Investigation and modeling of magnetization transfer effects in two-dimensional multislice turbo spin echo sequences with low constant or variable flip angles at 3 T.

abstract：:High-order radiofrequency transmitter coils are described that permit, in the context of NMR imaging, a knowledgeable trade-off between coil complexity and the degree of inhomogeneity over a specified volume of space. A mathematical formulation of high-order coils is developed for an axially symmetric polarizing dc fi...

journal_title：Magnetic resonance in medicine

authors： Sotgiu A,Hyde JS

更新日期：1986-02-01 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：:High-resolution turbo spin echo (TSE) images have demonstrated important details of carotid artery morphology; however, it is evident that pulsatile blood and wall motion related to the cardiac cycle are still significant sources of image degradation. Although ECG gating can reduce artifacts due to cardiac-induced pul...

journal_title：Magnetic resonance in medicine

authors： Mendes J,Parker DL,Hulet J,Treiman GS,Kim SE

更新日期：2011-11-01 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：: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

authors： Bieri O,Scheffler K

更新日期：2009-11-01 00:00:00

abstract：PURPOSE:To investigate whether nonlinear dimensionality reduction improves unsupervised classification of (1) H MRS brain tumor data compared with a linear method. METHODS:In vivo single-voxel (1) H magnetic resonance spectroscopy (55 patients) and (1) H magnetic resonance spectroscopy imaging (MRSI) (29 patients) dat...

journal_title：Magnetic resonance in medicine

authors： Yang G,Raschke F,Barrick TR,Howe FA

更新日期：2015-09-01 00:00:00

abstract：:Coronal proton and sodium images of control rats and rats with either increased permeability edema produced by intravenous alloxan (300 mg/kg) or increased pressure edema produced by saline infusion (2 ml/min) were obtained. Axial chest CT images were used to monitor the development of pulmonary edema. Immediately aft...

journal_title：Magnetic resonance in medicine

authors： Kundel HL,Shetty A,Joseph PM,Summers RM,Kassab EA,Moore B

更新日期：1988-04-01 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

authors： McVeigh ER,Guttman MA,Lederman RJ,Li M,Kocaturk O,Hunt T,Kozlov S,Horvath KA

更新日期：2006-11-01 00:00:00

abstract：PURPOSE:The optic nerve (ON) represents the sole pathway between the eyes and brain; consequently, diseases of the ON can have dramatic effects on vision. However, quantitative magnetization transfer (qMT) applications in the ON have been limited to ex vivo studies, in part because of the fatty connective tissue that s...

journal_title：Magnetic resonance in medicine

authors： Smith AK,Dortch RD,Dethrage LM,Lyttle BD,Kang H,Welch EB,Smith SA

更新日期：2017-02-01 00:00:00

abstract：PURPOSE:Going to ultrahigh field MRI (e.g., 7 Tesla [T]), the nonuniformity of the B1+ field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B1+, its field remains nonuniform. In this work, an RF pulse was designed that uses the slab selecti...

journal_title：Magnetic resonance in medicine

authors： van Kalleveen IM,Boer VO,Luijten PR,Klomp DW

更新日期：2015-08-01 00:00:00

abstract：PURPOSE:Magnetic resonance imaging (MRI)-based techniques for assessing liver iron concentration (LIC) have been limited by single scanner calibration against biopsy. Here, the calibration of spin-density projection-assisted (SDPA) R2-MRI (FerriScan®) in iron-overloaded β-thalassemia patients treated with the iron chel...

journal_title：Magnetic resonance in medicine

authors： St Pierre TG,El-Beshlawy A,Elalfy M,Al Jefri A,Al Zir K,Daar S,Habr D,Kriemler-Krahn U,Taher A

更新日期：2014-06-01 00:00:00

abstract：:Image reconstruction of tagged cardiac MR images using complementary spatial modulation of magnetization (CSPAMM) requires the subtraction of two complex datasets to remove the untagged signal. Although the resultant images typically have sharper and more persistent tags than images formed without complementary taggin...

