Abstract:
:Reduction of image-to-image signal fluctuations and imaging artifacts is important for fMRI studies. The imaging artifacts caused by respiration, cardiac pulsation, and gross head motion and the suppression of these artifacts have been studied for many years. However, the artifacts caused by eye movement and their effects on fMRI mapping are not well known. It is demonstrated in this report that involuntary eye movements during resting conditions can cause substantial signal fluctuations in the phase-encoding direction even for a fast echo-planar imaging sequence. An oblique slab presaturation technique is proposed for saturating the magnetization of eyes and suppressing the artifacts from eye movements with minimal signal loss of other brain tissues. The results show that the technique significantly reduces signal fluctuations and improves fMRI reliability for mapping functional activation in the human brain.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Chen W,Zhu XHdoi
10.1002/mrm.1910380407subject
Has Abstractpub_date
1997-10-01 00:00:00pages
546-50issue
4eissn
0740-3194issn
1522-2594journal_volume
38pub_type
杂志文章abstract::Four-dimensional (4D) flow imaging has been used to study flow patterns and pathophysiology, usually focused on specific thoracic vessels and cardiac chambers. Whole-heart 4D flow at high measurement accuracy covering the entire thoracic cardiovascular system would be desirable to simplify and improve hemodynamic asse...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22090
更新日期:2009-10-01 00:00:00
abstract::The fast spin-echo (FSE) sequence is frequently used as a fast data-readout technique in conjunction with other pulse sequence elements, such as in fluid-attenuated inversion-recovery (FLAIR) and double inversion-recovery (DIR) sequences. In order to implement those pulse sequences, an understanding is required of how...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20541
更新日期:2005-07-01 00:00:00
abstract:PURPOSE:The purpose of this project was to construct a physical brain phantom for MRI, mimicking structure and T1 relaxation properties of white matter (WM) and gray matter (GM). METHODS:The phantom design comprised 2 compartments, 1 resembling the WM and 1 resembling the GM. Their T1 relaxation times, as assessed usi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27464
更新日期:2019-02-01 00:00:00
abstract:PURPOSE:To develop and demonstrate the feasibility of a new technique for respiratory-gated, fat-suppressed, three-dimensional spoiled gradient-recalled echo (3D-SPGR) with navigator gating for more accurate and robust motion detection. METHODS:A navigator-gated 3D-SPGR technique was modified to include a wait period ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24902
更新日期:2014-07-01 00:00:00
abstract:PURPOSE:To reduce the influence of tidal volume on fractional ventilation (FV) derived by Fourier decomposition (FD). METHODS:Twelve volunteers were examined on a 1.5 Tesla scanner. Spoiled gradient echo imaging of coronal and sagittal slices of the lung were performed. The tidal volume variations between different ac...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26047
更新日期:2016-11-01 00:00:00
abstract:PURPOSE:Establishing a framework to evaluate performances of prospective motion correction (PMC) MRI considering motion variability between MRI scans. METHODS:A framework was developed to obtain quantitative comparisons between different motion correction setups, considering that varying intrinsic motion patterns betw...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25580
更新日期:2016-02-01 00:00:00
abstract:PURPOSE:To validate an automatic algorithm for offline T2* measurements, providing robust, vendor-independent T2*, and uncertainty estimates for iron load quantification in the heart and liver using clinically available imaging sequences. METHODS:A T2* region of interest (ROI)-based algorithm was developed for robustn...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25767
更新日期:2016-04-01 00:00:00
abstract::In vivo MR spectroscopy (MRS) studies have shown reductions in NAA/Cr levels in patients with severe neurocognitive deficits due to AIDS dementia complex (ADC), also known as neuroAIDS. The relationship between the cellular changes within the brain during neuroAIDS and the role of NAA/Cr as a metabolic marker remains ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21556
更新日期:2008-03-01 00:00:00
abstract:PURPOSE:To analyze the effect of B0 field drift on multivoxel MR spectroscopic imaging and to propose an approach for its correction. THEORY AND METHODS:It is shown, both theoretically and in a phantom, that for ∼30 min acquisitions a linear B0 drift (∼0.1 ppm/h) will cause localization errors that can reach several v...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24536
更新日期:2013-10-01 00:00:00
abstract::Nanostructured hydrogels have been developed as synthetic tissues and scaffolds for cell and drug delivery, and as guides for tissue regeneration. A fundamental problem in the development of synthetic hydrogels is that implanted gel structure is difficult to monitor noninvasively. This work demonstrates that the aggre...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22570
更新日期:2010-12-01 00:00:00
abstract::The aim of this study was to quantify changes in thoracic aortic wall shear stress (WSS) in asymptomatic patients with Marfan syndrome (MFS) compared with healthy controls. WSS in the thoracic aorta was quantified based on time-resolved 3D phase contrast MRI with three-directional velocity encoding (4D flow MRI, tempo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24562
更新日期:2013-10-01 00:00:00
abstract::The use of phase correlation to detect rigid-body translational motion is reviewed and applied to individual echotrains in turbo-spin-echo data acquisition. It is shown that when the same echotrain is acquired twice, the subsampled correlation provides an array of delta-functions, from which the motion that occurred b...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21883
更新日期:2009-03-01 00:00:00
abstract::A novel method based on selective detection of rapidly changing DeltaB(0) magnetic fields and suppression of slowly changing DeltaB(0) fields is presented. The ultimate goal of this work is to present a method that may allow detection of transient and subtle changes in B(0) in cortical tissue associated with electrica...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10159
更新日期:2002-06-01 00:00:00
