Abstract:
:A number of techniques that recently have been used for fast NMR-imaging are based on a hybrid sequence of echo planar imaging (EPI) and FLASH imaging: after each NMR excitation several k-space lines are measured. The complete k-space is covered by performance of several excitations. It has been observed that there is usually an optimal hybrid sequence that maximizes the signal-to-noise ratio. In this work, a method is presented that allows a determination of the optimal sequence as a function of the relaxation times T1 and T2*.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Deichmann R,Adolf H,Nöth U,Kuchenbrod E,Schwarzbauer C,Haase Adoi
10.1002/mrm.1910340328subject
Has Abstractpub_date
1995-09-01 00:00:00pages
481-9issue
3eissn
0740-3194issn
1522-2594journal_volume
34pub_type
杂志文章abstract::This article introduces a novel method named "Parallel Imaging and Noquist in Tandem" (PINOT) for accelerated image acquisition of cine cardiac magnetic resonance imaging. This method combines two prior information formalisms, the SPACE-RIP implementation of parallel imaging and the Noquist method for reduced-data ima...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22696
更新日期:2011-04-01 00:00:00
abstract::Recovery of the cerebral cortex after 10 min of cardiac arrest was studied in rat using noninvasive MRI techniques. The apparent diffusion coefficient (ADC) of brain water was imaged to document reversal of the metabolic impairment. Perfusion-weighted imaging and blood oxygen level dependent (BOLD) imaging were perfor...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910390516
更新日期:1998-05-01 00:00:00
abstract::Experiments were performed to determine whether changes in T2*-weighted MR images during and after hyperoxia differentiate tumors from normal tissue. Mammary adenocarcinomas implanted in the right hind limbs of rats were studied. Gradient echo images were obtained at 2 Tesla with an evolution time of 20 ms and a recyc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330306
更新日期:1995-03-01 00:00:00
abstract::In vivo echo-planar MR imaging was used to measure apparent diffusion coefficients (ADC) of cerebral tissues in a comprehensive noninvasive evaluation of early ischemic brain damage induced by occlusion of the middle cerebral artery (MCA) in a cat model of acute regional stroke. Within 10 min after arterial occlusion,...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910190220
更新日期:1991-06-01 00:00:00
abstract::Compressed sensing has been of great interest to speed up the acquisition of MR images. The k-t group sparse (k-t GS) method has recently been introduced for dynamic MR images to exploit not just the sparsity, as in compressed sensing, but also the spatial group structure in the sparse representation. k-t GS achieves ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24333
更新日期:2013-04-01 00:00:00
abstract:PURPOSE:Cross-relaxation imaging (CRI) is a family of quantitative magnetization transfer techniques that utilize images obtained with off-resonance saturation and longitudinal relaxation rate (R1) maps reconstructed by the variable flip angle (VFA) method. It was demonstrated recently that a significant bias in an app...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24677
更新日期:2014-02-01 00:00:00
abstract::Emerging applications of sodium bioscales derived from quantitative sodium magnetic resonance imaging assess temporal changes in regional sodium concentration over intervals that vary from hours (monitoring tissue viability in stroke) to weeks (monitoring brain tumor treatment during radiation therapy) or even years (...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23285
更新日期:2012-09-01 00:00:00
abstract::The authors describe a method for accurate in vivo multislice imaging of the active component of the B1 field which is based on a previously proposed method, which uses the signal intensity ratio of two images measured with different excitation angles, and a repetition time TR 5 > or = 5 T1. The new method essentially...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910350217
更新日期:1996-02-01 00:00:00
abstract::Paramagnetic ions complexed to proteins may lose, retain, or enhance solvent paramagnetic relaxation (SPR) relative to free solution. We measured T1 and T2 of three mouse cancers, their normal counterparts, and six additional tissues. Long T1 of cancers was not caused by necrosis or by different contents of water, fat...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910180204
更新日期:1991-04-01 00:00:00
abstract:PURPOSE:To investigate the relative gain in sensitivity of five histology coils designed in-house to accommodate tissue sections of various sizes and compare with commercial mouse head coils. METHODS:The coil set was tailored to house tissue sections ranging from 5 to1000 µm encased in either glass slides or coverslip...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24841
更新日期:2014-05-01 00:00:00
abstract::A method for collecting MRI data on a set of rotated trajectories that begin at the center of k-space is outlined. It is theoretically slightly faster, slightly less susceptible to off-resonance and motion-induced phase, and produces images with slightly better signal-to-noise ratio than methods using Archimedean spir...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199910)42:4<714::aid-mrm13
更新日期:1999-10-01 00:00:00
abstract::An arterial spin labeling technique using separate RF labeling and imaging coils was used to obtain multislice perfusion images of the human brain at 3 T. Continuous RF irradiation at a peak power of 0.3 W was applied to the carotid arteries to adiabatically invert spins. Labeling was achieved without producing magnet...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199906)41:6<1093::aid-mrm4
更新日期:1999-06-01 00:00:00
abstract::A new decoupling sequence, PBAR, is described for broadband heteronuclear decoupling in vivo in humans at 1.5T. The sequence uses non-adiabatic, frequency- and amplitude-modulated inversion pulses designed to minimize decoupling sidebands at low applied gammaB(2) RF field levels and to cover only the narrow range of r...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200102)45:2<226::aid-mrm1031>3.0
更新日期:2001-02-01 00:00:00
