Abstract：
:The ability to determine coil sensitivities implies that a method optimized in terms of maximized signal-to-noise ratio (SNR) can be applied to the combination of multiple coil images. An optimization of SNR subsequently results in a minimized variance in quantitative velocity measurements using phase-contrast imaging. When coil sensitivities are unknown, the weighted mean method, utilizing the square of the signal magnitude as weights, is suitable for combination of multiple phase images. In this study, the optimized method using estimated coil sensitivities was compared to the weighted mean method both theoretically and experimentally. It is shown that absence of noise correlation between the different coil images implies no difference between the methods regarding the variance of the phase. In the practical situation, noise correlation does exist, implying an opportunity for further reduction of phase variance using the optimized method. In vitro and in vivo studies showed, however, no significant difference between the two methods studied.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Thunberg P,Karlsson M,Wigström Ldoi
10.1016/j.mri.2005.06.002subject
Has Abstractpub_date
2005-09-01 00:00:00pages
795-9issue
7eissn
0730-725Xissn
1873-5894pii
S0730-725X(05)00221-3journal_volume
23pub_type
杂志文章abstract：:Signal fluctuations in functional magnetic resonance imaging (fMRI) can result from a number of sources that may have a neuronal, physiologic or instrumental origin. To determine the relative contribution of these sources, we recorded physiological (respiration and cardiac) signals simultaneously with fMRI in human vo...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2009.02.004
更新日期：2009-10-01 00:00:00
abstract：:Ten patients with biopsy-proved synovial sarcoma were evaluated by magnetic resonance (MR) imaging on a 1.5-T unit. The lesions showed intermediate signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images. Tumors were well-demarcated from normal tissues. Additional informati...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(89)90706-6
更新日期：1989-03-01 00:00:00
abstract：:A numerical method is applied to calculate an optimal distribution of currents in air which generate the magnetic field gradients required to spatially encode the radiofrequency signal in a NMR tomographic experiment. We compare the performances of the gradient circuits for the whole body air-core electromagnet descri...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(90)90242-t
更新日期：1990-01-01 00:00:00
abstract：PURPOSE:To evaluate whether semi-quantitative analysis of high temporal resolution dynamic contrast-enhanced MRI (DCE-MRI) acquired early in treatment can predict the response of locally advanced breast cancer (LABC) to neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS:As part of an IRB-approved prospective study,...
journal_title：Magnetic resonance imaging
pub_type： 临床试验,杂志文章
doi：10.1016/j.mri.2013.07.002
更新日期：2013-11-01 00:00:00
abstract：:Increasing scientific interest in the zebrafish as a model organism across a range of biomedical and biological research areas raises the need for the development of in vivo imaging tools appropriate to this subject. Development of the embryonic and early stage forms of the subject can currently be assessed using opti...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.10.013
更新日期：2017-04-01 00:00:00
abstract：:Within the magnetic resonance imaging (MRI) community the trend is going to higher and higher magnetic fields, ranging from 1.5 T to 7 T, corresponding to Larmor frequencies of 63.8-298 MHz. Since for high-field MRI the magnetization increases with the applied magnetic field, the signal-to-noise-ratio increases as wel...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2012.06.014
更新日期：2013-02-01 00:00:00
abstract：:Multi-echo pulse sequences for producing T2-weighted images in much reduced imaging times have recently been developed for routine clinical use. A number of recent articles have described the contrast obtained with fast spin-echo (FSE) sequences and have generally indicated that they depict tissues very similarly to c...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章,评审
doi：10.1016/0730-725x(92)90001-g
更新日期：1992-01-01 00:00:00
abstract：:Use of conjugated equine estrogens (CEE) has been linked to smaller regional brain volumes in women aged ≥65 years; however, it is unknown whether this results in a broad-based characteristic pattern of effects. Structural magnetic resonance imaging was used to assess regional volumes of normal tissue and ischemic les...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章,随机对照试验
