On the use of Bayesian probability theory for analysis of exponential decay data: an example taken from intravoxel incoherent motion experiments.

abstract：PURPOSE:To develop a postprocessing algorithm that corrects geometric distortions due to spatial variations of the static magnetic field amplitude, B0 , and effects from relaxation during signal acquisition in EPI. THEORY AND METHODS:An analytic, complex point-spread function is deduced for k-space trajectories of EPI...

journal_title：Magnetic resonance in medicine

authors： Patzig F,Mildner T,Schlumm T,Müller R,Möller HE

更新日期：2020-11-21 00:00:00

abstract：PURPOSE:To enable highly accelerated distortion-free MRI near metal by separating on- and off-resonance to exploit the redundancy of slice-phase encoding for the dominant on-resonance component. METHODS:Multispectral MRI techniques resolve off-resonance distortions by a combination of limited excitation bins and addit...

journal_title：Magnetic resonance in medicine

authors： Levine E,Stevens K,Beaulieu C,Hargreaves B

更新日期：2018-03-01 00:00:00

abstract：:Wavelet packet analysis is a mathematical transformation that can be used to post-process images, for example, to remove image noise ("denoising"). At a very low signal-to-noise ratio (SNR <5), standard magnitude magnetic resonance images have skewed Rician noise statistics that degrade denoising performance. Since th...

journal_title：Magnetic resonance in medicine

authors： Wood JC,Johnson KM

更新日期：1999-03-01 00:00:00

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：:Functional MRI (fMRI) was used to assess proprioceptive-associated cervical cord activity in 24 relapsing multiple sclerosis (MS) patients and 10 controls. Cord and brain conventional and diffusion tensor (DT) MRI were also acquired. fMRI was performed using a block design during a proprioceptive stimulation consistin...

journal_title：Magnetic resonance in medicine

authors： Agosta F,Valsasina P,Rocca MA,Caputo D,Sala S,Judica E,Stroman PW,Filippi M

更新日期：2008-05-01 00:00:00

abstract：:In vivo 1H MRS can be used to detect and quantify the lactate resonance at 1.3 ppm provided that overlapping lipid resonances are eliminated. A homonuclear spectral editing method was developed to acquire uncontaminated 1H spectra of lactate with adiabatic pulses. An advantage of the adiabatic pulse sequence is the ab...

journal_title：Magnetic resonance in medicine

authors： Schupp DG,Merkle H,Ellermann JM,Ke Y,Garwood M

更新日期：1993-07-01 00:00:00

abstract：:Manipulation of the data describing two-dimensional magnetic resonance (MR) images can be used to zoom an image, decrease image noise and artifacts by modeling, or emphasize object edges in the field of view. In this paper, a two-dimensional band-selectable digital filtering (2D-BSDF) technique is detailed. This can b...

journal_title：Magnetic resonance in medicine

authors： Mitchell DK,Nichols ST,Smith MR,Scott K

更新日期：1989-03-01 00:00:00

abstract：PURPOSE:To assess the feasibility of using dissolved hyperpolarized xenon-129 (129 Xe) MRI to study renal physiology in humans at 3 T. METHODS:Using a flexible transceiver RF coil, dynamic and spatially resolved 129 Xe spectroscopy was performed in the abdomen after inhalation of hyperpolarized 129 Xe gas with 3 healt...

journal_title：Magnetic resonance in medicine

authors： Chacon-Caldera J,Maunder A,Rao M,Norquay G,Rodgers OI,Clemence M,Puddu C,Schad LR,Wild JM

更新日期：2020-01-01 00:00:00

abstract：:If magnetic resonance spectroscopy (MRS) is to become a useful tool in clinical medicine, it will be necessary to find reliable methods for analyzing and classifying MRS data. Automated methods are desirable because they can remove user bias and can deal with large amounts of data, allowing the use of all the availabl...

journal_title：Magnetic resonance in medicine

authors： Tate AR,Watson D,Eglen S,Arvanitis TN,Thomas EL,Bell JD

更新日期：1996-06-01 00:00:00

abstract：:Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) was used to assess the temporal changes of high-energy phosphate metabolites in the region of acute myocardial ischemia of open-chest cats. Eight anesthetized cats were studied following ligation of the left anterior descending coronary artery. Creatine p...

