Abstract:
:It is shown that in vivo measurement of bile water apparent diffusion coefficient (ADC) by diffusion-weighted echo-planar imaging (EPI) in hamster gallbladder is possible providing motion artifact-free ADC values. These ADC values are used to estimate bile viscosity variation induced by normal diets, cholesterol gallstone-inducing diets, and an antilithiasic drug, and to determine if a link exists between bile viscosity and cholesterol gallstone formation. Measurements were performed at 4.7 T with respiratory triggering in five groups of hamsters fed a commercial (RC) or a semisynthetic (SSD) diet, a SSD containing 0.2% hyodeoxycholic acid (SSD+HDC) and two lithogenic diets (LD5, LD10). ADC decreased significantly in LD10 (2.15+/-0.07x 10(-3) mm(2)s(-1)) and SSD+HDC (2.03+/-0.04) compared to RC (2.40+/-0.05) but not in the most lithogenic LD5 diet (2.33+/-0.06). No direct relationship was found between bile viscosity and gallstone incidence; however, viscosity seems to be related to lipid contents of diets. Magn Reson Med 43:854-859, 2000.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Tiffon B,Parquet M,Dubrac S,Lutton C,Volk Adoi
10.1002/1522-2594(200006)43:6<854::aid-mrm11>3.0.csubject
Has Abstractpub_date
2000-06-01 00:00:00pages
854-9issue
6eissn
0740-3194issn
1522-2594pii
10.1002/1522-2594(200006)43:6<854::AID-MRM11>3.0.Cjournal_volume
43pub_type
杂志文章abstract::A 3.0 Tesla, 0.80-m bore magnet replaced our previous 1.9 Tesla, 0.76-m magnet. The 3.0 Tesla replacement magnet had a dipole moment of 1.7 with respect to that of the 1.9 Tesla magnet. The pre-existing cylindrically symmetric passive steel shielding was modified to confine the fringe fields of the replacement magnet ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910290319
更新日期:1993-03-01 00:00:00
abstract::TSENSE and TGRAPPA are autocalibrated parallel imaging techniques that can improve the temporal resolution and/or spatial resolution in dynamic magnetic resonance imaging applications. In its original form, TSENSE uses temporal low-pass filtering of the undersampled frames to create the sensitivity map. TGRAPPA uses a...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22766
更新日期:2011-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.27209
更新日期:2018-12-01 00:00:00
abstract:PURPOSE:To develop a method that fits a multipool model to z-spectra acquired from non-steady state sequences, taking into account the effects of variations in T1 or B1 amplitude and the results estimating the parameters for a four-pool model to describe the z-spectrum from the healthy brain. METHODS:We compared measu...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26459
更新日期:2017-08-01 00:00:00
abstract::Stimulated-echo localized spectroscopy was combined with phase- and frequency-encoding gradients to obtain "zoom" or magnified images of specific organs in situ. The technique requires neither surface coils nor an imaging coil arrangement that exclusively isolates the target organ. This technique can be readily applie...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910050412
更新日期:1987-10-01 00:00:00
abstract:PURPOSE:To test the efficacy of 7T MRS for in vivo detection of 2-hydroxyglutarate (2HG) in brain tumors. METHODS:The subecho times of point-resolved spectroscopy (PRESS) were optimized at 7T with density-matrix simulations and phantom validation to improve the 2HG signal selectivity with respect to the neighboring re...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26190
更新日期:2017-03-01 00:00:00
abstract:PURPOSE:Previous studies have associated low pH in intervertebral discs (IVDs) with discogenic back pain. The purpose of this study was to determine whether quantitative CEST (qCEST) MRI can be used to detect pH changes in IVDs in vivo. METHODS:The exchange rate ksw between glycosaminoglycan (GAG) protons and water pr...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26457
更新日期:2016-12-01 00:00:00
abstract::When using tracer kinetic modeling to analyze dynamic contrast-enhanced MRI (DCE-MRI) it is necessary to identify an appropriate arterial input function (AIF). The measured AIF is often poorly sampled in both clinical and preclinical MR systems due to the initial rapid increase in contrast agent concentration and the ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21959
更新日期:2009-05-01 00:00:00
abstract:PURPOSE:The use of electromagnetic (EM) modeling is critical for specific absorption rate (SAR) characterization in parallel transmission MRI. Radiofrequency arrays that include decoupling networks can be difficult to characterize accurately in simulation. A practical method of simplifying modeling is to exclude the de...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25504
更新日期:2015-11-01 00:00:00
abstract::A novel radio-frequency (RF) pulse design algorithm is presented that generates fast slice-selective excitation pulses that mitigate B+1 inhomogeneity present in the human brain at high field. The method is provided an estimate of the B+1 field in an axial slice of the brain and then optimizes the placement of sinc-li...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21585
更新日期:2008-06-01 00:00:00
abstract:PURPOSE:To develop histology-informed simulations of diffusion tensor cardiovascular magnetic resonance (DT-CMR) for typical in-vivo pulse sequences and determine their sensitivity to changes in extra-cellular space (ECS) and other microstructural parameters. METHODS:We synthesised the DT-CMR signal from Monte Carlo r...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27561
更新日期:2019-04-01 00:00:00
abstract:PURPOSE:To achieve rapid, high resolution whole-brain gray matter (GM) imaging by developing a novel, single-slab three-dimensional dual-echo fast-spin-echo pulse sequence and GM-selective reconstruction. METHODS:Unlike conventional GM imaging that uses time-consuming double-inversion-recovery preparation, the propose...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26910
更新日期:2017-11-01 00:00:00
abstract:PURPOSE:Cardiac T1 mapping has become an increasingly important imaging technique, contributing novel diagnostic options. However, currently utilized methods are often associated with accuracy problems because of heart rate variations and cardiac arrhythmia, limiting their value in clinical routine. This study aimed to...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27526
