Magnetic Resonance Imaging (MAGN RESON IMAGING )

Publisher: Elsevier

Description

Magnetic Resonance Imaging (MRI) is the first international multidisciplinary journal encompassing physical, life, and clinical science investigations as they relate to the development and use of magnetic resonance imaging. MRI is dedicated to both basic research and medical applications, providing a single forum for communication among radiologists, physicists, chemists, biochemists, biologists, engineers, internists, pathologists, physiologists, computer scientists, and mathematicians.

  • Impact factor
    2.06
    Show impact factor history
     
    Impact factor
  • 5-year impact
    2.29
  • Cited half-life
    8.10
  • Immediacy index
    0.36
  • Eigenfactor
    0.01
  • Article influence
    0.82
  • Website
    Magnetic Resonance Imaging website
  • Other titles
    Magnetic resonance imaging
  • ISSN
    0730-725X
  • OCLC
    8047251
  • Material type
    Periodical, Internet resource
  • Document type
    Journal / Magazine / Newspaper, Internet Resource

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Pre-print allowed on any website or open access repository
    • Voluntary deposit by author of authors post-print allowed on authors' personal website, arXiv.org or institutions open scholarly website including Institutional Repository, without embargo, where there is not a policy or mandate
    • Deposit due to Funding Body, Institutional and Governmental policy or mandate only allowed where separate agreement between repository and the publisher exists.
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months .
    • Set statement to accompany deposit
    • Published source must be acknowledged
    • Must link to journal home page or articles' DOI
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • NIH Authors articles will be submitted to PubMed Central after 12 months
    • Publisher last contacted on 18/10/2013
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 rigid registration setups such that an optimal quantification of morphological changes can be achieved possible.
    Magnetic Resonance Imaging 08/2014;
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    ABSTRACT: Objective To correlate the enhancement parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with prognostic factors and immunohistochemical subtypes of breast cancer. Material and Methods A total of 81 breast carcinomas were included in our study. We obtained the following enhancement parameters: 1) analysis of background parenchymal enhancement (BPE) and BPE coefficients (BEC) from bilateral breasts, 2) the number of vessels per breast as a representation of ipsilateral whole-breast vascularity. Additionally, in 50 patients, 3) semiquantitative parameters of tumors (the initial enhancement percentage (E1), the peak enhancement percentage (Epeak), the time to peak enhancement (TTP), the signal enhancement ratio (SER)) and 4) perfusion parameters (Ktrans, kep, ve and iAUC) from tumors and ipsilateral breasts were also obtained. Correlations among parameters and prognostic factors, including tumor size, axillary node status, nuclear grade, histologic grade, estrogen receptor (ER) expression, progesterone receptor (PR) expression, Ki-67, human epidermal growth factor receptor 2 (HER-2) expression, epidermal growth factor receptor (EGFR) expression, bcl-2, CK5/6 and subtypes categorized as luminal (ER or PR positive), triple negative (ER or PR negative, HER-2 negative) and HER2 (ER and PR negative with HER-2 overexpression) were analyzed. Results BPE was significantly correlated with EGFR expression (p = 0.040). BEC was significantly higher in tumors larger than 2 cm than in tumors smaller than 2 cm (p = 0.001). The vessel numbers in ipsilateral breasts were higher in tumors larger than 2 cm than in tumors smaller than 2 cm (p = 0.034), with higher nuclear grades (grade 3) than with lower nuclear grades (grade 1,2) (p = 0.001) and with PR-negative rather than with PR-positive (p = 0.010) results. The mean Ktrans was higher in Ki-67-positive tumors than Ki-67 negative tumors (p = 0.002). The mean kep was higher in Ki-67-positive tumors than in Ki-67-negative tumors (p = 0.005) and in CK5/6-positive tumors than in CK5/6-negative tumors (p = 0.015). The mean Ktrans was lower in the ipsilateral breast parenchyma with HER-2-positive tumors compared to HER-2-negative tumors (p = 0.012). Conclusion BPE, BEC and ipsilateral whole-breast vascularity, higher Ktrans and kep of the cancer and lower Ktrans and iAUC of ipsilateral breast parenchyma may serve as additional predictors of a poor breast cancer prognosis.
    Magnetic Resonance Imaging 08/2014;
  • Feng Wang, Rosie Jiang, Keiko Takahashi, John Gore, Raymond C. Harris, Takamune Takahashi, C. Chad Quarles
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    ABSTRACT: The purpose of this study is to evaluate the utility of high-resolution non-invasive endogenous high-field MRI methods for the longitudinal structural and quantitative assessments of mouse kidney disease using the model of unilateral ureter obstruction (UUO). T1-weighted, T2-weighted and magnetization transfer (MT) imaging protocols were optimized to improve the regional contrast in mouse kidney. Conventional T1 and T2 weighted images were collected in UUO mice on day 0 (~3 h), day 1, day 3 and day 6 after injury, on a 7 T small animal MRI system. Cortical and medullary thickness, corticomedullary contrast and Magnetization Transfer Ratio (MTR) were assessed longitudinally. Masson trichrome staining was used to histologically assess changes in tissue microstructure. Over the course of UUO progression there were significant (p b 0.05) changes in thickness of cortex and outer medulla, and regional changes in T2 signal intensity and MTR values. Histological changes included tubular cell death, tubular dilation, urine retention, and interstitial fibrosis, assessed by histology. The MRI measures of renal cortical and medullary atrophy, cortical–medullary differentiation and MTR changes provide an endogenous, non-invasive and quantitative evaluation of renal morphology and tissue composition during UUO progression.
