A pitfall associated with determination of transverse relaxation times of the 31P NMR signals of ATP using the Hahn spin-echo.

abstract：PURPOSE:T2 -weighted sequences are particularly sensitive to the radiofrequency (RF) field inhomogeneity problem at ultra-high-field because of the errors accumulated by the imperfections of the train of refocusing pulses. As parallel transmission (pTx) has proved particularly useful to counteract RF heterogeneities, u...

journal_title：Magnetic resonance in medicine

authors： Gras V,Mauconduit F,Vignaud A,Amadon A,Le Bihan D,Stöcker T,Boulant N

更新日期：2018-07-01 00:00:00

abstract：:Proton MRS (1 H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research...

journal_title：Magnetic resonance in medicine

authors： Wilson M,Andronesi O,Barker PB,Bartha R,Bizzi A,Bolan PJ,Brindle KM,Choi IY,Cudalbu C,Dydak U,Emir UE,Gonzalez RG,Gruber S,Gruetter R,Gupta RK,Heerschap A,Henning A,Hetherington HP,Huppi PS,Hurd RE,Kantarci K,Ka

更新日期：2019-08-01 00:00:00

abstract：:Radiofrequency induced pacemaker lead tip heating is one of the main reasons magnetic resonance imaging (MRI) is contraindicated for patients with pacemakers. The objective of this work was to evaluate the dependence of pacemaker lead tip heating during MRI scanning on the electrical conductivity of the medium surroun...

journal_title：Magnetic resonance in medicine

authors： Langman DA,Goldberg IB,Judy J,Paul Finn J,Ennis DB

更新日期：2012-08-01 00:00:00

abstract：PURPOSE:Breath-holding is an established strategy for reducing motion artifacts in abdominal imaging. However, the breath-holding capabilities of patients are often overstrained by scans with large coverage and high resolution. In this work, a new strategy for coping with resulting incomplete breath-holds in abdominal ...

journal_title：Magnetic resonance in medicine

authors： Gdaniec N,Eggers H,Börnert P,Doneva M,Mertins A

更新日期：2014-05-01 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

authors： Miller DH,Johnson G,Tofts PS,MacManus D,McDonald WI

更新日期：1989-09-01 00:00:00

abstract：:MRI using hyperpolarized (13) C-labeled pyruvate is a promising tool to biochemically profile tumors and monitor their response to therapy. This technique requires injection of pyruvate into tumor-bearing animals. Pyruvate is an endogenous entity but the influence of exogenously injected bolus doses of pyruvate on tum...

journal_title：Magnetic resonance in medicine

authors： Saito K,Matsumoto S,Devasahayam N,Subramanian S,Munasinghe JP,Morris HD,Lizak MJ,Ardenkjaer-Larsen JH,Mitchell JB,Krishna MC

更新日期：2012-03-01 00:00:00

abstract：PURPOSE:To investigate the uncertainties on relative Cramér-Rao lower bound (rCRB) estimates and demonstrate their biasing effects in MRS quantification. THEORY AND METHODS:Simulations were performed to calculate the distribution of the computed rCRB (noted rCRB*) for several rCRB levels. One hundred thousand simulati...

journal_title：Magnetic resonance in medicine

authors： Bonny JM,Pagès G

更新日期：2019-02-01 00:00:00

abstract：PURPOSE:To investigate for the first time the feasibility of aortic four-dimensional (4D) flow at 7T, both contrast enhanced (CE) and non-CE. To quantify the signal-to-noise ratio (SNR) in aortic 4D flow as a function of field strength and CE with gadobenate dimeglumine (MultiHance). METHODS:Six healthy male volunteer...

journal_title：Magnetic resonance in medicine

authors： Hess AT,Bissell MM,Ntusi NA,Lewis AJ,Tunnicliffe EM,Greiser A,Stalder AF,Francis JM,Myerson SG,Neubauer S,Robson MD

更新日期：2015-05-01 00:00:00

abstract：:Pattern recognition techniques (factor analysis and neural networks) were used to investigate and classify human brain tumors based on the 1H NMR spectra of chemically extracted biopsies (n = 118). After removing information from lactate (because of variable ischemia times), unsupervised learning suggested that the sp...

journal_title：Magnetic resonance in medicine

authors： Maxwell RJ,Martínez-Pérez I,Cerdán S,Cabañas ME,Arús C,Moreno A,Capdevila A,Ferrer E,Bartomeus F,Aparicio A,Conesa G,Roda JM,Carceller F,Pascual JM,Howells SL,Mazucco R,Griffiths JR

更新日期：1998-06-01 00:00:00

abstract：:Temperature estimation in proton resonance frequency (PRF) shift MR thermometry requires a reference, or pretreatment, phase image that is subtracted from image phase during thermal treatment to yield a phase difference image proportional to temperature change. Referenceless thermometry methods derive a reference phas...