更新日期:2019-03-01 00:00:00
abstract::We have demonstrated that echo-planar imaging can be used to produce high-quality snapshot images of the human fetus in utero in a fraction of a second. These images are free of motional artifact or blurring and allow detailed depiction of fetal structures in normal and pathological pregnancies. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910130214
更新日期:1990-02-01 00:00:00
abstract:PURPOSE:To evaluate proton density fat fraction (PDFF) and R2* as markers of bone marrow composition and structure in inflamed bone in patients with spondyloarthritis. METHODS:Phantoms containing fat, water, and trabecular bone were constructed with proton density fat fraction (PDFF) and bone mineral density (BMD) val...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26729
更新日期:2018-02-01 00:00:00
abstract::Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the exchange process between protons of nonequivalent chemical environments. To compare the characteristics of the CEST and SL approaches in the study of chemical exchange effects, we performed CEST and SL experiment...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22721
更新日期:2011-05-01 00:00:00
abstract:PURPOSE:We propose a new acquisition to minimize the per-excitation encoding duration and improve the imaging capability for short T2 * species. METHODS:In the proposed ramped hybrid encoding (RHE) technique, gradients are applied before the radiofrequency (RF) pulse as in pointwise encoding time reduction with radial...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25977
更新日期:2016-09-01 00:00:00
abstract::Functional magnetic resonance imaging in real time is an emerging tool for the assessment of dynamic changes in brain activation. The short response latency (tens of seconds) renders the technique more sensitive to motion artifacts. Motion correction in real time requires computationally efficient algorithms which can...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200101)45:1<167::aid-mrm1023>3.0
更新日期:2001-01-01 00:00:00
abstract::Whole-body NMR imaging antennas (probes) are strongly affected by the inevitable magnetic and controllable dielectric losses. Using a convenient parallelepiped model, the magnetic losses are evaluated. By introducing the "ideal power gain," the best possible antenna performance is delimited as a function of the freque...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910020403
更新日期:1985-08-01 00:00:00
abstract:PURPOSE:The primary purpose of this study is to propose a method for the simultaneous quantitative three-dimensional (3D) mapping of conductivity and susceptibility using double-echo ultrashort echo time (UTE) imaging. The secondary purpose is to investigate the changes of these properties over time during in vitro hem...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25869
更新日期:2016-07-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910300105
更新日期:1993-07-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910330407
更新日期:1995-04-01 00:00:00
abstract:PURPOSE:Conventional 31 P chemical shift imaging is time-consuming and yields only limited spatial resolution. The purpose of this study was to demonstrate feasibility of 31 P echo-planar spectroscopic imaging (EPSI) in vivo at 7T. METHODS:A 3D 31 P EPSI sequence with trapezoidal-shaped gradient pulses was implemented...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26785
更新日期:2018-03-01 00:00:00
abstract::A method is presented for the detection of quadrupole splitting in tissue, where the spectral line splittings are typically unobservable. The method used is a study of the rate of rotation of the flip angle as a function of radiofrequency (rf) amplitude. Our results with samples of skeletal muscle and cat brain indica...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910040108
更新日期:1987-01-01 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
pub_type: 杂志文章
doi:10.1002/mrm.21245
更新日期:2007-06-01 00:00:00
abstract:PURPOSE:Imaging gradients result in the generation of concomitant fields, or Maxwell fields, which are of increasing importance at higher gradient amplitudes. These time-varying fields cause additional phase accumulation, which must be compensated for to avoid image artifacts. In the case of gradient systems employing ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26790
更新日期:2018-03-01 00:00:00
abstract:PURPOSE:To develop and evaluate a novel two-dimensional self-gated imaging technique for free-breathing cardiac cine MRI that is free of motion-detection overhead and requires minimal planning for motion tracking. METHODS:Motion along the readout direction was extracted solely from normal Cartesian imaging readouts ne...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25834
更新日期:2016-08-01 00:00:00
abstract::In an effort to develop MRI methods for the evaluation of tumor angiogenesis (new blood vessel formation), MRI-derived cerebral blood volume (CBV) information has been compared to histologic measures of microvessel density (MVD). Although MVD is a standard marker of angiogenesis, it is not a direct correlate of the vo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1252
更新日期:2001-10-01 00:00:00
abstract:PURPOSE:Irreversible electroporation (IRE) is a nonthermal tissue ablation technique that represents a promising treatment option for unresectable liver tumors, but the effectively treated zone cannot be reliably predicted. We investigate the potential benefit of transcatheter intra-arterial perfusion (TRIP) -MRI for t...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28104
更新日期:2020-07-01 00:00:00
abstract:PURPOSE:To develop a method to use information from multiple MRI contrasts to produce a composite angiogram with reduced sequence-specific artifacts and improved vessel depiction. METHODS:Bayesian posterior vessel probability was determined as a function of black blood (BB), contrast enhanced angiography (CE-MRA), and...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27966
更新日期:2020-03-01 00:00:00