Improved estimation of velocity and flow rate using regularized three-point phase-contrast velocimetry.

abstract：:The harmonic phase (HARP) method provides automatic and rapid analysis of tagged magnetic resonance (MR) images for quantification and visualization of myocardial strain. In this article, the development and implementation of a pulse sequence that acquires HARP images in real time are described. In this pulse sequence...

journal_title：Magnetic resonance in medicine

authors： Sampath S,Derbyshire JA,Atalar E,Osman NF,Prince JL

更新日期：2003-07-01 00:00:00

abstract：PURPOSE:To investigate the effect of realistic microstructural geometry on the susceptibility-weighted MR signal in white matter (WM), with application to demyelination. METHODS:Previous work has modeled susceptibility-weighted signals under the assumption that axons are cylindrical. In this study, we explored the imp...

journal_title：Magnetic resonance in medicine

authors： Xu T,Foxley S,Kleinnijenhuis M,Chen WC,Miller KL

更新日期：2018-01-01 00:00:00

abstract：:A method for evaluating the sensitivity of MRI protocols to changes in an arbitrary number of tissue parameters over a broad range of parameter values is presented. This analysis is useful for choosing an optimal basis set of images for either a "survey" protocol or tissue segmentation algorithms. A survey protocol is...

journal_title：Magnetic resonance in medicine

authors： McVeigh ER,Henkelman RM,Bronskill MJ

更新日期：1990-02-01 00:00:00

abstract：PURPOSE:To design and demonstrate a new susceptibility-based tracking device with an artifact that can be mechanically turned on and off, thus permitting tracking and imaging at the device tip with limited artifact. METHODS:The magnetic susceptibilities of readily obtainable grades of titanium and graphite were measur...

journal_title：Magnetic resonance in medicine

authors： Dominguez-Viqueira W,Karimi H,Lam WW,Cunningham CH

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:To demonstrate the feasibility of imaging the first passage of a bolus of hyperpolarized (13)C urea through the rodent heart using flow-sensitizing gradients to reduce signal from the blood pool. METHODS:A flow-sensitizing bipolar gradient was optimized to reduce the bright signal within the cardiac chambers, ...

journal_title：Magnetic resonance in medicine

authors： Lau AZ,Miller JJ,Robson MD,Tyler DJ

更新日期：2016-04-01 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：:Stimulated-echo localized spectroscopy was combined with phase- and frequency-encoding gradients to obtain "zoom" or magnified images of specific organs in situ. The technique requires neither surface coils nor an imaging coil arrangement that exclusively isolates the target organ. This technique can be readily applie...

journal_title：Magnetic resonance in medicine

authors： Mills P,Chew W,Litt L,Moseley M

更新日期：1987-10-01 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：:In the present work, diffusion-weighted (DW)-NMR spectroscopy of glutamate was performed during a (13)C-labeled glucose infusion in monkey brain (six experiments). It is shown that glutamate (13)C labeling occurs significantly faster at higher diffusion weightings-slightly for glutamate in position C4, and more marked...

journal_title：Magnetic resonance in medicine

authors： Valette J,Chaumeil M,Guillermier M,Bloch G,Hantraye P,Lebon V

更新日期：2008-08-01 00:00:00

abstract：:Myocardial MR first-pass perfusion time courses are contaminated by signals from the ventricles (spillover) as a consequence of partial volume effects and motion. An early increase in the signal intensity from the myocardium is an indicator of contamination. This contamination leads to under- or overestimation of perf...

journal_title：Magnetic resonance in medicine

authors： Köstler H,Ritter C,Reiss-Zimmermann M,Beer M,Hahn D,Sandstede J

更新日期：2004-04-01 00:00:00

abstract：:Mumps virus-infected and normal newborn hamster brains were imaged with magnetic resonance (MR) within 24 h after birth and serially scanned. Hydrocephalus developed explosively on Day 6 postinfection and progressed until death occurred soon after Day 10. This study demonstrates the utility of MR in the investigation ...