abstract::The combination of a frequency nonselective excitation suppression method (1331 sequence) with selective excitation followed by gradient-induced dephasing of water transverse magnetization yielded suppression ratios of greater than 10,000:1. The need for gradient preemphasis and correction of B0 field shifts is discus...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910090114
更新日期:1989-01-01 00:00:00
abstract:PURPOSE:To develop histology-informed simulations of diffusion tensor cardiovascular magnetic resonance (DT-CMR) for typical in-vivo pulse sequences and determine their sensitivity to changes in extra-cellular space (ECS) and other microstructural parameters. METHODS:We synthesised the DT-CMR signal from Monte Carlo r...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27561
更新日期:2019-04-01 00:00:00
abstract:PURPOSE:We aim to leverage the power of deep-learning with high-fidelity training data to improve the reliability and processing speed of hemodynamic mapping with MR fingerprinting (MRF) arterial spin labeling (ASL). METHODS:A total of 15 healthy subjects were studied on a 3T MRI. Each subject underwent 10 runs of a m...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28560
更新日期:2021-04-01 00:00:00
abstract::The combination of cardiac viability and functional information enhances the identification of different heart tissues in the setting of ischemic heart disease. A method has recently been proposed for obtaining black-blood delayed-enhancement (DE) viability images using the stimulated-echo acquisition mode (STEAM) MRI...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21390
更新日期:2007-10-01 00:00:00
abstract::Kinetic analysis with mathematical models has become increasingly important to quantify physiological parameters in computed tomography (CT), positron emission tomography (PET), and dynamic contrast-enhanced MRI (DCE-MRI). The modified Kety/Tofts model and the graphical (Patlak) model have been widely applied to DCE-M...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22819
更新日期:2011-09-01 00:00:00
abstract::This study investigates the potential of in vivo 31P magnetic resonance spectroscopy (MRS) to characterize musculoskeletal tumors and to determine preoperative levels of histological necrosis, which is an important clinical indicator of patient response. Pretherapy MRS was performed on 28 patients with large musculosk...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910270204
更新日期:1992-10-01 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:PURPOSE:To test and implement a motion-robust and respiratory-resolved 3D Radial Flow framework that addresses the need for rapid, high resolution imaging in neonatal patients with congenital heart disease. METHODS:A 4-point velocity encoding and 3D radial trajectory with double-golden angle ordering was combined with...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27945
更新日期:2020-02-01 00:00:00
abstract::Formation of ternary complexes between Gd-DTPA, Gd-DTPA-BMA, and Gd-DOTA, used as contrast enhancement agents in MRI and the endogenously available carbonate and phosphate ions, has been demonstrated. The extent of ternary complex formation and its effect on the proton relaxation, measured at 9 MHz, rates is negligibl...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380120
更新日期:1997-07-01 00:00:00
abstract::The somatotopical organization of the human somatosensory cortex was analyzed with echo-planar imaging at 1.5 Tesla, utilizing deoxyhemoglobin as an endogenous contrast medium. Scrubbing stimulation at a frequency of 3 Hz was applied to one of three cutaneous areas: toes, fingertips, and tongue tip. Parasagittal echo-...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330521
更新日期:1995-05-01 00:00:00
abstract::T1 is often ill-determined. This means that an Ernst angle excitation often cannot be precisely defined for the simple pulse and acquire experiment. Here, published 31P T1 values of metabolites in human muscle, liver, heart, and brain are archived, some new data on heart and brain added, and overall confidence interva...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910320120
更新日期:1994-07-01 00:00:00
abstract::An in vitro study was performed to investigate the effects of B(o) inhomogeneity on magnetic resonance images of flow. Controlled inhomogeneity gradients (Gi) were applied and the magnitude of the artifacts produced was quantified for different echo delay times (TE). Both steady and pulsatile flows were examined. In t...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910350116
更新日期:1996-01-01 00:00:00
abstract::The resolution and homogeneity limitations of echo-planar imaging (EPI) are overcome by zoom imaging of an easily shimmed localized volume. Use of the stimulated echo enables single-shot localization. In vivo 0.5-mm resolution EPI images of selected regions of a cat brain at 4.7 T are presented. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140225
更新日期:1990-05-01 00:00:00
abstract::To detect perfusion abnormalities in areas of high magnetic susceptibility in the brain, an arterial spin-labeling MRI technique utilizing flow-sensitive alternating inversion recovery (FAIR) and half-Fourier single shot turbo spin-echo (HASTE) for spin preparation and image acquisition, respectively, was developed. I...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/1522-2594(200103)45:3<431::aid-mrm1056>3.0
更新日期:2001-03-01 00:00:00
abstract::Multislice, two-dimensional phosphorus 31 spectroscopic imaging (SI) of human brain was performed in 15 normal volunteers on a 3-Tesla magnetic resonance system. Images of free magnesium concentrations and pH as well as phosphoesters, inorganic phosphate, phosphocreatine, and adenosine triphosphate (ATP), were calcula...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199902)41:2<400::aid-mrm26
更新日期:1999-02-01 00:00:00
abstract:PURPOSE:High-resolution three-dimensional (3D) structural MRI is useful for delineating complex or small structures of the body. However, it requires long acquisition times and high SAR, limiting its clinical use. The purpose of this work is to accelerate the acquisition of high-resolution images by combining compresse...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27789
更新日期:2019-09-01 00:00:00
abstract::Using a 32-echo imaging pulse sequence, T2 relaxation decay curves were acquired from five white- and six gray-matter brain structures outlined in 12 normal volunteers. The water contents of white and gray matter were 0.71 (0.01) and 0.83 (0.03) g/ml, respectively. All white-matter structures had significantly higher ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910370107
更新日期:1997-01-01 00:00:00