Fast measurement of relaxation times by steady-state free precession of 129Xe in carrier agents for hyperpolarized noble gases.

abstract：:In vivo or ex vivo electron paramagnetic resonance imaging (EPRI) is a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. However, applications of EPRI have been limited by long projection acquisition times and the consequent fact t...

journal_title：Magnetic resonance in medicine

authors： Chen Z,Reyes LA,Johnson DH,Velayutham M,Yang C,Samouilov A,Zweier JL

更新日期：2013-02-01 00:00:00

abstract：:The assumption of linear time-invariance (LTI) in the human primary somatosensory cortex (SI) is assessed for fMRI signals generated by variable-duration vibrotactile stimuli. Predictions based on time-shifted summation (TSS) of responses to 2 s stimuli overestimate observed BOLD signal amplitudes in response to longe...

journal_title：Magnetic resonance in medicine

authors： Nangini C,Macintosh BJ,Tam F,Staines WR,Graham SJ

更新日期：2005-02-01 00:00:00

abstract：PURPOSE:Preclinical imaging of myocardial blood flow (MBF) can elucidate molecular mechanisms underlying cardiovascular disease. We compared the repeatability and variability of two methods, first-pass MRI and arterial spin labeling (ASL), for imaging MBF in mice. METHODS:Quantitative perfusion MRI in mice was perform...

journal_title：Magnetic resonance in medicine

authors： Naresh NK,Chen X,Moran E,Tian Y,French BA,Epstein FH

更新日期：2016-06-01 00:00:00

abstract：PURPOSE:To significantly reduce the background phase effects, especially at the air-tissue interface, and to enhance the desirable local structures of veins in susceptibility-weighted imaging. METHODS:In the proposed reconstruction method called Magnitude of Complex Filtering, a complex-valued magnetic resonance image...

journal_title：Magnetic resonance in medicine

authors： Lee Y,Han Y,Park H

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:We incorporate simultaneous multislice (SMS) acquisition into MR fingerprinting (MRF) to accelerate the MRF acquisition. METHODS:The t-Blipped SMS-MRF method is achieved by adding a Gz blip before each data acquisition window and balancing it with a Gz blip of opposing polarity at the end of each TR. Thus the ...

journal_title：Magnetic resonance in medicine

authors： Ye H,Ma D,Jiang Y,Cauley SF,Du Y,Wald LL,Griswold MA,Setsompop K

更新日期：2016-05-01 00:00:00

abstract：:MRI of hyperpolarized (129)Xe dissolved in pulmonary tissues, and blood has the potential to offer a new tool for regional evaluation of pulmonary gas exchange and perfusion; however, the extremely short T2* and low magnetization density make it difficult to acquire the image. In this study, an ultrashort echo-time se...

journal_title：Magnetic resonance in medicine

authors： Iguchi S,Imai H,Hori Y,Nakajima J,Kimura A,Fujiwara H

更新日期：2013-07-01 00:00:00

abstract：:Specific absorption rate management and excitation fidelity are key aspects of radiofrequency pulse design for parallel transmission at ultra-high magnetic field strength. The design of radiofrequency pulses for multiple channels is often based on the solution of regularized least-squares optimization problems for whi...

journal_title：Magnetic resonance in medicine

authors： Deniz CM,Alon L,Brown R,Sodickson DK,Zhu Y

更新日期：2012-01-01 00:00:00

abstract：PURPOSE:Real-time assessment of ventricular volumes requires high acceleration factors. Residual convolutional neural networks (CNN) have shown potential for removing artifacts caused by data undersampling. In this study, we investigated the ability of CNNs to reconstruct highly accelerated radial real-time data in pat...

journal_title：Magnetic resonance in medicine

authors： Hauptmann A,Arridge S,Lucka F,Muthurangu V,Steeden JA

更新日期：2019-02-01 00:00:00

abstract：:Breathing motion is one of the main sources of artifacts in MRI acquisitions that can severely impair diagnosis. In MRI with continuously moving table, the application of common motion compensation approaches such as breath holding or the synchronization of the measurement with the breathing motion can be problematic....

journal_title：Magnetic resonance in medicine

authors： Honal M,Leupold J,Huff S,Baumann T,Ludwig U

更新日期：2010-03-01 00:00:00

abstract：:The potential application of gas microbubbles as a unique intravascular susceptibility contrast agent for MRI has not been fully explored. In this study, the MR susceptibility effect of an ultrasound microbubble contrast agent, Optison, was studied with rat liver imaging at 7 T. Optison suspension in two different dos...

