Abstract:
PURPOSE:To develop velocity-selective (VS) MR angiography (MRA) protocols for arteriography and venography with whole-brain coverage. METHODS:Tissue suppression using velocity-selective saturation (VSS) pulse trains is sensitive to radiofrequency field (B1 +) inhomogeneity. To reduce its sensitivity, we replaced the low-flip-angle hard pulses in the VSS pulse train with optimal composite (OCP) pulses. Additionally, new pulse sequences for arteriography and venography were developed by placing spatially selective inversion pulses with a delay to null signals from either venous or arterial blood. The VS MRA techniques were compared to the time-of-flight (TOF) MRA in six healthy subjects and two patients at 3T. RESULTS:More uniform suppression of stationary tissue was observed when the hard pulses were replaced by OCP pulses in the VSS pulse trains, which improved contrast ratios between blood vessels and tissue background for both arteries (0.87 vs. 0.77) and veins (0.80 vs. 0.59). Both arteriograms and venograms depicted all major cervical and intracranial arteries and veins, respectively. Compared to TOF MRA, VS MRA not only offers larger spatial coverage but also depicts more small vessels. Initial clinical feasibility was shown in two patients with comparisons to TOF protocols. CONCLUSION:Noncontrast-enhanced whole-brain arteriography and venography can be obtained without losing sensitivity to small vessel detection. Magn Reson Med 79:2014-2023, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Li W,Xu F,Schär M,Liu J,Shin T,Zhao Y,van Zijl PCM,Wasserman BA,Qiao Y,Qin Qdoi
10.1002/mrm.26864subject
Has Abstractpub_date
2018-04-01 00:00:00pages
2014-2023issue
4eissn
0740-3194issn
1522-2594journal_volume
79pub_type
杂志文章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
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abstract::In a systematic study on the interdependence of linewidth, signal-to-noise ratio (SNR), and spatial resolution in 3D proton spectroscopic imaging ((1)H-SI) at 3 T, we demonstrate reduced linewidths with increased spatial resolution due to reduced magnetic inhomogeneity within the brain. High-precision quantitative dat...
journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.21758
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abstract::Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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abstract::It is demonstrated that a high-resolution (1)H NMR spectrum of excised rat liver can be obtained using the technique of magic angle turning (MAT) at a sample spinning rate of 1 Hz. A variant of the phase-corrected MAT (PHORMAT) pulse sequence that includes a water suppression segment was developed for the investigatio...
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abstract:PURPOSE:To assess the feasibility of using dissolved hyperpolarized xenon-129 (129 Xe) MRI to study renal physiology in humans at 3 T. METHODS:Using a flexible transceiver RF coil, dynamic and spatially resolved 129 Xe spectroscopy was performed in the abdomen after inhalation of hyperpolarized 129 Xe gas with 3 healt...
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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更新日期:2010-02-01 00:00:00
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更新日期:2008-06-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21793
更新日期:2009-04-01 00:00:00
abstract::Precise relaxation time (RT) measurements have been made, with a standard deviation of 3% for T1 and T2 in white matter in normal volunteers. This sets an upper limit to the instrumental random errors (imprecision). Achieving this precision requires careful adjustment and use of the imager. The wide variation in RTs s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910110307
更新日期:1989-09-01 00:00:00
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doi:10.1002/(sici)1522-2594(200005)43:5<739::aid-mrm17
更新日期:2000-05-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26903
更新日期:2018-05-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21345
更新日期:2008-01-01 00:00:00
abstract:PURPOSE:A target-pattern-driven (TD) trajectory design is introduced in combination with parallel transmit (pTX) radiofrequency (RF) pulses to provide localized suppression of unwanted signals. The design incorporates target-pattern and B1+ information to adjust denser sampling and coverage in k-space regions where the...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.25016
更新日期:2014-10-01 00:00:00
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doi:10.1002/mrm.24443
更新日期:2013-07-01 00:00:00
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doi:10.1002/mrm.20865
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更新日期:1997-10-01 00:00:00
abstract::Experiments have been performed to demonstrate and quantify cross-relaxation between water and methylene resonances in a simple model system. Inversion recovery experiments on aqueous solutions of polyethylene glycol produce a transient nuclear Overhauser effect that alters the recovery of the methylene resonance. The...
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doi:10.1002/mrm.1910090305
更新日期:1989-03-01 00:00:00
abstract::The ability to generate in vivo maps of lactate may have significant diagnostic utility in staging and treatment planning of a wide variety of cancers. The double selective multiple quantum filter technique (SelMQC) has been shown to be effective for nonlocalized detection of lactate with little or no interference fro...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21659
更新日期:2008-08-01 00:00:00
abstract:PURPOSE:The purpose of this work was to develop and evaluate a robust water-fat separation method for T1-weighted symmetric two-point Dixon data. THEORY AND METHODS:A method for water-fat separation by phase unwrapping of the opposite-phase images by phase-sensitive reconstruction (PSR) is introduced. PSR consists of ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26488
更新日期:2017-09-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27590
更新日期:2019-04-01 00:00:00
abstract::Longitudinal water proton relaxation rates of methemoglobin solutions show a strong dependence on temperature and pH. The increase of the relaxation rates with temperature is associated with shortened exchange lifetime of the coordinated water molecule. An accurate measurement of the relaxation rate of methemoglobin s...
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doi:10.1002/mrm.1910330613
更新日期:1995-06-01 00:00:00
abstract::Fluid-attenuated inversion recovery (FLAIR) images obtained during the administration of supplemental oxygen demonstrate a hyperintense signal within the cerebrospinal fluid (CSF) that is likely caused by T1 changes induced by paramagnetic molecular oxygen. Previous studies demonstrated a linear relationship between t...
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pub_type: 临床试验,杂志文章
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更新日期:2005-07-01 00:00:00
abstract:PURPOSE:We propose a constrained optimization approach for designing parallel transmit (pTx) pulses satisfying all regulatory and hardware limits. We study the trade-offs between excitation accuracy, local and global specific absorption rate (SAR), and maximum and average power for small flip-angle pTx (eight channels)...
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doi:10.1002/mrm.24800
更新日期:2014-04-01 00:00:00
abstract::Dynamic contrast-enhanced (DCE-) MRI is often used to evaluate the response to experimental antiangiogenic therapies in small animal models of cancer. Unfortunately, DCE-MRI studies often require a substantial investment of both time and money to achieve the desired level of statistical significance. Multiple-mouse MR...
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doi:10.1002/mrm.21348
更新日期:2007-09-01 00:00:00