Assessment of bias in experimentally measured diffusion tensor imaging parameters using SIMEX.

abstract：PURPOSE:Anisotropic transverse R2 (1/T2 ) relaxation of water proton is sensitive to cartilage degenerative changes. The purpose is to develop an efficient method to extract this relaxation metric in clinical studies. METHODS:Anisotropic R2 can be measured inefficiently by standard R2 mapping after removing an isotrop...

journal_title：Magnetic resonance in medicine

authors： Pang Y,Palmieri-Smith RM,Malyarenko DI,Swanson SD,Chenevert TL

更新日期：2019-06-01 00:00:00

abstract：:Dynamic contrast-enhanced (DCE-) MRI is often used to evaluate the response to experimental antiangiogenic therapies in small animal models of cancer. Unfortunately, DCE-MRI studies often require a substantial investment of both time and money to achieve the desired level of statistical significance. Multiple-mouse MR...

journal_title：Magnetic resonance in medicine

authors： Ramirez MS,Ragan DK,Kundra V,Bankson JA

更新日期：2007-09-01 00:00:00

abstract：:In MRI, imaging using receiving coil arrays with a large number of elements is an area of growing interest. With increasing channel numbers for parallel acquisition, longer reconstruction times have become a significant concern. Channel reduction techniques have been proposed to reduce the processing time of channel-b...

journal_title：Magnetic resonance in medicine

authors： Huang F,Lin W,Duensing GR,Reykowski A

更新日期：2012-03-01 00:00:00

abstract：:A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (3He) MRI has been developed. The method employs the build-up of the signal intensity after a variable number of (3)He breaths. A mathematical model of the signal dynamics is presented, from which the local ve...

journal_title：Magnetic resonance in medicine

authors： Deninger AJ,Månsson S,Petersson JS,Pettersson G,Magnusson P,Svensson J,Fridlund B,Hansson G,Erjefeldt I,Wollmer P,Golman K

更新日期：2002-08-01 00:00:00

abstract：:Dynamic imaging strategies often involve updating certain areas of k-space (i.e., the low spatial frequencies) more frequently than others. However, important dynamic signal changes may occur anywhere in k-space. In this study, a dynamic k-space sampling analysis method was developed to determine the energy error asso...

journal_title：Magnetic resonance in medicine

authors： Wu Y,Alexander AL

更新日期：2001-04-01 00:00:00

abstract：PURPOSE:To separate the spectrally overlapped lactate and lipid signals at 1.3 ppm using diffusion-weighted magnetic resonance spectroscopy (DW-MRS) based on their large diffusivity difference. METHODS:DW-MRS was applied to the gel phantoms containing lactate and lipid droplets, and to the rat brain tumors. Lactate an...

journal_title：Magnetic resonance in medicine

authors： Wang AM,Leung GK,Kiang KM,Chan D,Cao P,Wu EX

更新日期：2017-02-01 00:00:00

abstract：:Baseline distortion in NMR spectroscopy, caused by the "dead time" between signal excitation and detection, makes quantitative interpretation difficult and is aesthetically displeasing. Here the use of the CLEAN algorithm for deconvolving the effect of signal dead time to produce a distortionless baseline is discussed...

journal_title：Magnetic resonance in medicine

authors： McKinnon GC,Burger C,Boesiger P

更新日期：1990-01-01 00:00:00

abstract：:A gradient technique to measure electron paramagnetic resonance spectra simultaneously at several different locations is described. The technique is based on the use of point probes containing paramagnetic centers. The value of the magnetic field gradient is chosen to be sufficient to separate the EPR signals from the...

journal_title：Magnetic resonance in medicine

authors： Smirnov AI,Norby SW,Clarkson RB,Walczak T,Swartz HM

更新日期：1993-08-01 00:00:00

abstract：PURPOSE:To study the utility of fractional calculus in modeling gradient-recalled echo MRI signal decay in the normal human brain. METHODS:We solved analytically the extended time-fractional Bloch equations resulting in five model parameters, namely, the amplitude, relaxation rate, order of the time-fractional derivat...

journal_title：Magnetic resonance in medicine

authors： Qin S,Liu F,Turner IW,Yu Q,Yang Q,Vegh V

更新日期：2017-04-01 00:00:00

abstract：PURPOSE:A systematic study of the short-term and long-term variability of regional alveolar partial pressure of oxygen tension (pA O2 ) measurements using (3) He magnetic resonance imaging was presented. Additionally, the repeatability of the average evaluated pA O2 was compared with that of the standard pulmonary func...

