3T MR of the prostate: reducing susceptibility gradients by inflating the endorectal coil with a barium sulfate suspension.

abstract：:Functional MRI (fMRI) by means of spin-echo (SE) techniques provides an interesting alternative to gradient-echo methods because the contrast is based primarily on dynamic averaging associated with the blood oxygenation level-dependent (BOLD) effect. In this article the contributions from different brain compartments ...

journal_title：Magnetic resonance in medicine

authors： Jochimsen TH,Norris DG,Mildner T,Möller HE

更新日期：2004-10-01 00:00:00

abstract：:Homogeneous soft tissue, as regards its magnetic relaxation properties, is well-modeled by solutions of cross-linked protein (see Koenig and Brown, Prog. NMR Spectr. 22, 487 (1991)). Interactions at the solute-solvent interface alter the hydrodynamics of solvent water, and also couple the solute and solvent proton Zee...

journal_title：Magnetic resonance in medicine

authors： Koenig SH,Brown RD 3rd

更新日期：1993-12-01 00:00:00

abstract：:A method for the acquisition of localized 2D shift-correlated spectra, based on the combination of the stimulated-echo volume-selection and gradient-enhanced COSY experiments, is described. The sequence can be modified to perform a number of localized experiments including HOHAHA and DQF-COSY. The method is demonstrat...

journal_title：Magnetic resonance in medicine

authors： Brereton IM,Galloway GJ,Rose SE,Doddrell DM

更新日期：1994-08-01 00:00:00

abstract：:NMR relaxation times (T1 and T2) and the water content (WC) of in vitro rat lungs were measured during the course of endotoxin lung injury in rats. Measurements of normal lungs, untreated endotoxin-injured lungs, and endotoxin-injured lungs treated with methylprednisolone (MPSL) were compared. The untreated endotoxin ...

journal_title：Magnetic resonance in medicine

authors： Shioya S,Haida M,Tsuji C,Ono Y,Miyairi A,Fukuzaki M,Ohta Y,Yamabayashi H

更新日期：1990-08-01 00:00:00

abstract：PURPOSE:To develop a practical method for mapping macromolecule distribution in the brain using ultrashort-TE MRSI data. METHODS:An FID-based chemical shift imaging acquisition without metabolite-nulling pulses was used to acquire ultrashort-TE MRSI data that capture the macromolecule signals with high signal-to-noise...

journal_title：Magnetic resonance in medicine

authors： Lam F,Li Y,Clifford B,Liang ZP

更新日期：2018-05-01 00:00:00

abstract：:A single slice of z-magnetization is used to generate high-speed images. The slice selection step is achieved using two sin-sinc pulses. This procedure eliminates the need for continual slice gradient reversal, a requirement for the FLASH technique. The RAPID imaging method has less inherent T1 and/or T2 dependence th...

journal_title：Magnetic resonance in medicine

authors： Brooks WM,Brereton IM,Doddrell DM

更新日期：1987-08-01 00:00:00

abstract：:A precise understanding of human blood spin-spin relaxation is of major importance for numerous applications, particularly functional magnetic resonance imaging (fMRI), which is increasingly performed at 3 Tesla. It is well known that T2 measured from partially deoxygenated blood depends on the Carr-Purcell Meiboom-Gi...

journal_title：Magnetic resonance in medicine

authors： Chen JJ,Pike GB

更新日期：2009-02-01 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：:MRI has become an important tool to noninvasively assess global and regional cardiac function, infarct size, or myocardial blood flow in surgically or genetically modified mouse models of human heart disease. Constraints on scan time due to sensitivity to general anesthesia in hemodynamically compromised mice frequent...

journal_title：Magnetic resonance in medicine

authors： Schneider JE,Lanz T,Barnes H,Stork LA,Bohl S,Lygate CA,Ordidge RJ,Neubauer S

更新日期：2011-01-01 00:00:00

abstract：:Proton magnetic resonance spectroscopy ((1)H MRS) was used to determine brain temperature in healthy volunteers. Partially water-suppressed (1)H MRS data sets were acquired at 3T from four different gray matter (GM)/white matter (WM) volumes. Brain temperatures were determined from the chemical-shift difference betwee...

journal_title：Magnetic resonance in medicine

authors： Childs C,Hiltunen Y,Vidyasagar R,Kauppinen RA

更新日期：2007-01-01 00:00:00

abstract：PURPOSE:MR-based quantification of liver magnetic susceptibility may enable field strength-independent measurement of liver iron concentration (LIC). However, susceptibility quantification is challenging, due to nonlocal effects of susceptibility on the B0 field. The purpose of this work is to demonstrate feasibility o...

journal_title：Magnetic resonance in medicine

authors： Hernando D,Cook RJ,Diamond C,Reeder SB

更新日期：2013-09-01 00:00:00

abstract：:An array of 33 prototype polypeptides was examined as putative contrast agents that can be distinguished from each other based on the chemical exchange saturation transfer (CEST) mechanism. These peptides were chosen based on predictions of the chemical exchange rates of exchangeable amide, amine, and hydroxyl protons...

journal_title：Magnetic resonance in medicine

authors： McMahon MT,Gilad AA,DeLiso MA,Berman SM,Bulte JW,van Zijl PC

更新日期：2008-10-01 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：:Hyperpolarized 129Xe has been used to obtain gas phase images of mouse lung in vivo, showing distinct ventilation variation as a function of the breathing cycle. Spectra of 129Xe in the thorax show complex structure in both the gas phase (-4 to 3 ppm) and tissue-dissolved (190-205 ppm) regions. The alveolar gas peak s...