doi：10.1016/j.mri.2010.12.001
更新日期：2011-05-01 00:00:00
abstract：BACKGROUND:The diagnosis and management of mild traumatic brain injury (MTBI) continue to be subjects of debate, with varying opinions regarding the extent to which tissue-based impairments versus the impacts of other stressors cause ongoing disability. Detecting areas of the brain with abnormalities that can explain s...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2011.12.018
更新日期：2012-05-01 00:00:00
abstract：:The dependence of BOLD signal change (BSC) on baseline hematocrit is in the process of being characterized, primarily using conventional Gradient Echo (GE) echo planar imaging (EPI). We describe the first empiric exploration of this relationship using, in addition to GE, Spin Echo (SE) and two Asymmetric Spin Echo EPI...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(03)00083-3
更新日期：2003-07-01 00:00:00
abstract：:Functional MR (fMR) imaging techniques based on blood oxygenation level dependent (BOLD) effects were developed and applied to a rat brain tumor model to evaluate the potential utility of the method for characterizing tumor growth and regression following treatment. Rats bearing 9L brain tumors in situ were imaged dur...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(98)00208-2
更新日期：1999-05-01 00:00:00
abstract：:To establish the quantitative MR diagnostic criteria for discoid lateral meniscus, MR imaging of 60 knees with arthroscopically confirmed discoid lateral menisci and 134 knees with semilunar lateral menisci were analyzed. Following four quantitative parameters were measured. (1) Meniscal width (MW): The minimum menisc...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(02)00473-3
更新日期：2002-01-01 00:00:00
abstract：:A single injection of high-dose steroid (20 mg/kg) has been reported to induce necrotic lesions in the proximal metaphysis and diaphysis of the rabbit femur. In the rabbit osteonecrosis (ON) model induced by two-dose horse serum injections, contrast-enhanced magnetic resonance imaging (MRI) and T2*-weighted dynamic MR...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2008.07.001
更新日期：2009-02-01 00:00:00
abstract：:The clinical evaluation of three-dimensional time-of-flight MR angiography was prospectively performed in 16 patients with intracranial meningioma. MR angiographic techniques used in this study both with and without gadopentetate dimeglumine made it possible to demonstrate the topographic relationship between the tumo...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(93)90466-q
更新日期：1993-01-01 00:00:00
abstract：:Present knowledge suggests that in glioblastoma multiforme the value of the apparent diffusion coefficient (ADC) is elevated in the solid part and hyperintense in T1, in spite of the elevated cellularity, and also in areas where peritumoral vasogenic edema is present. The purpose of our study has been to verify in viv...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(02)00594-5
更新日期：2002-11-01 00:00:00
abstract：:The HASTE (half-Fourier acquisition single-shot turbo spin-echo) technique delivers images with T2-weighting in about half a second and could be ideal for fast dynamic studies when T2-weighting is needed. We evaluated cardiac-triggered HASTE to study cervical spine flexion/extension. The cervical spines of ten asympto...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(98)00176-3
更新日期：1999-04-01 00:00:00
abstract：OBJECTIVE:3D Time-of-flight (TOF) magnetic resonance angiography is commonly used for vascular analyses. A quantification of longitudinal morphological changes usually requires the registration of TOF image sequences acquired at different time points. The aim of this study was to evaluate the precision of different 3D ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2014.08.011
更新日期：2014-12-01 00:00:00
abstract：:The intraductal papillary-mucinous neoplasm (IPMN) is the rarest of the cystic pancreatic tumors. Endoscopic retrograde cholangiopancreatography (ERCP) is currently the gold standard for evaluating IPMN's and can demonstrate dilatation of the main duct or side branches, mural nodules, filling defects, and communicatio...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(01)00440-4
更新日期：2001-10-01 00:00:00
abstract：:When assessing liver iron content using relaxometry, an average relaxation rate (R1, R2 or R2*) is usually determined from a region of interest or the entire liver. This is commonly performed by fitting the signal decay in individual voxels to an appropriate relaxation function. The voxel-level parameters resulting fr...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2010.11.005
