Uncertainties of calculated Cramér-Rao lower bounds: implications for quantitative MRS.

abstract：:Orientational anisotropy of T2 and T1 relaxation times, diffusion, and magnetization transfer has been investigated for six different tissues: tendon, cartilage, kidney, muscle, white matter, and optic nerve. Relaxation anisotropy was observed for tendon and cartilage, and diffusional anisotropy was measured in kidney...

journal_title：Magnetic resonance in medicine

authors： Henkelman RM,Stanisz GJ,Kim JK,Bronskill MJ

更新日期：1994-11-01 00:00:00

abstract：PURPOSE:Recent MRI studies have suggested that the magnetic susceptibility of white matter (WM) in the human brain is anisotropic, providing a new contrast mechanism for the visualization of fiber bundles and allowing the extraction of cellular compartment-specific information. This study provides an independent confir...

journal_title：Magnetic resonance in medicine

authors： van Gelderen P,Mandelkow H,de Zwart JA,Duyn JH

更新日期：2015-11-01 00:00:00

abstract：:This study characterizes gains in sensitivity and spectral resolution of proton echo-planar spectroscopic imaging (PEPSI) with increasing magnetic field strength (B(0)). Signal-to-noise ratio (SNR) per unit volume and unit time, and intrinsic linewidth (LW) of N-acetyl-aspartate (NAA), creatine (Cr), and choline (Cho)...

journal_title：Magnetic resonance in medicine

authors： Otazo R,Mueller B,Ugurbil K,Wald L,Posse S

更新日期：2006-12-01 00:00:00

abstract：PURPOSE:For ultrahigh field (UHF) MRI, the expected local specific absorption rate (SAR) distribution is usually calculated by numerical simulations using a limited number of generic body models and adding a safety margin to take into account intersubject variability. Assessment of this variability with a large model d...

journal_title：Magnetic resonance in medicine

authors： Meliadò EF,van den Berg CAT,Luijten PR,Raaijmakers AJE

更新日期：2019-03-01 00:00:00

abstract：:Combining positron emission tomography and MRI modalities typically requires using either conventional MRI with a MR-compatible positron emission tomography system or a modified MR system with conventional positron emission tomography. A feature of field-cycled MRI is that all magnetic fields can be turned off rapidly...

journal_title：Magnetic resonance in medicine

authors： Bindseil GA,Gilbert KM,Scholl TJ,Handler WB,Chronik BA

更新日期：2011-07-01 00:00:00

abstract：PURPOSE:This study aims to identify work-related and personal factors associated with workers' exposure to static magnetic fields (SMF) and motion-induced time-varying magnetic fields (TVMF) from MRI scanners. METHODS:Measurements of personal exposure to SMF and TVMF were performed among MRI staff during 439 work shif...

journal_title：Magnetic resonance in medicine

authors： Schaap K,Christopher-De Vries Y,Cambron-Goulet É,Kromhout H

更新日期：2016-05-01 00:00:00

abstract：:In this work we aimed to study the possibility of using supervised classifiers to quantify the main components of carotid atherosclerotic plaque in vivo on the basis of multisequence MRI data. MRI data consisting of five MR weightings were obtained from 25 symptomatic subjects. Histological micrographs of endarterecto...

journal_title：Magnetic resonance in medicine

authors： Hofman JM,Branderhorst WJ,ten Eikelder HM,Cappendijk VC,Heeneman S,Kooi ME,Hilbers PA,ter Haar Romeny BM

更新日期：2006-04-01 00:00:00

abstract：PURPOSE:Respiratory motion makes hepatic ablation using high intensity focused ultrasound (HIFO) challenging. Previous HIFU liver treatment had required apnea induced during general anesthesia. We describe and test a system that allows treatment of the liver in the presence of breathing motion. METHODS:Mapping a signa...

journal_title：Magnetic resonance in medicine

authors： Holbrook AB,Ghanouni P,Santos JM,Dumoulin C,Medan Y,Pauly KB

更新日期：2014-02-01 00:00:00

abstract：:The advent of event-related functional magnetic resonance imaging (fMRI) has resulted in many exciting studies that have exploited its unique capability. However, the utility of event-related fMRI is still limited by several technical difficulties. One significant limitation in event-related fMRI is the low signal-to-...

journal_title：Magnetic resonance in medicine

authors： LaConte SM,Ngan SC,Hu X

更新日期：2000-11-01 00:00:00

abstract：:Amide proton transfer imaging, a specific form of chemical exchange saturation transfer imaging, has previously been applied to studies of acute ischemic acidosis, stroke, and cancer. However, interpreting the resulting contrast is complicated by its dependence on the exchange rate between amides and water, the amide ...

