Abstract:
:To quantify the extraction fraction, E, for gadopentetate across tumor capillaries, R3230 adenocarcinomas were implanted in the mammary fat pads of seven rats. The value of E was determined by using a two-compartment tissue model in which the endothelial transfer coefficient, K(PS) (ml x min(-1) x cc(-1) of tissue), was estimated from the model fitted to changes in R1 relaxation time (deltaR1; s(-1)) measured by dynamic three-dimensional spoiled gradient recalled magnetic resonance imaging after injection of 0.1 mmol x kg(-1) of gadopentetate dimeglumine. The plasma flow rate through the tumor capillaries, Fp, (ml x min(-1) x g(-1) of tissue), was independently measured with fluorescent microspheres. E could be calculated by the relationship, E = K(PS)/Fp. The mean E for gadopentetate in the R3230 tumor was 0.197 +/- 0.118 with a range of 0.123-0.454. The relatively small mean value of E for gadopentetate allows a fair approximation of the permeability surface area product by K(PS) in this R3230 tumor model.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Daldrup HE,Shames DM,Husseini W,Wendland MF,Okuhata Y,Brasch RCdoi
10.1002/mrm.1910400406subject
Has Abstractpub_date
1998-10-01 00:00:00pages
537-43issue
4eissn
0740-3194issn
1522-2594journal_volume
40pub_type
杂志文章abstract:PURPOSE:Dynamic phosphorus MR spectroscopic imaging (31 P-MRSI) experiments require temporal resolution on the order of seconds to concurrently assess different muscle groups. A highly accelerated pulse sequence combining flyback echo-planar spectroscopic imaging (EPSI) and compressed sensing was developed and tested i...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27682
更新日期:2019-06-01 00:00:00
abstract::An improved double quantum coherence (DQC) filter for the selective in vivo detection of glutathione (GSH) in the human brain at 1.5 Tesla is presented. The goal was to minimize contamination of the DQC-filtered GSH signal at 2.9 ppm with contributions arising from GABA. The modification consists of tailoring the freq...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1094
更新日期:2001-04-01 00:00:00
abstract::The study of lung perfusion in normal and diseased subjects is of great interest to physiologists and physicians. In this work we demonstrate the application of a liquid-phase hyperpolarized (HP) carbon-13 ((13)C) tracer to magnetic resonance imaging (MRI) of the pulmonary vasculature and pulmonary perfusion in a porc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21168
更新日期:2007-03-01 00:00:00
abstract::A robust postprocessing method to detect regions of magnetic field change is presented. High resolution gradient echo data is acquired to create a complex baseline image. From this image, two low resolution images are obtained by applying a low pass filter on the magnitude image and the complex image, respectively. Su...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910360518
更新日期:1996-11-01 00:00:00
abstract::The fast spin-echo (FSE) sequence is frequently used as a fast data-readout technique in conjunction with other pulse sequence elements, such as in fluid-attenuated inversion-recovery (FLAIR) and double inversion-recovery (DIR) sequences. In order to implement those pulse sequences, an understanding is required of how...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20541
更新日期:2005-07-01 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
pub_type: 杂志文章
doi:10.1002/mrm.26871
更新日期:2018-04-01 00:00:00
abstract::Multislice MR images obtained using a fast spin-echo (FSE) readout are strongly affected by magnetization transfer (MT) effects, which will cause a decrease in the observed longitudinal relaxation times for tissues with a large bound water component. This is pertinent for FSE-based inversion-recovery (IR) sequences, a...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21338
更新日期:2007-10-01 00:00:00
abstract::In the dynamic nuclear polarization process, microwave irradiation facilitates exchange of polarization from a radical's unpaired electron to nuclear spins at cryogenic temperatures, increasing polarization by >10,000. Doping samples with Gd(3+) ions further increases the achievable solid-state polarization. However, ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24207
更新日期:2012-12-01 00:00:00
abstract:PURPOSE:Establishing a high-resolution non-ECG-gated first-pass perfusion (FPP) cardiac MRI technique may improve accessibility and diagnostic capability of FPP imaging. We propose a non-ECG-gated FPP imaging technique using continuous magnetization-driven golden-angle radial acquisition. The main purpose of this preli...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25074
更新日期:2014-12-01 00:00:00
abstract::The equal-phase line (EPL) algorithm is proposed as a means of allowing rapid Fourier transform (FT) reconstruction of MR image data acquired on a non-Cartesian grid. The pixels on the image are grouped according to their positions. The pixels in a group have the same phase in the complex exponential function -exp[j2p...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10165
更新日期:2002-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.10234
更新日期:2002-09-01 00:00:00
abstract:PURPOSE:Cross-term spatiotemporal encoding (xSPEN) is a single-shot approach with exceptional immunity to field heterogeneities, the images of which faithfully deliver 2D spatial distributions without requiring a priori information or using postacquisition corrections. xSPEN, however, suffers from signal-to-noise ratio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26824
更新日期:2018-03-01 00:00:00
abstract::Introduction of a Gaussian weighting function into the phase encoding of the spin-echo imaging method via variable tip angle excitation, with concomitant optimization of the recycle delay, is shown to increase the sensitivity of T2-weighted imaging by up to 40%. In addition, the Gibbs artifact associated with sharp bo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910210216
