A high-field superferric NMR magnet.

abstract：:Fractional anisotropy (FA) and relative anisotropy (RA) are the two most commonly used scalar measures of anisotropy in diffusion tensor (DT) MRI. While a few published studies have shown that FA has superior noise immunity relative to RA, no theoretical basis has been proposed to explain this behavior. In the current...

journal_title：Magnetic resonance in medicine

authors： Hasan KM,Alexander AL,Narayana PA

更新日期：2004-02-01 00:00:00

abstract：:Focused ultrasound heating of ex vivo bovine kidney and liver was monitored using magnetic resonance imaging (MRI) to investigate the quantitative relationship between time-dependent temperature elevations and altered contrast in MR images due to thermal coagulation. Proton resonance frequency shift MR thermometry was...

journal_title：Magnetic resonance in medicine

authors： Graham SJ,Chen L,Leitch M,Peters RD,Bronskill MJ,Foster FS,Henkelman RM,Plewes DB

更新日期：1999-02-01 00:00:00

abstract：:Direct measurement of neural currents by means of MRI can potentially open a high temporal resolution (10-100 ms) window applicable for monitoring dynamics of neuronal activity without loss of the high spatial resolution afforded by MRI. Previously, we have shown that the alternating balanced steady state imaging affo...

journal_title：Magnetic resonance in medicine

authors： Buračas GT,Jung Y,Lee J,Buxton RB,Wong EC,Liu TT

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:Delta relaxation enhanced magnetic resonance (dreMR) imaging requires an auxiliary B0 electromagnet capable of shifting the main magnetic field within a clinical 1.5 Tesla (T) MR system. In this work, the main causes of interaction between an actively shielded, insertable resistive B0 electromagnet and a 1.5T s...

journal_title：Magnetic resonance in medicine

authors： Harris CT,Handler WB,Araya Y,Martínez-Santiesteban F,Alford JK,Dalrymple B,Van Sas F,Chronik BA,Scholl TJ

更新日期：2014-10-01 00:00:00

abstract：:This work presents a method applied to the design of short self-shielded gradient coils of cylindrical geometry. The method uses a hybrid technique that combines the simulated annealing and target field methods to optimize the standard stream functions. The optimized stream functions were parameterized using a few deg...

journal_title：Magnetic resonance in medicine

authors： Tomasi D

更新日期：2001-03-01 00:00:00

abstract：PURPOSE:To develop a pulsed CEST magnetization-transfer method for rapidly acquiring relayed nuclear Overhauser enhancement (rNOE)-weighted images with magnetic transfer contrast (MTC) suppression at clinical field strength (3 T). METHODS:Using a pulsed CEST magnetization-transfer method with low saturation powers (B1...

journal_title：Magnetic resonance in medicine

authors： Huang J,Han X,Chen L,Xu X,Xu J,Chan KWY

更新日期：2021-01-01 00:00:00

abstract：PURPOSE:To introduce a multiplatform, Python language-based, development environment called graphical programming interface for prototyping MRI techniques. METHODS:The interface allows developers to interact with their scientific algorithm prototypes visually in an event-driven environment making tasks such as paramet...

journal_title：Magnetic resonance in medicine

authors： Zwart NR,Pipe JG

更新日期：2015-11-01 00:00:00

abstract：:Cervical spinal cord spectroscopy has the potential to add metabolic information to spinal cord MRI and improve the clinical evaluation and research investigation of spinal cord diseases, such as multiple sclerosis (MS) and intraspinal tumors. However, in vivo proton MR spectroscopy ((1)H-MRS) of the spinal cord is di...

journal_title：Magnetic resonance in medicine

authors： Marliani AF,Clementi V,Albini-Riccioli L,Agati R,Leonardi M

更新日期：2007-01-01 00:00:00

abstract：PURPOSE:The feasibility of imaging musculoskeletal fibrous tissue components, such as menisci, ligaments, and tendons, with a conventional spoiled gradient echo technique is explored in vivo at 3 T and 7 T. METHODS:To this end, the echo time (TE1 ) of a conventional Fourier-encoded multicontrast three-dimensional SGPR...

journal_title：Magnetic resonance in medicine

authors： Deligianni X,Bär P,Scheffler K,Trattnig S,Bieri O

更新日期：2013-11-01 00:00:00

abstract：:Steady-state free precession (SSFP) methods have gained widespread recognition for their ability to provide fast scans at high signal-to-noise ratio. This paper demonstrates that such methods are also capable of reflecting functional information, particularly blood oxygenation state. It is well known that SSFP signals...

journal_title：Magnetic resonance in medicine

authors： Dharmakumar R,Hong J,Brittain JH,Plewes DB,Wright GA

更新日期：2005-03-01 00:00:00

abstract：:New algorithms for correlation analysis are presented that allow the mapping of brain activity from functional MRI (fMRI) data in real time during the ongoing scan. They combine the computation of the correlation coefficients between measured fMRI time-series data and a reference vector with "detrending", a technique ...

journal_title：Magnetic resonance in medicine

authors： Gembris D,Taylor JG,Schor S,Frings W,Suter D,Posse S

更新日期：2000-02-01 00:00:00

abstract：PURPOSE:To directly compare in vivo versus postmortem second-order motion-compensated spin-echo diffusion tensor imaging of the porcine heart. METHODS:Second-order motion-compensated spin-echo cardiac diffusion tensor imaging was performed during systolic contraction in vivo and repeated upon cardiac arrest by bariumc...

journal_title：Magnetic resonance in medicine

authors： Stoeck CT,von Deuster C,Fleischmann T,Lipiski M,Cesarovic N,Kozerke S

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:To examine the detection sensitivity for the rapidly exchanging hydroxyl protons of D-glucose using the recently developed on-resonance variable delay multi-pulse (onVDMP) chemical exchange saturation transfer (CEST) technique. METHODS:The onVDMP method was applied for the detection of water signal changes upo...

