Sensitivity of feedback-enhanced MRI contrast to macroscopic and microscopic field variations.

abstract：PURPOSE:This study evaluates biochemical imbalances in a rat model that reflects dysfunctional pathways in migraine. The high sensitivity and spectral dispersion available to 1 H MRS at 21.1 T expands metabolic profiling in this migraine model to include lactate (Lac), taurine (Tau), aspartate, and Gly-a mixture of gly...

journal_title：Magnetic resonance in medicine

authors： Abad N,Rosenberg JT,Roussel T,Grice DC,Harrington MG,Grant SC

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:Reference region models (RRMs) can quantify tumor perfusion in dynamic contrast-enhanced MRI without an arterial input function. Inspection of the RRM reveals that one of the free parameters in the fit is uniquely linked to the reference region and is common to all voxels. A two-step approach is proposed that t...

journal_title：Magnetic resonance in medicine

authors： Ahmed Z,Levesque IR

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:To develop a new parallel transmit (pTx) pulse design for simultaneous multiband (MB) excitation in order to tackle simultaneously the problems of transmit B1 (B1+) inhomogeneity and total radiofrequency (RF) power, so as to allow for optimal RF excitation when using MB pulses for slice acceleration for high an...

journal_title：Magnetic resonance in medicine

authors： Wu X,Schmitter S,Auerbach EJ,Moeller S,Uğurbil K,Van de Moortele PF

更新日期：2013-09-01 00:00:00

abstract：:High-field (>or=3 T) cardiac MRI is challenged by inhomogeneities of both the static magnetic field (B(0)) and the transmit radiofrequency field (B(1)+). The inhomogeneous B fields not only demand improved shimming methods but also impede the correct determination of the zero-order terms, i.e., the local resonance fre...

journal_title：Magnetic resonance in medicine

authors： Schär M,Vonken EJ,Stuber M

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:To develop a fast protocol for measuring T1 values in the internal carotid artery (ICA), to validate this technique with in vitro measurements, and to evaluate its reproducibility. METHODS:A modified Look-Locker sequence was optimized to enable rapid determination of T1 in the ICA at 3T. T1 values from the ICA...

journal_title：Magnetic resonance in medicine

authors： Li W,Liu P,Lu H,Strouse JJ,van Zijl PCM,Qin Q

更新日期：2017-06-01 00:00:00

abstract：PURPOSE:To demonstrate the feasibility of imaging the first passage of a bolus of hyperpolarized (13)C urea through the rodent heart using flow-sensitizing gradients to reduce signal from the blood pool. METHODS:A flow-sensitizing bipolar gradient was optimized to reduce the bright signal within the cardiac chambers, ...

journal_title：Magnetic resonance in medicine

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

更新日期：2016-04-01 00:00:00

abstract：:Reaching the full potential of magnetic resonance imaging (MRI)-positron emission tomography (PET) dual modality systems requires new methodologies in quantitative image analyses. In this study, methods are proposed to convert an arterial input function (AIF) derived from gadolinium-diethylenetriaminepentaacetic acid ...

journal_title：Magnetic resonance in medicine

authors： Poulin E,Lebel R,Croteau E,Blanchette M,Tremblay L,Lecomte R,Bentourkia M,Lepage M

更新日期：2013-03-01 00:00:00

abstract：PURPOSE:To develop a rapid and motion-robust technique for volumetric MRI, which is based on cross-sectional real-time MRI acquisitions with automatic advancement of the slice position. METHODS:Real-time MRI with a frame-by-frame moving cross-section is performed with use of highly undersampled radial gradient-echo se...

journal_title：Magnetic resonance in medicine

authors： Voit D,Kalentev O,van Zalk M,Joseph AA,Frahm J

更新日期：2020-05-01 00:00:00

abstract：:Magnetization transfer effects represent a major source of contrast in multislice turbo spin echo sequences (TSE)/fast spin echo sequences. Generally, low refocusing flip angles have become common in such MRI sequences, especially to mitigate specific absorption rate problems. Since the strength of magnetization trans...

journal_title：Magnetic resonance in medicine

authors： Weigel M,Helms G,Hennig J

更新日期：2010-01-01 00:00:00

abstract：:A novel method based on selective detection of rapidly changing DeltaB(0) magnetic fields and suppression of slowly changing DeltaB(0) fields is presented. The ultimate goal of this work is to present a method that may allow detection of transient and subtle changes in B(0) in cortical tissue associated with electrica...

