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 method to get good primary estimates of the resonance and phase offset parameters. The resulting estimation procedure is fully automatic and has proven to be robust for 31P data.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Burger C,McKinnon G,Buchli R,Boesiger Pdoi
10.1002/mrm.1910210206subject
Has Abstractpub_date
1991-10-01 00:00:00pages
216-21issue
2eissn
0740-3194issn
1522-2594journal_volume
21pub_type
杂志文章abstract::A double-tuned single coil probe for high field metabolic NMR studies has been designed and tested. The resonant coil is a single-turn of copper foil wound on a quartz cylinder. It is fed by a short length of parallel strip line made of the same material; the feeder is also used as a tuning capacitance. Electrical par...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910230216
更新日期:1992-02-01 00:00:00
abstract::MR oximetry requires a T2 measurement that is accurate within 5% in vivo. Simple methods are susceptible to signal loss and tend to underestimate T2. Current methods utilize RF pulses or RF cycling patterns that prevent signal loss at each data acquisition. However, using these methods with imperfect pulses, T2 tends ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380512
更新日期:1997-11-01 00:00:00
abstract:PURPOSE:High-resolution three-dimensional (3D) structural MRI is useful for delineating complex or small structures of the body. However, it requires long acquisition times and high SAR, limiting its clinical use. The purpose of this work is to accelerate the acquisition of high-resolution images by combining compresse...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27789
更新日期:2019-09-01 00:00:00
abstract:PURPOSE:Noninvasive imaging techniques that quantify renal tissue composition are needed to more accurately ascertain prognosis and monitor disease progression in polycystic kidney disease (PKD). Given the success of magnetization transfer (MT) imaging to characterize various tissue remodeling pathologies, it was teste...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25701
更新日期:2016-04-01 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
pub_type: 杂志文章
doi:10.1002/mrm.22809
更新日期:2011-08-01 00:00:00
abstract::The mechanics of the macrocirculation are examined as a basis for imaging blood flow within the system. The macrocirculation is defined as that part of the circulation in which inertial forces are not negligible compared to viscous forces and as such in human subjects comprises the heart and large blood vessels. Becau...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140204
更新日期:1990-05-01 00:00:00
abstract::Four-dimensional (4D) flow imaging has been used to study flow patterns and pathophysiology, usually focused on specific thoracic vessels and cardiac chambers. Whole-heart 4D flow at high measurement accuracy covering the entire thoracic cardiovascular system would be desirable to simplify and improve hemodynamic asse...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22090
更新日期:2009-10-01 00:00:00
abstract:PURPOSE:A purely experimental method for MRI-based transfer function (TF) determination is presented. A TF characterizes the potential for radiofrequency heating of a linear implant by relating the incident tangential electric field to a scattered electric field at its tip. We utilize the previously introduced transfer...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27974
更新日期:2020-03-01 00:00:00
abstract::The recently developed technique of gradient, high-resolution magic-angle spinning NMR (g-hr-MAS-NMR) spectroscopy was applied to the study of ex vivo human lipoma and liposarcoma tissue. Compared with conventional 1H-NMR, the g-hr-MAS method yielded a large improvement in spectral resolution and permitted the detecti...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380307
更新日期:1997-09-01 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::The assumption of linear time-invariance (LTI) in the human primary somatosensory cortex (SI) is assessed for fMRI signals generated by variable-duration vibrotactile stimuli. Predictions based on time-shifted summation (TSS) of responses to 2 s stimuli overestimate observed BOLD signal amplitudes in response to longe...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/mrm.20363
更新日期:2005-02-01 00:00:00
abstract::Function and morphology of the cerebral vasculature were studied in the amyloid (Abeta) plaque-containing double-transgenic (TG) B6.PS2APP Alzheimer's disease (AD) mouse model with MRI at an age range of 10 to 17 months. Perfusion, blood volume, and average vessel geometry were assessed in the brain and compared to ag...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21985
更新日期:2009-07-01 00:00:00
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
pub_type: 杂志文章
doi:10.1002/mrm.1910030108
更新日期:1986-02-01 00:00:00
abstract::The feasibility of MR subtraction imaging of lung ventilation using air against oxygen using a multiple inversion recovery half-Fourier single-shot turbo spin echo (MIR-HASTE) sequence was investigated. Eight healthy, nonsmoking volunteers (3 males, 5 females; from 27 to 48 years of age) were studied on a 1.5 T MR uni...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/1522-2594(200006)43:6<913::aid-mrm21>3.0.c
更新日期:2000-06-01 00:00:00
abstract:PURPOSE:To assess the use of image registration for correcting respiratory motion in free breathing lung T1 mapping acquisition in patients with idiopathic pulmonary fibrosis (IPF). THEORY AND METHODS:The method presented used image registration to synthetic images during postprocessing to remove respiratory motion. S...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28342