journal_title：Magnetic resonance in medicine

authors： Narayana PA,Wolinsky JS,Jensen DJ

更新日期：1987-06-01 00:00:00

abstract：:A simple (2)H NMR method for quantifying absolute (2)H-enrichments in all seven aliphatic positions of glucose following its derivatization to monoacetone glucose is presented. The method is based on the addition of a small quantity of (2)H-enriched formate to the NMR sample. When the method was applied to [2-(2)H]mon...

journal_title：Magnetic resonance in medicine

authors： Jones JG,Perdigoto R,Rodrigues TB,Geraldes CF

更新日期：2002-09-01 00:00:00

abstract：:As a high-speed imaging technique based on stimulated echoes single-shot STEAM MRI is insensitive to chemical shift artifacts and magnetic susceptibility differences. The achievable signal-to-noise ratio (SNR) is limited by the fact that high flip angles of the read-out excitation pulses cause a steep decay of the sti...

journal_title：Magnetic resonance in medicine

authors： Finsterbusch J,Frahm J

更新日期：2002-03-01 00:00:00

abstract：:Spin-echo images of 10 myocardial infarcts in nine mini-pigs were obtained at 30 h, 3 days, and approximately 10 days postinfarction. Infarcts were not detected at all at 30 h in five out of five cases examined. At 3 days postembolization (six cases) one infarct was certainly detected, whilst at 10 days (nine cases) a...

journal_title：Magnetic resonance in medicine

authors： Checkley D,Loveday BE,Waterton JC,Zhu XP,Isherwood I

更新日期：1987-09-01 00:00:00

abstract：:Phase-contrast MRI can provide high-resolution angiographic velocity images, especially in conjunction with non-Cartesian k-space sampling. However, acquisitions can be sensitive to errors from artifacts from main magnetic field inhomogeneities and chemical shift from fat. Particularly in body imaging, fat content can...

journal_title：Magnetic resonance in medicine

authors： Johnson KM,Wieben O,Samsonov AA

更新日期：2010-06-01 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 develop a prospective baseline enhancement that compensates for intermingled background effects in Z-spectra to achieve sensitivity enhancement of peaks related to CEST and nuclear Overhauser effect. METHODS:An MRI sequence-specific compensation of background effects is achieved through variation of the pul...

journal_title：Magnetic resonance in medicine

authors： Lenich T,Pampel A,Mildner T,Möller HE

更新日期：2019-04-01 00:00:00

abstract：PURPOSE:To explore the temperature-induced signal change in two-dimensional multi-spectral imaging (2DMSI) for fast thermometry near metallic hardware to enable MR-guided focused ultrasound surgery (MRgFUS) in patients with implanted metallic hardware. METHOD:2DMSI was optimized for temperature sensitivity and applied...

journal_title：Magnetic resonance in medicine

authors： Weber H,Ghanouni P,Pascal-Tenorio A,Pauly KB,Hargreaves BA

更新日期：2018-07-01 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：:Due to a delayed echo-formation, echo-shifted gradient echo sequences (ES-GRE) allow for an enhanced T(2)*-weighting at short repetition times. While they are in use with and without RF spoiling, analytical solutions are only known for the latter. The signal formation in the former could only be assessed in approximat...

journal_title：Magnetic resonance in medicine

authors： Ganter C

更新日期：2006-10-01 00:00:00

abstract：:In vivo echo-planar MR imaging was used to measure apparent diffusion coefficients (ADC) of cerebral tissues in a comprehensive noninvasive evaluation of early ischemic brain damage induced by occlusion of the middle cerebral artery (MCA) in a cat model of acute regional stroke. Within 10 min after arterial occlusion,...

journal_title：Magnetic resonance in medicine

authors： Kucharczyk J,Mintorovitch J,Asgari HS,Moseley M

更新日期：1991-06-01 00:00:00

abstract：PURPOSE:Magnetization transfer ratio (MTR) histograms are used widely for the assessment of diffuse pathological changes in the brain. For broad clinical application, MTR scans should not only be fast, but confounding factors should also be minimized for high reproducibility. To this end, a 1-minute whole-brain spiral ...

