Manifold Learning in MR spectroscopy using nonlinear dimensionality reduction and unsupervised clustering.

abstract：:A method for collecting MRI data on a set of rotated trajectories that begin at the center of k-space is outlined. It is theoretically slightly faster, slightly less susceptible to off-resonance and motion-induced phase, and produces images with slightly better signal-to-noise ratio than methods using Archimedean spir...

journal_title：Magnetic resonance in medicine

authors： Pipe JG

更新日期：1999-10-01 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：:A simple theoretical model was developed to compare the sensitivities (i.e., signal-to-noise ratios per unit imaging time) of two-dimensional (2D) multislice and 3D imaging sequences. The model shows that the sensitivities of 3D and 2D multislice MRI sequences are usually similar. Sensitivities are identical in T2-wei...

journal_title：Magnetic resonance in medicine

authors： Johnson G,Wadghiri YZ,Turnbull DH

更新日期：1999-04-01 00:00:00

abstract：PURPOSE:To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). METHODS:A conventional flow-compensated and flow-encoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experim...

journal_title：Magnetic resonance in medicine

authors： Middione MJ,Wu HH,Ennis DB

更新日期：2014-12-01 00:00:00

abstract：:A non-invasive method for studying the modifications induced in lipid depots by hormonal stimulation could extend knowledge of adipose tissues. We studied the effect of adrenergic stimulation on interscapular brown adipose tissue (IBAT) of rats using contrast-enhanced MRI. Controls and rats pre-treated with adrenaline...

journal_title：Magnetic resonance in medicine

authors： Sbarbati A,Cavallini I,Marzola P,Nicolato E,Osculati F

更新日期：2006-04-01 00:00:00

abstract：:Magnetic resonance imaging has achieved clinical importance and has become the primary tool in the investigation of head, spinal cord, pelvis, cancellous bone, pericardium (with gating), gallbladder, lymph node masses, and very soon, in the evaluation of joints. In many areas, particularly with respiratory and ECG gat...

journal_title：Magnetic resonance in medicine

authors： Margulis AR,Fisher MR

更新日期：1985-08-01 00:00:00

abstract：PURPOSE:A purely experimental method for MRI-based transfer function (TF) determination is presented. A TF characterizes the potential for radiofrequency heating of a linear implant by relating the incident tangential electric field to a scattered electric field at its tip. We utilize the previously introduced transfer...

journal_title：Magnetic resonance in medicine

authors： Tokaya JP,Raaijmakers AJE,Luijten PR,Sbrizzi A,van den Berg CAT

更新日期：2020-03-01 00:00:00

abstract：:A MultiEcho Segmented EPI with z-shimmed BAckground gradient Compensation (MESBAC) pulse sequence is proposed and validated for functional MRI (fMRI) study in regions suffering from severe susceptibility artifacts. This sequence provides an effective tradeoff between spatial and temporal resolution and reduces image d...

journal_title：Magnetic resonance in medicine

authors： Li Z,Wu G,Zhao X,Luo F,Li SJ

更新日期：2002-08-01 00:00:00

abstract：:A novel iterative k-space data-driven technique, namely parallel reconstruction using null operations (PRUNO), is presented for parallel imaging reconstruction. In PRUNO, both data calibration and image reconstruction are formulated into linear algebra problems based on a generalized system model. An optimal data cali...

journal_title：Magnetic resonance in medicine

authors： Zhang J,Liu C,Moseley ME

更新日期：2011-11-01 00:00:00

abstract：:A technique for noninvasively quantifying the concentration of sodium ((23) Na) ions was applied to the study of ischemic stroke. (23) Na-magnetic resonance imaging techniques have shown considerable potential for measuring subtle changes in ischemic tissue, although studies to date have suffered primarily from poor s...

journal_title：Magnetic resonance in medicine

authors： Wetterling F,Gallagher L,Macrae IM,Junge S,Fagan AJ

更新日期：2012-03-01 00:00:00

abstract：PURPOSE:To model and correct the dephasing effects in the gradient-echo signal for arbitrary RF excitation pulses with large flip angles in the presence of macroscopic field variations. METHODS:The dephasing of the spoiled 2D gradient-echo signal was modeled using a numerical solution of the Bloch equations to calcula...

