Measurement of the blood-brain barrier permeability and leakage space using dynamic MR imaging. 1. Fundamental concepts.

abstract：:Evaluation of water diffusion in the brain has revealed both fast- and slow-diffusing water populations. It has been suggested that these populations represent extra- and intracellular water, respectively. We have identified and characterized both populations in the intracellular space of the Xenopus oocyte. We have a...

journal_title：Magnetic resonance in medicine

authors： Sehy JV,Ackerman JJ,Neil JJ

更新日期：2002-11-01 00:00:00

abstract：:An eight-channel receive-only brain coil and table-top detunable volume transmit coil were developed and tested at 7 T for human imaging. Optimization of this device required attention to sources of interaction between the array elements, between the transmit and receive coils and minimization of common mode currents ...

journal_title：Magnetic resonance in medicine

authors： Wiggins GC,Potthast A,Triantafyllou C,Wiggins CJ,Wald LL

更新日期：2005-07-01 00:00:00

abstract：:Calculations and experiments that provide support for our previously stated theorem are presented: If two coils simultaneously receiving magnetic resonance signals from the same anatomic region exhibit zero mutual inductance, there can be no correlation of the noise. It is shown that correlation does not exist even in...

journal_title：Magnetic resonance in medicine

authors： Jesmanowicz A,Hyde JS,Froncisz W,Kneeland JB

更新日期：1991-07-01 00:00:00

abstract：:Function and morphology of the cerebral vasculature were studied in the amyloid (Abeta) plaque-containing double-transgenic (TG) B6.PS2APP Alzheimer's disease (AD) mouse model with MRI at an age range of 10 to 17 months. Perfusion, blood volume, and average vessel geometry were assessed in the brain and compared to ag...

journal_title：Magnetic resonance in medicine

authors： Weidensteiner C,Metzger F,Bruns A,Bohrmann B,Kuennecke B,von Kienlin M

更新日期：2009-07-01 00:00:00

abstract：:Strong, extensive magnetic fringe fields are a significant problem with magnetic resonance imaging magnets. This is particularly acute with 4-T, whole-body research magnets. To date this problem has been addressed by restricting an extensive zone around the unshielded magnet or by placing external unsaturated iron shi...

journal_title：Magnetic resonance in medicine

authors： Huson FR,Bryan RN,MacKay WW,Herrick RC,Colvin J,Ford JJ,Pissanetzky S,Plishker GA,Rocha R,Schmidt W

更新日期：1993-01-01 00:00:00

abstract：PURPOSE:To develop a novel analytical method for quantification of chemical exchange saturation transfer (CEST) in the transient state. The proposed method aims to reduce the effects of non-chemical-exchange (non-CE) parameters on the CEST signal, emphasizing the effect of chemical exchange. METHODS:The difference in ...

journal_title：Magnetic resonance in medicine

authors： Wang Y,Zhang Y,Zhao X,Wu B,Gao JH

更新日期：2017-11-01 00:00:00

abstract：PURPOSE:To develop and validate a regularization approach of optimizing B1 insensitivity of the quantitative magnetization transfer (qMT) pool-size ratio (F). METHODS:An expression describing the impact of B1 inaccuracies on qMT fitting parameters was derived using a sensitivity analysis. To simultaneously optimize fo...

journal_title：Magnetic resonance in medicine

authors： Boudreau M,Pike GB

更新日期：2018-12-01 00:00:00

abstract：:The diffusional kurtosis is an indicator for diffusion restrictions in biological tissue. It is observed experimentally that the kurtosis is largest for directions perpendicular to the fiber direction in white matter. The directional dependence of the kurtosis can be described by the diffusion kurtosis tensor. Since t...

journal_title：Magnetic resonance in medicine

authors： Kuder TA,Stieltjes B,Bachert P,Semmler W,Laun FB

更新日期：2012-05-01 00:00:00

abstract：:We have noninvasively produced low-resolution, quantitative nuclear magnetic resonance images of cerebral blood flow in 2-ml voxels in eight cats. Typical signal-to-noise of 4 to 1 was obtained in cerebral voxels in 16.5-s epochs. Mean flow during normocapnia (paCO2 = 39 +/- 4 mm Hg) and hypercapnia (paCO2 = 62 +/- 4 ...