journal_title：Magnetic resonance in medicine

authors： Afshari R,Santini F,Heule R,Meyer CH,Pfeuffer J,Bieri O

更新日期：2020-12-08 00:00:00

abstract：:Radial MRI sequences are frequently used to obtain images with reduced sensitivity to motion. To decrease imaging time, multiple spin-echo acquisitions can be incorporated into radial sequences. In this case, different radial lines of Fourier data have different TE times and the resulting images can contain streaking ...

journal_title：Magnetic resonance in medicine

authors： Theilmann RJ,Gmitro AF,Altbach MI,Trouard TP

更新日期：2004-04-01 00:00:00

abstract：:Recently, a technique based on arterial spin labeling, called dynamic arterial spin labeling (DASL (Magn Reson Med 1999;41:299-308)), has been introduced to measure simultaneously the transit time of the labeled blood from the labeling plane to the exchange site, the longitudinal relaxation time of the tissue, and the...

journal_title：Magnetic resonance in medicine

authors： Barbier EL,Silva AC,Kim SG,Koretsky AP

更新日期：2001-06-01 00:00:00

abstract：PURPOSE:To significantly reduce the background phase effects, especially at the air-tissue interface, and to enhance the desirable local structures of veins in susceptibility-weighted imaging. METHODS:In the proposed reconstruction method called Magnitude of Complex Filtering, a complex-valued magnetic resonance image...

journal_title：Magnetic resonance in medicine

authors： Lee Y,Han Y,Park H

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:Oscillating gradient (OG) enables the access of short diffusion times for time-dependent diffusion MRI (dMRI); however, it poses several technical challenges for clinical use. This study proposes a 3D oscillating gradient-prepared gradient spin-echo (OGprep-GRASE) sequence to improve SNR and shorten acquisition...

journal_title：Magnetic resonance in medicine

authors： Wu D,Liu D,Hsu YC,Li H,Sun Y,Qin Q,Zhang Y

更新日期：2021-01-01 00:00:00

abstract：PURPOSE:To verify MR measurements of myocardial extracellular volume fraction (ECV) based on clinically applicable T1-mapping sequences against ECV measurements by radioisotope tracer in pigs and to relate the results to those obtained in volunteers. METHODS:Between May 2016 and March 2017, 8 volunteers (25 ± 4 years,...

journal_title：Magnetic resonance in medicine

authors： Nordlund D,Xanthis C,Bidhult S,Jablonowski R,Kanski M,Kopic S,Carlsson M,Engblom H,Aletras AH,Arheden H

更新日期：2020-02-01 00:00:00

abstract：:The design of a piezoelectric-controlled trimmer capacitor and its use as a tuning element of an MRI surface coil at 63.8 MHz are described. It is found that image quality does not depend strongly on match of the coil to the transmission line but that tuning can be a significant factor. The work is intended to lead ev...

journal_title：Magnetic resonance in medicine

authors： Hyde JS,Rilling RJ,Jesmanowicz A,Kneeland JB

更新日期：1989-10-01 00:00:00

abstract：:The utility of MRI using magnetization transfer (MT) enhanced pulse sequences to diagnose hepatic cirrhosis in a rat model was investigated. Hepatic T1 was measured with and without MT off-resonance RF pulses in 17 treated and six control rats. The livers were evaluated histologically, and the hydroxyproline content q...

journal_title：Magnetic resonance in medicine

authors： Aisen AM,Doi K,Swanson SD

更新日期：1994-05-01 00:00:00

abstract：:When deoxygenated, blood behaves as an effective susceptibility contrast agent. Changes in brain oxygenation can be monitored using gradient-echo echo-planar imaging. With this technique, difference images also demonstrate that blood oxygenation is increased during periods of recovery from respiratory challenge. ...

journal_title：Magnetic resonance in medicine

authors： Turner R,Le Bihan D,Moonen CT,Despres D,Frank J

更新日期：1991-11-01 00:00:00