Cardiac perfusion imaging using hyperpolarized (13)C urea using flow sensitizing gradients.

abstract：:MRI of myocardial perfusion observed with an extracellular contrast agent has proven valuable for the detection of coronary artery disease. During contrast enhancement transient dark rim artifacts are sometimes visible, complicating diagnosis and quantification. In this work a quantification of the frequency offsets c...

journal_title：Magnetic resonance in medicine

authors： Ferreira P,Gatehouse P,Bucciarelli-Ducci C,Wage R,Firmin D

更新日期：2008-10-01 00:00:00

abstract：:Parallel imaging presents a promising approach for MRI of hyperpolarized nuclei, as the penalty in signal-to-noise ratio typically encountered with (1)H MRI due to a reduction in acquisition time can be offset by an increase in flip angle. The signal-to-noise ratio of hyperpolarized MRI generally exhibits a strong dep...

journal_title：Magnetic resonance in medicine

authors： Deppe MH,Parra-Robles J,Marshall H,Lanz T,Wild JM

更新日期：2011-12-01 00:00:00

abstract：:Vascular-space-occupancy (VASO) MRI exploits the difference between blood and tissue T1 to null blood signal and measure cerebral blood volume changes using the residual tissue signal. VASO imaging is more difficult at higher field because of sensitivity loss due to the convergence of tissue and blood T1 values and in...

journal_title：Magnetic resonance in medicine

authors： Hua J,Jones CK,Qin Q,van Zijl PC

更新日期：2013-04-01 00:00:00

abstract：:Rapid flow imaging was achieved with a partial field of view (pFOV) spiral motion-encoded technique. The FOV and the acquisition time were reduced by a factor of 2 by undersampling k-space. The pFOV spiral k-space trajectory aliased signals from outside a circular ring whose radius was inversely proportional to the di...

journal_title：Magnetic resonance in medicine

authors： Nezafat R,Thompson RB,Derbyshire JA,McVeigh ER

更新日期：2006-09-01 00:00:00

abstract：PURPOSE:To improve ultrahigh field diffusion-weighted imaging (DWI) in the presence of inhomogeneous transmit B1 field by designing a novel semi-adiabatic single-refocused DWI technique. METHODS:A 180° slice-selective, adiabatic radiofrequency (RF) pulse of 4 ms duration was designed using the adiabatic Shinnar-Le Rou...

journal_title：Magnetic resonance in medicine

authors： Dyvorne H,O'Halloran R,Balchandani P

更新日期：2016-05-01 00:00:00

abstract：:MR acoustic, or sound, noise due to gradient pulsing has been one of the problems in MRI, both in patient scanning as well as in many areas of psychiatric and neuroscience research, such as brain fMRI. Especially in brain fMRI, sound noise is one of the serious noise sources that obscures the small signals obtainable ...

journal_title：Magnetic resonance in medicine

authors： Cho ZH,Chung SC,Lim DW,Wong EK

更新日期：1998-02-01 00:00:00

abstract：:Generalized MR interferography allows the measurement of parameters which affect the phase of the MR signal. Interference is generated by the simultaneous generation of two echoes in one excitation cycle. Local variations of the signal phase are transformed into displacement of the stripe pattern generated by interfer...

journal_title：Magnetic resonance in medicine

authors： Hennig J

更新日期：1990-12-01 00:00:00

abstract：:A novel method for detecting neural activity in functional magnetic resonance imaging (fMRI) data is introduced. It is based on canonical correlation analysis (CCA), which is a multivariate extension of the univariate correlation analysis widely used in fMRI. To detect homogeneous regions of activity, the method combi...

journal_title：Magnetic resonance in medicine

authors： Friman O,Cedefamn J,Lundberg P,Borga M,Knutsson H

更新日期：2001-02-01 00:00:00

abstract：PURPOSE:To demonstrate the feasibility of imaging a bolus of co-polarized [1-13 C]pyruvate and 13 C-urea to simultaneously assess both metabolism and perfusion in the rodent heart. METHODS:Copolarized [1-13 C]pyruvate and 13 C-urea was imaged using a multi-echo, flow-sensitized spiral pulse sequence. Healthy rats were...

