Abstract:
PURPOSE:Application of phase rotation to the STRESS (=STEAM+PRESS) localization scheme, to shorten echo time, minimize J-coupling dephasing and estimate B1+ inhomogeneity. STRESS (=STEAM + PRESS) simultaneously refocuses and acquires the double spin echo (SE123 ) and stimulated echo (STE- ) pathways, combining PRESS-like signal with lower chemical shift displacement as in STEAM. Phase rotation effectively separates coherence pathways, allows reduction of spoiling gradients moments leading to reduction in echo time. Implementing it in STRESS allows one to individually phase-correct SE123 and STE- prior to combination. Moreover, B1+ inhomogeneity can be assessed by comparing the measured ratio of resonance intensities of SE123 and STE- pathways to the simulated one. METHODS:In vivo spectra were acquired from a single voxel placed in the sensory-motor cortex of 10 healthy volunteers, using phase rotation-STRESS/PRESS/STEAM sequences at 3 T scanner. The phases of each slice-selective pulse were incremented by Δϕ1/2/3=22.5°/-45°/45°. RESULTS:Phase rotation-STRESS showed quantification accuracy (% Cramer Rao lower bounds) and reproducibility (% coefficients of variation) comparable to PRESS and STEAM, in both phantoms and in vivo study. Minimal echo time achieved was 13 ms. CONCLUSION:Phase rotation complements STRESS by reducing echo time, allowing processing of each pathway individually prior to addition and providing B1+ estimation in single voxel proton magnetic resonance spectroscopy. Magn Reson Med 79:2481-2490, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Volovyk O,Tal Adoi
10.1002/mrm.26911subject
Has Abstractpub_date
2018-05-01 00:00:00pages
2481-2490issue
5eissn
0740-3194issn
1522-2594journal_volume
79pub_type
杂志文章abstract:PURPOSE:In this work, 22 configurations for remote radiofrequency (RF) coil arrays consisting of different transmit element designs for 7 Tesla (T) ultrahigh-field MRI are compared by numerical simulations. METHODS:Investigated transmit RF element types are rectangular loops, micro striplines, micro striplines with me...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26704
更新日期:2018-02-01 00:00:00
abstract::Chemical shift imaging benefits from signal-to-noise ratio (SNR) and chemical shift dispersion increases at stronger main field such as 7 Tesla, but the associated shorter radiofrequency (RF) wavelengths encountered require B1+ mitigation over both the spatial field of view (FOV) and a specified spectral bandwidth. Th...
journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.20601
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abstract::The reconstruction of MR images from nonrectilinearly sampled data is complicated by the fact that the inverse 2D Fourier transform (FT) cannot be performed directly on the acquired k-space data set. k-Space gridding is commonly used because it is an efficient reconstruction method. However, conventional gridding requ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10692
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abstract::The role of relative cerebral blood volume (rCBV) in the early response of blood oxygenation level-dependent (BOLD) signal following sensory stimulation was assessed. Magnetic resonance imaging (MRI) measurements of rCBV and BOLD signal as a function of time (t) were compared with relative cerebral blood flow (rCBF) o...
journal_title:Magnetic resonance in medicine
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abstract::Longitudinal P-31 relaxation rate enhancements of phosphate groups have been measured at pH 7-7.2 and 310 degrees K on aqueous solutions containing adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi) and some lanthanide complexes (Gd-DOTA, Gd-HPDO3A, Gd-DO3A, Gd-DTPA, Gd-DTPA-BMA). The macroc...
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更新日期:1987-10-01 00:00:00
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pub_type: 临床试验,杂志文章
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更新日期:2003-07-01 00:00:00
abstract::Due to a delayed echo-formation, echo-shifted gradient echo sequences (ES-GRE) allow for an enhanced T(2)*-weighting at short repetition times. While they are in use with and without RF spoiling, analytical solutions are only known for the latter. The signal formation in the former could only be assessed in approximat...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.21010
更新日期:2006-10-01 00:00:00
abstract::Aggregation of human erythrocytes at physiological hematocrit by hydroxyethyl starch (HES) was investigated with a 1H nuclear magnetic resonance method which measures the erythrocyte mean water exchange time, tau a. A relationship that takes into account the effect of the aggregate as the water-exchanging unit was use...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910050108
更新日期:1987-07-01 00:00:00
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更新日期:2004-06-01 00:00:00
abstract:PURPOSE:Compare the transmural distribution of forward creatine kinase reaction (kf,CK ) and ATP hydrolysis rate (kr,ATPase ) in the myocardium of normal porcine heart. Rate constants were extracted from partially relaxed spectra by applying the T1nom method, effectively reducing data acquisition time by up to an order...
journal_title:Magnetic resonance in medicine
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更新日期:2016-05-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910350306
更新日期:1996-03-01 00:00:00
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更新日期:2016-12-01 00:00:00
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更新日期:2008-08-01 00:00:00
abstract::A novel method, called relaxo-oximetry, for rapid spatially resolved in vivo measurements of oxygen concentration using time-domain radiofrequency (RF) electron paramagnetic resonance (EPR) is described. Time-domain data from triaryl methyl (TAM)-based single-electron contrast agents were processed by systematic delet...
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更新日期:2017-02-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:1990-03-01 00:00:00
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更新日期:2017-04-01 00:00:00
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更新日期:2011-03-01 00:00:00
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更新日期:2017-03-01 00:00:00
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更新日期:2016-03-01 00:00:00