Effect of distortion corrections on the tractography quality in spinal cord diffusion-weighted imaging.

abstract：PURPOSE:Multi-slice radiofrequency (RF) pulses have higher specific absorption rates, more peak RF power, and longer pulse durations than single-slice RF pulses. Gradient field design techniques using a z-gradient array are investigated for exciting multiple slices with a single-band RF pulse. THEORY AND METHODS:Two d...

journal_title：Magnetic resonance in medicine

authors： Ertan K,Taraghinia S,Sadeghi A,Atalar E

更新日期：2018-07-01 00:00:00

abstract：:Electron paramagnetic resonance imaging using nitroxides is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. Typically, however, data acquisition times have been too slow to obtain a sufficient number of projections for three-dimensional images, when using continuous wave-elect...

journal_title：Magnetic resonance in medicine

authors： Fujii H,Sato-Akaba H,Kawanishi K,Hirata H

更新日期：2011-01-01 00:00:00

abstract：:Intra-plaque hemorrhage (IPH) and lipid core, characteristics of rupture prone carotid plaques, are often visualized in vivo with MRI using T1 weighted gradient and spin echo, respectively. Increasing magnetic field strength may help to identify IPH and lipid core better. As a proof of concept, automatic segmentation ...

journal_title：Magnetic resonance in medicine

authors： te Boekhorst BC,van 't Klooster R,Bovens SM,van de Kolk KW,Cramer MJ,van Oosterhout MF,Doevendans PA,van der Geest RJ,Pasterkamp G,van Echteld CJ

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a fast protocol for measuring T1 values in the internal carotid artery (ICA), to validate this technique with in vitro measurements, and to evaluate its reproducibility. METHODS:A modified Look-Locker sequence was optimized to enable rapid determination of T1 in the ICA at 3T. T1 values from the ICA...

journal_title：Magnetic resonance in medicine

authors： Li W,Liu P,Lu H,Strouse JJ,van Zijl PCM,Qin Q

更新日期：2017-06-01 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：PURPOSE:Human connectomics necessitates high-throughput, whole-brain reconstruction of multiple white matter fiber bundles. Scaling up tractography to meet these high-throughput demands yields new fiber tracking challenges, such as minimizing spurious connections and controlling for gyral biases. The aim of this study ...

journal_title：Magnetic resonance in medicine

authors： Sarwar T,Ramamohanarao K,Zalesky A

更新日期：2019-02-01 00:00:00

abstract：:The utility of a noninvasive steady state susceptibility-contrast MRI technique for continuous measurement of relative cerebral blood volume (rCBV) during global transient ischemia and subsequent hyperemia in a feline ischemia model is demonstrated. The measurements were obtained during a 10-min period of occlusion an...

journal_title：Magnetic resonance in medicine

authors： Hamberg LM,Boccalini P,Stranjalis G,Hunter GJ,Huang Z,Halpern E,Weisskoff RM,Moskowitz MA,Rosen BR

更新日期：1996-02-01 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：:Time-resolved three-dimensional phase-contrast MRI is an important tool for physiological as well as clinical studies of blood flow in the heart and vessels. The application of the technique is, however, limited by the long scan times required. In this work, we investigate the feasibility of using spiral readouts to r...

journal_title：Magnetic resonance in medicine

authors： Sigfridsson A,Petersson S,Carlhäll CJ,Ebbers T

更新日期：2012-10-01 00:00:00

abstract：:The aim of this study was to quantify changes in thoracic aortic wall shear stress (WSS) in asymptomatic patients with Marfan syndrome (MFS) compared with healthy controls. WSS in the thoracic aorta was quantified based on time-resolved 3D phase contrast MRI with three-directional velocity encoding (4D flow MRI, tempo...

journal_title：Magnetic resonance in medicine

authors： Geiger J,Arnold R,Herzer L,Hirtler D,Stankovic Z,Russe M,Langer M,Markl M

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:To design hyperbolic secant (HS) excitation pulses to reduce signal dropout in the orbitofrontal and inferior temporal regions in gradient-echo echo-planar imaging (GE-EPI) for functional MRI (fMRI) applications. METHODS:An algorithm based on Bloch simulations optimizes the HS pulse parameters needed to give t...

journal_title：Magnetic resonance in medicine

authors： Wastling SJ,Barker GJ

更新日期：2015-09-01 00:00:00

abstract：PURPOSE:To develop a modular magnetization preparation sequence for combined T2 -preparation and multidimensional outer volume suppression (OVS) for coronary artery imaging. METHODS:A combined T2 -prepared 1D OVS sequence with fat saturation was defined to contain a 90°-60 180°60 composite nonselective tip-down pulse,...

journal_title：Magnetic resonance in medicine

authors： Zeng DY,Baron CA,Malavé MO,Kerr AB,Yang PC,Hu BS,Nishimura DG

更新日期：2020-06-01 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：:For diffusion-weighted magnetic resonance imaging and under circumstances where patient movement can be modeled as rigid body motion, it is shown both theoretically and experimentally that translations and rotations produce phase errors which are zero- and first-order, respectively, in position. While a navigator echo...

journal_title：Magnetic resonance in medicine

authors： Anderson AW,Gore JC

更新日期：1994-09-01 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: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:The diseased myocardium lacks metabolic flexibility and responds to stimuli differently compared with healthy hearts. Here, we report the use of hyperpolarized 13C NMR spectroscopy to detect sudden changes in cardiac metabolism in isolated, perfused rat hearts in response to adrenergic stimulation. METHODS:Met...

