Abstract:
:In vivo lactate detection using gradient enhanced double quantum coherence transfer (DQCT) was significantly improved by addition of short-time-inversion-recovery (STIR). Phantom studies demonstrated lipid suppression down to the background noise level with 33% loss of lactate signal. In vivo studies using a rabbit model of hypoxic and unilateral-ischemic brain injury showed reduction down to 29 +/- 11% in lipids with inversion times between 140 and 170 ms. Lactate signals on the ischemic side were 51 +/- 53% higher than the nonischemic side at the peak of hypoxia. STIR-DQCT can be a useful robust method of obtaining metabolic maps of lactate in vivo.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Nakai T,Rhine WD,Okada T,Stevenson DK,Spielman DMdoi
10.1002/mrm.1910400416subject
Has Abstractpub_date
1998-10-01 00:00:00pages
629-32issue
4eissn
0740-3194issn
1522-2594journal_volume
40pub_type
杂志文章abstract::Black blood MRI is an attractive tool for monitoring normal and pathological wall thickening; however, limited spatial resolutions can conspire with complex vascular geometries to distort the appearance of the wall in ways hitherto unclear. To elucidate this, a thin-walled cylinder model was developed to predict the c...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21758
更新日期:2008-11-01 00:00:00
abstract:PURPOSE:To reduce the influence of tidal volume on fractional ventilation (FV) derived by Fourier decomposition (FD). METHODS:Twelve volunteers were examined on a 1.5 Tesla scanner. Spoiled gradient echo imaging of coronal and sagittal slices of the lung were performed. The tidal volume variations between different ac...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26047
更新日期:2016-11-01 00:00:00
abstract::Sequential albumin-Gd-DTPA and Gd-DTPA dynamic enhancement studies were performed in an animal tumor model for the comparison of regional vascularity and permeability parameters measured by these two different sizes of contrast agents. The early albumin-Gd-DTPA enhancement arises from the vascular compartment, and the...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910340318
更新日期:1995-09-01 00:00:00
abstract:PURPOSE:Delta relaxation enhanced magnetic resonance (dreMR) imaging requires an auxiliary B0 electromagnet capable of shifting the main magnetic field within a clinical 1.5 Tesla (T) MR system. In this work, the main causes of interaction between an actively shielded, insertable resistive B0 electromagnet and a 1.5T s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25014
更新日期:2014-10-01 00:00:00
abstract::A new k-space direct matrix inversion (DMI) method is proposed here to accelerate non-Cartesian SENSE reconstructions. In this method a global k-space matrix equation is established on basic MRI principles, and the inverse of the global encoding matrix is found from a set of local matrix equations by taking advantage ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20974
更新日期:2006-08-01 00:00:00
abstract:PURPOSE:A new approach to design parallel transmit (pTx) head arrays is proposed that integrates transmit radiofrequency pulse designs with electromagnetic modeling of array coil elements. THEORY AND METHODS:An approach to design pTx head arrays is proposed that finds optimal groupings of a large number of coils into ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28068
更新日期:2020-06-01 00:00:00
abstract:PURPOSE:Diffusion-weighted imaging (DWI) and 18 F-fluorodeoxyglucose-positron emission tomography (18 F-FDG-PET) independently correlate with malignancy in breast cancer, but the relationship between their structural and metabolic metrics is not completely understood. This study spatially correlates diffusion, perfusio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26505
更新日期:2017-09-01 00:00:00
abstract::Partial-volume effects (PVE) in stroke imaging could hinder proper delineation of normal, ischemic, and at-risk tissues. Cerebral-blood-flow (CBF) and apparent diffusion coefficient (ADC) were measured at high and low resolution (HR = 128 x 128, LR = 64 x 64) in focal ischemia in rats during the acute phase. The data ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20299
更新日期:2004-12-01 00:00:00
abstract::Introduction of a Gaussian weighting function into the phase encoding of the spin-echo imaging method via variable tip angle excitation, with concomitant optimization of the recycle delay, is shown to increase the sensitivity of T2-weighted imaging by up to 40%. In addition, the Gibbs artifact associated with sharp bo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910210216
更新日期:1991-10-01 00:00:00
abstract::Three-dimensional magnetization-prepared (MP) MR angiography (MRA) was applied to the carotid and vertebral arteries by using ECG triggering, a slab selective RF inversion pulse, centric phase encoding and acquisition during diastole. Both theoretically and experimentally, the MP MRA sequence was shown to perform well...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910370219
更新日期:1997-02-01 00:00:00
abstract:PURPOSE:Structure-guided total variation is a recently introduced prior that allows reconstruction of images using knowledge of the location and orientation of edges in a reference image. In this work, we demonstrate the advantages of a variant of structure-guided total variation known as directional total variation (D...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28245
更新日期:2020-10-01 00:00:00
abstract::A type of local coil (or surface coil) for magnetic resonance imaging and spectroscopy is described in which two circular loops of the same diameter are disposed axially with respect to each other and in which counter rotating currents (CRC) are supported in the two loops. This type of coil has been used for localized...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910030412
更新日期:1986-08-01 00:00:00
abstract:PURPOSE:To separate the spectrally overlapped lactate and lipid signals at 1.3 ppm using diffusion-weighted magnetic resonance spectroscopy (DW-MRS) based on their large diffusivity difference. METHODS:DW-MRS was applied to the gel phantoms containing lactate and lipid droplets, and to the rat brain tumors. Lactate an...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26144