journal_title：Magnetic resonance in medicine

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

更新日期：2017-01-01 00:00:00

abstract：:Activity-induced manganese-dependent contrast (AIM) MRI is a hemodynamic-independent functional MRI method that used manganese ion as an MR-detectable contrast agent. In AIM, MnCl(2) is infused intra-arterially after the blood-brain barrier (BBB) is opened with a hyperosmolar agent. Upon functional stimulation of the ...

journal_title：Magnetic resonance in medicine

authors： Aoki I,Tanaka C,Takegami T,Ebisu T,Umeda M,Fukunaga M,Fukuda K,Silva AC,Koretsky AP,Naruse S

更新日期：2002-12-01 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：: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：:Phase contrast flow velocity measurements were performed in six healthy volunteers and 30 patients with arteriosclerotic disease. The iliac arteries were investigated in 8 cases and the femoral arteries in 28 cases. In the first 24 patients, 16 evenly distributed data sets were acquired during one cardiac cycle. In th...

journal_title：Magnetic resonance in medicine

authors： Krug B,Kugel H,Harnischmacher U,Heindel W,Schmidt R,Krings F

更新日期：1995-11-01 00:00:00

abstract：:A common type of motion present in clinical magnetic resonance imaging examinations is rotational motion, such as that due to voluntary motion during head examinations. The correction scheme presented in this work offers a method for eliminating the effects of rotations within the imaging plane. Integral to the implem...

journal_title：Magnetic resonance in medicine

authors： Korin HW,Felmlee JP,Riederer SJ,Ehman RL

更新日期：1995-05-01 00:00:00

abstract：PURPOSE:Head motion continues to be a major source of artifacts and data quality degradation in MRI. The goal of this work was to develop and demonstrate a novel technique for prospective, 6 degrees of freedom (6DOF) rigid body motion estimation and real-time motion correction using inductively coupled wireless nuclear...

journal_title：Magnetic resonance in medicine

authors： Sengupta S,Tadanki S,Gore JC,Welch EB

更新日期：2014-10-01 00:00:00

abstract：:A gradient coil design algorithm capable of controlling the position of the homogeneous region of interest (ROI) with respect to the current-carrying wires is required for many advanced imaging and spectroscopy applications. A modified minimum inductance target field method that allows the placement of a set of constr...

journal_title：Magnetic resonance in medicine

authors： Chronik BA,Rutt BK

更新日期：1998-02-01 00:00:00

abstract：:A cerebrospinal fluid (CSF)-suppressed flow-attenuated inversion recovery (FLAIR) double-shot diffusion echo-planar imaging (EPI) sequence was developed and used, along with a non-CSF-suppressed version of the sequence, to determine the extent of the contribution of CSF partial-volume averaging to the apparent diffusi...

journal_title：Magnetic resonance in medicine

authors： Falconer JC,Narayana PA

更新日期：1997-01-01 00:00:00

abstract：PURPOSE:The purpose of this study is to increase the robustness of MR fingerprinting (MRF) toward subject motion. METHODS:A novel reconstruction algorithm, MOtion insensitive MRF (MORF), was developed, which uses an iterative reconstruction based retrospective motion correction approach. Each iteration loops through t...

journal_title：Magnetic resonance in medicine

authors： Mehta BB,Ma D,Pierre EY,Jiang Y,Coppo S,Griswold MA

更新日期：2018-12-01 00:00:00

abstract：PURPOSE:To evaluate the role of true diffusion and flow-related pseudodiffusion in cerebral blood flow (CBF) quantification using arterial spin labeling (ASL) with single-shot or segmented 3D gradient and spin echo (GRASE) readouts. THEORY:The extended phase graph (EPG) algorithm, originally designed to model the effe...