更新日期:2020-12-01 00:00:00
abstract::A modified inversion-recovery sequence is introduced which performs subtraction angiography by varying time-of-flight effects of blood flowing into an imaged slab. The selective 180 degrees excitation inverts different regions between measurements to isolate arterial and/or venous blood. On normal human subjects, high...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910040214
更新日期:1987-02-01 00:00:00
abstract:PURPOSE:The purpose of this study is to increase the robustness of MR fingerprinting (MRF) toward subject motion. METHODS:A novel reconstruction algorithm, MOtion insensitive MRF (MORF), was developed, which uses an iterative reconstruction based retrospective motion correction approach. Each iteration loops through t...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27227
更新日期:2018-12-01 00:00:00
abstract::An intermolecular double-quantum coherence (iDQC) imaging technique was used to study auditory activation in the human brain at 1.5T with a dual temporal lobe surface phased array coil and a quadrature head coil. Preliminary results demonstrate that it is feasible to obtain auditory activation maps using iDQC imaging ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200103)45:3<356::aid-mrm1046>3.0
更新日期:2001-03-01 00:00:00
abstract::Diffusion tensor imaging is gaining increasing importance for anatomical imaging of the developing mouse brain. However, the application of diffusion tensor imaging to mouse brain imaging at microscopic levels is hindered by the limitation on achievable spatial resolution. In this study, fast diffusion tensor microima...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22426
更新日期:2010-07-01 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
pub_type: 杂志文章
doi:10.1002/mrm.22145
更新日期:2010-01-01 00:00:00
abstract::Functional MRI (fMRI) by means of spin-echo (SE) techniques provides an interesting alternative to gradient-echo methods because the contrast is based primarily on dynamic averaging associated with the blood oxygenation level-dependent (BOLD) effect. In this article the contributions from different brain compartments ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20221
更新日期:2004-10-01 00:00:00
abstract::Localized 7Li MR point-resolved spectroscopy (PRESS) was developed as a technique to measure lithium (Li) concentration in rat brain in vivo. Localized 7Li spectra could be obtained at 4.7 T in a 0.7-ml voxel in rat brain over the entire therapeutic range of serum Li for humans. Localized 7Li spin-lattice (T1) and spi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20112
更新日期:2004-07-01 00:00:00
abstract:PURPOSE:Fluorescence lifetime imaging microscopy (FLIM) of endogenous fluorescent metabolites permits the measurement of cellular metabolism in cell, tissue and animal models. In parallel, magnetic resonance spectroscopy (MRS) of dynamic nuclear (hyper)polarized (DNP) 13 C-pyruvate enables measurement of metabolism at ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27644
更新日期:2019-05-01 00:00:00
abstract::Brain water proton (1H2O) longitudinal relaxation time constants (T1) were obtained from three healthy individuals at magnetic field strengths (B0) of 0.2 Tesla (T), 1.0T, 1.5T, 4.0T, and 7.0T. A 5-mm midventricular axial slice was sampled using a modified Look-Locker technique with 1.5 mm in-plane resolution, and 32 ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21122
更新日期:2007-02-01 00:00:00
abstract::Fucose is believed to be a marker for cancer that may be detectable by the 2D proton NMR (COSY) of human plasma. However, the COSY technique is time consuming and prone to error. These problems may be alleviated by using the SUPERCOSY pulse sequence; this technique shows that there are many other cross peaks in the re...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910150102
更新日期:1990-07-01 00:00:00
abstract::The assessment of myocardial fibrosis and extracellular volume requires accurate estimation of myocardial T1 s. While image acquisition using the modified Look-Locker inversion recovery technique is clinically feasible for myocardial T1 mapping, respiratory motion can limit its applicability. Moreover, the conventiona...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24385
更新日期:2013-05-01 00:00:00
abstract::The harmonic phase (HARP) method provides automatic and rapid analysis of tagged magnetic resonance (MR) images for quantification and visualization of myocardial strain. In this article, the development and implementation of a pulse sequence that acquires HARP images in real time are described. In this pulse sequence...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/mrm.10509
更新日期:2003-07-01 00:00:00
abstract::The authors present their 1-year experience with the use of 3DFT, time-of-flight MR angiography for the evaluation of vascular diseases of the head and neck. Their experience with over 150 patients indicates that this examination may be performed in conjunction with standard spin-echo imaging with only a minimal incre...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140215
更新日期:1990-05-01 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
pub_type: 杂志文章
doi:10.1002/mrm.20317
更新日期:2005-01-01 00:00:00
abstract:PURPOSE:To develop velocity-selective (VS) MR angiography (MRA) protocols for arteriography and venography with whole-brain coverage. METHODS:Tissue suppression using velocity-selective saturation (VSS) pulse trains is sensitive to radiofrequency field (B1 +) inhomogeneity. To reduce its sensitivity, we replaced the l...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26864
更新日期:2018-04-01 00:00:00