journal_title：Magnetic resonance in medicine

authors： Branch CA,Ewing JR,Helpern JA,Ordidge RJ,Butt S,Welch KM

更新日期：1992-11-01 00:00:00

abstract：PURPOSE:To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. METHODS:A T1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and...

journal_title：Magnetic resonance in medicine

authors： Bane O,Hectors SJ,Wagner M,Arlinghaus LL,Aryal MP,Cao Y,Chenevert TL,Fennessy F,Huang W,Hylton NM,Kalpathy-Cramer J,Keenan KE,Malyarenko DI,Mulkern RV,Newitt DC,Russek SE,Stupic KF,Tudorica A,Wilmes LJ,Yankeelov TE

更新日期：2018-05-01 00:00:00

abstract：:The accuracy of the outcome in a diffusion tensor imaging (DTI) experiment depends on the acquisition scheme as well as the postprocessing methods used. In the present study, the DTI results acquired after applying different combinations of diffusion-weighted (DW) gradient orientations were initially compared. Then, s...

journal_title：Magnetic resonance in medicine

authors： Arfanakis K,Cordes D,Haughton VM,Carew JD,Meyerand ME

更新日期：2002-02-01 00:00:00

abstract：:Accumulation of lipids in atherosclerotic plaques causes progressive narrowing of the arterial lumen, often followed by thrombosis and ischemia. Currently several different methods, most requiring disruption of the plaque, are used to study the physical properties of lipids accumulated in plaques, and lipid compositio...

journal_title：Magnetic resonance in medicine

authors： Guo W,Morrisett JD,Lawrie GM,DeBakey ME,Hamilton JA

更新日期：1998-02-01 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：:The radial trajectory has found applications in cardiac imaging because of its resilience to undersampling and motion artifacts. Recent work has shown that interleaved and weighted radial imaging can produce images with multiple contrasts from a single data set. This feature was investigated for inversion recovery ima...

journal_title：Magnetic resonance in medicine

authors： Peters DC,Botnar RM,Kissinger KV,Yeon SB,Appelbaum EA,Manning WJ

更新日期：2006-05-01 00:00:00

abstract：PURPOSE:Acquisition of high-resolution imaging data using multiple excitations without the sensitivity to fluctuations of the transverse magnetization phase, which is a major problem of multi-shot MRI. THEORY AND METHODS:The concept of superresolution MRI based on microscopic tagging is analyzed using an analogy with ...

journal_title：Magnetic resonance in medicine

authors： Hennel F,Tian R,Engel M,Pruessmann KP

更新日期：2018-12-01 00:00:00

abstract：PURPOSE:We sought to assess whether machine learning-based classification approaches can improve the classification of pancreatic tumor models relative to more simplistic analysis methods, using T1 relaxation, CEST, and DCE MRI. METHODS:The T1 relaxation time constants, % CEST at five saturation frequencies, and vascu...

journal_title：Magnetic resonance in medicine

authors： Goldenberg JM,Cárdenas-Rodríguez J,Pagel MD

更新日期：2019-01-01 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：:Perfusion imaging with pulsed arterial spin labeling techniques, like flow-sensitive alternating inversion recovery (FAIR), may suffer from inflow of fresh, i.e., unlabeled, spins. Inflow of fresh spins is caused by the arrival of unlabeled spins in the image slice and can lead to underestimation of the perfusion if n...

journal_title：Magnetic resonance in medicine

authors： Schepers J,van Osch MJ,Bartels LW,Heukels SN,Viergever MA,Nicolay K

更新日期：2005-06-01 00:00:00

abstract：:Functional magnetic resonance imaging (fMRI) has recently been adopted as an investigational tool in the field of neuroscience. The signal changes induced by brain activations are small ( approximately 1-2%) at 1.5T. Therefore, the signal-to-noise ratio (SNR) of the time series used to calculate the functional maps is...

journal_title：Magnetic resonance in medicine

authors： Parrish TB,Gitelman DR,LaBar KS,Mesulam MM

更新日期：2000-12-01 00:00:00

abstract：:Magnetic resonance imaging allows numerous k-space sampling schemes such as cartesian, polar, spherical, and other non-rectilinear trajectories. Non-rectilinear MR acquisitions permit fast scan times and can suppress motion artifacts. Still, these sampling schemes may adversely affect the image characteristics due to ...