journal_title：Magnetic resonance in medicine

authors： Bodurka J,Bandettini PA

更新日期：2002-06-01 00:00:00

abstract：PURPOSE:To investigate a computationally efficient method for optimizing the Cramér-Rao Lower Bound (CRLB) of quantitative sequences without using approximations or an analytical expression of the signal. METHODS:Automatic differentiation was applied to Bloch simulations and used to optimize several quantitative seque...

journal_title：Magnetic resonance in medicine

authors： Lee PK,Watkins LE,Anderson TI,Buonincontri G,Hargreaves BA

更新日期：2019-10-01 00:00:00

abstract：PURPOSE:To develop a rapid imaging framework for balanced steady-state free precession (bSSFP) that jointly reconstructs undersampled data (by a factor of R) across multiple coils (D) and multiple acquisitions (N). To devise a multi-acquisition coil compression technique for improved computational efficiency. METHODS:...

journal_title：Magnetic resonance in medicine

authors： Biyik E,Ilicak E,Çukur T

更新日期：2018-05-01 00:00:00

abstract：:The suppression of water signals in in vivo proton spectra by means of multiple-quantum filtering can be brought about in several ways. This communication exposes the shortcomings of using purely subtractive filtering techniques to observe signals from metabolites that contain proton couplings of the form AX3. ...

journal_title：Magnetic resonance in medicine

authors： Nosel W,Trimble LA,Shen JF,Allen PS

更新日期：1989-09-01 00:00:00

abstract：PURPOSE:To quantify chemical exchange saturation transfer contrast in upper extremities of participants with lymphedema before and after standardized lymphatic mobilization therapy using correction procedures for B0 and B1 heterogeneity, and T1 relaxation. METHODS:Females with (n = 12) and without (n = 17) breast canc...

journal_title：Magnetic resonance in medicine

authors： Crescenzi R,Donahue PMC,Mahany H,Lants SK,Donahue MJ

更新日期：2020-05-01 00:00:00

abstract：:Leakage of Gd-DTPA through a defective blood-brain barrier is measured quantitatively using dynamic MRI scanning, in which repeated scans are made after a bolus injection. Image registration artifacts are minimized; a dose of 0.1 mM/kg and an IR sequence enable enhancement to be measured quantitatively. The triexponen...

journal_title：Magnetic resonance in medicine

authors： Tofts PS,Kermode AG

更新日期：1991-02-01 00:00:00

abstract：:Quantitative measurement of lung microstructure is of great significance in assessment of pulmonary disease, particularly in the earliest stages. The technique for MRI-based 3He lung morphometry was previously developed and validated for human lungs, and was recently extended to ex vivo mouse lungs. The technique yiel...

journal_title：Magnetic resonance in medicine

authors： Wang W,Nguyen NM,Yablonskiy DA,Sukstanskii AL,Osmanagic E,Atkinson JJ,Conradi MS,Woods JC

更新日期：2011-03-01 00:00:00

abstract：PURPOSE:The apparent propagator anisotropy (APA) is a new diffusion MRI metric that, while drawing on the benefits of the ensemble averaged propagator anisotropy (PA) compared to the fractional anisotropy (FA), can be estimated from single-shell data. THEORY AND METHODS:Computation of the full PA requires acquisition ...

journal_title：Magnetic resonance in medicine

authors： Aja-Fernández S,Tristán-Vega A,Jones DK

更新日期：2020-12-13 00:00:00

abstract：:Human brain white matter exhibits an uncommonly strong dispersion of 1/T1 at high fields. An additional relaxation pathway via the myelin lipids, which are not directly visible to medical NMR due to their fast T2 decay, is proposed. Relaxation dispersion data are successfully analyzed on the basis of this model. ...

journal_title：Magnetic resonance in medicine

authors： Fischer HW,Van Haverbeke Y,Schmitz-Feuerhake I,Muller RN

更新日期：1989-03-01 00:00:00

abstract：PURPOSE:To propose and evaluate a deep learning model for rapid and accurate calculation of myocardial T1 /T2 values based on a previously proposed Bloch equation simulation with slice profile correction (BLESSPC) method. METHODS:Deep learning Bloch equation simulations (DeepBLESS) models are proposed for rapid and ac...

journal_title：Magnetic resonance in medicine

authors： Shao J,Ghodrati V,Nguyen KL,Hu P

更新日期：2020-11-01 00:00:00

abstract：:Parallel magnetic resonance imaging (pMRI) using multichannel receiver coils has emerged as an effective tool to reduce imaging time in various applications. However, the issue of accurate estimation of coil sensitivities has not been fully addressed, which limits the level of speed enhancement achievable with the tec...