journal_title：Magnetic resonance in medicine

authors： Zu Z,Janve VA,Li K,Does MD,Gore JC,Gochberg DF

更新日期：2012-09-01 00:00:00

abstract：:An approach to efficiently measure three-dimensional velocity vector fields and turbulent kinetic energy of blood flow is presented. Multipoint phase-contrast imaging is used in combination with Bayesian analysis to map both mean and fluctuating velocities over a large dynamic range and for practically relevant signal...

journal_title：Magnetic resonance in medicine

authors： Binter C,Knobloch V,Manka R,Sigfridsson A,Kozerke S

更新日期：2013-05-01 00:00:00

abstract：:We have noninvasively produced low-resolution, quantitative nuclear magnetic resonance images of cerebral blood flow in 2-ml voxels in eight cats. Typical signal-to-noise of 4 to 1 was obtained in cerebral voxels in 16.5-s epochs. Mean flow during normocapnia (paCO2 = 39 +/- 4 mm Hg) and hypercapnia (paCO2 = 62 +/- 4 ...

journal_title：Magnetic resonance in medicine

authors： Branch CA,Ewing JR,Helpern JA,Ordidge RJ,Butt S,Welch KM

更新日期：1992-11-01 00:00:00

abstract：:A method is presented that improves the effectiveness of RF-spoiling whenever an image consists of the averaging of several identical single acquisitions. Using this method, it becomes possible to reduce the necessary moment of the spoiler gradient by a factor equal to the number of averages. The idea is to perform th...

journal_title：Magnetic resonance in medicine

authors： Leupold J,Hennig J

更新日期：2011-10-01 00:00:00

abstract：PURPOSE:To develop a method to correct for geometric distortions in non-Cartesian echo planar imaging using data acquired in a fast prescan. METHODS:Echo planar images were obtained using a non-Cartesian density weighted k-space trajectory. In contrast to linear Cartesian acquisition, distortions arising in non-Cartes...

journal_title：Magnetic resonance in medicine

authors： Zeller M,Müller A,Hahn D,Köstler H

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:Magnetic resonance imaging of humans at high magnetic field strengths is strongly influenced by the interference of the radiofrequency (RF) electromagnetic field and the body. To minimize this effect, multiple RF sources could be used. A novel setup (called multimode, coaxial waveguide) is proposed that facilit...

journal_title：Magnetic resonance in medicine

authors： Andreychenko A,Kroeze H,Boer VO,Lagendijk JJ,Luijten PR,van den Berg CA

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:To demonstrate feasibility of exploiting the spatial distribution of off-resonance surrounding metallic implants for accelerating multispectral imaging techniques. THEORY AND METHODS:Multispectral imaging (MSI) techniques perform time-consuming independent three-dimensional acquisitions with varying radio freq...

journal_title：Magnetic resonance in medicine

authors： Smith MR,Artz NS,Koch KM,Samsonov A,Reeder SB

更新日期：2014-12-01 00:00:00

abstract：:Dynamic contrast-enhanced MRI data in vertebral bone marrow (vBM) are currently analyzed with descriptive indices. The purpose of this study was to develop and evaluate a quantitative approach, considering the tissue composition of vBM. Therefore, a measurement of the water fraction, f(wat), and the precontrast relaxa...

journal_title：Magnetic resonance in medicine

authors： Biffar A,Sourbron S,Schmidt G,Ingrisch M,Dietrich O,Reiser MF,Baur-Melnyk A

更新日期：2010-07-01 00:00:00

abstract：:Spiral k-space magnetic resonance spectroscopic imaging (MRSI) requires high performance from gradient hardware systems. During the readout phase, oscillating gradients are continuously played out, which can cause undesired effects. These effects on the quality of SI data are non-intuitive because of their time-varyin...

journal_title：Magnetic resonance in medicine

authors： Kim DH,Spielman DM

更新日期：2006-07-01 00:00:00

abstract：PURPOSE:Magnetic resonance imaging (MRI)-based techniques for assessing liver iron concentration (LIC) have been limited by single scanner calibration against biopsy. Here, the calibration of spin-density projection-assisted (SDPA) R2-MRI (FerriScan®) in iron-overloaded β-thalassemia patients treated with the iron chel...

journal_title：Magnetic resonance in medicine

authors： St Pierre TG,El-Beshlawy A,Elalfy M,Al Jefri A,Al Zir K,Daar S,Habr D,Kriemler-Krahn U,Taher A

更新日期：2014-06-01 00:00:00

abstract：:Rapid flow imaging was achieved with a partial field of view (pFOV) spiral motion-encoded technique. The FOV and the acquisition time were reduced by a factor of 2 by undersampling k-space. The pFOV spiral k-space trajectory aliased signals from outside a circular ring whose radius was inversely proportional to the di...

