Abstract：
:Several recent articles have assessed the relative efficiency of nuclear magnetic resonance (NMR) pulse sequences. One consideration that has received little attention is the effect on image contrast of displaying images without information on the sign of the reconstructed signals. The radiofrequency receivers currently used on most NMR imaging systems are quadrature detectors that preserve both the magnitude and sign of the NMR signal. Usually, however, sign or phase information is not used in the final image presentation. We point out that in imaging sequences that may have negative signals, such as inversion recovery, this loss of sign information produces a reduction in contrast between some tissues in an NMR image. We discuss the tissue parameters and interpulse delay times that result in contrast loss in inversion recovery and indicate the extent of contrast loss. We point out that for some tissues with unequal hydrogen spin densities, the region of contrast loss coincides with the region where maximum contrast would occur if sign information were preserved.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Hendrick RE,Nelson TR,Hendee WRdoi
10.1016/0730-725x(84)90193-0subject
Has Abstractpub_date
1984-01-01 00:00:00pages
279-83issue
4eissn
0730-725Xissn
1873-5894pii
0730-725X(84)90193-0journal_volume
2pub_type
杂志文章abstract：:The CNS involvement is frequently found in human immunodeficiency virus (HIV) infection. The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement in neurologically asymptomatic HIV-infected patients with normal MR imagings and to find the corre...
journal_title：Magnetic resonance imaging
pub_type： 临床试验,杂志文章
doi：10.1016/s0730-725x(00)00173-9
更新日期：2000-09-01 00:00:00
abstract：:NMR offers, in the complex proton relaxation properties of biological tissues, a unique and potentially powerful tool of tissue characterization. The difficulties encountered so far in comparing the results of in vitro and in vivo NMR studies carried out in different laboratories inhibit NMR methodologies from fully e...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(88)90447-x
更新日期：1988-03-01 00:00:00
abstract：:Forty-two patients with clinically suspected osteomyelitis were examined using magnetic resonance imaging (MRI). Twenty-seven patients (64%) had previous surgery or fracture, and 15 (36%) were referred for differentiation of acute osteomyelitis from bone tumors or other pathologic conditions. MRI was compared with com...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(85)90350-9
更新日期：1985-01-01 00:00:00
abstract：:The effects of varying the inversion or excitation RF pulse flip angles on image contrast and imaging time have been investigated in IR imaging theoretically, with phantoms and with normal volunteers. Signal intensity in an IR pulse sequence as a function of excitation, inversion and refocusing pulse flip angles was c...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(92)90481-e
更新日期：1992-01-01 00:00:00
abstract：:With the recent development of integrated positron emission tomography-magnetic resonance imaging (PET-MRI) scanners, new possibilities for quantitative molecular imaging of cancer are realized. However, the practical advantages and potential clinical benefits of the ability to record PET and MRI data simultaneously m...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章,评审
doi：10.1016/j.mri.2012.06.001
更新日期：2012-11-01 00:00:00
abstract：OBJECTIVE:The pathological changes in Parkinson disease begin in the brainstem; reach the limbic system and ultimately spread to the cerebral cortex. In Parkinson disease (PD) patients, we evaluated the alteration of cingulate fibers, which comprise part of the limbic system, by using diffusional kurtosis imaging (DKI)...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.06.009
更新日期：2013-11-01 00:00:00
abstract：:Functional magnetic resonance imaging (fMRI) has found widespread clinical interest. Difficulties in clinical use of the fMRI technique arise, considering the lack of knowledge about activation task performance. This accounts especially for sensorimotor activation studies, in which performance of the sensorimotor acti...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(95)02052-u
更新日期：1996-01-01 00:00:00
abstract：PURPOSE:To evaluate the utility of fat fraction (FF) for the differentiation of different breast tissues and in various breast tumor subtypes using in vivo proton (1H) magnetic resonance spectroscopy (MRS). METHODS:1H MRS was performed on 68 malignant, 35 benign, and 30 healthy volunteers at 1.5 T. Malignant breast ti...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.02.004
更新日期：2018-06-01 00:00:00
abstract：:The purpose of this study was to test whether an empirical mathematical model (EMM) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can distinguish between benign and malignant breast lesions. A modified clinical protocol was used to improve the sampling of contrast medium uptake and washout. T(1)-we...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2006.10.011
更新日期：2007-06-01 00:00:00