journal_title：Magnetic resonance in medicine

authors： Wong KK,Huang I,Kim YR,Tang H,Yang ES,Kwong KK,Wu EX

更新日期：2004-09-01 00:00:00

abstract：PURPOSE:Magnetic resonance imaging is a promising alternative to computed tomography for lung imaging. However, organ motion and poor signal-to-noise ratio, arising from short T2*, impair image quality. To alleviate these issues, a new retrospective gating method was implemented and tested with an ultra-short echo time...

journal_title：Magnetic resonance in medicine

authors： Delacoste J,Chaptinel J,Beigelman-Aubry C,Piccini D,Sauty A,Stuber M

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Imaging gradients result in the generation of concomitant fields, or Maxwell fields, which are of increasing importance at higher gradient amplitudes. These time-varying fields cause additional phase accumulation, which must be compensated for to avoid image artifacts. In the case of gradient systems employing ...

journal_title：Magnetic resonance in medicine

authors： Weavers PT,Tao S,Trzasko JD,Frigo LM,Shu Y,Frick MA,Lee SK,Foo TK,Bernstein MA

更新日期：2018-03-01 00:00:00

abstract：:Localized 7Li MR point-resolved spectroscopy (PRESS) was developed as a technique to measure lithium (Li) concentration in rat brain in vivo. Localized 7Li spectra could be obtained at 4.7 T in a 0.7-ml voxel in rat brain over the entire therapeutic range of serum Li for humans. Localized 7Li spin-lattice (T1) and spi...

journal_title：Magnetic resonance in medicine

authors： Komoroski RA,Pearce JM

更新日期：2004-07-01 00:00:00

abstract：:The purpose of the present study was to examine whether single human carcinoma cells labeled with iron oxide nanoparticles could be detected by magnetic resonance (MR) imaging on a clinical 3-T scanner using a surface coil only. WiDr human colon carcinoma cells were loaded with two kinds of iron oxide nanoparticles di...

journal_title：Magnetic resonance in medicine

authors： Pinkernelle J,Teichgräber U,Neumann F,Lehmkuhl L,Ricke J,Scholz R,Jordan A,Bruhn H

更新日期：2005-05-01 00:00:00

abstract：:A precise understanding of human blood spin-spin relaxation is of major importance for numerous applications, particularly functional magnetic resonance imaging (fMRI), which is increasingly performed at 3 Tesla. It is well known that T2 measured from partially deoxygenated blood depends on the Carr-Purcell Meiboom-Gi...

journal_title：Magnetic resonance in medicine

authors： Chen JJ,Pike GB

更新日期：2009-02-01 00:00:00

abstract：:Algorithms to reliably detect motion in navigator echoes are crucial to many MRI motion suppression techniques. The accuracy of these algorithms is affected by noise and deformation of navigator echo profile caused by physiologic motion. This study compared the performance of algorithms based on correlation and least ...

journal_title：Magnetic resonance in medicine

authors： Wang Y,Grimm RC,Felmlee JP,Riederer SJ,Ehman RL

更新日期：1996-07-01 00:00:00

abstract：PURPOSE:To optimize 3D radial ultrashort echo time MRI for high resolution whole-lung imaging. METHODS:3D radial ultrashort echo time was implemented on a 3T scanner to investigate the effects of: (1) limited field-of-view excitation, (2) variable density readouts, and (3) radial oversampling. Improvements in noise pe...

journal_title：Magnetic resonance in medicine

authors： Johnson KM,Fain SB,Schiebler ML,Nagle S

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. METHODS:MR acquisition consiste...

journal_title：Magnetic resonance in medicine

authors： Celicanin Z,Auboiroux V,Bieri O,Petrusca L,Santini F,Viallon M,Scheffler K,Salomir R

更新日期：2014-10-01 00:00:00

abstract：PURPOSE:Going to ultrahigh field MRI (e.g., 7 Tesla [T]), the nonuniformity of the B1+ field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B1+, its field remains nonuniform. In this work, an RF pulse was designed that uses the slab selecti...

journal_title：Magnetic resonance in medicine

authors： van Kalleveen IM,Boer VO,Luijten PR,Klomp DW

更新日期：2015-08-01 00:00:00

abstract：:In vivo echo-planar MR imaging was used to measure apparent diffusion coefficients (ADC) of cerebral tissues in a comprehensive noninvasive evaluation of early ischemic brain damage induced by occlusion of the middle cerebral artery (MCA) in a cat model of acute regional stroke. Within 10 min after arterial occlusion,...

