Abstract:
:A methodology is presented for estimating T(1) using a two-point technique with a standard multislice gradient echo sequence. The method explicitly corrects for the shape of the RF pulse and for spatial variations in transmitted RF field intensity. Including these factors in the calculation of T(1) gives a substantial improvement in accuracy and precision of two-point gradient echo T(1) measurements in the presence of RF nonuniformity and non-ideal pulse profiles. The mean accuracy of the technique was found to be 1.4%. The mean precision was found to be 3.0%. The mean variation along the axis of a head coil was found to be 2.3%.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Parker GJ,Barker GJ,Tofts PSdoi
10.1002/mrm.1112subject
Has Abstractpub_date
2001-05-01 00:00:00pages
838-45issue
5eissn
0740-3194issn
1522-2594pii
10.1002/mrm.1112journal_volume
45pub_type
杂志文章abstract::Mumps virus-infected and normal newborn hamster brains were imaged with magnetic resonance (MR) within 24 h after birth and serially scanned. Hydrocephalus developed explosively on Day 6 postinfection and progressed until death occurred soon after Day 10. This study demonstrates the utility of MR in the investigation ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910040611
更新日期:1987-06-01 00:00:00
abstract::Radial MRI sequences are frequently used to obtain images with reduced sensitivity to motion. To decrease imaging time, multiple spin-echo acquisitions can be incorporated into radial sequences. In this case, different radial lines of Fourier data have different TE times and the resulting images can contain streaking ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20031
更新日期:2004-04-01 00:00:00
abstract::To date, most functional imaging centers have relied on ultrafast imaging approaches such as echo-planar imaging (EPI) techniques for acquiring functional brain activation data. These methods require specialized hardware and are not yet installed widely on clinical MR imagers, thus limiting the application of function...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380417
更新日期:1997-10-01 00:00:00
abstract::Using a material that already is in widespread use in humans, India ink, the first EPR measurements in a human have been made, using the India ink in a pre-existing tattoo. The EPR spectra of India ink are very sensitive to the partial pressure of oxygen (pO2), thereby making it feasible to use this approach to measur...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910310218
更新日期:1994-02-01 00:00:00
abstract:PURPOSE:Undiagnosed dehydration compromises health outcomes across many populations. Existing dehydration diagnostics require invasive bodily fluid sampling or are easily confounded by fluid and electrolyte intake, environment, and physical activity limiting widespread adoption. We present a portable MR sensor designed...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28004
更新日期:2020-04-01 00:00:00
abstract:PURPOSE:The apparent propagator anisotropy (APA) is a new diffusion MRI metric that, while drawing on the benefits of the ensemble averaged propagator anisotropy (PA) compared to the fractional anisotropy (FA), can be estimated from single-shell data. THEORY AND METHODS:Computation of the full PA requires acquisition ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28620
更新日期:2020-12-13 00:00:00
abstract:PURPOSE:To develop a fast three-dimensional (3D) k-space encoding method based on spiral projection imaging (SPI) with an interleaved golden-angle approach and to validate this novel sequence on small animal models. METHODS:A disk-like trajectory, in which each disk contained spirals, was developed. The 3D encoding wa...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26263
更新日期:2017-05-01 00:00:00
abstract::Ferumoxytol is an ultrasmall superparamagnetic iron oxide agent marketed for the treatment of anemia. There has been increasing interest in its properties as an MRI contrast agent as well as greater awareness of its adverse event profile. This mini-review summarizes the current state of knowledge of the risks of ferum...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章,评审
doi:10.1002/mrm.26151
更新日期:2016-05-01 00:00:00
abstract::The Shinnar-Le Roux (SLR) radiofrequency (RF) pulse design algorithm is widely used for designing slice-selective RF pulses due to its intuitiveness, optimality, and speed. SLR is limited, however, in that it is only capable of designing one-dimensional pulses played along constant gradients. We present a nonuniform S...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23269
更新日期:2012-09-01 00:00:00
abstract::Measurements of the volume magnetic susceptibility of solids using the classical Gouy balance approach are hampered by variations in apparent density of the packed powder. In this paper a quantitative NMR measurement of the volume magnetic susceptibility of powdered solids is described and the volume susceptibility of...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910370404
更新日期:1997-04-01 00:00:00
abstract::A non-invasive method for studying the modifications induced in lipid depots by hormonal stimulation could extend knowledge of adipose tissues. We studied the effect of adrenergic stimulation on interscapular brown adipose tissue (IBAT) of rats using contrast-enhanced MRI. Controls and rats pre-treated with adrenaline...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20851
更新日期:2006-04-01 00:00:00
abstract::Breathing motion is one of the main sources of artifacts in MRI acquisitions that can severely impair diagnosis. In MRI with continuously moving table, the application of common motion compensation approaches such as breath holding or the synchronization of the measurement with the breathing motion can be problematic....