abstract：PURPOSE:Rapid regional fluctuations in GABA may result in inhomogeneous concentrations throughout the brain parenchyma. The goal of this study is to provide further insight into the natural distribution of GABA throughout the brain and thus determine if a surrogate site may be used for spectroscopy when evaluating moto...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2015.02.015
更新日期：2015-06-01 00:00:00
abstract：:The application of MRI-visible paramagnetic tracers to reveal in vivo connectivity can provide important subject-specific information for multisite, multielectrode intracortical recordings in combined behavioral and physiology experiments. To establish the use of such tracers in the nonhuman primate, we recently compa...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.12.031
更新日期：2006-05-01 00:00:00
abstract：PURPOSE:Intramuscular fat infiltration is a dynamic process, in response to exercise and muscle health, which can be quantified by estimating fat fraction (FF) from Dixon MRI. Healthy hip abductor muscles are a good indicator of a healthy hip and an active lifestyle as they have a fundamental role in walking. The autom...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2020.06.019
更新日期：2020-10-01 00:00:00
abstract：PURPOSE:To establish an optimized sequence design for fast acceleration of arterial spin labeling (ASL)-based time-resolved magnetic resonance angiography (MRA) by acquisition of control and labeled images in the same shot (fast ACTRESS) and a scan time of <1min, for the evaluation of intracranial vessels. MATERIALS A...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.07.026
更新日期：2017-11-01 00:00:00
abstract：:The objective of this study was to describe magnetic resonance (MR) findings with a 1.5T imager for hepatic parenchymal changes after proton beam radiotherapy. Thirty-two patients who received proton radiotherapy with doses of 50-87 Gy underwent MR imaging 1-75 months (mean 22 months) after the start of irradiation. A...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(00)00152-1
更新日期：2000-07-01 00:00:00
abstract：:Non-invasive assessment of cartilage properties, specifically water content, could prove helpful in the diagnosis of early degenerative joint diseases. Transverse relaxation times T(2) of human articular cartilage (34 cartilage slices of three donors) were measured on a pixel-by-pixel basis in a clinical whole body MR...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(99)00144-7
更新日期：2000-05-01 00:00:00
abstract：:1H-nuclear magnetic resonance (NMR) measurements have been carried out on a banded sandstone to investigate the effects of structural inhomogeneities on the fluid dynamics of the sample as a whole. The results obtained from average propagator measurements (the probability of a displacement z in a time delta or P delta...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(98)00043-5
更新日期：1998-06-01 00:00:00
abstract：:T1 and T2 relaxation times are fundamental parameters for signal contrast behaviour in MRI. A number of ex vivo relaxometry studies have dealt with the magnetic field dispersion of T1. By means of multicenter study within the frame of the COMAC BME Concerted Action on Tissue Characterization by MRI and MRS, the in viv...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章,多中心研究
doi：10.1016/0730-725x(93)90202-o
更新日期：1993-01-01 00:00:00
abstract：:A new phantom and evaluation method for experimental evaluation of 1H-magnetic resonance spectroscopy single volume localization techniques regarding signal contamination (C), defined as the part of the signal originating outside the volume of interest, is presented. The quality assessment method is based on a spheric...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(99)00076-4
更新日期：1999-12-01 00:00:00
abstract：:Diffraction ideas were first introduced to NMR by Mansfield and Grannell. Here we compare "Mansfield (k-space) diffraction" with the "diffusive (q-space) diffraction," noting their similarities and differences. The diffusive-diffraction concept is extremely helpful in elucidating the Pulsed Gradient Spin Echo NMR expe...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(96)00152-x
更新日期：1996-01-01 00:00:00
abstract：PURPOSE:To evaluate the clinical outcomes of conservative management by observation with MRI of patients with branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs). MATERIALS AND METHODS:Twenty-three consecutive patients, who were followed up by MRI with magnetic resonance cholangiopancreatography (MRCP) ove...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2010.06.026
更新日期：2010-12-01 00:00:00
abstract：:The advantages of the application of NMR imaging to the studies of enhanced oil recovery methods that include polymer slug flooding, combination slug flooding, and thermal soaking are described. ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(96)00192-0
更新日期：1996-01-01 00:00:00
abstract：:Contrast-enhanced 3D MR voiding urethrography (CE 3D MRVU) was performed on 5 healthy volunteers and 18 patients with urethral disease. After intravenous injection of 0.3 ml/kg gadolinium, the images of the three consecutive acquisitions of the 3D MRVU technique were obtained during voiding. The raw data were reconstr...