更新日期:1991-10-01 00:00:00
abstract::The purpose of this study was to evaluate an optimized multislice acquisition technique for oxygen-enhanced MRI of the lung using slice-selective inversion and refocusing pulses in combination with parallel imaging. An inversion recovery HASTE sequence was implemented with respiratory triggering to perform imaging in ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20495
更新日期:2005-06-01 00:00:00
abstract::Precise relaxation time (RT) measurements have been made, with a standard deviation of 3% for T1 and T2 in white matter in normal volunteers. This sets an upper limit to the instrumental random errors (imprecision). Achieving this precision requires careful adjustment and use of the imager. The wide variation in RTs s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910110307
更新日期:1989-09-01 00:00:00
abstract::The theoretical description of steady state free precession (SSFP) sequences is generally well accepted and unquestioned, although it is based on instantaneously acting radiofrequency (RF) pulses. In practice, however, all excitation processes are finite, thereby questioning the overall validity of the common SSFP sig...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22116
更新日期:2009-11-01 00:00:00
abstract::Minimally invasive cardiac surgery requires arresting and emptying of the heart, which compromises visualization of the surgical field. In this feasibility study a novel surgical procedure is demonstrated in which real-time MRI is used to guide the placement of a prosthetic aortic valve in the beating heart via direct...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21044
更新日期:2006-11-01 00:00:00
abstract:PURPOSE:To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). METHODS:A conventional flow-compensated and flow-encoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experim...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25059
更新日期:2014-12-01 00:00:00
abstract::In radiotherapy, target tissues are defined best on MR images due to their superior soft tissue contrast. Computed tomography imaging is geometrically accurate and it is needed for dose calculation and generation of reference images for treatment localization. Co-registration errors between MR and computed tomography ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章,随机对照试验
doi:10.1002/mrm.24459
更新日期:2013-07-01 00:00:00
abstract::Variations in T(1ρ) with locking-field strength (T(1ρ) dispersion) may be used to estimate proton exchange rates. We developed a novel approach utilizing the second derivative of the dispersion curve to measure exchange in a model system of cross-linked polyacrylamide gels. These gels were varied in relative compositi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22947
更新日期:2011-12-01 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
pub_type: 杂志文章
doi:10.1002/mrm.22000
更新日期:2009-07-01 00:00:00
abstract::This study investigated the use of peritoneal dialysis fluid (dialyzate) as a MR contrast agent to visualize the liver structure and peritoneal adhesion in rats at 7 T. Intraperitoneal injection of dialyzate (approximately 0.1 ml/g) yielded excellent and consistent intraperitoneal enhancement that delineated the liver...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21506
更新日期:2008-05-01 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
pub_type: 杂志文章
doi:10.1002/mrm.20299
更新日期:2004-12-01 00:00:00
abstract::Generating flow-specific images (arteriograms, venograms) with optimal signal-to-noise ratios for time-resolved MR angiography is a conditional maximum problem, and its solutions are generalized matched filters. We have investigated six matched filters, corresponding to all possible combinations of three flow suppress...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910300511
更新日期:1993-11-01 00:00:00
abstract::The effects of macroscopic background field gradients upon 2D gradient echo images of inhaled (3)He in the human lung were investigated at 1.5 T. Effective compensation of in-slice signal loss in (3)He gradient echo images was then demonstrated using a multiple acquisition interleaved single gradient echo sequence. Th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10549
更新日期:2003-08-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910310614
更新日期:1994-06-01 00:00:00
abstract:PURPOSE:Previous work has evaluated the quality of different analytic methods for extracting relaxation times from magnitude imaging data exhibiting Rician noise. However, biexponential analysis of relaxation in tissue, including cartilage, and materials is of increasing interest. We, therefore, analyzed biexponential ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25111
更新日期:2015-01-01 00:00:00
abstract:PURPOSE:To develop velocity-selective (VS) MR angiography (MRA) protocols for arteriography and venography with whole-brain coverage. METHODS:Tissue suppression using velocity-selective saturation (VSS) pulse trains is sensitive to radiofrequency field (B1 +) inhomogeneity. To reduce its sensitivity, we replaced the l...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26864
更新日期:2018-04-01 00:00:00
abstract::The spin-lattice relaxation time T1 of multicomponent tissues is often determined by fitting relaxation data to monoexponential functions. This process can lead to large errors in the relaxation time. We describe a procedure using chemical-shift imaging (CSI) which separates the NMR signal into water and lipid compone...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910130307
更新日期:1990-03-01 00:00:00
abstract:PURPOSE:To design short parallel transmission (pTx) pulses for excitation of arbitrary three-dimensional (3D) magnetization patterns. METHODS:We propose a joint optimization of the pTx radiofrequency (RF) and gradient waveforms for excitation of arbitrary 3D magnetization patterns. Our optimization of the gradient wav...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26021
更新日期:2016-10-01 00:00:00