Ramped hybrid encoding for improved ultrashort echo time imaging.

abstract：:The purpose of the study was to test a newly developed, MR-compatible, liquid nitrogen-cooled cryoprobe. The probe has an outer diameter of 3.5 mm and was specifically developed for percutaneous, MR-guided, interstitial cryotherapy. The probe was inserted percutaneously into the livers of 10 rabbits. The cryotherapy p...

journal_title：Magnetic resonance in medicine

authors： Tacke J,Adam G,Speetzen R,Brucksch K,Bücker A,Heshel I,Prescher A,van Vaals JJ,Hunter DW,Rau G,Günther RW

更新日期：1998-03-01 00:00:00

abstract：:Magnetization transfer imaging (MT) and localized proton spectroscopy (1H-MRS) were utilized in the evaluation of lesions (high signal abnormalities on T2-weighted images) and normal-appearing white matter (NAWM) in multiple sclerosis (MS). Eleven patients with a clinical diagnosis of MS were independently evaluated w...

journal_title：Magnetic resonance in medicine

authors： Hiehle JF Jr,Lenkinski RE,Grossman RI,Dousset V,Ramer KN,Schnall MD,Cohen JA,Gonzalez-Scarano F

更新日期：1994-09-01 00:00:00

abstract：PURPOSE:Recent MRI studies have suggested that the magnetic susceptibility of white matter (WM) in the human brain is anisotropic, providing a new contrast mechanism for the visualization of fiber bundles and allowing the extraction of cellular compartment-specific information. This study provides an independent confir...

journal_title：Magnetic resonance in medicine

authors： van Gelderen P,Mandelkow H,de Zwart JA,Duyn JH

更新日期：2015-11-01 00:00:00

abstract：:Intracranial vascular territories are usually visualized with the use of angiographic techniques. However, because it is difficult to visualize the distal vascular bed with any angiographic technique, it is also difficult to infer the parenchymal borders of vascular territories. Arterial spin labeling (ASL) MRI provid...

journal_title：Magnetic resonance in medicine

authors： Günther M

更新日期：2006-09-01 00:00:00

abstract：:Typically, MR-elastography (MRE) encodes the propagation of monochromatic acoustic waves in the MR-phase images via sinusoidal gradients characterized by a detection frequency equal to the frequency of the mechanical vibration. Therefore, the echo time of a conventional MRE sequence is typically longer than the vibrat...

journal_title：Magnetic resonance in medicine

authors： Robert B,Sinkus R,Gennisson JL,Fink M

更新日期：2009-11-01 00:00:00

abstract：:As the static magnetic field strength used in human magnetic resonance imaging increases, the wavelength of the corresponding radiofrequency field becomes comparable to the dimensions of the coil and volume of interest. The dielectric resonance effects that arise in this full wavelength regime may be partially compens...

journal_title：Magnetic resonance in medicine

authors： Pinkerton RG,Barberi EA,Menon RS

更新日期：2005-08-01 00:00:00

abstract：PURPOSE:To investigate a computationally efficient method for optimizing the Cramér-Rao Lower Bound (CRLB) of quantitative sequences without using approximations or an analytical expression of the signal. METHODS:Automatic differentiation was applied to Bloch simulations and used to optimize several quantitative seque...

journal_title：Magnetic resonance in medicine

authors： Lee PK,Watkins LE,Anderson TI,Buonincontri G,Hargreaves BA

更新日期：2019-10-01 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：PURPOSE:Either SENSE+CG or POCS-ICE methods can be used to correct for motion-induced phase errors in navigator-free multishot diffusion imaging. SENSE+CG has the advantage of a fast convergence, however, occasionally the convergence can be unstable, thus degrading the image quality. POCS-ICE has a stable convergence a...

journal_title：Magnetic resonance in medicine

authors： Hu Z,Ma X,Truong TK,Song AW,Guo H

更新日期：2017-07-01 00:00:00

abstract：:Measurements of the volume magnetic susceptibility of solids using the classical Gouy balance approach are hampered by variations in apparent density of the packed powder. In this paper a quantitative NMR measurement of the volume magnetic susceptibility of powdered solids is described and the volume susceptibility of...