journal_title：Magnetic resonance in medicine

authors： Lauzon ML,Rutt BK

更新日期：1996-12-01 00:00:00

abstract：PURPOSE:To evaluate the use of variable flip angle refocusing pulse trains in single-shot three-dimensional gradient and spin-echo (3D-GRASE) to reduce blurring and increase the spatial coverage for high spatial resolution T2 -weighted functional MRI at 7 Tesla. METHODS:Variable flip angle refocusing schemes in 3D-GRA...

journal_title：Magnetic resonance in medicine

authors： Kemper VG,De Martino F,Yacoub E,Goebel R

更新日期：2016-09-01 00:00:00

abstract：:Simulations of dynamic susceptibility contrast (DSC) MRI are frequently performed by assuming a certain shape for the input function and the microvascular response function. However, to investigate the influence of parameters that will affect the shape of the input function, a more complex model of the human vasculatu...

journal_title：Magnetic resonance in medicine

authors： van Osch MJ,Vonken EJ,Wu O,Viergever MA,van der Grond J,Bakker CJ

更新日期：2003-09-01 00:00:00

abstract：:Each k-space segment in multishot diffusion-weighted MRI is affected by a different spatially varying phase which is caused by unavoidable motions and amplified by the diffusion-encoding gradients. A proper image reconstruction therefore requires phase maps for each segment. Such maps are commonly derived from two-dim...

journal_title：Magnetic resonance in medicine

authors： Uecker M,Karaus A,Frahm J

更新日期：2009-11-01 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：PURPOSE:The objective of this study was to determine whether a sodium phased array would improve sodium breast MRI at 3 T. The secondary objective was to create acceptable proton images with the sodium phased array in place. METHODS:A novel composite array for combined proton/sodium 3 T breast MRI is compared with a c...

journal_title：Magnetic resonance in medicine

authors： Kaggie JD,Hadley JR,Badal J,Campbell JR,Park DJ,Parker DL,Morrell G,Newbould RD,Wood AF,Bangerter NK

更新日期：2014-06-01 00:00:00

abstract：:Using NMR spectroscopy, we studied purified, human T lymphocytes in a serum-free medium. Purified cells were entrapped inside agarose beads and induced to proliferate by the mitogens phorbol-12-myristate-13-acetate and ionomycin. T lymphocytes in standard culture and inside agarose beads exhibit comparable viability, ...

journal_title：Magnetic resonance in medicine

authors： Bental M,Deutsch C

更新日期：1993-03-01 00:00:00

abstract：:Problems with in vivo proton spectroscopy include strong water and lipid signals, and the very complicated structures of the spectra. Multiple-quantum experiments can be designed to overcome these difficulties. Using a volume selective refocusing technique, one can demonstrate how multiple-quantum experiments can be p...

journal_title：Magnetic resonance in medicine

authors： McKinnon GC,Bosiger P

更新日期：1988-03-01 00:00:00

abstract：PURPOSE:To develop a method for acquiring whole-heart 3D image-based navigators (iNAVs) with isotropic resolution for tracking and correction of localized motion in coronary magnetic resonance angiography (CMRA). METHODS:To monitor motion in all regions of the heart during a free-breathing scan, a variable-density con...

journal_title：Magnetic resonance in medicine

authors： Addy NO,Ingle RR,Luo J,Baron CA,Yang PC,Hu BS,Nishimura DG

更新日期：2017-05-01 00:00:00

abstract：:Images of hyperpolarized 3He were acquired during breath-hold in four healthy volunteers with the use of an optimized 3D gradient-echo sequence. The images were compared with existing 2D gradient-echo methods. The average SNR from a 13-mm-thick slice in the peripheral lung was 1.4 times greater with 3D. In the airways...

journal_title：Magnetic resonance in medicine

authors： Wild JM,Woodhouse N,Paley MN,Fichele S,Said Z,Kasuboski L,van Beek EJ

更新日期：2004-09-01 00:00:00

abstract：:The myelin sheath, which is wrapped around the axons in the brain, can be affected by many diseases, resulting in cognitive and physical disability. Other work showed water in the myelin sheath has a T2 approximately 15 ms. The current standard technique to estimate the fraction of myelin water in vivo is to collect m...

journal_title：Magnetic resonance in medicine

authors： Jones CK,Xiang QS,Whittall KP,MacKay AL

更新日期：2004-03-01 00:00:00