journal_title：Magnetic resonance in medicine

authors： Kucharczyk J,Mintorovitch J,Asgari HS,Moseley M

更新日期：1991-06-01 00:00:00

abstract：:The concept of temporal echo multiplexing is defined and used to develop rapid biphasic spin-echo sequences for imaging the heart. Three imaging sequences, based on four-echo and two-echo multiplexing and rapid single echo (i.e., conventional spin-echo imaging), are compared. Preliminary results indicate that two-echo...

journal_title：Magnetic resonance in medicine

authors： Parker DL,Caputo GR,Frederick PR

更新日期：1989-07-01 00:00:00

abstract：:Proton MR spectroscopy ((1)H-MRS) has been used for in vivo quantification of intracellular triglycerides within the sarcolemma. The purpose of this study was to assess whether breath-hold dual-echo in- and out-of-phase MRI at 3.0 T can quantify the fat content of the myocardium. Biases, including T(1), T*(2), and noi...

journal_title：Magnetic resonance in medicine

authors： Liu CY,Redheuil A,Ouwerkerk R,Lima JA,Bluemke DA

更新日期：2010-04-01 00:00:00

abstract：:Certain kinds of artifacts have been reported when projection reconstruction (PR) techniques are used in magnetic resonance imaging (MRI). These will occur if the spacing between samples in k-space is too large. It has been suggested that PR requires finer k-space sampling than does two-dimensional Fourier reconstruct...

journal_title：Magnetic resonance in medicine

authors： Joseph PM

更新日期：1998-09-01 00:00:00

abstract：:A new methodology is introduced that characterizes the intravoxel orientation distribution function (ODF) based on a single-fiber model of the diffusion MRI signal. Using a Bayesian framework the probability of finding a fiber in a specific orientation is obtained. The proposed ODF estimation relies on a cigar-like di...

journal_title：Magnetic resonance in medicine

authors： Canales-Rodríguez EJ,Melie-García L,Iturria-Medina Y,Martínez-Montes E,Alemán-Gómez Y,Lin CP

更新日期：2008-09-01 00:00:00

abstract：:Fractional anisotropy (FA) and relative anisotropy (RA) are the two most commonly used scalar measures of anisotropy in diffusion tensor (DT) MRI. While a few published studies have shown that FA has superior noise immunity relative to RA, no theoretical basis has been proposed to explain this behavior. In the current...

journal_title：Magnetic resonance in medicine

authors： Hasan KM,Alexander AL,Narayana PA

更新日期：2004-02-01 00:00:00

abstract：:The pulse wave velocity (PWV) of aortic blood flow is considered a surrogate for aortic compliance. A new method using phase-contrast (PC)-MRI is presented whereby the spatial and temporal profiles of axial velocity along the descending aorta can be analyzed. Seventeen young healthy volunteers (the YH group), six olde...

journal_title：Magnetic resonance in medicine

authors： Yu HY,Peng HH,Wang JL,Wen CY,Tseng WY

更新日期：2006-10-01 00:00:00

abstract：:Free induction decay signals are analyzed by fitting a model function directly in the time domain. No starting values are needed for linear model parameters, and omission of corrupted data points poses no problems. A significant gain of accuracy is achieved by imposing prior knowledge about the model parameters. ...

journal_title：Magnetic resonance in medicine

authors： van der Veen JW,de Beer R,Luyten PR,van Ormondt D

更新日期：1988-01-01 00:00:00

abstract：:A method is presented that employs the inherent spectral selectivity of the Steady-State Free Precession (SSFP) pulse sequence to provide a spectral band of suppression. At TE = TR/2, SSFP partitions the magnetization into two phase-opposed spectral components. Z-storing one of these components simultaneously further ...

journal_title：Magnetic resonance in medicine

authors： Derbyshire JA,Herzka DA,McVeigh ER

更新日期：2005-10-01 00:00:00

abstract：PURPOSE:A new T1 mapping method is proposed that is accurate, rapid, and robust to motion. Considering these features, the method is dubbed "T-One with Enhanced Robustness and Speed (TOWERS)." METHODS:TOWERS is composed of inversion recovery (IR) and saturation recovery (SR) acquisitions. In the IR acquisitions, a sli...

journal_title：Magnetic resonance in medicine

authors： Eldeniz C,Finsterbusch J,Lin W,An H

更新日期：2016-07-01 00:00:00

abstract：:T2-weighted MRI of edema in acute myocardial infarction (MI) provides a means of differentiating acute and chronic MI, and assessing the area at risk of infarction. Conventional T2-weighted imaging of edema uses a turbo spin-echo (TSE) readout with dark-blood preparation. Clinical applications of dark-blood TSE method...

journal_title：Magnetic resonance in medicine

authors： Kellman P,Aletras AH,Mancini C,McVeigh ER,Arai AE

更新日期：2007-05-01 00:00:00