journal_title：Magnetic resonance in medicine

authors： Ying L,Sheng J

更新日期：2007-06-01 00:00:00

abstract：:The interactive use of magnetic resonance imaging (MRI) techniques is increasing in operating theaters. A study was performed on 17 male company volunteers to assess the neurobehavioral effects of exposure to magnetic fields from a 1.5 Tesla MRI system. The subjects' neurobehavioral performances on a neurobehavioral t...

journal_title：Magnetic resonance in medicine

authors： de Vocht F,van-Wendel-de-Joode B,Engels H,Kromhout H

更新日期：2003-10-01 00:00:00

abstract：:Accurate and fast quantification of myocardial blood flow (MBF) with MR first-pass perfusion imaging techniques on a pixel-by-pixel basis remains difficult due to relatively long calculation times and noise-sensitive algorithms. In this study, Zierler's central volume principle was used to develop an algorithm for the...

journal_title：Magnetic resonance in medicine

authors： Goldstein TA,Jerosch-Herold M,Misselwitz B,Zhang H,Gropler RJ,Zheng J

更新日期：2008-06-01 00:00:00

abstract：PURPOSE:Spiral-based trajectories for magnetic resonance imaging can be advantageous, but are often cumbersome to design or create. This work presents a flexible numerical algorithm for designing trajectories based on explicit definition of radial undersampling, and also gives several analytical expressions for charact...

journal_title：Magnetic resonance in medicine

authors： Pipe JG,Zwart NR

更新日期：2014-01-01 00:00:00

abstract：:Cervical spinal cord spectroscopy has the potential to add metabolic information to spinal cord MRI and improve the clinical evaluation and research investigation of spinal cord diseases, such as multiple sclerosis (MS) and intraspinal tumors. However, in vivo proton MR spectroscopy ((1)H-MRS) of the spinal cord is di...

journal_title：Magnetic resonance in medicine

authors： Marliani AF,Clementi V,Albini-Riccioli L,Agati R,Leonardi M

更新日期：2007-01-01 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：:When developing new techniques for NMR imaging and in vivo spectroscopy it is a major advantage to be able to calculate the magnetization slice profiles, at any point during a pulse sequence in the presence of a field gradient. While this has frequently been done by treating the problem as a number of discrete resonan...

journal_title：Magnetic resonance in medicine

authors： Bulsing JM,Galloway GJ,Brereton IM,Doddrell DM

更新日期：1987-11-01 00:00:00

abstract：PURPOSE:A method for the quantification of perfusion in murine myocardium is demonstrated. The method allows for the reconstruction of perfusion maps on arbitrary time points in the heart cycle while addressing problems that arise due to the irregular heart beat of mice. METHODS:A flow-sensitive alternating inversion ...

journal_title：Magnetic resonance in medicine

authors： Gutjahr FT,Kampf T,Winter P,Meyer CB,Williams T,Jakob PM,Bauer WR,Ziener CH,Helluy X

更新日期：2015-12-01 00:00:00

abstract：:Head motion is a fundamental problem in functional magnetic resonance imaging and is often a limiting factor in its clinical implementation. This work presents a rigid-body motion correction strategy for echo-planar imaging sequences that uses micro radiofrequency coil "active markers" for real-time, slice-by-slice pr...

journal_title：Magnetic resonance in medicine

authors： Ooi MB,Krueger S,Muraskin J,Thomas WJ,Brown TR

更新日期：2011-07-01 00:00:00

abstract：:In past decades, much effort has been invested in developing therapies for spinal injuries. Lack of standardization of clinical read-out measures, however, makes direct comparison of experimental therapies difficult. Damage and therapeutic effects in vivo are routinely evaluated using rather subjective behavioral test...

journal_title：Magnetic resonance in medicine

authors： Stieltjes B,Klussmann S,Bock M,Umathum R,Mangalathu J,Letellier E,Rittgen W,Edler L,Krammer PH,Kauczor HU,Martin-Villalba A,Essig M

更新日期：2006-05-01 00:00:00

abstract：:Steady-state free precession (SSFP) methods have been very successful due to their high signal and short imaging times. These properties make them good candidates for applications that intrinsically suffer from low signal such as low gamma nuclei imaging. A new chemical shift imaging (CSI) technique based on the SSFP ...

journal_title：Magnetic resonance in medicine

authors： Speck O,Scheffler K,Hennig J

更新日期：2002-10-01 00:00:00