic resonance in medicine

authors： Dietrich O,Losert C,Attenberger U,Fasol U,Peller M,Nikolaou K,Reiser MF,Schoenberg SO

更新日期：2005-06-01 00:00:00

abstract：:The orientation dependence of the free induction decay (FID) of 1H NMR water signal in ex vivo bovine digital flexor tendon at the native level of hydration is reported. Residual dipolar coupling due to the overall tissue anisotropy produces a 6:1 change in the signal intensity as an angle between the long axis of a s...

journal_title：Magnetic resonance in medicine

authors： Krasnosselskaia LV,Fullerton GD,Dodd SJ,Cameron IL

更新日期：2005-08-01 00:00:00

abstract：PURPOSE:Applications of dynamic shimming require high field fidelity, and characterizing the shim field dynamics is therefore necessary. Modeling the system as linear and time-invariant, the purpose of this work was to measure the impulse response function with optimal sensitivity. THEORY AND METHODS:Frequency-swept p...

journal_title：Magnetic resonance in medicine

authors： Vannesjo SJ,Dietrich BE,Pavan M,Brunner DO,Wilm BJ,Barmet C,Pruessmann KP

更新日期：2014-08-01 00:00:00

abstract：:In vivo MR spectroscopy (MRS) studies have shown reductions in NAA/Cr levels in patients with severe neurocognitive deficits due to AIDS dementia complex (ADC), also known as neuroAIDS. The relationship between the cellular changes within the brain during neuroAIDS and the role of NAA/Cr as a metabolic marker remains ...

journal_title：Magnetic resonance in medicine

authors： Lentz MR,Westmoreland SV,Lee V,Ratai EM,Halpern EF,González RG

更新日期：2008-03-01 00:00:00

abstract：:The goal of this work was to develop an MRI method for mapping the clearance of interstitial macromolecular plasma proteins after their extravasation from permeable blood vessels. To that end, a well-defined window of exposure to elevated blood levels was generated by inducing rapid clearance of macromolecular contras...

journal_title：Magnetic resonance in medicine

authors： Dafni H,Gilead A,Nevo N,Eilam R,Harmelin A,Neeman M

更新日期：2003-11-01 00:00:00

abstract：:We used high-field (13)C NMR (18.8 T) to assign unambiguously the isotopic shifts induced by the deuterium substitutions of the H3(proR) and H3(proS) hydrogens of (2-(13)C) glutamate in extracts of the brain from deuterated animals. Monodeuterated H3R or H3S glutamate diastereoisomers were produced stereospecifically ...

journal_title：Magnetic resonance in medicine

authors： Rodrigues TB,Violante IR,Cerdán S

更新日期：2010-04-01 00:00:00

abstract：:Assuming that the SSFP magnetization response maintains a steady state which is periodic in the presence of diffusion, we can solve for the diffusion effect in such sequences. Formulating a Fourier series decomposition solution to the Bloch-Torrey equation and imposing the steady-state condition, analytical expression...

journal_title：Magnetic resonance in medicine

authors： Carney CE,Wong ST,Patz S

更新日期：1991-06-01 00:00:00

abstract：:The investigation of flow behavior in coronary arteries is of great importance for an understanding of heart failure and heart regulation mechanisms. The purpose of the present study was to demonstrate that flow velocity can be quantified in the coronary arteries of the isolated rat heart with high-resolution phase co...

journal_title：Magnetic resonance in medicine

authors： Köhler S,Hiller KH,Jakob PM,Bauer WR,Haase A

更新日期：2003-09-01 00:00:00

abstract：:The potential of quantitative parameter images of the relaxation times T1 and T2, the proton density rho and the apparent diffusion coefficient (ADC) to characterize three different experimental rat brain tumors (F98 glioma, RN6 Schwannoma, and E376 neuroblastoma) was studied. All parameter values, as determined in hi...

journal_title：Magnetic resonance in medicine

authors： Eis M,Els T,Hoehn-Berlage M

更新日期：1995-12-01 00:00:00

abstract：:The proton exchange rates between water and the hydroxyl protons of threonine, serine, tyrosine, the amino protons of lysine, and the guanidinium protons of arginine were measured in the pH range 0.5 to 8.5 and for the temperatures 4 degrees C, 10 degrees C, 20 degrees C, 30 degrees C, and 36 degrees C. The intrinsic ...

journal_title：Magnetic resonance in medicine

authors： Liepinsh E,Otting G

更新日期：1996-01-01 00:00:00