Abstract:
:MR imaging experiments were conducted to investigate the feasibility of estimating vascular pulse pressure waveforms from measurements of blood flow rates and vessel cross-sectional area. Blood flow waveforms were measured in the aorta's of three 25-30-kg pigs at multiple imaging sections using phase-contrast velocity imaging. Estimates of pulse pressure were derived from these data by evaluating a model characterizing the relationship between pressure, flow, and the cross-sectional area of a vessel segment. Comparisons between the MR-derived estimates of pressure and those obtained from a micromanometer pressure catheter indicate that accurate measurements (mean error +/- SD = 8.2 +/- 3.4, n = 6) can be obtained using conventional velocity imaging techniques. Optimization of the method will require the application of rapid imaging techniques and the development of strategies for obtaining a more localized measurement. With these improvements, our results suggest that MR-based measurement of pulse pressure and related elastic parameters is feasible.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Urchuk SN,Fremes SE,Plewes DBdoi
10.1002/mrm.1910380209subject
Has Abstractpub_date
1997-08-01 00:00:00pages
215-23issue
2eissn
0740-3194issn
1522-2594journal_volume
38pub_type
杂志文章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:PURPOSE:To establish a series of relationships defining how muscle microstructure and diffusion tensor imaging (DTI) are related. METHODS:The relationship among key microstructural features of skeletal muscle (fiber size, fibrosis, edema, and permeability) and the diffusion tensor were systematically simulated over ph...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26993
更新日期:2018-07-01 00:00:00
abstract::A transrectal probe for 1H imaging and 31P MR spectroscopy of the prostate gland is described. The probe is covered with plastic and consists of an insectional portion containing an rf coil and a handle containing a tuning and matching circuit. Using this transrectal probe, 1H MR images and the first 31P MR spectra of...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章,评审
doi:10.1002/mrm.1910110209
更新日期:1989-08-01 00:00:00
abstract::An improved double quantum coherence (DQC) filter for the selective in vivo detection of glutathione (GSH) in the human brain at 1.5 Tesla is presented. The goal was to minimize contamination of the DQC-filtered GSH signal at 2.9 ppm with contributions arising from GABA. The modification consists of tailoring the freq...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1094
更新日期:2001-04-01 00:00:00
abstract::The vascular space occupancy (VASO) method was recently proposed as a functional MRI (fMRI) method that is capable of detecting activation-related changes in blood volume (CBV), without the need for a blood-pool contrast agent. In the present work we introduce a new whole-brain VASO technique that is based on a parall...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22000
更新日期:2009-07-01 00:00:00
abstract::A novel ultra-rapid gradient echo (URGE) NMR imaging technique is introduced, which is capable of continuous high resolution 3D scanning while neither subject to fast gradient switching nor excessive RF power deposition. Sampling free induction decays instead of creating spin echoes enables maintaining a workable stea...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330123
更新日期:1995-01-01 00:00:00
abstract:PURPOSE:To systematically evaluate the dependence of intravoxel-incoherent-motion (IVIM) parameters on the b-value threshold separating the perfusion and diffusion compartment, and to implement and test an algorithm for the standardized computation of this threshold. METHODS:Diffusion weighted images of the upper abdo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25506
更新日期:2015-11-01 00:00:00
abstract::A three-axis uniplanar gradient coil was designed and built to provide order-of-magnitude increases in gradient strength of up to 500 mT/m on the x- and y-axes, and 1000 mT/m for the z-axis at 640 A input over a limited FOV ( approximately 16 cm) for superficial regions, compared to conventional gradient coils, with s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21263
更新日期:2007-07-01 00:00:00
abstract::In in vivo phosphorus magnetic resonance spectroscopy (MRS), spectroscopic imaging (SI) can be used as a flexible localization technique, producing spectra from multiple volumes in a single examination. Presented here are phosphorus SI studies of human organs in which a selective-volume SI reconstruction was used rath...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910120302
更新日期:1989-12-01 00:00:00
abstract::In rapidly acquired gradient echo images, lipid regions usually appear as areas of high signal intensity. In 2D inflow angiograms processed by the maximum intensity projection algorithm, this high lipid signal may prevent angiographic visualization of some blood vessels. We present a new approach to suppress the lipid...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910210110
更新日期:1991-09-01 00:00:00
abstract:PURPOSE:In diffusion MRI, the actual b-value played out on the scanner may deviate from the nominal value due to magnetic field imperfections. A simple image-based correction method for this problem is presented. METHODS:The apparent diffusion constant (ADC) of a water phantom was measured voxel-wise along 64 diffusio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28078
更新日期:2020-06-01 00:00:00
abstract:PURPOSE:It has been shown, theoretically and in vivo, that using the Stejskal-Tanner pulsed-gradient, or linear tensor encoding (LTE), and in tissue exhibiting a "stick-like" diffusion geometry, the direction-averaged diffusion-weighted MRI signal at high b-values ( ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28191
更新日期:2020-09-01 00:00:00
abstract:PURPOSE:To design and demonstrate a new susceptibility-based tracking device with an artifact that can be mechanically turned on and off, thus permitting tracking and imaging at the device tip with limited artifact. METHODS:The magnetic susceptibilities of readily obtainable grades of titanium and graphite were measur...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24899