journal_title：Magnetic resonance in medicine

authors： NessAiver M,Prince JL

更新日期：2003-08-01 00:00:00

abstract：PURPOSE:Preclinical imaging of myocardial blood flow (MBF) can elucidate molecular mechanisms underlying cardiovascular disease. We compared the repeatability and variability of two methods, first-pass MRI and arterial spin labeling (ASL), for imaging MBF in mice. METHODS:Quantitative perfusion MRI in mice was perform...

journal_title：Magnetic resonance in medicine

authors： Naresh NK,Chen X,Moran E,Tian Y,French BA,Epstein FH

更新日期：2016-06-01 00:00:00

abstract：:A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume fo...

journal_title：Magnetic resonance in medicine

authors： Pisani L,Bammer R,Glover G

更新日期：2007-02-01 00:00:00

abstract：:MRI after a constant infusion (CI) of Gd-DTPA has been used to identify the extent of myocardial infarction (MI). However, Gd-DTPA-enhanced "viability" imaging is more commonly performed with a bolus (for "delayed-enhancement" (DE) imaging). This study sought to determine how image delay time and time postinfarction i...

journal_title：Magnetic resonance in medicine

authors： Thornhill RE,Prato FS,Wisenberg G,Moran GR,Sykes J

更新日期：2004-11-01 00:00:00

abstract：:Phase-sensitive inversion-recovery (PSIR) imaging may provide enhanced T(1) contrast. However, clinical implementation of PSIR imaging is hindered because image reconstruction with this method often lacks robustness and requires manual intervention, particularly for data acquired in multiple slices and with phased-arr...

journal_title：Magnetic resonance in medicine

authors： Ma J

更新日期：2005-04-01 00:00:00

abstract：:A novel multiple quantum filtering method is proposed that uses a doubly selective pulse termed Delays Alternating with Nutations for Tailored Excitation (DANTE) for multiple quantum preparation. This method selectively prepares GABA-3 and GABA-4 into a multiple quantum state and suppresses all other resonances at 3.0...

journal_title：Magnetic resonance in medicine

authors： Shen J,Rothman DL,Brown P

更新日期：2002-03-01 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-based multipoint water-fat separation methods have been applied in balanced steady-state free precession (bSSFP) sequences because of the high signal-to-noise-ratio (SNR) attainable. In this approach the echo formation is approximated to occur concurrently for both water and fat at an echo time (TE) equ...

journal_title：Magnetic resonance in medicine

authors： Kim H,Pinus AB,Wang J,Murphy PS,Constable RT

更新日期：2007-08-01 00:00:00

abstract：:A general analytical framework is presented for the design of birdcage radiofrequency resonators on cylindrical formers having arbitrary cross-sectional shape. The primary objective of such shapes would be to improve the sensitivity of the NMR experiment to noncircular regions of the human anatomy while maintaining fi...

journal_title：Magnetic resonance in medicine

authors： De Zanche N,Yahya A,Vermeulen FE,Allen PS

更新日期：2005-01-01 00:00:00

abstract：PURPOSE:To optimize 3D radial ultrashort echo time MRI for high resolution whole-lung imaging. METHODS:3D radial ultrashort echo time was implemented on a 3T scanner to investigate the effects of: (1) limited field-of-view excitation, (2) variable density readouts, and (3) radial oversampling. Improvements in noise pe...

journal_title：Magnetic resonance in medicine

authors： Johnson KM,Fain SB,Schiebler ML,Nagle S

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:High field T2* -weighted MR images of the cerebral cortex are increasingly used to study tissue susceptibility changes related to aging or pathologies. This paper presents a novel automated method for the computation of quantitative cortical measures and group-wise comparison using 7 Tesla T2* -weighted magnitu...

journal_title：Magnetic resonance in medicine

authors： Doan NT,van Rooden S,Versluis MJ,Buijs M,Webb AG,van der Grond J,van Buchem MA,Reiber JHC,Milles J

