Abstract:
:Longitudinal water proton relaxation rates of methemoglobin solutions show a strong dependence on temperature and pH. The increase of the relaxation rates with temperature is associated with shortened exchange lifetime of the coordinated water molecule. An accurate measurement of the relaxation rate of methemoglobin solutions thus requires careful control of the experimental temperature. This observation prompted the authors to look for an improved version of the relaxometric in vitro determination of methemoglobin. The method is based on transforming methemoglobin into the corresponding fluoromethemoglobin derivative, which shows both a higher relaxivity and a negligible dependence on temperature. The proposed method has been found to be in good agreement with data from spectrophotometric assays.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Aime S,Fasano M,Paoletti S,Arnelli A,Ascenzi Pdoi
10.1002/mrm.1910330613subject
Has Abstractpub_date
1995-06-01 00:00:00pages
827-31issue
6eissn
0740-3194issn
1522-2594journal_volume
33pub_type
杂志文章abstract:PURPOSE:The primary purpose of this study is to propose a method for the simultaneous quantitative three-dimensional (3D) mapping of conductivity and susceptibility using double-echo ultrashort echo time (UTE) imaging. The secondary purpose is to investigate the changes of these properties over time during in vitro hem...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25869
更新日期:2016-07-01 00:00:00
abstract::Metabolite signals with short T(1) or T(2) are difficult to localize with full sensitivity. This limitation was overcome with the development and implementation of a single-shot, complete three-dimensional "non-echo" localization method with reduced sensitivity to spatial B(1) variation, which is suitable for measurin...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200009)44:3<387::aid-mrm8>3.0.co
更新日期:2000-09-01 00:00:00
abstract::Quantification of cerebral blood flow using QUIPSSII pulsed arterial spin labeling requires that the QUIPSS saturation delay TI1 is shorter than the natural temporal bolus width. Yet the duration of the bolus of tagged spins entering the region of interest varies during vasoactive stimuli such as gaseous challenges or...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24412
更新日期:2013-06-01 00:00:00
abstract::The dependence of 1/T1 on the magnetic field strength (the relaxation dispersion) has been measured at 37 degrees C on autopsy samples of human brain gray and white matter at field strengths corresponding to proton Larmor frequencies between 10 kHz and 50 MHz (0.0002-1.2 T). Additional measurements of 1/T1 and 1/T2 ha...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910160212
更新日期:1990-11-01 00:00:00
abstract::Dynamic imaging strategies often involve updating certain areas of k-space (i.e., the low spatial frequencies) more frequently than others. However, important dynamic signal changes may occur anywhere in k-space. In this study, a dynamic k-space sampling analysis method was developed to determine the energy error asso...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1074
更新日期:2001-04-01 00:00:00
abstract:PURPOSE:To investigate previously unreported effects of signal drift as a result of temporal scanner instability on diffusion MRI data analysis and to propose a method to correct this signal drift. METHODS:We investigated the signal magnitude of non-diffusion-weighted EPI volumes in a series of diffusion-weighted imag...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26124
更新日期:2017-01-01 00:00:00
abstract:PURPOSE:In typical MRI protocols, time is spent acquiring a field map to calculate the shim settings for best image quality. We propose a fast template-based field map prediction method that yields near-optimal shims without measuring the field. METHODS:The template-based prediction method uses prior knowledge of the ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27020
更新日期:2018-07-01 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::The clinical application of 3D proton spectroscopic imaging (3D SI) of the human prostate requires a robust suppression of periprostatic lipid signal contamination, minimal intervoxel signal contamination, and the shortest possible measurement time. In this work, a weighted elliptical sampling of k-space, combined wit...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20103
更新日期:2004-07-01 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:PURPOSE:Cardiac T1 mapping has become an increasingly important imaging technique, contributing novel diagnostic options. However, currently utilized methods are often associated with accuracy problems because of heart rate variations and cardiac arrhythmia, limiting their value in clinical routine. This study aimed to...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27526
更新日期:2019-03-01 00:00:00
abstract::We have developed a method for measuring the electrocardiogram (ECG) continuously during MR examinations. In contrast to ECG acquisition by wires, our new method is to amplify and convert the ECG into an optical signal directly above the patient's heart. The optical signal is transmitted out of the magnet bore by opti...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910320416
更新日期:1994-10-01 00:00:00
abstract::This paper describes a technique for characterizing the gradient subsystem of a magnetic resonance (MR) system. The technique uses a Fourier-transform analysis to directly measure the k-space trajectory produced by an arbitrary gradient waveform. In addition, the method can be easily extended to multiple dimensions an...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910390411
更新日期:1998-04-01 00:00:00
abstract::Magnetic resonance imaging allows numerous k-space sampling schemes such as cartesian, polar, spherical, and other non-rectilinear trajectories. Non-rectilinear MR acquisitions permit fast scan times and can suppress motion artifacts. Still, these sampling schemes may adversely affect the image characteristics due to ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910360617
更新日期:1996-12-01 00:00:00