journal_title：Magnetic resonance in medicine

authors： Grissom WA,Lustig M,Holbrook AB,Rieke V,Pauly JM,Butts-Pauly K

更新日期：2010-10-01 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：:We present new diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models. The phantom design permits the application of imaging parameters that are typically employed in studies of the human brain. The phantoms were made of small-diameter acrylic fibers, chose...

journal_title：Magnetic resonance in medicine

authors： Poupon C,Rieul B,Kezele I,Perrin M,Poupon F,Mangin JF

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:To present a double diffusion encoding MRI sequence on a clinical scanner to analyze micro-structure and micro-vasculature of tumors. METHODS:The sequence was tested on phantoms, asparaguses, and 2 tumors allografts in a rodent. Results were analyzed using an adapted VERDICT model to estimate microstructural p...

journal_title：Magnetic resonance in medicine

authors： Duchêne G,Abarca-Quinones J,Leclercq I,Duprez T,Peeters F

更新日期：2020-04-01 00:00:00

abstract：PURPOSE:To propose an explicit Balanced steady-state free precession (bSSFP) signal model that predicts eddy current-induced steady-state disruptions and to provide a prospective, practical, and general eddy current compensation method. THEORY AND METHODS:Gradient impulse response functions (GIRF) were used to simulat...

journal_title：Magnetic resonance in medicine

authors： Bruijnen T,Stemkens B,van den Berg CAT,Tijssen RHN

更新日期：2020-07-01 00:00:00

abstract：:To enhance contrast between flow and static tissue, NMR projective angiographic methods usually require data subtraction, or alternatively the application of special data processing routines such as the "maximum intensity projection" algorithm. We have successfully developed a direct projection method which yields suf...

journal_title：Magnetic resonance in medicine

authors： Matsuda T,Doyle M,Pohost GM

更新日期：1991-04-01 00:00:00

abstract：:This study examines the effect of feature extraction methods prior to automated pattern recognition based on magnetic resonance spectroscopy (MRS) for brain tumor diagnosis. Since individual inspection of spectra is time-consuming and requires specific spectroscopic expertise, the introduction of clinical decision sup...

journal_title：Magnetic resonance in medicine

authors： Luts J,Poullet JB,Garcia-Gomez JM,Heerschap A,Robles M,Suykens JA,Van Huffel S

更新日期：2008-08-01 00:00:00

abstract：:Any number of coils can in principle be used simultaneously and independently in magnetic resonance imaging if the mutual inductances are sufficiently small. Surface coils and head or body coils have equal sensitivity at some crossover depth of the order of 6 to 10 cm. Using a 7.5-cm-diameter surface coil that was int...

journal_title：Magnetic resonance in medicine

authors： Hyde JS,Froncisz W,Jesmanowicz A,Kneeland JB

更新日期：1988-02-01 00:00:00

abstract：:A modified high-speed stimulated-echo acquisition mode (STEAM) diffusion sequence (90 degrees-TE/2-90 degrees-TM-[alpha-TE/2-STE]n) incorporating bipolar diffusion gradients that are less sensitive to macroscopic motion-induced artifacts is presented. Diffusion encoding was performed only during the first echo interva...

journal_title：Magnetic resonance in medicine

authors： Yongbi MN,Ding S,Dunn JF

更新日期：1996-06-01 00:00:00

abstract：:We developed a quantitative magnetic resonance imaging method to permit a rapid assessment of brain water content during osmotic brain edema produced by intraperitoneal (ip) injection of distilled water. Fifteen minutes after water injection, the normalized mean image intensity (MIn) from a spin-echo pulse sequence (T...

journal_title：Magnetic resonance in medicine

authors： Olson JE,Katz-Stein A,Reo NV,Jolesz FA

更新日期：1992-03-01 00:00:00

abstract：:The preovulatory rat follicle reaches a diameter of 1 mm with no internal blood vessels. Nutrient supply to the enclosed oocyte depends solely on passive diffusion across the follicular wall and the follicular fluid. Spin-echo and stimulated-echo NMR microscopy experiments were applied here for studying modulations in...

journal_title：Magnetic resonance in medicine

authors： Tempel C,Schiffenbauer YS,Meir G,Neeman M

更新日期：1995-08-01 00:00:00

abstract：:Ferumoxytol is an ultrasmall superparamagnetic iron oxide agent marketed for the treatment of anemia. There has been increasing interest in its properties as an MRI contrast agent as well as greater awareness of its adverse event profile. This mini-review summarizes the current state of knowledge of the risks of ferum...