abstract::A novel multislice B₁-mapping method dubbed dual refocusing echo acquisition mode is proposed, able to cover the whole transmit coil volume in only one second, which is more than an order of magnitude faster than established approaches. The dual refocusing echo acquisition mode technique employs a stimulated echo acqu...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24158
更新日期:2012-11-01 00:00:00
abstract::Quantitative artificial neural network analysis for 1550 ex vivo 31P nuclear magnetic resonance spectra from hypothermically reperfused pig livers was assessed. These spectra show wide ranges of metabolite concentrations and have been analyzed using metabolite prior knowledge based lineshape fitting analysis which had...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380522
更新日期:1997-11-01 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
pub_type: 杂志文章
doi:10.1002/mrm.28607
更新日期:2020-12-04 00:00:00
abstract:PURPOSE:To develop and validate a regularization approach of optimizing B1 insensitivity of the quantitative magnetization transfer (qMT) pool-size ratio (F). METHODS:An expression describing the impact of B1 inaccuracies on qMT fitting parameters was derived using a sensitivity analysis. To simultaneously optimize fo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27337
更新日期:2018-12-01 00:00:00
abstract::A 3D sequence for dynamic susceptibility imaging is proposed which combines echo-shifting principles (such as PRESTO), sensitivity encoding (SENSE), and partial-Fourier acquisition. The method uses a moderate SENSE factor of 2 and takes advantage of an alternating partial k-space acquisition in the "slow" phase encode...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10599
更新日期:2003-10-01 00:00:00
abstract::To enhance contrast between flow and static tissue, NMR projective angiographic methods usually require data subtraction, or alternatively the application of special data processing routines such as the "maximum intensity projection" algorithm. We have successfully developed a direct projection method which yields suf...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910180213
更新日期:1991-04-01 00:00:00
abstract:PURPOSE:Sensitivity encoding (SENSE) reconstruction of multiband echo planar imaging (EPI) may cause artifacts when simultaneously excited slices require different phase correction to remove the EPI-specific ghost shifted by half of the matrix size (N). We propose a simplified solution of this problem that combines SEN...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25915
更新日期:2016-09-01 00:00:00
abstract::Cortical bone in the mature skeleton has a short T(2)* and produces no detectable signal with conventional MR sequences. A two-dimensional ultrashort echo time (UTE) sequence employing half radio frequency (RF) pulse excitations and radial ramp sampling reduces the effective TE to 8 micros and is capable of detecting ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21397
更新日期:2007-11-01 00:00:00
abstract::Magnetic resonance elastography (MRE) is a recently developed technique for determining the mechanical properties of biological tissue. In dynamic MRE, electromagnetic units (actuators) are widely used to generate shear waves in tissue. These actuators exploit the interaction between the static magnetic field B(0) and...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10479
更新日期:2003-07-01 00:00:00
abstract::The pulse wave velocity (PWV) of aortic blood flow is considered a surrogate for aortic compliance. A new method using phase-contrast (PC)-MRI is presented whereby the spatial and temporal profiles of axial velocity along the descending aorta can be analyzed. Seventeen young healthy volunteers (the YH group), six olde...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21034
更新日期:2006-10-01 00:00:00
abstract::Velocity-encoded phase contrast imaging is being used increasingly in clinical imaging for quantization of blood flow. In this study, the accuracy and precision of ascending aorta flow measurements were found to depend on several subtle aspects of the scan prescription and image analysis. While the usual scan paramete...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910260115
更新日期:1992-07-01 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
pub_type: 杂志文章
doi:10.1002/mrm.27518
更新日期:2019-03-01 00:00:00
abstract::We developed a quantitative magnetic resonance imaging method to permit a rapid assessment of brain water content during osmotic brain edema produced by intraperitoneal (ip) injection of distilled water. Fifteen minutes after water injection, the normalized mean image intensity (MIn) from a spin-echo pulse sequence (T...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910240107
更新日期:1992-03-01 00:00:00
abstract::We present new diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models. The phantom design permits the application of imaging parameters that are typically employed in studies of the human brain. The phantoms were made of small-diameter acrylic fibers, chose...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21789
更新日期:2008-12-01 00:00:00
abstract::Some of the important features of how pulsatile flow generates artifacts in three-dimensional magnetic resonance imaging are analyzed and demonstrated. Time variations in the magnetic resonance signal during the heart cycle lead to more complex patterns of artifacts in 3D imaging than in 2D imaging. The appearance and...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910300305
更新日期:1993-09-01 00:00:00
abstract::Most prostate MRI/MRS examinations are performed with an endorectal coil inflated with air, leading to an air-tissue interface that induces magnetic susceptibility gradients within the gland. Inflation of the coil with a barium sulfate suspension is described and compared to inflation with air or liquid perfluorocarbo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21166
更新日期:2007-05-01 00:00:00
abstract::The manufacturing of intravascular imaging coils poses several challenges. Due to their size, it can be difficult to incorporate local matching networks and signal amplifiers. The goal of this study is to investigate tuning and amplification strategies for intravascular coils and to assess the signal-to-noise benefits...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24134
更新日期:2012-11-01 00:00:00