journal_title：Magnetic resonance in medicine

authors： Hopkins JA,Wehrli FW

更新日期：1997-04-01 00:00:00

abstract：:To achieve optimal image quality and highest spatial resolution for inner ear imaging with a 3D gradient echo sequence, it is necessary to minimize susceptibility dephasing effects by using very short TE. Fractional RF pulses and echoes can yield short TE for moderate spatial resolution; however, for voxel size of les...

journal_title：Magnetic resonance in medicine

authors： Ying K,Schmalbrock P,Clymer B

更新日期：1995-01-01 00:00:00

abstract：:For patients with impaired breath-hold capacity and/or arrhythmias, real-time cine MRI may be more clinically useful than breath-hold cine MRI. However, commercially available real-time cine MRI methods using parallel imaging typically yield relatively poor spatio-temporal resolution due to their low image acquisition...

journal_title：Magnetic resonance in medicine

authors： Feng L,Srichai MB,Lim RP,Harrison A,King W,Adluru G,Dibella EV,Sodickson DK,Otazo R,Kim D

更新日期：2013-07-01 00:00:00

abstract：:The incorporation of RF coils into the tips of intravascular devices has been shown to enable the localization of catheters and guidewires under MR guidance. Furthermore, such coils can be used for endoluminal imaging. The long cable required to connect the coil with the scanner input inadvertently acts as a dipole an...

journal_title：Magnetic resonance in medicine

authors： Ladd ME,Quick HH

更新日期：2000-04-01 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：:Quantitative estimation of T1 is a challenging but important task inherent to many clinical applications. The most commonly used paradigm for estimating T1 in vivo involves performing a sequence of spoiled gradient-recalled echo acquisitions at different flip angles, followed by fitting of an exponential model to the ...

journal_title：Magnetic resonance in medicine

authors： Trzasko JD,Mostardi PM,Riederer SJ,Manduca A

更新日期：2013-06-01 00:00:00

abstract：PURPOSE:Spiral-based trajectories for magnetic resonance imaging can be advantageous, but are often cumbersome to design or create. This work presents a flexible numerical algorithm for designing trajectories based on explicit definition of radial undersampling, and also gives several analytical expressions for charact...

journal_title：Magnetic resonance in medicine

authors： Pipe JG,Zwart NR

更新日期：2014-01-01 00:00:00

abstract：:In this study, a spin- and gradient-echo echo-planar imaging (SAGE EPI) MRI pulse sequence is presented that allows simultaneous measurements of gradient-echo and spin-echo dynamic susceptibility-contrast perfusion-weighted imaging data. Following signal excitation, five readout trains were acquired using spin- and gr...

journal_title：Magnetic resonance in medicine

authors： Schmiedeskamp H,Straka M,Newbould RD,Zaharchuk G,Andre JB,Olivot JM,Moseley ME,Albers GW,Bammer R

更新日期：2012-07-01 00:00:00

abstract：:Developing a method to noninvasively monitor tissue-engineered constructs is critical for the optimization of construct design and for assessing therapeutic efficacy. For this purpose, NMR is a powerful technique that can be used to obtain both images and spectroscopic data. But the inherent sensitivity of NMR limits ...

journal_title：Magnetic resonance in medicine

authors： Volland NA,Mareci TH,Constantinidis I,Simpson NE

更新日期：2010-04-01 00:00:00

abstract：PURPOSE:To analyze the effect of B0 field drift on multivoxel MR spectroscopic imaging and to propose an approach for its correction. THEORY AND METHODS:It is shown, both theoretically and in a phantom, that for ∼30 min acquisitions a linear B0 drift (∼0.1 ppm/h) will cause localization errors that can reach several v...

journal_title：Magnetic resonance in medicine

authors： Tal A,Gonen O

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:To improve the imaging quality of vessel walls with an endoesophageal Wireless Amplified NMR Detector (WAND). METHODS:A cylindrically shaped double-frequency resonator has been constructed with a single metal wire that is self-connected by a pair of nonlinear capacitors. The double-frequency resonator can conv...