journal_title：Magnetic resonance in medicine

authors： Wagshul ME,Button TM,Li HF,Liang Z,Springer CS,Zhong K,Wishnia A

更新日期：1996-08-01 00:00:00

abstract：:We present preliminary results for a 3D finite element calculation to evaluate RF penetration in conducting dielectric materials at high field strengths. A tetrahedral mesh is used along with a Coulomb gauge constraint in a finite element method that yields excellent numerical stability at high frequencies. Accuracy i...

journal_title：Magnetic resonance in medicine

authors： Petropoulos LS,Haacke EM,Brown RW,Boerner E

更新日期：1993-09-01 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：:An effective shield for the dc fringing fields produced by a large-bore, high field magnet intended for imaging and in vivo spectroscopy is presented. While limiting the extent of fringe fields, the shield has little effect on the homogeneity of the central field of the magnet. The effect of institutional safety polic...

journal_title：Magnetic resonance in medicine

authors： Ewing JR,Timms W,Williams JE,Welch KM

更新日期：1985-10-01 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：:Experimental procedures for obtaining localized 31P NMR spectra of humans by means of the ISIS sequence are discussed in detail. The technique is optimized for use with volume coils and with surface coils in order to measure localized 31P NMR spectra of different tissues and organs. Selective frequency-modulated (FM) ...

journal_title：Magnetic resonance in medicine

authors： Luyten PR,Groen JP,Vermeulen JW,den Hollander JA

更新日期：1989-07-01 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：:Longitudinal and transverse relaxation rates for the 11B resonances in sodium borocaptate (BSH) at varying concentrations were measured in undiluted horse serum in a 4.7 Tesla field. The results could be fit by a model that assumes fast exchange of the BSH molecule between a free and a bound state, using values of 0.7...

journal_title：Magnetic resonance in medicine

authors： Bendel P,Frantz A,Zilberstein J,Kabalka GW,Salomon Y

更新日期：1998-03-01 00:00:00

abstract：:Lactate is a key metabolite and its rates of cellular uptake and release, its production rates from glucose and glycogen, and its interconversion rate with pyruvate are important determinants of cellular energy production. If lactate precursors such as pyruvate and glucose are labeled appropriately with (13)C, (1)H NM...

journal_title：Magnetic resonance in medicine

authors： Lloyd SG,Zeng H,Wang P,Chatham JC

更新日期：2004-06-01 00:00:00

abstract：:In active catheter tracking, small RF coils are attached to the catheter for localization. For interactive catheter steering at vessel branchings, it is necessary to visualize not only a single point near the catheter tip but also the entire shape and orientation of the catheter's distal end. Therefore, a 35-mm-long t...

journal_title：Magnetic resonance in medicine

authors： Zuehlsdorff S,Umathum R,Volz S,Hallscheidt P,Fink C,Semmler W,Bock M

更新日期：2004-07-01 00:00:00

abstract：:Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a ...

journal_title：Magnetic resonance in medicine

authors： Weber OM,Martin AJ,Higgins CB

更新日期：2003-12-01 00:00:00

abstract：:Diffusion tensor imaging enables in vivo investigation of tissue cytoarchitecture through parameter contrasts sensitive to water diffusion barriers at the micrometer level. Parameters are derived through an estimation process that is susceptible to noise and artifacts. Estimated parameters (e.g., fractional anisotropy...

journal_title：Magnetic resonance in medicine

authors： Lauzon CB,Crainiceanu C,Caffo BC,Landman BA

更新日期：2013-03-01 00:00:00

abstract：PURPOSE:Parameter mapping in sodium MRI data is challenging due to inherently low SNR and spatial resolution, prompting the need to employ robust models and estimation techniques. This work aims to develop a continuum model of sodium T 2 ...

journal_title：Magnetic resonance in medicine

authors： Syeda W,Blunck Y,Kolbe S,Cleary JO,Johnston LA

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:To develop and demonstrate the feasibility of a new technique for respiratory-gated, fat-suppressed, three-dimensional spoiled gradient-recalled echo (3D-SPGR) with navigator gating for more accurate and robust motion detection. METHODS:A navigator-gated 3D-SPGR technique was modified to include a wait period ...

journal_title：Magnetic resonance in medicine

authors： Iwadate Y,Brau AC,Vasanawala SS,Kabasawa H

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:A multi-turn transmit surface coil design was presented to improve B1 efficiency when used with current source amplification. METHODS:Three different coil designs driven by an on-coil current-mode class-D amplifier with current envelope feedback were tested on the benchtop and through imaging in a 1.5 T scanne...

journal_title：Magnetic resonance in medicine

authors： Gudino N,Griswold MA

更新日期：2013-04-01 00:00:00

abstract：:Experiments were performed to determine whether changes in T2*-weighted MR images during and after hyperoxia differentiate tumors from normal tissue. Mammary adenocarcinomas implanted in the right hind limbs of rats were studied. Gradient echo images were obtained at 2 Tesla with an evolution time of 20 ms and a recyc...

journal_title：Magnetic resonance in medicine

authors： Kuperman VYu,River JN,Lewis MZ,Lubich LM,Karczmar GS

更新日期：1995-03-01 00:00:00

abstract：:The goal of this work was to develop and evaluate a numerically optimized inversion pulse to be used with a homonuclear editing sequence to measure human cerebral GABA in vivo at 4.1 T in the occipital lobe. The optimized pulse was constructed using pallindromic symmetry with 30 pulses and 29 delays. The optimized pul...

journal_title：Magnetic resonance in medicine

authors： Hetherington HP,Newcomer BR,Pan JW

更新日期：1998-01-01 00:00:00