journal_title：Magnetic resonance in medicine

authors： Nezafat R,Thompson RB,Derbyshire JA,McVeigh ER

更新日期：2006-09-01 00:00:00

abstract：PURPOSE:Image-guided prostate biopsies are routinely acquired in the diagnosis and treatment monitoring of prostate cancer, yielding useful tissue for identifying metabolic biomarkers and therapeutic targets. We developed an optimized biopsy tissue culture protocol in combination with [1,6-13 C2 ]glucose labeling and q...

journal_title：Magnetic resonance in medicine

authors： Bancroft Brown J,Sriram R,VanCriekinge M,Delos Santos R,Sun J,Delos Santos J,Tabatabai ZL,Shinohara K,Nguyen H,Peehl DM,Kurhanewicz J

更新日期：2019-08-01 00:00:00

abstract：:Although promising for visualizing the structure of ordered tissues, MR diffusion tensor imaging (DTI) has been hampered by long acquisition time and low spatial resolution associated with its inherently low signal-to-noise ratio (SNR). Moreover, the uncertainty in the DTI measurements has a direct impact on the accur...

journal_title：Magnetic resonance in medicine

authors： Chen B,Hsu EW

更新日期：2005-08-01 00:00:00

abstract：:Keyhole acquisition techniques have been used to reduce image acquisition times primarily in contrast agent studies and via simulation in interventional MRI procedures. More recent simulations have suggested that improved definition of an interventional device [e.g., biopsy needles, radio frequency (RF) electrodes] co...

journal_title：Magnetic resonance in medicine

authors： Hwang KP,Lim J,Wendt M,Merkle E,Lewin JS,Duerk JL

更新日期：1999-09-01 00:00:00

abstract：PURPOSE:Reference region models (RRMs) can quantify tumor perfusion in dynamic contrast-enhanced MRI without an arterial input function. Inspection of the RRM reveals that one of the free parameters in the fit is uniquely linked to the reference region and is common to all voxels. A two-step approach is proposed that t...

journal_title：Magnetic resonance in medicine

authors： Ahmed Z,Levesque IR

更新日期：2017-10-01 00:00:00

abstract：:We improved the three-point phase-contrast method by regularization of MR velocity data after acquisition of a low velocity-to-noise ratio (VNR) velocity image and a high VNR aliased velocity image. The phase unwrapping algorithm is based on the assumed correlation of the velocity of adjacent flow voxels on the low VN...

journal_title：Magnetic resonance in medicine

authors： Herment A,Mousseaux E,Jolivet O,DeCesare A,Frouin F,Todd-Pokropek A,Bittoun J

更新日期：2000-07-01 00:00:00

abstract：:Cirrhosis is an important and growing public health problem, affecting millions of Americans and many more people internationally. A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide thera...

journal_title：Magnetic resonance in medicine

authors： Chung S,Breton E,Mannelli L,Axel L

更新日期：2011-04-01 00:00:00

abstract：:High-resolution magic-angle spinning has become a valuable tool to study biologic samples; however, there are only a few high-resolution magic-angle spinning methodologies that have been explored specifically to deal with small semisolid biomaterials such as tissues. Here, we report a novel high-resolution (1)H NMR sp...

journal_title：Magnetic resonance in medicine

authors： Wong A,Aguiar PM,Sakellariou D

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:In contrast to conventional linear gradients, gradient coil arrays with arbitrary spatial dependency might experience strong mutual coupling. Although conventional gradient power amplifiers with feedback loop might compensate the effect of coupling, required voltages for the compensation are generally unknown a...

journal_title：Magnetic resonance in medicine

authors： Ertan K,Taraghinia S,Atalar E

更新日期：2019-09-01 00:00:00

abstract：:Conventional approaches for MR elastography (MRE) using surface drivers have difficulty achieving sufficient shear wave propagation in the prostate gland due to attenuation. In this study we evaluate the feasibility of generating shear wave propagation in the prostate gland using a transurethral device. A novel transu...

journal_title：Magnetic resonance in medicine

authors： Chopra R,Arani A,Huang Y,Musquera M,Wachsmuth J,Bronskill M,Plewes D

更新日期：2009-09-01 00:00:00

abstract：:In the dynamic nuclear polarization process, microwave irradiation facilitates exchange of polarization from a radical's unpaired electron to nuclear spins at cryogenic temperatures, increasing polarization by >10,000. Doping samples with Gd(3+) ions further increases the achievable solid-state polarization. However, ...

journal_title：Magnetic resonance in medicine

authors： Gordon JW,Fain SB,Rowland IJ

更新日期：2012-12-01 00:00:00