Abstract：
:Due to the presence of artifacts induced by fast-imaging acquisition in functional magnetic resonance imaging (fMRI) studies, it is very difficult to estimate the variance of thermal noise by traditional methods in magnitude images. Moreover, the existence of incidental phase fluctuations impairs the validity of currently available solutions based on complex datasets. In this article, a time-domain model is proposed to generalize the analysis of complex datasets for nonbrain regions by incorporating artifacts and phase fluctuations. Based on this model, a novel estimation schema has been developed to find an appropriate set of voxels in nonbrain regions according to their levels of artifact and phase fluctuation. In addition, noise intensity from these voxels is estimated. The whole schema is named COmplex-Model-Based Estimation (COMBE). Theoretical and experimental results demonstrate that the proposed COMBE method provides a better estimation of thermal noise in fMRI studies compared with previously proposed methods and suggest that the new method can adapt to a broader range of applications, such as functional connectivity studies, evaluation of sequence designs and reconstruction schemas.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Xu Y,Wu G,Rowe DB,Ma Y,Zhang R,Xu G,Li SJdoi
10.1016/j.mri.2006.12.007subject
Has Abstractpub_date
2007-09-01 00:00:00pages
1079-88issue
7eissn
0730-725Xissn
1873-5894pii
S0730-725X(06)00442-5journal_volume
25pub_type
杂志文章abstract：:1H Magnetic resonance imaging and 31P magnetic resonance spectroscopy (MRS) have been carried out in experimental rodent filariasis, i.e., Acanthocheilonema viteae infection in the rodent host, Mastomys coucha. The T2-weighted image of the infected host shows fine hyperintense thread like structures of adult filariid ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(97)00180-x
更新日期：1997-01-01 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：:Functional magnetic resonance imaging (fMRI) was used to investigate the spatial distribution of cortical activation in frontal and parietal lobes during auditory and visual oddball tasks in 10 healthy subjects. The purpose of the study was to compare activation within auditory and visual modalities and identify commo...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(00)00128-4
更新日期：2000-06-01 00:00:00
abstract：:In this contribution, we explore the potential of proton electron double resonance imaging (PEDRI) in environmental science (hydrogeological) applications. After a discussion of the hydrogeological motivation for studies of free radical transport in environmental matrices, we present results from first experiments tha...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2004.11.027
更新日期：2005-02-01 00:00:00
abstract：PURPOSE:The detection of small parenchymal hepatic lesions identified by preoperative imaging remains a challenge for traditional pathologic methods in large specimens. We developed a magnetic resonance imaging (MRI) compatible localization device for imaging of surgical specimens aimed to improve identification and lo...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.11.021
更新日期：2017-04-01 00:00:00
abstract：:We present the case of a 44-year-old man who complained of cervical pain. He was treated with physiotherapy and analgetics. Because of persistent pain, computed tomography (CT) scan and MRI were performed. They revealed an osteolytic destruction of the fourth cervical vertebra. The patient was treated surgically for r...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章,评审
doi：10.1016/j.mri.2004.01.006
更新日期：2004-05-01 00:00:00
abstract：:Non-CE MRA techniques (true steady-state free-precession, SSFP) have been used effectively for the selective visualization of the portal venous system and inferior vena cava. Budd-Chiari Syndrome (BCS) encompasses a number of conditions that cause the obstruction of the hepatic outflow tract from the small hepatic vei...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.10.006
更新日期：2017-02-01 00:00:00
abstract：:Fifty-four independent scans were performed in two volunteers covering one anatomic region in each (the brain and knee) with the purpose of ascertaining the agreement between predicted and measured signal-to-noise ratios (SNR). Systematically varied parameters were number of excitations (NEX), field of view (FOV), sec...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(90)90009-q
更新日期：1990-01-01 00:00:00
abstract：:The purpose of this study is to report the significant differences found in the identification of lesions in cervical spinal cord of two patients with multiple sclerosis when using the BLADE T2-TSE and BLADE T2-TIRM sequences as opposed to the conventional T2-TSE and T2-TIRM sequences for sagittal acquisition at 1.5T....
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.07.008
更新日期：2013-12-01 00:00:00
abstract：:The medical specialty radiology has experienced a number of extremely important and influential technical developments in the past that have affected how medical imaging is deployed. Artificial intelligence (AI) is potentially another such development that will introduce fundamental changes into the practice of radiol...