journal_title：Magnetic resonance in medicine

authors： Stein PD,Goldstein S,Sabbah HN,Liu ZQ,Helpern JA,Ewing JR,Lakier JB,Chopp M,LaPenna WF,Welch KM

更新日期：1986-04-01 00:00:00

abstract：:Any number of coils can in principle be used simultaneously and independently in magnetic resonance imaging if the mutual inductances are sufficiently small. Surface coils and head or body coils have equal sensitivity at some crossover depth of the order of 6 to 10 cm. Using a 7.5-cm-diameter surface coil that was int...

journal_title：Magnetic resonance in medicine

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

更新日期：1988-02-01 00:00:00

abstract：:Two-dimensional intersecting k-space trajectories have previously been demonstrated to allow fast multispectral imaging. Repeated sampling of k-space points leads to destructive interference of the signal coming from the off-resonance spectral peaks; on-resonance data reconstruction yields images of the on-resonance p...

journal_title：Magnetic resonance in medicine

authors： Bucholz EK,Song J,Johnson GA,Hancu I

更新日期：2008-03-01 00:00:00

abstract：:Changes in molecular expression or apoptotic behavior, induced by malignant transformation or anticancer treatment, are frequently reflected in cellular metabolism and oxygen consumption. A technique to monitor oxygen consumption, cell physiology, and metabolism noninvasively would provide a better understanding of in...

journal_title：Magnetic resonance in medicine

authors： Pilatus U,Aboagye E,Artemov D,Mori N,Ackerstaff E,Bhujwalla ZM

更新日期：2001-05-01 00:00:00

abstract：:Fitting a model to an experimental spectrum is a difficult nonlinear estimation problem. The solution presented here is to start an iterative search procedure sufficiently close to the optimal model parameter set. This is achieved by providing tissue-dependent a priori peak information and by a novel correlation metho...

journal_title：Magnetic resonance in medicine

authors： Burger C,McKinnon G,Buchli R,Boesiger P

更新日期：1991-10-01 00:00:00

abstract：PURPOSE:To illustrate the potential bias caused by imaging gradients in correlation MRI sequences using longitudinal magnetization storage (LS) and examine the case of filter exchange imaging (FEXI) yielding maps of the apparent exchange rate (AXR). METHODS:The effects of imaging gradients in FEXI were observed on yea...

journal_title：Magnetic resonance in medicine

authors： Lasič S,Lundell H,Topgaard D,Dyrby TB

更新日期：2018-04-01 00:00:00

abstract：:The Shinnar-Le Roux (SLR) radiofrequency (RF) pulse design algorithm is widely used for designing slice-selective RF pulses due to its intuitiveness, optimality, and speed. SLR is limited, however, in that it is only capable of designing one-dimensional pulses played along constant gradients. We present a nonuniform S...

journal_title：Magnetic resonance in medicine

authors： Grissom WA,McKinnon GC,Vogel MW

更新日期：2012-09-01 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：:The experiments reported herein are the first MRI investigations of the orientational dependence of T(2) relaxation in articular cartilage at microscopic resolution over the 360 degrees angular space. For each of six canine cartilage specimens, 48 independent T(2)-weighted proton images were acquired for 12 different ...

journal_title：Magnetic resonance in medicine

authors： Xia Y,Moody JB,Alhadlaq H

更新日期：2002-09-01 00:00:00

abstract：:This study demonstrates the in vitro displacement and strain of articular cartilage in a cyclically-compressed and intact joint using displacement-encoded imaging with stimulated echoes (DENSE) and fast spin echo (FSE). Deformation and strain fields exhibited complex and heterogeneous patterns. The displacements in th...

journal_title：Magnetic resonance in medicine

authors： Chan DD,Neu CP,Hull ML

更新日期：2009-04-01 00:00:00

abstract：PURPOSE:To achieve artifact-suppressed whole-brain pass-band-balanced steady-state free precession functional MRI from a single functional magnetic resonance imaging (fMRI) scan. METHODS:A complete and practical data acquisition sequence for alt-SSFP fMRI was developed. First, multishot flyback-echo-planar imaging (EP...

