In vivo field-cycling relaxometry using an insert coil for magnetic field offset.

abstract：PURPOSE:Quantitative susceptibility map (QSM) reconstruction is ill posed due to the zero values on the "magic angle cone" that make the maps prone to streaking artifacts. We propose projection onto convex sets (POCS) in the method of steepest descent (SD) for QSM reconstruction. METHODS:Two convex projections, an obj...

journal_title：Magnetic resonance in medicine

authors： Deng W,Boada F,Poser BA,Schirda C,Stenger VA

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:To develop a flexible fast spin echo (FSE) triple-echo Dixon (FTED) technique. METHODS:An FSE pulse sequence was modified by replacing each readout gradient with three fast-switching bipolar readout gradients with minimal interecho dead time. The corresponding three echoes were used to generate three raw image...

journal_title：Magnetic resonance in medicine

authors： Son JB,Hwang KP,Madewell JE,Bayram E,Hazle JD,Low RN,Ma J

更新日期：2017-03-01 00:00:00

abstract：:In radiotherapy, target tissues are defined best on MR images due to their superior soft tissue contrast. Computed tomography imaging is geometrically accurate and it is needed for dose calculation and generation of reference images for treatment localization. Co-registration errors between MR and computed tomography ...

journal_title：Magnetic resonance in medicine

authors： Kapanen M,Collan J,Beule A,Seppälä T,Saarilahti K,Tenhunen M

更新日期：2013-07-01 00:00:00

abstract：PURPOSE:To verify MR measurements of myocardial extracellular volume fraction (ECV) based on clinically applicable T1-mapping sequences against ECV measurements by radioisotope tracer in pigs and to relate the results to those obtained in volunteers. METHODS:Between May 2016 and March 2017, 8 volunteers (25 ± 4 years,...

journal_title：Magnetic resonance in medicine

authors： Nordlund D,Xanthis C,Bidhult S,Jablonowski R,Kanski M,Kopic S,Carlsson M,Engblom H,Aletras AH,Arheden H

更新日期：2020-02-01 00:00:00

abstract：PURPOSE:To test and implement a motion-robust and respiratory-resolved 3D Radial Flow framework that addresses the need for rapid, high resolution imaging in neonatal patients with congenital heart disease. METHODS:A 4-point velocity encoding and 3D radial trajectory with double-golden angle ordering was combined with...

journal_title：Magnetic resonance in medicine

authors： Schrauben EM,Lim JM,Goolaub DS,Marini D,Seed M,Macgowan CK

更新日期：2020-02-01 00:00:00

abstract：:The mechanics of the macrocirculation are examined as a basis for imaging blood flow within the system. The macrocirculation is defined as that part of the circulation in which inertial forces are not negligible compared to viscous forces and as such in human subjects comprises the heart and large blood vessels. Becau...

journal_title：Magnetic resonance in medicine

authors： Caro CG,Parker KH

更新日期：1990-05-01 00:00:00

abstract：PURPOSE:The oxygen extraction fraction (OEF) is an important biomarker for tissue-viability. MRI enables noninvasive estimation of the OEF based on the blood-oxygenation-level-dependent (BOLD) effect. Quantitative OEF-mapping is commonly applied using least-squares regression (LSR) to an analytical tissue model. Howeve...

journal_title：Magnetic resonance in medicine

authors： Domsch S,Mürle B,Weingärtner S,Zapp J,Wenz F,Schad LR

更新日期：2018-02-01 00:00:00

abstract：:Fitting a model to an experimental spectrum is a difficult nonlinear estimation problem. The solution presented here is to start an iterative search procedure sufficiently close to the optimal model parameter set. This is achieved by providing tissue-dependent a priori peak information and by a novel correlation metho...

journal_title：Magnetic resonance in medicine

authors： Burger C,McKinnon G,Buchli R,Boesiger P

更新日期：1991-10-01 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：:Problems with in vivo proton spectroscopy include strong water and lipid signals, and the very complicated structures of the spectra. Multiple-quantum experiments can be designed to overcome these difficulties. Using a volume selective refocusing technique, one can demonstrate how multiple-quantum experiments can be p...