journal_title：Magnetic resonance in medicine

authors： Khemtong C,Carpenter NR,Lumata LL,Merritt ME,Moreno KX,Kovacs Z,Malloy CR,Sherry AD

更新日期：2015-08-01 00:00:00

abstract：PURPOSE:Phosphorus spectroscopy (31 P-MRS) is a proven method to probe cardiac energetics. Studies typically report the phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. We focus on another 31 P signal: inorganic phosphate (Pi), whose chemical shift allows computation of myocardial pH, with Pi/PCr providing ...

journal_title：Magnetic resonance in medicine

authors： Apps A,Valkovič L,Peterzan M,Lau JYC,Hundertmark M,Clarke W,Tunnicliffe EM,Ellis J,Tyler DJ,Neubauer S,Rider OJ,Rodgers CT,Schmid AI

更新日期：2021-03-01 00:00:00

abstract：:Three-dimensional magnetization-prepared (MP) MR angiography (MRA) was applied to the carotid and vertebral arteries by using ECG triggering, a slab selective RF inversion pulse, centric phase encoding and acquisition during diastole. Both theoretically and experimentally, the MP MRA sequence was shown to perform well...

journal_title：Magnetic resonance in medicine

authors： Wilman AH,Huston J 3rd,Riederer SJ

更新日期：1997-02-01 00:00:00

abstract：:This article describes an EPR spectrometer specifically designed and constructed for EPR spectroscopy in humans. The spectrometer is based on a permanent magnet, suitable for measurements at 1200 MHz. The magnet has a full 50 cm gap between the poles, which facilitates accurate and comfortable placement of the subject...

journal_title：Magnetic resonance in medicine

authors： Salikhov I,Walczak T,Lesniewski P,Khan N,Iwasaki A,Comi R,Buckey J,Swartz HM

更新日期：2005-11-01 00:00:00

abstract：:A novel linear parameterization for the variable flip angle method for longitudinal relaxation time T(1) quantification from spoiled steady state MRI is derived from the half angle tangent transform, τ, of the flip angle. Plotting the signal S at coordinates x=Sτ and y=S/τ, respectively, establishes a line that render...

journal_title：Magnetic resonance in medicine

authors： Helms G,Dathe H,Weiskopf N,Dechent P

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:The goal of this work was to detect disease-related microstructural changes to the liver using magnetic resonance imaging. Chronic liver disease can cause microstructural changes in the liver that reduce plasma access to the perisinusoidal space--the site of exchange between the blood plasma and the hepatic par...

journal_title：Magnetic resonance in medicine

authors： Beeman SC,Mandarino LJ,Georges JF,Bennett KM

更新日期：2013-12-01 00:00:00

abstract：:A novel multislice B₁-mapping method dubbed dual refocusing echo acquisition mode is proposed, able to cover the whole transmit coil volume in only one second, which is more than an order of magnitude faster than established approaches. The dual refocusing echo acquisition mode technique employs a stimulated echo acqu...

journal_title：Magnetic resonance in medicine

authors： Nehrke K,Börnert P

更新日期：2012-11-01 00:00:00

abstract：:In proton magnetic resonance imaging (MRI) metallic substances lead to magnetic field distortions that often result in signal voids in the adjacent anatomic structures. Thus, metallic objects and superparamagnetic iron oxide (SPIO)-labeled cells appear as hypointense artifacts that obscure the underlying anatomy. The ...

journal_title：Magnetic resonance in medicine

authors： Stuber M,Gilson WD,Schär M,Kedziorek DA,Hofmann LV,Shah S,Vonken EJ,Bulte JW,Kraitchman DL

更新日期：2007-11-01 00:00:00

abstract：:Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) was used to assess the temporal changes of high-energy phosphate metabolites in the region of acute myocardial ischemia of open-chest cats. Eight anesthetized cats were studied following ligation of the left anterior descending coronary artery. Creatine p...

journal_title：Magnetic resonance in medicine

authors： Stein PD,Goldstein S,Sabbah HN,Liu ZQ,Helpern JA,Ewing JR,Lakier JB,Chopp M,LaPenna WF,Welch KM

更新日期：1986-04-01 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：:Successful radiofrequency (RF) thermal ablation was performed on VX2 tumors implanted in 23 rabbit livers under magnetic resonance (MR) guidance using a C-arm-shaped low-field 0.2 T system. RF application and immediate postprocedure MRI of all animals was performed [T2-weighted, turbo short tau inversion recovery (STI...

journal_title：Magnetic resonance in medicine

authors： Merkle EM,Boll DT,Boaz T,Duerk JL,Chung YC,Jacobs GH,Varnes ME,Lewin JS

更新日期：1999-07-01 00:00:00

abstract：:A magnetic resonance imaging (MRI) method is presented to detect, localize, and quantify myocardial kinematics by measuring the material rate-of-strain tensor at each pixel in gated NMR images of the heart. The immediate, local effect of muscular activity is self-deformation, and the strain tensor is the basic mathema...

journal_title：Magnetic resonance in medicine

authors： Wedeen VJ

更新日期：1992-09-01 00:00:00

abstract：:The echo-planar k-space trajectory can be used as the basis for any two-dimensional selective pulse. The main application is spectral-spatial pulses, which must be based on the echo-planar trajectory. In this paper we show how echo-planar spin-echo (EPSE) pulses may be designed. ...

journal_title：Magnetic resonance in medicine

authors： Pauly J,Spielman D,Macovski A

更新日期：1993-06-01 00:00:00