更新日期:2014-07-01 00:00:00
abstract::In guinea pigs immunized with myelin basic protein (MBP) in complete Freund's adjuvant, experimental allergic encephalomyelitis (EAE) shows a characteristic clinical and pathological course. This study characterized the proton nuclear magnetic resonance (NMR) properties of the central nervous system prior to the onset...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910050203
更新日期:1987-08-01 00:00:00
abstract::Maximal intensity projection (MIP) is routinely used to view MRA and other volumetric angiographic data. The straightforward implementation of MIP is ray casting that traces a volumetric data set in a computationally expensive manner. This article reports a fast MIP algorithm using shear warp factorization and reduced...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10114
更新日期:2002-04-01 00:00:00
abstract:PURPOSE:The correlation between glutamine metabolism and oncogene expression in cancers has led to a renewed interest in the role of glutamine in cancer cell survival. Hyperpolarized [5-(13) C]glutamine is evaluated as a potential biomarker for noninvasive metabolic measurements of drug response in prostate cancer cell...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25360
更新日期:2015-06-01 00:00:00
abstract::The purpose of the study was to test a newly developed, MR-compatible, liquid nitrogen-cooled cryoprobe. The probe has an outer diameter of 3.5 mm and was specifically developed for percutaneous, MR-guided, interstitial cryotherapy. The probe was inserted percutaneously into the livers of 10 rabbits. The cryotherapy p...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910390304
更新日期:1998-03-01 00:00:00
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::A new ultrafast MR imaging method is proposed and tested, which enables whole-brain fMRI with a true temporal resolution of 1 sec. The method combines a 3D PRESTO pulse sequence with the concept of sensitivity-encoding with multiple receiver coils (SENSE). The so-called PRESTO-SENSE technique is demonstrated on a set ...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/1522-2594(200006)43:6<779::aid-mrm1>3.0.co
更新日期:2000-06-01 00:00:00
abstract:PURPOSE:To develop a practical method for mapping macromolecule distribution in the brain using ultrashort-TE MRSI data. METHODS:An FID-based chemical shift imaging acquisition without metabolite-nulling pulses was used to acquire ultrashort-TE MRSI data that capture the macromolecule signals with high signal-to-noise...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26896
更新日期:2018-05-01 00:00:00
abstract::31P NMR spectroscopy was used to study renal allografts in rats subjected to allograft rejection, cyclosporine toxicity, ischemia, and ureteral obstruction. Parameters of relative peak areas and intracellular pH were accurately distinguished among the different causes of graft dysfunction. Ureteral obstruction was cle...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910050405
更新日期:1987-10-01 00:00:00
abstract::The relative distributions of N-acetylaspartate (NAA) + N-acetylaspartylglutamate (NAAG), creatine + phosphocreatine (Cr/PCr), and choline (Cho) in the gray and white matter of human brain were determined by utilizing proton magnetic resonance spectroscopic imaging (SI). The SI data was processed using an automated sp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330603
更新日期:1995-06-01 00:00:00
abstract:PURPOSE:A generalized intravoxel incoherent motion (IVIM) model, called the GIVIM, was proposed to better account for complex perfusion present in the tissues having various vessels and flow regimes, such as the liver. THEORY AND METHODS:The notions of continuous pseudodiffusion variable as well as perfusion fraction ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26064
更新日期:2016-11-01 00:00:00
abstract::Echo-planar spectroscopic imaging (EPSI) can be used for fast spectroscopic imaging of water and fat resonances at high resolution to improve structural and functional imaging. Because of the use of oscillating gradients during the free induction decay (FID), spectra obtained with EPSI are often degraded by Nyquist gh...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10485
更新日期:2003-06-01 00:00:00
abstract::This communication describes the design and application of a receiver coil operating at liquid nitrogen temperature and intended as a surface coil in a whole-body imager. Its particular application is seen as the external receiver for parasitic internal or implanted detectors. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910070211
更新日期:1988-06-01 00:00:00
abstract:PURPOSE:The aim of this study was to develop a technique for rapid collection of chemical exchange saturation transfer images with the saturation varied to modulate signal loss transfer and enhance contrast. METHODS:Multi-echo Length and Offset VARied Saturation (MeLOVARS) divides the saturation pulse of length Tsat i...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25567
更新日期:2015-02-01 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::This study determines the accuracy and feasibility of using localized spin-lattice (T1) relaxation time measurements from magnetic resonance (MR) images to follow changes in extracellular/intracellular fluid ratios in defined subvolumes of living tissue. A red blood cell suspension was used as a test system and a simp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910150107
更新日期:1990-07-01 00:00:00
abstract:PURPOSE:To investigate Shift Undersampling improves Parametric mapping Efficiency and Resolution (SUPER), a novel blockwise curve-fitting method for accelerating parametric mapping with very fast reconstruction. METHODS:SUPER uses interleaved k-space undersampling, which enables a blockwise decomposition of the otherw...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27662
更新日期:2019-06-01 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