journal_title：Magnetic resonance in medicine

authors： He X,Wengler K,Schweitzer ME

更新日期：2018-08-01 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：:Magnetic resonance (MR) diffusion imaging is a useful technique with which to increase our understanding of pathologic damage to the central nervous system. To fully quantitate diffusion and anisotropy in the spinal cord, as in other tissues, it is necessary to determine the diffusion tensor. If spinal cord diffusion ...

journal_title：Magnetic resonance in medicine

authors： Clark CA,Werring DJ,Miller DH

更新日期：2000-01-01 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：:Designing multidimensional radiofrequency pulses for clinical application must take into account the local specific absorption rate (SAR) as controlling the global SAR does not guarantee suppression of hot spots. The maximum peak SAR, averaged over an N grams cube (local NgSAR), must be kept under certain safety limit...

journal_title：Magnetic resonance in medicine

authors： Sbrizzi A,Hoogduin H,Lagendijk JJ,Luijten P,Sleijpen GL,van den Berg CA

更新日期：2012-03-01 00:00:00

abstract：:The natural abundance 13C NMR intensity of the glycogen C1 resonance was measured in the surgically exposed liver of rabbits in vivo (n = 17) by integration from 98 to 104 ppm and compared double blindedly to the subsequent biochemical measurement. Coil loading was measured each time from a reference sphere at the coi...

journal_title：Magnetic resonance in medicine

authors： Gruetter R,Magnusson I,Rothman DL,Avison MJ,Shulman RG,Shulman GI

更新日期：1994-06-01 00:00:00

abstract：PURPOSE:We describe a 2 × 6 channel sodium/proton array for knee MRI at 3T. Multielement coil arrays are desirable because of well-known signal-to-noise ratio advantages over volume and single-element coils. However, low tissue-coil coupling that is characteristic of coils operating at low frequency can make the potent...

journal_title：Magnetic resonance in medicine

authors： Brown R,Lakshmanan K,Madelin G,Alon L,Chang G,Sodickson DK,Regatte RR,Wiggins GC

更新日期：2016-10-01 00:00:00

abstract：:A magnetic resonance imaging method is presented for quantifying the degree to which water diffusion in biologic tissues is non-Gaussian. Since tissue structure is responsible for the deviation of water diffusion from the Gaussian behavior typically observed in homogeneous solutions, this method provides a specific me...

journal_title：Magnetic resonance in medicine

authors： Jensen JH,Helpern JA,Ramani A,Lu H,Kaczynski K

更新日期：2005-06-01 00:00:00

abstract：:The goal of this study was to measure the interindividual reproducibility of glutamate quantification in 1.5-T (1)H MRS of human brains. To determine the effective echo time (TE) for glutamate quantification, spectra from a phantom and 12 participants were obtained with TE = 30, 35, 40, and 144 ms (repetition time (TR...

journal_title：Magnetic resonance in medicine

authors： Jang DP,Lee JM,Lee E,Park S,Kim JJ,Namkoong K,Yoon KJ,Kim IY,Kim SI

更新日期：2005-03-01 00:00:00

abstract：PURPOSE:Quantitative mapping of the native T1 of the heart using the modified look-locker inversion recovery (MOLLI) technique provides high quality diagnostic information without requiring contrast agents. Previous work has considered the effects of T2 relaxation on MOLLI T1 measurements, finding that the T1 measured ...

journal_title：Magnetic resonance in medicine

authors： Robson MD,Piechnik SK,Tunnicliffe EM,Neubauer S

更新日期：2013-09-01 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:To obtain whole-brain high-resolution T2 maps in 2 minutes by combining simultaneous multislice excitation and low-power PINS (power independent of number of slices) refocusing pulses with undersampling and a model-based reconstruction. METHODS:A multi-echo spin-echo sequence was modified to acquire multiple s...

journal_title：Magnetic resonance in medicine

authors： Hilbert T,Schulz J,Marques JP,Thiran JP,Krueger G,Norris DG,Kober T

更新日期：2019-12-01 00:00:00