journal_title：Magnetic resonance in medicine

authors： McKinnon GC,Bosiger P

更新日期：1988-03-01 00:00:00

abstract：:A multimodal MR study including relaxometry, diffusion tensor imaging (DTI), and MR spectroscopy was performed on patients with classical phenylketonuria (PKU) and matched controls, to improve our understanding of white matter (WM) lesions. Relaxometry yields information on myelin loss or malformation and may substant...

journal_title：Magnetic resonance in medicine

authors： Vermathen P,Robert-Tissot L,Pietz J,Lutz T,Boesch C,Kreis R

更新日期：2007-12-01 00:00:00

abstract：:The authors introduce several sets of time-efficient gradient waveforms for applying isotropic diffusion weighting in NMR experiments. This creates signal attenuation that depends on the trace of the diffusion tensor and is therefore rotationally invariant. Numerical methods for the calculation of such gradient sets a...

journal_title：Magnetic resonance in medicine

authors： Wong EC,Cox RW,Song AW

更新日期：1995-08-01 00:00:00

abstract：PURPOSE:Recent literature shows that diffusion tensor properties can be estimated more accurately with diffusion kurtosis imaging (DKI) than with diffusion tensor imaging (DTI). Furthermore, the additional non-Gaussian diffusion features from DKI can be sensitive markers for tissue characterization. Despite these benef...

journal_title：Magnetic resonance in medicine

authors： Tax CM,Otte WM,Viergever MA,Dijkhuizen RM,Leemans A

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:To achieve rapid, high resolution whole-brain gray matter (GM) imaging by developing a novel, single-slab three-dimensional dual-echo fast-spin-echo pulse sequence and GM-selective reconstruction. METHODS:Unlike conventional GM imaging that uses time-consuming double-inversion-recovery preparation, the propose...

journal_title：Magnetic resonance in medicine

authors： Lee H,Kim EY,Sohn CH,Park J

更新日期：2017-11-01 00:00:00

abstract：PURPOSE:To characterize the fundamental limits of MRI near metallic implants on RF excitation, frequency encoding, and chemical shift-encoding water-fat separation. METHODS:Multicomponent three-dimensional (3D) digital models of a total hip and a total knee replacement were used to construct material-specific suscepti...

journal_title：Magnetic resonance in medicine

authors： Smith MR,Artz NS,Wiens C,Hernando D,Reeder SB

更新日期：2015-12-01 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：:In order to determine if an increase in myocardial oxygen consumption is accompanied by changes in high energy phosphates in normal subjects and patients with dilated cardiomyopathy, phosphorus-31 spectra were acquired under resting conditions and during dobutamine infusion. In seven normal subjects, dobutamine raised...

journal_title：Magnetic resonance in medicine

authors： Schaefer S,Schwartz GG,Steinman SK,Meyerhoff DJ,Massie BM,Weiner MW

更新日期：1992-06-01 00:00:00

abstract：:New algorithms for correlation analysis are presented that allow the mapping of brain activity from functional MRI (fMRI) data in real time during the ongoing scan. They combine the computation of the correlation coefficients between measured fMRI time-series data and a reference vector with "detrending", a technique ...

journal_title：Magnetic resonance in medicine

authors： Gembris D,Taylor JG,Schor S,Frings W,Suter D,Posse S

更新日期：2000-02-01 00:00:00

abstract：:Myocardial tagging is a new noninvasive MRI method that allows the study of myocardial motion with high accuracy. However, with conventional tagging techniques tagging contrast is impaired at later heart phases due to longitudinal relaxation. An improved method, called Complementary SPAtial Modulation of Magnetization...

journal_title：Magnetic resonance in medicine

authors： Fischer SE,McKinnon GC,Maier SE,Boesiger P

更新日期：1993-08-01 00:00:00

abstract：:The previously reported concept for quantitative magnetization transfer (MT) imaging using balanced steady-state free precession (SSFP) is applied to nonbalanced SSFP sequences. This offers the possibility to derive quantitative MT parameters of targets with high-susceptibility variations such as the musculoskeletal s...

journal_title：Magnetic resonance in medicine

authors： Gloor M,Scheffler K,Bieri O

更新日期：2010-07-01 00:00:00

abstract：:An optimized multislice data acquisition scheme for phase acquisition of composite echoes (PACE) imaging is presented. This new scheme uses a repetition time equal to the mixing time and an appropriate phase cycling scheme, which allows for more efficient exploitation of all composite echoes. These modifications provi...