journal_title：Magnetic resonance imaging
pub_type： 社论
doi：10.1016/j.mri.2019.12.006
更新日期：2020-05-01 00:00:00
abstract：:Pellets of HeLa from suspension cultured cells in isotonic medium (300 mosmolar) were introduced into a Bruker CXP100 NMR spectrophotometer at 80 mHz within 5 min of the start of centrifugation. T1 and T2 times were measured within a total elapsed time of 20-25 min at 80 mHz and 37 degrees C, and averaged 1430 msec an...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(90)90101-7
更新日期：1990-01-01 00:00:00
abstract：:We implemented pseudo-continuous ASL (pCASL) with 2D and 3D balanced steady state free precession (bSSFP) readout for mapping blood flow in the human brain, retina, and kidney, free of distortion and signal dropout, which are typically observed in the most commonly used echo-planar imaging acquisition. High resolution...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.03.024
更新日期：2013-09-01 00:00:00
abstract：PURPOSE:The purpose of this study was to determine the pre- and postpubertal 1H magnetic resonance spectroscopic characteristics of the normal testis to establish baseline values for further clinical studies. MATERIALS AND METHODS:The subjects consisted of male volunteers, of whom 19 were prepubertal with ages between...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2007.06.008
更新日期：2008-02-01 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：BACKGROUND:Since the advent of magnetic resonance imaging, metal artifacts have posed an important diagnostic problem in different fields of medicine. However, this has not been systematically studied in patients undergoing surgery for brain tumors. OBJECTIVE:This study was planned to assess whether metal artifacts ca...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2012.11.001
更新日期：2013-06-01 00:00:00
abstract：:Ultra-high field magnetic resonance imaging data obtained using a multi-echo gradient echo sequence has been shown to contain information on tissue microstructure. Quantitative assessment of water fraction, relaxation time and frequency shift using multi-compartment signal modelling may help improve our understanding ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2019.05.011
更新日期：2019-09-01 00:00:00
abstract：:The general aims of functional brain magnetic resonance imaging (fMRI) studies are to ascertain which areas of the brain are activated during a specific task, the extent of this activation, whether different groups of subjects demonstrate different patterns of activation, and how these groups behave in different tasks...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(97)00278-6
更新日期：1998-04-01 00:00:00
abstract：:The advantages of event-related functional Magnetic Resonance Imaging (fMRI) and the increasing use of fMRI in cognitive experiments are both driving the development of techniques that allow images sensitive to the blood oxygen level-dependent effect to be acquired at ever-higher temporal resolution. Here, we present ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.12.030
更新日期：2006-05-01 00:00:00
abstract：:We compared the efficacy of rapidly acquired magnetization prepared gradient-echo (MP-GRE) sequences with CT and standard MRI pulse sequences for the detection of focal liver lesions. Fourteen patients with 28 focal liver lesions were scanned. TI times of 300, 450, and 600 ms were used. MP-GRE lesion conspicuity was c...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(94)92198-9
更新日期：1994-01-01 00:00:00
abstract：PURPOSE:To provide a single open-source platform for comprehensive MR algorithm development inclusive of simulations, pulse sequence design and deployment, reconstruction, and image analysis. METHODS:We integrated the "Pulseq" platform for vendor-independent pulse programming with Graphical Programming Interface (GPI)...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.03.008
更新日期：2018-10-01 00:00:00
abstract：:Primary epiploic appendagitis (PEA) occurs secondary to inflammation of an epiploic appendage, and is considered to be a rare cause of acute abdomen. In this case report, we describe the magnetic resonance imaging (MRI) findings of PEA correlated with computed tomographic (CT) findings. MRI findings included an oval s...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(02)00478-2
更新日期：2002-01-01 00:00:00
abstract：:Compressed sensing has shown great potential in reducing data acquisition time in magnetic resonance imaging (MRI). In traditional compressed sensing MRI methods, an image is reconstructed by enforcing its sparse representation with respect to a preconstructed basis or dictionary. In this paper, patch-based directiona...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2012.02.019
更新日期：2012-09-01 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：:Partial volume effects in proton magnetic resonance spectroscopy in the brain have been studied previously in terms of proper water concentration calculations, but there is a lack of disclosure in terms of voxel placement techniques that would affect the calculations. The purpose of this study is to facilitate a fully...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.04.001
更新日期：2013-09-01 00:00:00
abstract：BACKGROUND:Doppler based mitral annular velocities are an integral part of echocardiographic left ventricular diastolic function assessment. Although these measurements can be obtained by phase contrast cardiac magnetic resonance imaging (PC-CMR), this approach has limitations. The aims of this study were to assess the...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.08.018
更新日期：2019-01-01 00:00:00
abstract：:Perceptions of sensation and pain in healthy people are believed to be the net result of sensory input and descending modulation from brainstem and cortical regions depending on emotional and cognitive factors. Here, the influence of attention on neural activity in the spinal cord during thermal sensory stimulation of...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2010.07.012
更新日期：2011-01-01 00:00:00
abstract：:The development of NMR diffusion imaging and diffusion tensor imaging (DTI) has offered the possibility of studying the porous structures beyond anatomical imaging. In fact, random molecular motions, within tissue components, probe tissue microstructures. Up to now, the DTI method was mainly used to investigate cerebr...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2004.11.018
更新日期：2005-02-01 00:00:00
abstract：:Tracking of signal intensity changes in soft tissue over time is often hampered by deformation of the tissue. In this study a method is described that uses finite element modeling to compensate for tissue deformation. The method is applied to the quantification of fluid redistribution in an intervertebral disc that de...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(97)00251-8
更新日期：1998-01-01 00:00:00
abstract：PURPOSE:Visual review of individual spectra in magnetic resonance spectroscopic imaging (MRSI) data benefits from the application of spectral smoothing; however, if this processing step is applied prior to spectral analysis this can impact the accuracy of the quantitation. This study aims to analyze the effect of spect...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2020.04.013
更新日期：2020-07-01 00:00:00
abstract：:Current density imaging (CDI) has been shown to be a feasible method to map spatial distribution of electric currents through bone structures and for studying osteoporosis and bone fracture models. For the osteoporosis model, bone sample was moistened in a solution of a sodium salt of ethylendiamintetraacetic acid (ED...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(97)00038-6
更新日期：1997-01-01 00:00:00
