Abstract:
:For a number of reasons, it is desirable to fabricate coils which, for a known current, shall produce predetermined values of the magnetic field intensity at a number of points within a nuclear magnetic resonance imager. The calculation of the magnetic field intensity at a set of points involves the integration of the Biot-Savart equation for all components of the segments of conductor which make up the coil. This process in itself is a rather formidable task. When this process is parameterized in terms of coil diameter, coil spacing, etc. the problem is to determine the values of these parameters to match values of magnetic field intensities which are desired. The problem thereby increases in complexity to the point where, by ordinary methods, the problem becomes intractable. This note describes an algorithm and offers a computer subroutine to calculate magnetic fields for coils of arbitrary shape and complexity for fixed currents.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Letcher JHdoi
10.1016/0730-725x(89)90524-9subject
Has Abstractpub_date
1989-11-01 00:00:00pages
581-3issue
6eissn
0730-725Xissn
1873-5894pii
0730-725X(89)90524-9journal_volume
7pub_type
杂志文章abstract::The clinical evaluation of three-dimensional time-of-flight MR angiography was prospectively performed in 16 patients with intracranial meningioma. MR angiographic techniques used in this study both with and without gadopentetate dimeglumine made it possible to demonstrate the topographic relationship between the tumo...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(93)90466-q
更新日期:1993-01-01 00:00:00
abstract::Diffusion tensor imaging (DTI) was used to investigate the involvement of brain white matter in Williams syndrome (WS), a genetic neurodevelopmental disorder. Whole-brain DTIs were obtained from 16 young adults with WS and 16 normal controls. A voxel-based analysis was performed to compare fractional anisotropy (FA) v...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2011.07.012
更新日期:2011-11-01 00:00:00
abstract::Magnetic resonance imaging (MRI) and localized proton MR spectroscopy (MRS) techniques have been applied for studying different maturation processes in the histochemistry of coconut (Cocos nucifera). Images of the tender and mature coconut are characterized by protons of the aqueous solution present in the cavity and ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(95)00033-d
更新日期:1995-01-01 00:00:00
abstract:OBJECTIVE:The purpose of this study is to investigate the correlation between the liver kinetics of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and liver histopathology in a mouse model of NASH by using dynamic contrast-enhanced MRI. MATERIALS AND METHODS:Twenty male C57/BL6 mice aged 8we...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.03.009
更新日期:2016-07-01 00:00:00
abstract::The purpose of the study was to determine whether diffusion-weighted magnetic resonance imaging (DWI) could identify focal lesions that develop in ischemia-sensitive cerebral tissues during reperfusion following global brain ischemia. Localized 1H-Magnetic Resonance Spectroscopy (1H-MRS) measurements were also obtaine...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(96)00094-x
更新日期:1996-01-01 00:00:00
abstract::In this work, magnetic resonance imaging (MRI) was employed to observe the in-situ formation and dissociation of methane hydrates in porous media. Methane hydrate was formed in a high-pressure cell with controlled temperature, and then the hydrate was dissociated by thermal injection. The process was photographed by t...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2014.12.010
更新日期:2015-05-01 00:00:00
abstract:OBJECTIVE:In magnetic resonance-guided breast vacuum biopsies, the contrast agent for targeting suspicious lesions can typically be applied only once during an intervention, due to the slow elimination of the gadolinium chelate from the extracellular fluid space. This study evaluated the feasibility of diffusion-weight...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.12.006
更新日期:2017-05-01 00:00:00
abstract::To investigate whether diffusion-related compartmentalization could be observed in skeletal muscle and whether this compartmentalization was affected by exercising, attenuation curves of signal against diffusion weighting were obtained in skeletal muscle of nine healthy volunteers at rest and after an exercise. Fiftee...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)00096-l
更新日期:1995-01-01 00:00:00
abstract::The physiological parameters measured in the tracer kinetics modeling of data from a dynamic contrast-enhanced magnetic resonance (MR) breast exam (blood flow-extraction fraction product [FE], volume of the extracellular extravascular space [Ve], and blood volume [Vb]) may enable non-invasive diagnosis of breast cance...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(98)00130-1
更新日期:1998-11-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Slice-encoding metal artifact corrections (SEMAC)-view-angle tilting (VAT) sequences have recently been used in clinical protocols to reduce metal artifacts in MR scans of patients with spinal instrumentation. The objective of this study was to compare the SEMAC-VAT sequence with the conventional...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.08.002
更新日期:2018-12-01 00:00:00
abstract::Constrained energy minimization (CEM) has proven highly effective for hyperspectral (or multispectral) target detection and classification. It requires a complete knowledge of the desired target signature in images. This work presents "Unsupervised CEM (UCEM)," a novel approach to automatically target detection and cl...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2010.03.009
更新日期:2010-06-01 00:00:00
abstract::Dynamic contrast-enhanced 2D MR imaging of the breast has shown high sensitivity and specificity for the detection and characterization of breast lesions. We investigated the ability of a dynamic fast 3D MR imaging technique that repeatedly scans the whole breast in 44-s intervals without an interscan delay time to ob...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(95)02112-7
更新日期:1996-01-01 00:00:00
abstract::The adiabatic Shinnar-Le Roux (SLR) algorithm for radiofrequency (RF) pulse design enables systematic control of pulse parameters such as bandwidth, RF energy distribution and duration. Some applications, such as diffusion-weighted imaging (DWI) at high magnetic fields, would benefit from RF pulses that can provide gr...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2014.04.003
更新日期:2014-09-01 00:00:00