journal_title：Magnetic resonance in medicine

authors： Hamedani H,Kadlecek SJ,Ishii M,Emami K,Kuzma NN,Xin Y,Rossman M,Rizi RR

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:To improve multichannel compressed sensing (CS) reconstruction for MR proton resonance frequency (PRF) shift thermography, with application to MRI-induced RF heating evaluation and MR guided high intensity focused ultrasound (MRgFUS) temperature monitoring. METHODS:A new compressed sensing reconstruction is pr...

journal_title：Magnetic resonance in medicine

authors： Cao Z,Gore JC,Grissom WA

更新日期：2019-06-01 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：:A technique for noninvasively quantifying the concentration of sodium ((23) Na) ions was applied to the study of ischemic stroke. (23) Na-magnetic resonance imaging techniques have shown considerable potential for measuring subtle changes in ischemic tissue, although studies to date have suffered primarily from poor s...

journal_title：Magnetic resonance in medicine

authors： Wetterling F,Gallagher L,Macrae IM,Junge S,Fagan AJ

更新日期：2012-03-01 00:00:00

abstract：:This work presents a method that allows for the assessment of 3D murine myocardial motion in vivo at microscopic resolution. Phase-contrast (PC) magnetic resonance imaging (MRI) at 17.6 T was applied to map myocardial motion in healthy mice along three gradient directions. High-resolution velocity maps were acquired a...

journal_title：Magnetic resonance in medicine

authors： Herold V,Mörchel P,Faber C,Rommel E,Haase A,Jakob PM

更新日期：2006-05-01 00:00:00

abstract：PURPOSE:We sought to develop and test a clinically feasible 1-point Dixon, three-dimensional (3D) radial acquisition strategy to create isotropic 3D MR images of (129)Xe in the airspaces, barrier, and red blood cells (RBCs) in a single breath. The approach was evaluated in healthy volunteers and subjects with idiopathi...

journal_title：Magnetic resonance in medicine

authors： Kaushik SS,Robertson SH,Freeman MS,He M,Kelly KT,Roos JE,Rackley CR,Foster WM,McAdams HP,Driehuys B

更新日期：2016-04-01 00:00:00

abstract：:For sodium imaging of the human brain, Gibbs' ringing can degrade image appearance and confound image analysis; k-space filtering is generally required. In this work, the signal to noise ratio (SNR) advantage of sampling density weighted apodization (SDWA) over uniform k-space sampling with postacquisition filtering a...

journal_title：Magnetic resonance in medicine

authors： Stobbe R,Beaulieu C

更新日期：2008-10-01 00:00:00

abstract：:Subject motion during scan is a major source of artifacts in MR examinations. Prospective motion correction is a promising technique that tracks subject motion and adjusts the imaging volume in real time; however, additional retrospective correction may be necessary to achieve robust image quality and compatibility wi...

journal_title：Magnetic resonance in medicine

authors： Banerjee S,Beatty PJ,Zhang JZ,Shankaranarayanan A

更新日期：2013-02-01 00:00:00

abstract：:Chemical shifts were extracted from in vivo 3-dimensional 31P NMR CSI data and pH images were constructed. The images could spatially resolve tissue pH ranging from 5.8 to 7.2 (with uncertainty of 0.11-0.17 pH unit) in an ischemia-reperfusion model of diabetic rat calf muscles. ...

journal_title：Magnetic resonance in medicine

authors： Morikawa S,Inubushi T,Kito K,Kido C

更新日期：1993-02-01 00:00:00

abstract：PURPOSE:Multi-slice radiofrequency (RF) pulses have higher specific absorption rates, more peak RF power, and longer pulse durations than single-slice RF pulses. Gradient field design techniques using a z-gradient array are investigated for exciting multiple slices with a single-band RF pulse. THEORY AND METHODS:Two d...

journal_title：Magnetic resonance in medicine

authors： Ertan K,Taraghinia S,Sadeghi A,Atalar E

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:To present and validate a new method that formalizes a direct link between k-space and wavelet domains to apply separate undersampling and reconstruction for high- and low-spatial-frequency k-space data. THEORY AND METHODS:High- and low-spatial-frequency regions are defined in k-space based on the separation o...