journal_title：Magnetic resonance in medicine

authors： Soellradl M,Lesch A,Strasser J,Pirpamer L,Stollberger R,Ropele S,Langkammer C

更新日期：2020-08-01 00:00:00

abstract：:A simple (2)H NMR method for quantifying absolute (2)H-enrichments in all seven aliphatic positions of glucose following its derivatization to monoacetone glucose is presented. The method is based on the addition of a small quantity of (2)H-enriched formate to the NMR sample. When the method was applied to [2-(2)H]mon...

journal_title：Magnetic resonance in medicine

authors： Jones JG,Perdigoto R,Rodrigues TB,Geraldes CF

更新日期：2002-09-01 00:00:00

abstract：PURPOSE:Multi-echo spin-echo (MSE) transverse relaxometry mapping using multi-component models is used to study disease activity in neuromuscular disease by assessing the T2 of the myocytic component (T2water ). Current extended phase graph algorithms are not optimized for fat fractions above 50% and the effects of ina...

journal_title：Magnetic resonance in medicine

authors： Keene KR,Beenakker JM,Hooijmans MT,Naarding KJ,Niks EH,Otto LAM,van der Pol WL,Tannemaat MR,Kan HE,Froeling M

更新日期：2020-11-01 00:00:00

abstract：:The effects of reducing the pulse repetition time from 2500 ms to 1000 ms when using spin-density-projection-assisted R2-magnetic resonance imaging for the purpose of measuring liver iron concentration were evaluated. Repeated liver R2 measurements were made using both protocols on 60 subjects with liver iron concentr...

journal_title：Magnetic resonance in medicine

authors： Pavitt HL,Aydinok Y,El-Beshlawy A,Bayraktaroglu S,Ibrahim AS,Hamdy MM,Pang W,Sharples C,St Pierre TG

更新日期：2011-05-01 00:00:00

abstract：:A current limitation of many myocardial tag acquisitions employing SPAMM encoding is the relatively rapid loss of tag contrast over the cardiac cycle. Acquisition schemes that apply line tags produce prolonged tag contrast compared with directly excited grid tags. However, a grid-tag series can be generated by combini...

journal_title：Magnetic resonance in medicine

authors： Doyle M,Walsh EG,Foster RE,Pohost GM

更新日期：1997-05-01 00:00:00

abstract：PURPOSE:Oscillating gradient (OG) enables the access of short diffusion times for time-dependent diffusion MRI (dMRI); however, it poses several technical challenges for clinical use. This study proposes a 3D oscillating gradient-prepared gradient spin-echo (OGprep-GRASE) sequence to improve SNR and shorten acquisition...

journal_title：Magnetic resonance in medicine

authors： Wu D,Liu D,Hsu YC,Li H,Sun Y,Qin Q,Zhang Y

更新日期：2021-01-01 00:00:00

abstract：:Perfusion-based event-related functional MRI was performed by measuring flow-sensitive alternating inversion recovery (FAIR) signal changes during repeated single-trial, short visual stimulation (250 msec). In the visual cortex activation area, the blood flow increases immediately after the stimulus, reaches the maxim...

journal_title：Magnetic resonance in medicine

authors： Liu HL,Gao JH

更新日期：1999-12-01 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...

journal_title：Magnetic resonance in medicine

authors： Ramirez MS,Ragan DK,Kundra V,Bankson JA

更新日期：2007-09-01 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：PURPOSE:A generalized intravoxel incoherent motion (IVIM) model, called the GIVIM, was proposed to better account for complex perfusion present in the tissues having various vessels and flow regimes, such as the liver. THEORY AND METHODS:The notions of continuous pseudodiffusion variable as well as perfusion fraction ...

journal_title：Magnetic resonance in medicine

authors： Kuai ZX,Liu WY,Zhang YL,Zhu YM

更新日期：2016-11-01 00:00:00

abstract：:Optimization of experimental settings of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), like the contrast administration protocol, is of great importance for reliable quantification of the microcirculatory properties, such as the volume transfer-constant K(trans). Using system identification theory an...