journal_title：Magnetic resonance in medicine

authors： Vasanawala SS,Nguyen KL,Hope MD,Bridges MD,Hope TA,Reeder SB,Bashir MR

更新日期：2016-05-01 00:00:00

abstract：:The apparent diffusion coefficient (ADC) in the optic nerve was measured from diffusion-weighted magnetic resonance imaging using an intravoxel incoherent motion (IVIM) sequence. The subjects were seven normal volunteers and eight patients with multiple sclerosis (MS) with a total of four optic nerves with acute neuri...

journal_title：Magnetic resonance in medicine

authors： Iwasawa T,Matoba H,Ogi A,Kurihara H,Saito K,Yoshida T,Matsubara S,Nozaki A

更新日期：1997-09-01 00:00:00

abstract：:Cardiac metabolism was studied with 31P NMR in 7 dogs and 4 cats to determine whether animals adapted for different life-styles (stalk and sprint vs endurance running) respond to increased work loads (heart rate X blood pressure product) with different high-energy phosphate kinetics. Hearts were exposed via a left lat...

journal_title：Magnetic resonance in medicine

authors： Ligeti L,Osbakken MD,Clark BJ,Schnall M,Bolinger L,Subramanian H,Leigh JS,Chance B

更新日期：1987-02-01 00:00:00

abstract：:Cerebral blood volume changes with arterial carbon dioxide were monitored by proton T1-weighted MR images following administration of the intravascular contrast agent Gd-DTPA labeled with human serum albumin. Without MR contrast, no significant image intensity changes were observed with PaCO2. Following contrast, regi...

journal_title：Magnetic resonance in medicine

authors： Moseley ME,Chew WM,White DL,Kucharczyk J,Litt L,Derugin N,Dupon J,Brasch RC,Norman D

更新日期：1992-01-01 00:00:00

abstract：:A new contrast preparation based on modified driven equilibrium Fourier transfer is introduced and evaluated for generation of T1-weighted images for assessment of the myocardial perfusion with contrast agent first-pass kinetics. The new preparation scheme produces T1 contrast with insensitivity to arrhythmias in pros...

journal_title：Magnetic resonance in medicine

authors： Tsekos NV,Zhang Y,Merkle H,Wilke N,Jerosch-Herold M,Stillman A,Uğurbil K

更新日期：1995-10-01 00:00:00

abstract：PURPOSE:To design, evaluate, and apply a bow tie antenna transceiver radiofrequency (RF) coil array tailored for cardiac MRI at 7.0 Tesla (T). METHODS:The radiofrequency (RF) coil array comprises 16 building blocks each containing a bow tie shaped λ/2-dipole antenna. Numerical simulations were used for transmission fi...

journal_title：Magnetic resonance in medicine

authors： Oezerdem C,Winter L,Graessl A,Paul K,Els A,Weinberger O,Rieger J,Kuehne A,Dieringer M,Hezel F,Voit D,Frahm J,Niendorf T

更新日期：2016-06-01 00:00:00

abstract：:To quantify metabolite and cation concentrations using NMR spectroscopy, the volumes of intracellular and extracellular spaces must be known. We describe a simple 31P NMR spectroscopic method that employs dimethyl methylphosphonate (DMMP) as a marker of total water space and phenylphosphonate (PPA) as a marker of extr...

journal_title：Magnetic resonance in medicine

authors： Clarke K,Anderson RE,Nédélec JF,Foster DO,Ally A

更新日期：1994-08-01 00:00:00

abstract：PURPOSE:Transverse relaxation time (T2 ) mapping with MRI has a plethora of clinical and research applications. Current T2 mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-...

journal_title：Magnetic resonance in medicine

authors： Wang X,Hernando D,Reeder SB

更新日期：2020-08-01 00:00:00

abstract：PURPOSE:To measure the T1 and T2 relaxation times of water, metabolites, and macromolecules in the rat brain in vivo at 17.2T and achieve absolute quantification of the neurochemical profile. Relaxation times were compared with values from the literature found at lower magnetic fields. METHODS:(1) H NMR spectra were m...

journal_title：Magnetic resonance in medicine

authors： Lopez-Kolkovsky AL,Mériaux S,Boumezbeur F

更新日期：2016-02-01 00:00:00

abstract：PURPOSE:To develop a semiautomatic method for rapid segmentation of myocardial tissue phase mapping (TPM) data. METHODS:Manual segmentation of the myocardium was performed at end-diastole and end-systole. The points in both user-defined masks were then automatically tracked over the entire cardiac cycle using temporal...

journal_title：Magnetic resonance in medicine

authors： Espe EKS,Skårdal K,Aronsen JM,Zhang L,Sjaastad I

更新日期：2017-09-01 00:00:00