更新日期:2017-02-01 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::MRI using hyperpolarized (13) C-labeled pyruvate is a promising tool to biochemically profile tumors and monitor their response to therapy. This technique requires injection of pyruvate into tumor-bearing animals. Pyruvate is an endogenous entity but the influence of exogenously injected bolus doses of pyruvate on tum...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23065
更新日期:2012-03-01 00:00:00
abstract::Human cardiac 31P nuclear magnetic resonance (NMR) spectra are usually quantified in relative terms, i.e., the ratio of metabolite signals is calculated. If 31P NMR spectroscopy of the heart is to emerge as a clinically relevant diagnostic modality, reliable quantification of absolute concentrations of 31P metabolites...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199904)41:4<657::aid-mrm3>
更新日期:1999-04-01 00:00:00
abstract::A study was made of the in vivo detectability of a pH-sensitive, imidazolidine spin probe, and the efficacy of low-frequency electron spin resonance (ESR)-based techniques for pH measurement in vitro and in vivo in rats. The techniques used were longitudinally-detected ESR (LODESR) and field-cycled dynamic nuclear pol...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10392
更新日期:2003-03-01 00:00:00
abstract:PURPOSE:To develop and evaluate a method for RF envelope correction without extra hardware or synchronization. METHODS:Transmitted RF waveforms are measured through a simple pulse sequence called the gradient reversal approach to evaluate RF (GRATER). The measured RF waveforms are used to compute predistorted RF wavef...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27930
更新日期:2020-01-01 00:00:00
abstract::We applied diffusion-sensitive echo planar (Instascan) imaging to study thermal changes caused by a Nd:YAG laser. Images of phantom materials and normal rabbit brain tissue in vivo, acquired in 150 ms, every 2s, clearly showed the dynamics of temperature-related signal intensity changes in the regions irradiated by th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910210116
更新日期:1991-09-01 00:00:00
abstract::Typically, MR-elastography (MRE) encodes the propagation of monochromatic acoustic waves in the MR-phase images via sinusoidal gradients characterized by a detection frequency equal to the frequency of the mechanical vibration. Therefore, the echo time of a conventional MRE sequence is typically longer than the vibrat...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22124
更新日期:2009-11-01 00:00:00
abstract::A multiple quantum filter strategy is presented for spectrally discriminating metabolites with strongly coupled spins from those whose spins are either uncoupled or weakly coupled. The strategy also includes a means for selectively suppressing the background multiplets of metabolites that also have strongly coupled sp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10697
更新日期:2004-02-01 00:00:00
abstract::The natural abundance 13C NMR intensity of the glycogen C1 resonance was measured in the surgically exposed liver of rabbits in vivo (n = 17) by integration from 98 to 104 ppm and compared double blindedly to the subsequent biochemical measurement. Coil loading was measured each time from a reference sphere at the coi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910310602
更新日期:1994-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.24982
更新日期:2014-09-01 00:00:00
abstract::SENSitivity Encoding (SENSE) greatly enhances the quality of diffusion-weighted echo-planar imaging (EPI) by reducing blurring and off-resonance artifacts. Such improvement would also be desirable for diffusion tensor imaging (DTI), but measures derived from the diffusion tensor can be extremely sensitive to any kind ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10184
更新日期:2002-07-01 00:00:00
abstract::T2-weighted MRI of edema in acute myocardial infarction (MI) provides a means of differentiating acute and chronic MI, and assessing the area at risk of infarction. Conventional T2-weighted imaging of edema uses a turbo spin-echo (TSE) readout with dark-blood preparation. Clinical applications of dark-blood TSE method...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21215
更新日期:2007-05-01 00:00:00
abstract::A pulse sequence is presented for obtaining a single image with combined T1/T2 weighting. T2 relaxation is made to increase intensity, in cooperation with the effect of T1 relaxation, by providing T2 weighting with a 90 degrees-180 degrees-90 degrees driven inversion pulse triplet in an inversion recovery method. Unli...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910150307
更新日期:1990-09-01 00:00:00
abstract::In a research environment, a magnetic resonance imaging system's manufacturer-supplied protection against excessive rf power deposition in the sample is often compromised. This paper presents a widely applicable scheme, based on a commonly available fuse, that simply and effectively limits the average rf power into a ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910090213
更新日期:1989-02-01 00:00:00
abstract::A potential relationship between structural compartments in neural tissue and NMR parameters may increase the specificity of MRI in diagnosing diseases. Nevertheless, our understanding of MR of nerves and white matter is limited, particularly the influence of various water compartments on the MR signal is not known. I...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199911)42:5<911::aid-mrm11
更新日期:1999-11-01 00:00:00
abstract::Balanced steady-state free precession (SSFP) imaging is sensitive to off-resonance effects, which can lead to considerable artifacts during a transient phase following magnetization preparation or steady-state interruption. In addition, nonlinear k-space encoding is required if contrast-relevant k-space regions need t...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20615
更新日期:2005-10-01 00:00:00
abstract::When deoxygenated, blood behaves as an effective susceptibility contrast agent. Changes in brain oxygenation can be monitored using gradient-echo echo-planar imaging. With this technique, difference images also demonstrate that blood oxygenation is increased during periods of recovery from respiratory challenge. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910220117
更新日期:1991-11-01 00:00:00