journal_title：Magnetic resonance in medicine

authors： Zeng X,Barbic M,Chen L,Qian C

更新日期：2017-11-01 00:00:00

abstract：:Nonlinear feedback interactions have been shown to amplify contrast due to small differences in resonance frequency arising from microscopic susceptibility variations. Determining whether the selectivity of feedback-based contrast enhancement for small resonance frequency variations remains valid even in the presence ...

journal_title：Magnetic resonance in medicine

authors： Huang SY,Yang SS,Lin YY

更新日期：2009-04-01 00:00:00

abstract：:Cortical spreading depression (CSD) was visualized using manganese-enhanced MRI (MEMRI) following topical application of KCl to the exposed rat cortex. MEMRI signal increase in the ipsilateral cortex relative to the contralateral control region was 60 +/- 30% following two KCl applications. MEMRI signal increase for a...

journal_title：Magnetic resonance in medicine

authors： Henning EC,Meng X,Fisher M,Sotak CH

更新日期：2005-04-01 00:00:00

abstract：:A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (3He) MRI has been developed. The method employs the build-up of the signal intensity after a variable number of (3)He breaths. A mathematical model of the signal dynamics is presented, from which the local ve...

journal_title：Magnetic resonance in medicine

authors： Deninger AJ,Månsson S,Petersson JS,Pettersson G,Magnusson P,Svensson J,Fridlund B,Hansson G,Erjefeldt I,Wollmer P,Golman K

更新日期：2002-08-01 00:00:00

abstract：PURPOSE:To develop a deep learning-based Bayesian estimation for MRI reconstruction. METHODS:We modeled the MRI reconstruction problem with Bayes's theorem, following the recently proposed PixelCNN++ method. The image reconstruction from incomplete k-space measurement was obtained by maximizing the posterior possibili...

journal_title：Magnetic resonance in medicine

authors： Luo G,Zhao N,Jiang W,Hui ES,Cao P

更新日期：2020-10-01 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：:For perfusion-based functional magnetic resonance imaging, the previously introduced flow-sensitive alternating inversion recovery (FAIR) technique is combined with single-shot RARE (rapid acquisition with relaxation enhancement) and GRASE (gradient and spin echo) imaging sequences. The advantages of these sequences c...

journal_title：Magnetic resonance in medicine

authors： Crelier GR,Hoge RD,Munger P,Pike GB

更新日期：1999-01-01 00:00:00

abstract：:Combined MRI and 3D spectroscopic imaging (MRI/3D-MRSI) was used to study the metabolic effects of hormone-deprivation therapy in 65 prostate cancer patients, who underwent either short, intermediate, or long-term therapy, compared to 30 untreated control patients. There was a significant time-dependent loss of the pr...

journal_title：Magnetic resonance in medicine

authors： Mueller-Lisse UG,Swanson MG,Vigneron DB,Hricak H,Bessette A,Males RG,Wood PJ,Noworolski S,Nelson SJ,Barken I,Carroll PR,Kurhanewicz J

更新日期：2001-07-01 00:00:00

abstract：:Unusually high image contrast in vivo magnetic resonance imaging of the brain becomes observable at high magnetic fields when the blood oxygenation level is lowered. The cause of the contrast has been attributed to a magnetic susceptibility effect induced by paramagnetic deoxyhemoglobin in red cells. When the cylinder...

journal_title：Magnetic resonance in medicine

authors： Ogawa S,Lee TM

更新日期：1990-10-01 00:00:00

abstract：PURPOSE:The heterogeneous tumor cell population and dynamic microenvironment within a tumor lead to regional variations in cell proliferation, migration, and differentiation. In this work, MRI and optical projection tomography were used to examine and compare the redistribution of a cellular label in two mouse glioma m...

journal_title：Magnetic resonance in medicine

authors： Gazdzinski LM,Nieman BJ

更新日期：2014-04-01 00:00:00

abstract：:Partial-volume effects (PVE) in stroke imaging could hinder proper delineation of normal, ischemic, and at-risk tissues. Cerebral-blood-flow (CBF) and apparent diffusion coefficient (ADC) were measured at high and low resolution (HR = 128 x 128, LR = 64 x 64) in focal ischemia in rats during the acute phase. The data ...

journal_title：Magnetic resonance in medicine

authors： Ren H,Shen Q,Bardutzky J,Fisher M,Duong TQ

更新日期：2004-12-01 00:00:00