abstract:PURPOSE:T2 -relaxation-under-spin-tagging (TRUST) is an MR technique for the non-invasive assessment of whole-brain cerebral oxygen extraction fraction (OEF), through measurement of the venous blood T2 relaxation time in the sagittal sinus. A key limitation of TRUST, however, is the lack of spatial specificity of the m...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27823
更新日期:2019-10-01 00:00:00
abstract::The selective multiple-quantum coherence transfer method has been applied to image polyunsaturated fatty acids (PUFA) distributions in human breast tissues in vivo for cancer detection, with complete suppression of the unwanted lipid and water signals in a single scan. The Cartesian k-space mapping of PUFA in vivo usi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22901
更新日期:2012-01-01 00:00:00
abstract:PURPOSE:To investigate the heating induced by (pseudo)-continuous arterial spin labeling ((p)CASL) sequences in vivo at 9.4T and to evaluate the benefit of a dedicated labeling coil. METHODS:Temperature was measured continuously in the brain, neck, and rectum of 9 rats with fiber-optic temperature probes while running...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27931
更新日期:2020-01-01 00:00:00
abstract:PURPOSE:The purpose of this work was to develop a rapid and robust whole-body fat-water MRI (FWMRI) method using a continuously moving table (CMT) with dynamic field corrections at 3 Tesla. METHODS:CMT FWMRI was developed at 3 Tesla with a multiecho golden angle (GA) radial trajectory and dynamic B0 field shimming. Wh...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25848
更新日期:2016-07-01 00:00:00
abstract:PURPOSE:To develop a one-step quantification approach that accounts for joint preprocessing and quantification of whole-range kinetics (early and late-phase washout) of dynamic contrast-enhanced (DCE) MRI of indeterminate adnexal masses. METHODS:Preoperative DCE-MRI of 43 (24 benign, 19 malignant) sonographically inde...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26743
更新日期:2018-02-01 00:00:00
abstract:PURPOSE:To demonstrate the feasibility of a novel, ellipse fitting approach, named PLANET, for simultaneous estimation of relaxation times T1 and T2 from a single 3D phase-cycled balanced steady-state free precession (bSSFP) sequence. METHODS:A method is presented in which the elliptical signal model is used to descri...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26717
更新日期:2018-02-01 00:00:00
abstract:PURPOSE:To develop a novel, simultaneous multislice reconstruction method that exploits Hankel subspace learning (SMS-HSL) for aliasing separation in the slice direction. METHODS:An SMS signal model with the Hankel-structured matrix was proposed. To efficiently suppress interslice leakage artifacts from a signal subsp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26527
更新日期:2017-10-01 00:00:00
abstract::The accuracy of the outcome in a diffusion tensor imaging (DTI) experiment depends on the acquisition scheme as well as the postprocessing methods used. In the present study, the DTI results acquired after applying different combinations of diffusion-weighted (DW) gradient orientations were initially compared. Then, s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10046
更新日期:2002-02-01 00:00:00
abstract:PURPOSE:To achieve highly accelerated submillimeter resolution T 2 -weighted functional MRI at 7T by developing a three-dimensional gradient and spin echo imaging (GRASE) with inner-volume sel...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28589
更新日期:2020-11-24 00:00:00
abstract::The role of relative cerebral blood volume (rCBV) in the early response of blood oxygenation level-dependent (BOLD) signal following sensory stimulation was assessed. Magnetic resonance imaging (MRI) measurements of rCBV and BOLD signal as a function of time (t) were compared with relative cerebral blood flow (rCBF) o...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199902)41:2<247::aid-mrm6>
更新日期:1999-02-01 00:00:00
abstract:PURPOSE:The purpose of this study was to investigate the feasibility of in vivo imaging of human pancreatic ductal cells by OATP1B3 reporter gene under MRI. METHODS:A human cell line (PANC-1) derived from the pancreatic ductal epithelium was used in this study. After transduction of OATP1B3, the cellular physiological...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27749
更新日期:2019-08-01 00:00:00
abstract:PURPOSE:Diffusion-weighted magnetic resonance imaging suffers from physiological noise, such as artifacts caused by motion or system instabilities. Therefore, there is a need for robust diffusion parameter estimation techniques. In the past, several techniques have been proposed, including RESTORE and iRESTORE (Chang e...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25351
更新日期:2015-06-01 00:00:00
abstract::The authors present their 1-year experience with the use of 3DFT, time-of-flight MR angiography for the evaluation of vascular diseases of the head and neck. Their experience with over 150 patients indicates that this examination may be performed in conjunction with standard spin-echo imaging with only a minimal incre...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140215
更新日期:1990-05-01 00:00:00
abstract::Optimization of experimental settings of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), like the contrast administration protocol, is of great importance for reliable quantification of the microcirculatory properties, such as the volume transfer-constant K(trans). Using system identification theory an...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21575
更新日期:2008-05-01 00:00:00
abstract:PURPOSE:Measurement of venous oxygenation (Yv) is a critical step toward quantitative assessment of brain oxygen metabolism, a key index in many brain disorders. The present study aims to develop a noninvasive, rapid, and reproducible method to measure Yv in a vessel-specific manner. THEORY:The method, T2-Relaxation-U...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24750
更新日期:2014-03-01 00:00:00
abstract::We developed a live high-field multiple-mouse magnetic resonance imaging method to increase the throughput of imaging studies involving large numbers of mice. Phantom experiments were performed in 7 shielded radiofrequency (RF) coils for concurrent imaging on a 7 Tesla MRI scanner outfitted with multiple transmit and ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20683
更新日期:2005-11-01 00:00:00