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22162
更新日期:2010-03-01 00:00:00
abstract:PURPOSE:Balanced steady state free precession (bSSFP) imaging suffers from off-resonance artifacts such as signal modulation and banding. Solutions for removal of bSSFP off-resonance dependence are described and compared, and an optimal solution is proposed. THEORY AND METHODS:An Algebraic Solution (AS) that complemen...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26150
更新日期:2017-02-01 00:00:00
abstract::A lactate editing sequence based on the use of spin-locking pulses with surface coils is described. The sequence retains more than 90% of the available lactate magnetization and suppresses at least 95% of the lipid signal in a single scan and ca. 99.5% after a simple two step cycle. The technique allows simultaneous o...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910290320
更新日期:1993-03-01 00:00:00
abstract:PURPOSE:Lung pO2 mapping with (3)He MRI assumes that the sources of signal decay with time during a breath-hold are radiofrequency depolarization and oxygen-dependent T1 relaxation, but the method is sensitive to other sources of spatio-temporal signal change such as diffusion. The purpose of this work was to assess th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24779
更新日期:2014-03-01 00:00:00
abstract:PURPOSE:To investigate the effect of realistic microstructural geometry on the susceptibility-weighted MR signal in white matter (WM), with application to demyelination. METHODS:Previous work has modeled susceptibility-weighted signals under the assumption that axons are cylindrical. In this study, we explored the imp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26689
更新日期:2018-01-01 00:00:00
abstract:PURPOSE:The goal of this study is to characterize and improve the accuracy of 2D magnetic resonance fingerprinting (MRF) scans in the presence of slice profile (SP) and B1 imperfections, which are two main factors that affect quantitative results in MRF. METHODS:The SP and B1 imperfections are characterized and correc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26580
更新日期:2017-11-01 00:00:00
abstract::The protocol for delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was adapted for the evaluation of transplanted osteochondral allograft cartilage. Eight patients with focal grade 4 cartilage defects of the femoral condyle were treated with single cylindrical osteochondral allografts. At 1 and 2 years, dGEMRIC i...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/mrm.24419
更新日期:2013-06-01 00:00:00
abstract::Spatial resolution in 3D breath-hold coronary MR angiography (MRA) is limited by imaging time. The purpose of this work was to investigate the feasibility of improving the spatial resolution of coronary MRA using generalized autocalibrating partially parallel acquisition (GRAPPA) and fast imaging with steady state pre...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20153
更新日期:2004-07-01 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::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:PURPOSE:To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25101
更新日期:2015-01-01 00:00:00
abstract:PURPOSE:To characterize pseudo-continuous arterial spin labeling (pCASL) through simulations of spin inversion and to discuss suitable parameter settings for measuring cerebral perfusion. METHODS:Simulations of arterial spin inversion in pCASL were performed based on the Bloch equation. Both the labeling and the contr...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26805
更新日期:2018-03-01 00:00:00
abstract::We exploit the intrinsic difference in magnetic resonance spin-spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue in order to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain. In normal vo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910310614
更新日期:1994-06-01 00:00:00
abstract:PURPOSE:Nicotinamide adenine dinucleotide (NAD), in oxidized (NAD(+) ) or reduced (NADH) form, plays key roles in cellular metabolism. Intracellular NAD(+) /NADH ratio represents the cellular redox state; however, it is difficult to measure in vivo. We report here a novel in vivo (31) P MRS method for noninvasive measu...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24859
更新日期:2014-06-01 00:00:00
abstract::AFI (actual flip angle imaging) represents an interesting approach to map the B(1) transmit fields by measuring the spatial variations of the effective flip angle. However, the accuracy of the technique relies on the adequate spoiling of transverse magnetization. In the present work configuration theory was employed t...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21592
更新日期:2009-01-01 00:00:00
abstract::Brain water diffusion in response to transient global ischemia (12 min), reperfusion (60 min), and cardiac arrest was monitored by localized proton magnetic resonance spectroscopy. The trace of the apparent diffusion coefficient tensor (ADC(Av)) was determined at high temporal resolution (10 sec) to assess the putativ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199910)42:4<798::aid-mrm23
更新日期:1999-10-01 00:00:00
abstract::Dynamic susceptibility contrast (DSC) MRI is now increasingly used for measuring perfusion in many different applications. The quantification of DSC data requires the measurement of the arterial input function (AIF) and the deconvolution of the tissue concentration time curve. One of the most accepted deconvolution me...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200009)44:3<466::aid-mrm18>3.0.c
更新日期:2000-09-01 00:00:00
abstract::Three-dimensional (3D) coronary imaging has the potential to overcome problems resulting from vessel tortuosity and to reduce partial volume effects. With these techniques, however, acquisition times are long and respiratory motion artifacts problematical. This work describes the development of a method that applies p...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199903)41:3<555::aid-mrm19
更新日期:1999-03-01 00:00:00
abstract::Radiofrequency (RF) -spoiled gradient echo sequences were developed with the aim to produce images with T(1) weighted contrast within short acquisition time. Over the past two decades, this type of sequence has proven to be a robust technique and represents a reliable workhorse in clinical MRI. This study presents an ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21614
更新日期:2008-07-01 00:00:00