journal_title：Magnetic resonance in medicine

authors： Sung K,Hargreaves BA

更新日期：2013-11-01 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：PURPOSE:For ultrahigh field (UHF) MRI, the expected local specific absorption rate (SAR) distribution is usually calculated by numerical simulations using a limited number of generic body models and adding a safety margin to take into account intersubject variability. Assessment of this variability with a large model d...

journal_title：Magnetic resonance in medicine

authors： Meliadò EF,van den Berg CAT,Luijten PR,Raaijmakers AJE

更新日期：2019-03-01 00:00:00

abstract：:Direct measurement of neural currents by means of MRI can potentially open a high temporal resolution (10-100 ms) window applicable for monitoring dynamics of neuronal activity without loss of the high spatial resolution afforded by MRI. Previously, we have shown that the alternating balanced steady state imaging affo...

journal_title：Magnetic resonance in medicine

authors： Buračas GT,Jung Y,Lee J,Buxton RB,Wong EC,Liu TT

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:To obtain three-dimensional (3D) MR angiography having high contrast between vessel and stationary background tissue, a novel technique called sliding time of flight (TOF) is proposed. METHODS:The proposed method relies on the property that flow-related enhancement (FRE) is maximized at the blood-entering slic...

journal_title：Magnetic resonance in medicine

authors： Choi J,Seo H,Lim Y,Han Y,Park H

更新日期：2015-03-01 00:00:00

abstract：PURPOSE:A new method, called Transmit and Receive Patterns from Low-Tip-angle gradient-Echo Images (TRIPLET), is described which simultaneously maps the B1+ and B1- fields of a transmit/receive radiofrequency coil array. The input data are low-tip-angle gradient-echo images, which can be acquired in a relatively short ...

journal_title：Magnetic resonance in medicine

authors： Sbrizzi A,Raaijmakers AJ,Hoogduin H,Lagendijk JJ,Luijten PR,van den Berg CA

更新日期：2014-07-01 00:00:00

abstract：:Healthy human brain diffusion anisotropy maps derived from standard spin echo diffusion tensor imaging (DTI) were compared with those using fluid-attenuated inversion recovery (FLAIR) preparation prior to DTI to null the signal from cerebrospinal fluid (CSF). Consistent comparisons entailed development of DTI postproc...

journal_title：Magnetic resonance in medicine

authors： Papadakis NG,Martin KM,Mustafa MH,Wilkinson ID,Griffiths PD,Huang CL,Woodruff PW

更新日期：2002-08-01 00:00:00

abstract：:Chemical shift imaging benefits from signal-to-noise ratio (SNR) and chemical shift dispersion increases at stronger main field such as 7 Tesla, but the associated shorter radiofrequency (RF) wavelengths encountered require B1+ mitigation over both the spatial field of view (FOV) and a specified spectral bandwidth. Th...

journal_title：Magnetic resonance in medicine

authors： Setsompop K,Alagappan V,Gagoski BA,Potthast A,Hebrank F,Fontius U,Schmitt F,Wald LL,Adalsteinsson E

更新日期：2009-02-01 00:00:00

abstract：:In spin echo imaging, magnetization is assigned to a location defined by its frequency of rotation. In the presence of a static magnetic field inhomogeneity, however, this location does not correspond to the true location of the magnetization. This paper describes a magnetic resonance imaging technique called phase co...

journal_title：Magnetic resonance in medicine

authors： Kim JK,Plewes DB,Henkelman RM

更新日期：1995-04-01 00:00:00

abstract：:For in vivo magnetic resonance imaging at high field (> or =3 T) it is essential to consider the homogeneity of the active B(1) field (B(1)+), particularly if surface coils are used for RF transmission. A new method is presented for highly rapid B(1)+ magnitude mapping. It combines the double angle method with a B(1)-...

journal_title：Magnetic resonance in medicine

authors： Cunningham CH,Pauly JM,Nayak KS

更新日期：2006-06-01 00:00:00

abstract：:Proteoglycan (PG) depletion-induced changes in T1rho (spin-lattice relaxation in rotating frame) relaxation and dispersion in articular cartilage were studied at 4T. Using a spin-lock cluster pre-encoded fast spin echo sequence, T1rho maps of healthy bovine specimens and specimens that were subjected to PG depletion w...

journal_title：Magnetic resonance in medicine

authors： Akella SV,Regatte RR,Gougoutas AJ,Borthakur A,Shapiro EM,Kneeland JB,Leigh JS,Reddy R

更新日期：2001-09-01 00:00:00