journal_title：Magnetic resonance in medicine

authors： Xu X,Xu J,Chan KWY,Liu J,Liu H,Li Y,Chen L,Liu G,van Zijl PCM

更新日期：2019-01-01 00:00:00

abstract：:A novel and automated technique is described for removing fMRI image artifacts resulting from motion outside of the imaging field of view. The technique is based on the Stockwell transform (ST), a mathematical operation that provides the frequency content at each time point within a time-varying signal. Using this tec...

journal_title：Magnetic resonance in medicine

authors： Goodyear BG,Zhu H,Brown RA,Mitchell JR

更新日期：2004-01-01 00:00:00

abstract：:Optimal control theory has been applied in the past for the design of RF pulses for selective excitation. This was the outcome of having established the controllability of the MR spin system for the selective excitation problem. "Minimum distance" was the main formulation used for the solution. Because of their robust...

journal_title：Magnetic resonance in medicine

authors： Rosenfeld D,Zur Y

更新日期：1996-09-01 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

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：:Metallic particles have shaped the use of magnetic resonance imaging (MRI) for molecular and cellular imaging. Although these particles have generally been developed for extracellular residence, either as blood pool contrast agents or targeted contrast agents, the coopted use of these particles for intracellular label...

journal_title：Magnetic resonance in medicine

authors： Shapiro EM

更新日期：2015-01-01 00:00:00

abstract：:Diffusion-weighted imaging (DWI) is frequently used to diagnose stroke. However, the origin of the observed reduction in the apparent diffusion coefficient (ADC) in the acute phase following ischemia is not well understood. Although cell swelling is considered to play an important role, it is unclear whether this can ...

journal_title：Magnetic resonance in medicine

authors： van Pul C,Jennekens W,Nicolay K,Kopinga K,Wijn PF

更新日期：2005-02-01 00:00:00

abstract：:Pattern recognition techniques (factor analysis and neural networks) were used to investigate and classify human brain tumors based on the 1H NMR spectra of chemically extracted biopsies (n = 118). After removing information from lactate (because of variable ischemia times), unsupervised learning suggested that the sp...

journal_title：Magnetic resonance in medicine

authors： Maxwell RJ,Martínez-Pérez I,Cerdán S,Cabañas ME,Arús C,Moreno A,Capdevila A,Ferrer E,Bartomeus F,Aparicio A,Conesa G,Roda JM,Carceller F,Pascual JM,Howells SL,Mazucco R,Griffiths JR

更新日期：1998-06-01 00:00:00

abstract：:A planar YBa2Cu3Ox (YBCO) coil has been used as a pick-up coil in a nuclear magnetic resonance imager. It was found that the quality factor (Q) of the YBCO coil was greater than its copper counterpart by approaching 50% even in a field of 0.15 T. The Q of the copper coil at 77 K and in a field of 0.15 T was 1200 while...

journal_title：Magnetic resonance in medicine

authors： Hall AS,Alford NM,Button TW,Gilderdale DJ,Gehring KA,Young IR

更新日期：1991-08-01 00:00:00

abstract：:A three-axis uniplanar gradient coil was designed and built to provide order-of-magnitude increases in gradient strength of up to 500 mT/m on the x- and y-axes, and 1000 mT/m for the z-axis at 640 A input over a limited FOV ( approximately 16 cm) for superficial regions, compared to conventional gradient coils, with s...

journal_title：Magnetic resonance in medicine

authors： Aksel B,Marinelli L,Collick BD,Von Morze C,Bottomley PA,Hardy CJ

更新日期：2007-07-01 00:00:00

abstract：:The vascular space occupancy (VASO) method was recently proposed as a functional MRI (fMRI) method that is capable of detecting activation-related changes in blood volume (CBV), without the need for a blood-pool contrast agent. In the present work we introduce a new whole-brain VASO technique that is based on a parall...

journal_title：Magnetic resonance in medicine

authors： Poser BA,Norris DG

更新日期：2009-07-01 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 develop and evaluate a method for RF envelope correction without extra hardware or synchronization. METHODS:Transmitted RF waveforms are measured through a simple pulse sequence called the gradient reversal approach to evaluate RF (GRATER). The measured RF waveforms are used to compute predistorted RF wavef...

journal_title：Magnetic resonance in medicine

authors： Landes VL,Nayak KS

更新日期：2020-01-01 00:00:00

abstract：:Reduction of image-to-image signal fluctuations and imaging artifacts is important for fMRI studies. The imaging artifacts caused by respiration, cardiac pulsation, and gross head motion and the suppression of these artifacts have been studied for many years. However, the artifacts caused by eye movement and their eff...

journal_title：Magnetic resonance in medicine

authors： Chen W,Zhu XH

更新日期：1997-10-01 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：:The eigenimage filter was used to evaluate the results of a MRI study of cerebral ischemia in a rat model. This linear filter segments a desired feature in an image sequence from other features which may interfere with its observation. The animals were imaged temporally, after occlusion of the middle cerebral artery, ...

journal_title：Magnetic resonance in medicine

authors： Peck DJ,Spickler EM,Knight RA,Hearshen DO,Windham JP

更新日期：1992-08-01 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：:A method is presented for the detection of quadrupole splitting in tissue, where the spectral line splittings are typically unobservable. The method used is a study of the rate of rotation of the flip angle as a function of radiofrequency (rf) amplitude. Our results with samples of skeletal muscle and cat brain indica...

journal_title：Magnetic resonance in medicine

authors： Joseph PM,Summers RM

更新日期：1987-01-01 00:00:00