更新日期：2011-05-01 00:00:00
abstract：:The hippocampal formation possesses an important role in the development and maintenance of short-term memory. In this study, magnetic resonance imaging (MRI) and gross histology were used to quantify the volume of the hippocampal formation in canines. High resolution MRI, using 1 mm thick slices and an intraplanar re...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(95)02083-6
更新日期：1996-01-01 00:00:00
abstract：:Macroscopic protonation constants were measured for a series of DTPA mono- and bis-amide ligands using potentiometric titrations. Proton NMR pH titrations yielded protonation populations of the various nitrogen and oxygen basic sites of the ligands for the different protonation stages. Amide formation decreased the ba...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(94)00117-l
更新日期：1995-01-01 00:00:00
abstract：:The objective of this study was to determine the value of magnetic resonance (MR) imaging in diagnosing local recurrence of Ewing sarcoma. We retrospectively reviewed radiographs, Tc99m-methylene diphosphonate (MDP) skeletal scintigraphy, computed tomography scans, and MR studies of 11 patients who had local recurrenc...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(94)90079-7
更新日期：1994-01-01 00:00:00
abstract：PURPOSE:To determine the diagnostic performance of diffusion-weighted MRI and MR volumetry for the assessment of tumor response after preoperative chemoradiotherapy (CRT) in patients with locally advanced rectal cancer. MATERIALS AND METHODS:Forty-three patients with rectal cancer who underwent preoperative CRT were p...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2014.08.041
更新日期：2015-02-01 00:00:00
abstract：OBJECT:Dynamic in vivo31P-NMR spectroscopy in combination with Magnetic Resonance Imaging (MRI) was used to study muscle bioenergetics of boreal and Arctic scallops (Pecten maximus and Chlamys islandica) to test the hypothesis that future Ocean Warming and Acidification (OWA) will impair the performance of marine inver...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2019.06.003
更新日期：2019-09-01 00:00:00
abstract：:Functional magnetic resonance imaging (FMRI) is a major tool for the evaluation of brain function and architecture. It is widely used by physicians, neuroscientists, psychologists and others. In order to process the data collected using FMRI, it is necessary to use post-acquisition processing software that employs mot...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2005.04.007
更新日期：2005-06-01 00:00:00
abstract：:A new method for generating diffusion contrast in magnetic resonance imaging is presented. This technique is robust enough to allow implementation on conventional imaging systems without hardware modifications. Results from phantom measurements are reported. Qualitative contrast changes in magnetic resonance images de...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(93)90069-p
更新日期：1993-01-01 00:00:00
abstract：:Brain alcohol was measured in rhesus monkeys (Macaca mulatta) by proton magnetic resonance spectroscopy (MRS) following acute nasogastric alcohol administration (0.8 g/kg). Monkeys were anesthetized with ketamine and xylazine. A 1.5 T whole body imager and a 3-inch surface coil were used to acquire TE 30 and 270 ms sp...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(94)90089-a
更新日期：1994-01-01 00:00:00
abstract：PURPOSE:To analyze several histopathological features and their possible correlations with whole lesion histogram analysis derived from ADC maps in meningioma. MATERIALS AND METHODS:The retrospective study involved 36 patients with primary meningiomas. For every tumor, the following histogram analysis parameters of ap...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2018.05.009
更新日期：2018-09-01 00:00:00
abstract：:In this work an interleaved multiple-gradient-echo chemical shift imaging (IMGE-CSI) technique was designed, implemented and evaluated at 1.5 and 4T for high-resolution lipid quantification and R(2)* measurement in-vivo. The method is analogous to echo planar CSI but utilizes conventional gradient echoes, exploiting t...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(00)00165-x
更新日期：2000-09-01 00:00:00
abstract：:Functional MR imaging of the alert, behaving monkey is being used more and more often to detect activation patterns and guide electrophysiological research investigating the neural basis of behavior. Several labs have reported fMRI data from the awake monkey, but none of them has studied and systematically corrected t...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2007.03.002
更新日期：2007-07-01 00:00:00