更新日期：2015-07-01 00:00:00

abstract：:Accurate quantification of myocardial perfusion remains challenging due to saturation of the arterial input function at high contrast concentrations. A method for estimating the arterial input function directly from tissue curves in the myocardium that avoids these difficulties is presented. In this constrained altern...

journal_title：Magnetic resonance in medicine

authors： Fluckiger JU,Schabel MC,DiBella EV

更新日期：2011-08-01 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 develop and evaluate a free-breathing chemical-shift-encoded (CSE) spoiled gradient-recalled echo (SPGR) technique for whole-heart water-fat imaging at 3 Tesla (T). METHODS:We developed a three-dimensional (3D) multi-echo SPGR pulse sequence with electrocardiographic gating and navigator echoes and evaluate...

journal_title：Magnetic resonance in medicine

authors： Taviani V,Hernando D,Francois CJ,Shimakawa A,Vigen KK,Nagle SK,Schiebler ML,Grist TM,Reeder SB

更新日期：2014-09-01 00:00:00

abstract：:Respiratory motion and pulsatile blood flow can generate artifacts in morphological and functional lung imaging. Total acquisition time, and thus the achievable signal to noise ratio, is limited when performing breath-hold and/or electrocardiogram-triggered imaging. To overcome these limitations, imaging during free r...

journal_title：Magnetic resonance in medicine

authors： Oechsner M,Pracht ED,Staeb D,Arnold JF,Köstler H,Hahn D,Beer M,Jakob PM

更新日期：2009-03-01 00:00:00

abstract：PURPOSE:The aim of the study was to investigate whether incorrectly compensated eddy currents are the source of persistent X-nuclear spectroscopy and imaging artifacts, as well as methods to correct this. METHODS:Pulse-acquire spectra were collected for 1 H and X-nuclei (23 Na or 31 P) using the minimum TR permitted o...

journal_title：Magnetic resonance in medicine

authors： McLean MA,Hinks RS,Kaggie JD,Woitek R,Riemer F,Graves MJ,McIntyre DJO,Gallagher FA,Schulte RF

更新日期：2020-12-04 00:00:00

abstract：PURPOSE:To develop and evaluate a novel 2D phase-unwrapping method that works robustly in the presence of severe noise, rapid phase changes, and disconnected regions. THEORY AND METHODS:The MR phase map usually varies rapidly in regions adjacent to wraps. In contrast, the phasors can vary slowly, especially in regions...

journal_title：Magnetic resonance in medicine

authors： Cheng J,Mei Y,Liu B,Guan J,Liu X,Wu EX,Feng Q,Chen W,Feng Y

更新日期：2018-01-01 00:00:00

abstract：PURPOSE:To accelerate the acquisition of J-resolved proton magnetic resonance spectroscopic imaging (1 H-MRSI) data for high-resolution mapping of brain metabolites and neurotransmitters. METHODS:The proposed method used a subspace model to represent multidimensional spatiospectral functions, which significantly reduc...

journal_title：Magnetic resonance in medicine

authors： Tang L,Zhao Y,Li Y,Guo R,Clifford B,El Fakhri G,Ma C,Liang ZP,Luo J

更新日期：2021-01-01 00:00:00

abstract：PURPOSE:To design, evaluate, and apply a bow tie antenna transceiver radiofrequency (RF) coil array tailored for cardiac MRI at 7.0 Tesla (T). METHODS:The radiofrequency (RF) coil array comprises 16 building blocks each containing a bow tie shaped λ/2-dipole antenna. Numerical simulations were used for transmission fi...

journal_title：Magnetic resonance in medicine

authors： Oezerdem C,Winter L,Graessl A,Paul K,Els A,Weinberger O,Rieger J,Kuehne A,Dieringer M,Hezel F,Voit D,Frahm J,Niendorf T

更新日期：2016-06-01 00:00:00