abstract::Gravity drainage characteristics are important to improve our understanding of gas-liquid or liquid-liquid two-phase flow in porous media. Stable or unstable displacement fronts that controlled by the capillary force, viscous force, gravitational force, etc., are relevant features of immiscible two-phase flow. In this...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.03.004
更新日期:2016-09-01 00:00:00
abstract:PURPOSE:We present three-dimensional adiabatic inversion recovery prepared ultrashort echo time Cones (3D IR-UTE-Cones) imaging of cortical bone in the hip of healthy volunteers using a clinical 3T scanner. METHODS:A 3D IR-UTE-Cones sequence, based on a short pulse excitation followed by a 3D Cones trajectory, with a ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2017.07.012
更新日期:2017-12-01 00:00:00
abstract::Disseminated osseous tuberculosis is a rare disease. This is a report of two cases of disseminated osseous tuberculosis imaged with MRI at 1.5-T, CT, plain radiography and bone scintigraphy. CT and plain radiography demonstrated either highly destructive or cystic lesions with sclerotic margins. Bone scintigraphy and ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(87)90384-5
更新日期:1987-01-01 00:00:00
abstract::We used magnetic resonance imaging (MRI) and water-suppressed proton MR spectroscopic imaging (1H MRSI) to study the effects of human immunodeficiency virus (HIV) infection on the brain. Our recent in vivo finding of lower N-acetylaspartate (NAA), a putative marker of neurons, in the supraventricular brain of cognitiv...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)92460-0
更新日期:1994-01-01 00:00:00
abstract::Etched particle tracks produced after heavy ion irradiation of polymer foils are used as model systems to test the performance of NMR in a newly developed ultrahigh magnetic field gradient system. The stimulated NMR echo decay of molecules diffusing in the channels, formulated in terms of the self part of the intermed...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)91527-x
更新日期:1994-01-01 00:00:00
abstract::Trabecular bone structure and bone density contribute to the strength of bone and are important in the study of osteoporosis. Wavelets are a powerful tool in characterizing and quantifying texture in an image. The purpose of this study was to validate wavelets as a tool in computing trabecular bone thickness directly ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.09.020
更新日期:2007-04-01 00:00:00
abstract::In this study, in order to differentiate cavernous hemangioma and hepatic metastases, rapid acquisition relaxation enhanced (RARE) sequence was used. First, in vivo measurements of T1, T2 relaxation times and proton density were obtained using T1, T2 calculation protocol (TOMIKON S50, 0.5T) and multipoint techniques. ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(99)00008-9
更新日期:1999-06-01 00:00:00
abstract::A case report of trismus after a dental procedure is evaluated by MR imaging. The medial and lateral pterygoid muscles showed inflammatory changes. Etiologies of trismus are reviewed. ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(90)90148-u
更新日期:1990-01-01 00:00:00
abstract::Recently, we have demonstrated that the fine-digit topography (millimeter sized) previously identified in the primary somatosensory cortex (SI), using electrophysiology and intrinsic signal optical imaging, can also be mapped with submillimeter resolution using blood-oxygenation-level-dependent (BOLD) functional magne...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2007.05.002
更新日期:2007-07-01 00:00:00
abstract:PURPOSE:To evaluate the performance of combined integrated slice-by-slice shimming and readout-segmented EPI (irsEPI) for diffusion-weighted MR imaging (DWI) of the neck at 3Tesla. METHODS:This study was approved by the local ethics committee. An anthropometric phantom of the head/neck region incorporating compartment...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2017.05.004
更新日期:2017-10-01 00:00:00
abstract::Super paramagnetic iron oxide Fe(3)O(4) nanoparticles prepared via photochemical reaction in pure form were used for inducing hyperthermia to treat subcutaneous Ehrlich carcinoma implanted in female mice. Our results indicate that the mean temperature profiles at the rectum, periphery of the tumor surface and at the c...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2010.08.010
更新日期:2011-02-01 00:00:00
abstract::Resting fluctuations in arterial CO2 (a cerebral vasodilator) are believed to be an important source of low-frequency blood oxygenation level dependent (BOLD) signal fluctuations. In this study we focus on the two commonly used resting-states in functional magnetic resonance imaging experiments, eyes open and eyes clo...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.06.013
更新日期:2013-04-01 00:00:00
abstract::The effects of bone on marrow relaxation in the trabecular volume of the most proximal 3 cm in the left tibia were studied with a RF-spoiled gradient echo MRI protocol on a 1.0 T MR unit. The MR measurements were performed on six healthy volunteers, and repeated within one month in order to assess the precision of the...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(98)00159-3
更新日期:1999-01-01 00:00:00
abstract::One of the most critical structural parameters in elastomeric materials is the density of cross-linking between the polymeric chains. This chemical feature greatly affects chain motions and is determinant in controlling mechanical properties of the final product. NMR techniques are widely and efficiently applied to in...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(01)00257-0
更新日期:2001-04-01 00:00:00
abstract::Changes in both blood flow and blood oxygenation determine the functional MRI (fMRI) signal. In the present study factors responsible for blood oxygenation (e.g., FiO(2)) were held constant so that changes in pixel count would above all reflect changes in regional cerebral blood flow (rCBF). Continuous positive airway...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(00)00229-0
更新日期:2001-01-01 00:00:00
abstract::In this paper, we have presented a two stage method, using kernel principal component analysis (KPCA) and rough set theory (RST), for denoising volumetric MRI data. A rough set theory (RST) based clustering technique has been used for voxel based processing. The method groups similar voxels (3D cubes) using class and ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.10.010
更新日期:2017-02-01 00:00:00
abstract:PURPOSE:To assess the ability and reproducibility of Non-contrast Magnetic Resonance Lymphography (NMRL) in detecting and quantify lymphedema, using a semiquantitative scoring system. METHODS AND MATERIAL:This is a monocentric retrospective study of 134 consecutive patients with a clinical diagnosis of limb lymphedema...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2020.02.004
更新日期:2020-05-01 00:00:00