journal_title：Magnetic resonance in medicine

authors： Aerts HJ,van Riel NA,Backes WH

更新日期：2008-05-01 00:00:00

abstract：:A three-axis uniplanar gradient coil was designed and built to provide order-of-magnitude increases in gradient strength of up to 500 mT/m on the x- and y-axes, and 1000 mT/m for the z-axis at 640 A input over a limited FOV ( approximately 16 cm) for superficial regions, compared to conventional gradient coils, with s...

journal_title：Magnetic resonance in medicine

authors： Aksel B,Marinelli L,Collick BD,Von Morze C,Bottomley PA,Hardy CJ

更新日期：2007-07-01 00:00:00

abstract：:For sodium imaging of the human brain, Gibbs' ringing can degrade image appearance and confound image analysis; k-space filtering is generally required. In this work, the signal to noise ratio (SNR) advantage of sampling density weighted apodization (SDWA) over uniform k-space sampling with postacquisition filtering a...

journal_title：Magnetic resonance in medicine

authors： Stobbe R,Beaulieu C

更新日期：2008-10-01 00:00:00

abstract：:Accurate quantification of myocardial perfusion remains challenging due to saturation of the arterial input function at high contrast concentrations. A method for estimating the arterial input function directly from tissue curves in the myocardium that avoids these difficulties is presented. In this constrained altern...

journal_title：Magnetic resonance in medicine

authors： Fluckiger JU,Schabel MC,DiBella EV

更新日期：2011-08-01 00:00:00

abstract：:A cerebrospinal fluid (CSF)-suppressed flow-attenuated inversion recovery (FLAIR) double-shot diffusion echo-planar imaging (EPI) sequence was developed and used, along with a non-CSF-suppressed version of the sequence, to determine the extent of the contribution of CSF partial-volume averaging to the apparent diffusi...

journal_title：Magnetic resonance in medicine

authors： Falconer JC,Narayana PA

更新日期：1997-01-01 00:00:00

abstract：:Functional MRI (fMRI) by means of spin-echo (SE) techniques provides an interesting alternative to gradient-echo methods because the contrast is based primarily on dynamic averaging associated with the blood oxygenation level-dependent (BOLD) effect. In this article the contributions from different brain compartments ...

journal_title：Magnetic resonance in medicine

authors： Jochimsen TH,Norris DG,Mildner T,Möller HE

更新日期：2004-10-01 00:00:00

abstract：:Proton-electron double-resonance imaging (PEDRI) was used to assess renal function by monitoring the flow of the exogenous nitroxide free radical proxyl carboxylic acid (PCA) through normal and injured kidneys in the living rat. Kidney damage was induced by treatment with 2-bromoethylamine (BEA), which provides a well...

journal_title：Magnetic resonance in medicine

authors： Seimenis I,Foster MA,Lurie DJ,Hutchison JM,Whiting PH,Payne S

更新日期：1998-08-01 00:00:00

abstract：:We propose a new magnetic resonance imaging (MRI) technique that is sensitive to myocardial tissue perfusion that obviates the use of an extrinsic contrast agent. Significant advantages of such a technique are that it avoids accumulation of contrast agent when repeated studies are performed on the same subject and tha...

journal_title：Magnetic resonance in medicine

authors： Prasad PV,Burstein D,Edelman RR

更新日期：1993-08-01 00:00:00

abstract：PURPOSE:To design, construct, and evaluate quantitative MR phantoms that mimic MRI signals from the liver with simultaneous control of three parameters: proton-density fat fraction (PDFF), R 2 ∗ ...

journal_title：Magnetic resonance in medicine

authors： Zhao R,Hamilton G,Brittain JH,Reeder SB,Hernando D

更新日期：2021-02-01 00:00:00

abstract：PURPOSE:To develop and validate a regularization approach of optimizing B1 insensitivity of the quantitative magnetization transfer (qMT) pool-size ratio (F). METHODS:An expression describing the impact of B1 inaccuracies on qMT fitting parameters was derived using a sensitivity analysis. To simultaneously optimize fo...

journal_title：Magnetic resonance in medicine

authors： Boudreau M,Pike GB

更新日期：2018-12-01 00:00:00