journal_title：Magnetic resonance in medicine

authors： Jou T,Patterson S,Pauly JM,Bowen CV

更新日期：2016-05-01 00:00:00

abstract：:Multiple receivers can be utilized to enhance the spatiotemporal resolution of MRI by employing the parallel imaging technique. Previously, we have reported the L-curve Tikhonov regularization technique to mitigate noise amplification resulting from the geometrical correlations between channels in a coil array. Nevert...

journal_title：Magnetic resonance in medicine

authors： Lin FH,Wang FN,Ahlfors SP,Hämäläinen MS,Belliveau JW

更新日期：2007-10-01 00:00:00

abstract：:Functional MRI studies to date have been generally performed using the blood oxygenation level dependent (BOLD) contrast mechanism. Recently, it has been proposed that dynamic change in the apparent diffusion coefficient (ADC), measured using intravoxel incoherent motion (IVIM) weighting, can be used as a robust funct...

journal_title：Magnetic resonance in medicine

authors： Harshbarger TB,Song AW

更新日期：2004-12-01 00:00:00

abstract：PURPOSE:Within multiple sclerosis (MS) lesions iron is present in chronically activated microglia. Thus, iron detection with MRI might provide a biomarker for chronic inflammation within lesions. Here, we examine contributions of iron and myelin to magnetic susceptibility of lesions on quantitative susceptibility mappi...

journal_title：Magnetic resonance in medicine

authors： Wisnieff C,Ramanan S,Olesik J,Gauthier S,Wang Y,Pitt D

更新日期：2015-08-01 00:00:00

abstract：:The remarkable success of magnetic resonance imaging of adult brain relates to the unusually large ratio of the longitudinal relaxation rates 1/T1 of white and gray matter, approximately 2:1 at physiological temperature and traditional imaging fields. Several investigators have conjectured that myelin is the source of...

journal_title：Magnetic resonance in medicine

authors： Koenig SH,Brown RD 3rd,Spiller M,Lundbom N

更新日期：1990-06-01 00:00:00

abstract：:This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T2* mapping of the heart. First, T2* maps are presented for oil phantoms ...

journal_title：Magnetic resonance in medicine

authors： Heinrichs U,Utting JF,Frauenrath T,Hezel F,Krombach GA,Hodenius MA,Kozerke S,Niendorf T

更新日期：2009-09-01 00:00:00

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：:Diffusion-weighted single voxel experiments conducted at b-values up to 1 x 10(4) smm-2 yielded biexponential signal attenuation curves for both normal and ischemic brain. The relative fractions of the rapidly and slowly decaying components (f1, f2) are f1 = 0.80 +/- 0.02, f2 = 0.17 +/- 0.02 in healthy adult rat brain...

journal_title：Magnetic resonance in medicine

authors： Niendorf T,Dijkhuizen RM,Norris DG,van Lookeren Campagne M,Nicolay K

更新日期：1996-12-01 00:00:00

abstract：:Flow-sensitive dephasing (FSD) magnetization preparation has been developed for black-blood vessel wall MRI and noncontrast MR angiography. The first-order gradient moment, m(1) , is a measure of the flow-sensitization imparted by an FSD preparative module. Determination of the optimal m(1) for each individual is high...

journal_title：Magnetic resonance in medicine

authors： Fan Z,Zhou X,Bi X,Dharmakumar R,Carr JC,Li D

更新日期：2011-04-01 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：:A kinetic analysis of water signal intensity changes measured in human visual cortex by PRESS localized 1H spectroscopy at 500 ms resolution with light-emitting diode (LED) goggle stimulation was used to determine vascular transit times for transitions between rest and activation. Monoexponential curve fitting was use...

journal_title：Magnetic resonance in medicine

authors： Detre JA,Wang Z,Stecker MM,Zimmerman RA

更新日期：1995-09-01 00:00:00