    Magnetic Resonance Imaging 01/2014; 32:1125-1132.
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    ABSTRACT: An automated method was evaluated to detect blood flow in small pulmonary arteries and classify each as artery or vein, based on a temporal correlation analysis of their blood-flow velocity patterns. The method was evaluated using velocity-sensitive phase-contrast magnetic resonance data collected in vitro with a pulsatile flow phantom and in vivo in 11 human volunteers. The accuracy of the method was validated in vitro, which showed relative velocity errors of 12% at low spatial resolution (four voxels per diameter), but was reduced to 5% at increased spatial resolution (16 voxels per diameter). The performance of the method was evaluated in vivo according to its reproducibility and agreement with manual velocity measurements by an experienced radiologist. In all volunteers, the correlation analysis was able to detect and segment peripheral pulmonary vessels and distinguish arterial from venous velocity patterns. The intrasubject variability of repeated measurements was approximately 10% of peak velocity, or 2.8 cm/s root-mean-variance, demonstrating the high reproducibility of the method. Excellent agreement was obtained between the correlation analysis and radiologist measurements of pulmonary velocities, with a correlation of R2=0.98 (P<.001) and a slope of 0.99+/-0.01.
    Magnetic Resonance Imaging 01/2009; 27(1):38-47.
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    ABSTRACT: The objectives of this study were (1) to determine whether superparamagnetic iron oxide (SPIO) affects viability, transdifferentiation potential and cell-factor secretion of adipose-derived stem cells (ASCs); and (2) to determine whether SPIO-enhanced magnetic resonance (MR) imaging highlights living stem cells. Rat ASCs were incubated in SPIO-containing cell culture medium for 2 days. The SPIO-treated ASCs were then subjected to adipogenic, osteogenic and myogenic transdifferentiation. Expression of vascular endothelial growth factor, hepatocyte growth factor and insulin-like growth factor 1 by the SPIO-treated ASCs was measured using reverse transcription polymerase chain reaction. Cell viability was assessed using trypan blue stain. For in vivo experiments, SPIO-labeled ASCs were injected into 10 rat hearts. The hearts were monitored using MRI. We found that survival rate of the ASCs cultured in the SPIO-containing medium was very high (97-99%). The SPIO-treated ASCs continued to express specific markers for the three types of transdifferentiation. Expression of the cell factors by the ASCs was not affected by SPIO. Signal voids on MR images were associated with the living SPIO-labeled ASCs in the rat hearts. We conclude that SPIO does not affect viability, transdifferentiation potential or cell-factor secretion of ASCs. MRI mainly highlights living SPIO-labeled stem cells.
    Magnetic Resonance Imaging 01/2009; 27(1):108-19.
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    ABSTRACT: To evaluate the apparent diffusion coefficient (ADC) of skeletal muscle based on signal intensity (SI) attenuation vs. increasing b values and to determine ADC differences in skeletal muscles between genders, age groups and muscles. Diffusion-weighted images (b values in the range of 0-750 s/mm2 at increments of 50 s/mm2) of the ankle dorsiflexors (116 subjects) and the erector spinae muscles (86 subjects) were acquired with a 1.5-T MR device. From the two different slopes obtained in SI vs. b-value logarithmic plots, ADCb0-50 (b values=0 and 50 s/mm2) reflected diffusion and perfusion, while ADCb50-750 (b values in the range of 50-750 s/mm2 at increments of 50 s/mm2) approximated the true diffusion coefficient. Moreover, to evaluate whether this b-value combination is appropriate for assessing the flow component within muscles, diffusion-weighted images of the ankle dorsiflexors (10 subjects) were obtained before and during temporal arterial occlusion. ADCb0-50 and ADCb50-750 were found to be 2.64x10(-3) and 1.44x10(-3) mm2/s in the ankle dorsiflexors, and 3.02x10(-3) and 1.49x10(-3) mm2/s in the erector spinae muscles, respectively. ADCb0-50 was significantly higher than ADCb50-750 in each muscle (P<.01). The erector spinae muscles showed significantly higher ADC values than the ankle dorsiflexors (P<.01). However, for each muscle, there were few significant gender- and age-related ADC differences. Following temporal occlusion, ADCb0-50 of the ankle dorsiflexors decreased significantly from 2.49 to 1.6x10(-3) mm2/s (P<.01); however, ADCb50-750 showed no significant change. Based on the SI attenuation pattern, muscle ADC could be divided into ADC that reflects both diffusion and perfusion, and ADC that approximates a true diffusion coefficient. There were significant differences in ADC of functionally distinct muscles. However, we barely found any gender- or age-related ADC differences for each muscle.
    Magnetic Resonance Imaging 01/2009; 27(1):69-78.