journal_title：Magnetic resonance imaging
pub_type： 临床试验,杂志文章
doi：10.1016/j.mri.2004.09.008
更新日期：2004-11-01 00:00:00
abstract：OBJECT:Virtual Phantom Magnetic Resonance Imaging (ViP MRI) is a method to generate reference signals on MR images, using external radiofrequency (RF) signals. The aim of this study was to assess the feasibility of ViP MRI to generate complex-data images of phantoms mimicking water-fat systems. MATERIALS AND METHODS:V...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2015.12.002
更新日期：2016-06-01 00:00:00
abstract：PURPOSE:While PRESS is often employed to measure glutamate concentrations, MEGA-PRESS enables simultaneous Glx (glutamate and glutamine) and GABA measurements. This study aimed to compare validation, repeatability, and concordance of different approaches for glutamate quantification at 3T to aid future studies in their...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.12.029
更新日期：2018-05-01 00:00:00
abstract：:We describe a lesion with the magnetic resonance imaging (MRI) characteristics of a glioblastoma mutiforme and demonstrate how perfusion MRI and proton MR spectroscopic imaging can be used to differentiate necrotizing cerebritis from what appeared to be a high-grade glioma. A 43-year-old woman presented to her physici...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2006.09.028
更新日期：2007-02-01 00:00:00
abstract：:Fast gradient echo sequences, such as echo planer imaging (EPI) and spiral imaging, are vulnerable to artifacts resulting from B(0) inhomogeneities. A major contribution to these artifacts is the susceptibility variation across the head, which is most severe in regions adjacent to air-tissue interfaces, such as the mo...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.07.011
更新日期：2005-11-01 00:00:00
abstract：:The prevalence of cartilage lesions is much higher in football athletes than in the general population. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been shown to quantify regional variations of glycosaminoglycan (GAG) concentrations which is an indicator of early cartilage degeneration. The goal of this...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.01.008
更新日期：2017-06-01 00:00:00
abstract：PURPOSE:To implement and evaluate interleaved blip-up, blip-down, non-segmented 3D echo planar imaging (EPI) with pseudo-continuous arterial spin labeling (pCASL) and post-processing for reduced susceptibility artifact cerebral blood flow (CBF) maps. MATERIALS AND METHODS:3D EPI non-segmented acquisition with a pCASL ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.08.011
更新日期：2017-12-01 00:00:00
abstract：:The analysis of functional magnetic resonance imaging (fMRI) data involves multiple stages of data pre-processing before the activation can be statistically detected. Spatial smoothing is a very common pre-processing step in the analysis of functional brain imaging data. This study presents a broad perspective on the ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2007.08.006
更新日期：2008-05-01 00:00:00
abstract：:In the present work, we reported a new nuclear Overhauser enhancement (NOE)-mediated magnetization transfer (MT) signal at around -1.6ppm (NOE(-1.6)) in rat brain and investigated its application in the detection of acute ischemic stroke in rodent model. Using continuous wave (CW) MT sequence, the NOE(-1.6) is reliabl...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.05.002
更新日期：2016-10-01 00:00:00