journal_title：Magnetic resonance in medicine

authors： Ropele S,Stollberger R,Kapeller P,Hartung HP,Fazekas F

更新日期：1999-12-01 00:00:00

abstract：:We have demonstrated that echo-planar imaging can be used to produce high-quality snapshot images of the human fetus in utero in a fraction of a second. These images are free of motional artifact or blurring and allow detailed depiction of fetal structures in normal and pathological pregnancies. ...

journal_title：Magnetic resonance in medicine

authors： Stehling MK,Mansfield P,Ordidge RJ,Coxon R,Chapman B,Blamire A,Gibbs P,Johnson IR,Symonds EM,Worthington BS

更新日期：1990-02-01 00:00:00

abstract：:In spin echo imaging, magnetization is assigned to a location defined by its frequency of rotation. In the presence of a static magnetic field inhomogeneity, however, this location does not correspond to the true location of the magnetization. This paper describes a magnetic resonance imaging technique called phase co...

journal_title：Magnetic resonance in medicine

authors： Kim JK,Plewes DB,Henkelman RM

更新日期：1995-04-01 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：:For diffusion-weighted magnetic resonance imaging and under circumstances where patient movement can be modeled as rigid body motion, it is shown both theoretically and experimentally that translations and rotations produce phase errors which are zero- and first-order, respectively, in position. While a navigator echo...

journal_title：Magnetic resonance in medicine

authors： Anderson AW,Gore JC

更新日期：1994-09-01 00:00:00

abstract：:In numerical analyses of radiofrequency (RF) fields for MRI, RF power is often permitted to radiate out of the problem region. In reality, RF power will be confined by the magnet bore and RF screen enclosing the magnet room. We present numerical calculations at different frequencies for various surface and volume coil...

journal_title：Magnetic resonance in medicine

authors： Liu W,Kao CP,Collins CM,Smith MB,Yang QX

更新日期：2013-01-01 00:00:00

abstract：PURPOSE:Atherosclerotic carotid plaques can be quantified in vivo by MRI. However, the accuracy in segmentation and quantification of components such as the thin fibrous cap (FC) and lipid-rich necrotic core (LRNC) remains unknown due to the lack of a submillimeter scale ground truth. METHODS:A novel approach was take...

journal_title：Magnetic resonance in medicine

authors： Nieuwstadt HA,Geraedts TR,Truijman MT,Kooi ME,van der Lugt A,van der Steen AF,Wentzel JJ,Breeuwer M,Gijsen FJ

更新日期：2014-07-01 00:00:00

abstract：:The absolute partial pressure of oxygen (pO(2)) in the mammary gland pad and femoral muscle of female mice was measured using EPR oximetry at 700 MHz. A small quantity of lithium phthalocyanine (LiPc) crystals was implanted in both mammary and femoral muscle tissue of female C3H mice. Subsequent EPR measurements were ...

journal_title：Magnetic resonance in medicine

authors： Matsumoto A,Matsumoto S,Sowers AL,Koscielniak JW,Trigg NJ,Kuppusamy P,Mitchell JB,Subramanian S,Krishna MC,Matsumoto K

更新日期：2005-12-01 00:00:00

abstract：:Paramagnetic ions complexed to proteins may lose, retain, or enhance solvent paramagnetic relaxation (SPR) relative to free solution. We measured T1 and T2 of three mouse cancers, their normal counterparts, and six additional tissues. Long T1 of cancers was not caused by necrosis or by different contents of water, fat...

journal_title：Magnetic resonance in medicine

authors： Negendank W,Corbett T,Crowley M,Kellogg C

更新日期：1991-04-01 00:00:00

abstract：PURPOSE:We demonstrate the feasibility of MRI with missing-pulse steady-state free precession (MP-SSFP) in a 4T magnet with artificially degraded homogeneity. METHODS:T1 , T2 , and diffusion contrast of MP-SSFP was simulated with constant and alternate radiofrequency (RF) phase using an extended phase graph. To valida...

journal_title：Magnetic resonance in medicine

authors： Kobayashi N,Parkinson B,Idiyatullin D,Adriany G,Theilenberg S,Juchem C,Garwood M

更新日期：2021-02-01 00:00:00