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    ABSTRACT: We demonstrate an experimental method for the measurement of heat transfer coefficient for a fluid system by magnetic resonance imaging. In this method, the temporal variation of thermally induced nuclear shielding is monitored and the average heat transfer coefficient is measured as a function of fluid velocity. We examine the cases of natural convection and forced convection at fluid velocity up to 0.8 m s(-1). These cases correspond to low dimensionless Biot (Bi) number where the heat transfer is limited by thermal convection. We demonstrate the NMR method for two simple geometries, a cylinder and a sphere, to experimentally determine the heat transfer coefficient (h) in two NMR imaging and spectroscopy systems through measuring three NMR parameters, the chemical shift, magnetization and spin self diffusion coefficient.
    Magnetic Resonance Imaging 11/2008; 26(9):1323-8.
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    ABSTRACT: In functional magnetic resonance imaging (fMRI) analysis, although the univariate general linear model (GLM) is currently the dominant approach to brain activation detection, there is growing interest in multivariate approaches such as principal component analysis, canonical variate analysis (CVA), independent component analysis and cluster analysis, which have the potential to reveal neural networks and functional connectivity in the brain. To understand the effect of processing options on performance of multivariate model-based fMRI processing pipelines with real fMRI data, we investigated the impact of commonly used fMRI preprocessing steps and optimized the associated multivariate CVA-based, single-subject processing pipelines with the NPAIRS (nonparametric prediction, activation, influence and reproducibility resampling) performance metrics [prediction accuracy and statistical parametric image (SPI) reproducibility] on the Fiswidgets platform. We also compared the single-subject SPIs of univariate GLM with multivariate CVA-based processing pipelines from SPM, FSL.FEAT, NPAIRS.GLM and NPAIRS.CVA software packages (or modules) using a novel second-level CVA. We found that for the block-design data, (a) slice timing correction and global intensity normalization have little consistent impact on the fMRI processing pipeline, but spatial smoothing, temporal detrending or high-pass filtering, and motion correction significantly improved pipeline performance across all subjects; (b) the combined optimization of spatial smoothing, temporal detrending and CVA model parameters on average improved between-subject reproducibility; and (c) the most important pipeline choices include univariate or multivariate statistical models and spatial smoothing. This study suggests that considering options other than simply using GLM with a fixed spatial filter may be of critical importance in determining activation patterns in BOLD fMRI studies.
    Magnetic Resonance Imaging 11/2008; 27(2):264-78.
  • Magnetic Resonance Imaging 10/2008; 26(8):1197–1199.
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    ABSTRACT: To evaluate the liver-to-muscle signal intensity and R2* methods to gain a transferable, clinical application for liver iron measurement. Sixteen liver phantoms and 33 human subjects were examined using three 1.5-T MRI scanners from two different vendors. Phantom-to-muscle and liver-to-muscle signal intensity ratios were analyzed to determine MRI estimated phantom and hepatic iron concentration (M-PIC and M-HIC, respectively). R2* was calculated for the phantoms and the liver of human subjects. Seven patients' biochemical hepatic iron concentration was obtained. M-PIC and R2* results of three scanners correlated linearly to phantom iron concentrations (r=0.984 to 0.989 and r=0.972 to 0.981, respectively), and no significant difference between the scanners was found (P=.482 and P=.846, respectively) in vitro. The patients' R2* correlated linearly to M-HIC of the standard scanner (r=0.981). M-HIC values did not differ from those obtained from the biopsy specimens (P=.230). The difference in M-HIC was significant, but the difference in R2* was not significant between the scanners (P<.0001 and P=.505, respectively) in vivo. Both methods, M-HIC and R2*, are reliable iron concentration indicators with linear dependence on iron concentration in vivo and in vitro. The R2* method was found to be comparable among different scanners. Transferability testing is needed for the use of the methods at various scanners.
    Magnetic Resonance Imaging 10/2008; 26(8):1175-82.
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    ABSTRACT: The purpose of this study was to investigate the effects of biophysical factors on the diffusion and the relaxation time T(2) independently. Certain properties of the extracellular and the intracellular space may change radically in pathological conditions resulting in water diffusion changes. A tissue model consisting of red blood cells was studied. The extra- and intracellular spaces were modified osmotically and by suspending medium concentration. Diffusion measurements were evaluated with regard to the effective medium theory. Neither the nature of the protein in the extracellular space nor an increased level of intracellular hydration caused a significant net water diffusion change in the cell suspension. The relaxation time T(2) exhibited very little dependence on the extracellular volume fraction or the concentration or the nature of the protein in the extracellular space. An increased level of intracellular hydration resulted in systematically larger T(2) values. It seems probable that increases in extracellular protein concentrations or in the extent of intracellular hydration do not play a significant role in the diffusion changes detected in pathological conditions. T(2) appears to depend on the level of hydration or the total water content but is seemingly less dependent of the concentration and the nature of the extracellular protein in our model solutions.
    Magnetic Resonance Imaging 10/2008; 27(2):279-84.