Abstract:
PURPOSE:A ghost correction strategy for Simultaneous Multi-Slice (SMS) EPI methods that provides improved ghosting artifact reduction compared to conventional methods is presented. Conventional Nyquist ghost correction methods for SMS-EPI rely on navigator data that contain phase errors from all slices in the simultaneously acquired slice-group. These navigator data may contain spatially nonlinear phase differences near regions of B0 inhomogeneity, which violates the linear model employed by most EPI ghost correction algorithms, resulting in poor reconstructions. METHODS:Dual-Polarity GRAPPA (DPG) was previously shown to accurately model and correct both spatially nonlinear and 2D phase errors in conventional single-slice EPI data. Here, an extension we call Dual-Polarity slice-GRAPPA (DPsG) is adapted to the slice-GRAPPA method and applied to SMS-EPI data for slice separation and ghost correction concurrently-eliminating the need for a separate ghost correction step while also providing improved slice-specific EPI phase error correction. RESULTS:Images from in vivo SMS-EPI data reconstructed using DPsG in place of conventional Nyquist ghost correction and slice-GRAPPA are presented. DPsG is shown to reduce ghosting artifacts and provide improved temporal SNR compared to the conventional reconstruction. CONCLUSION:The proposed use of DPsG for SMS-EPI reconstruction can provide images with lower artifact levels, higher image fidelity, and improved time-series stability compared to conventional reconstruction methods.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Hoge WS,Setsompop K,Polimeni JRdoi
10.1002/mrm.27113subject
Has Abstractpub_date
2018-10-01 00:00:00pages
1364-1375issue
4eissn
0740-3194issn
1522-2594journal_volume
80pub_type
杂志文章abstract::Magnetic resonance imaging measurements of the apparent rate of water diffusion in tumors are sensitive to variations in tissue cellularity, which have been shown useful for characterizing tumors and their responses to treatments. However, because of technical limitations on most MRI systems, conventional pulse gradie...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21793
更新日期:2009-04-01 00:00:00
abstract::It has been suggested that orientational changes in the collagen network of articular cartilage account for the depthwise T2 anisotropy of MRI through the magic angle effect. To investigate the relationship between laminar T2 appearance and collagen organization (anisotropy), bovine osteochondral plugs (N = 9) were T2...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1218
更新日期:2001-09-01 00:00:00
abstract:PURPOSE:To develop a novel, simultaneous multislice reconstruction method that exploits Hankel subspace learning (SMS-HSL) for aliasing separation in the slice direction. METHODS:An SMS signal model with the Hankel-structured matrix was proposed. To efficiently suppress interslice leakage artifacts from a signal subsp...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26527
更新日期:2017-10-01 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
pub_type: 杂志文章,多中心研究
doi:10.1002/mrm.24854
更新日期:2014-06-01 00:00:00
abstract::A new spherical navigator echo (SNAV) registration technique is presented. This technique starts by collecting a set of SNAV templates at a reference position. These templates are acquired by rotating the gradient system to result in rotation angles that uniformly cover a predefined range of rotation. The rotation ang...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22629
更新日期:2011-02-01 00:00:00
abstract::Phase contrast flow velocity measurements were performed in six healthy volunteers and 30 patients with arteriosclerotic disease. The iliac arteries were investigated in 8 cases and the femoral arteries in 28 cases. In the first 24 patients, 16 evenly distributed data sets were acquired during one cardiac cycle. In th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910340508
更新日期:1995-11-01 00:00:00
abstract:PURPOSE:Cross-relaxation imaging (CRI) is a family of quantitative magnetization transfer techniques that utilize images obtained with off-resonance saturation and longitudinal relaxation rate (R1) maps reconstructed by the variable flip angle (VFA) method. It was demonstrated recently that a significant bias in an app...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24677
更新日期:2014-02-01 00:00:00
abstract::A regularized algorithm is presented for localized in vivo shimming. The technique uses first- (X,Y,Z), second- (Z(2), ZX, ZY, X(2)-Y(2), XY), and third-order (Z(3)) shim coils, and is robust when applied to arbitrarily-shaped, as well as off-center, regions of interest (ROIs). A single-shot spiral pulse sequence is u...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10267
更新日期:2002-10-01 00:00:00
abstract::The orientation dependence of the free induction decay (FID) of 1H NMR water signal in ex vivo bovine digital flexor tendon at the native level of hydration is reported. Residual dipolar coupling due to the overall tissue anisotropy produces a 6:1 change in the signal intensity as an angle between the long axis of a s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20540
更新日期:2005-08-01 00:00:00
abstract::A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume fo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21115
更新日期:2007-02-01 00:00:00
abstract::Compressed sensing has been of great interest to speed up the acquisition of MR images. The k-t group sparse (k-t GS) method has recently been introduced for dynamic MR images to exploit not just the sparsity, as in compressed sensing, but also the spatial group structure in the sparse representation. k-t GS achieves ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24333
更新日期:2013-04-01 00:00:00
abstract::The aim of this work was to identify ventricular shape-based biomarkers in MR images to discriminate between patients with Alzheimer's disease (AD) and healthy elderly. Clinical MR images were collected for 58 patients and 28 age-matched healthy controls. After normalizing all the images the ventricular cerebrospinal ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21471
更新日期:2008-02-01 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
pub_type: 杂志文章
doi:10.1002/mrm.25799
更新日期:2016-05-01 00:00:00
abstract::Short image acquisition times and sensitivity to magnetic susceptibility favor the use of gradient echo imaging methods in functional MRI (fMRI). However, magnetic susceptibility effects attributed to air-tissue interfaces also lead to severe signal loss in images of the large inferior frontal and lateral temporal cor...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910370304
更新日期:1997-03-01 00:00:00
abstract::In the present work, diffusion-weighted (DW)-NMR spectroscopy of glutamate was performed during a (13)C-labeled glucose infusion in monkey brain (six experiments). It is shown that glutamate (13)C labeling occurs significantly faster at higher diffusion weightings-slightly for glutamate in position C4, and more marked...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21661
更新日期:2008-08-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910130214
更新日期:1990-02-01 00:00:00
abstract::Two-dimensional 1H-31P correlation spectroscopy and relaxation time measurements of intact diseased pancreas were performed in order to identify an unknown peak appearing at -0.18 +/- 0.04 ppm in a 31P NMR spectrum of taurocholate-induced experimental acute pancreatitis in rats. The signal was identified as a solubili...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910100111
更新日期:1989-04-01 00:00:00
abstract:PURPOSE:To obtain three-dimensional (3D) MR angiography having high contrast between vessel and stationary background tissue, a novel technique called sliding time of flight (TOF) is proposed. METHODS:The proposed method relies on the property that flow-related enhancement (FRE) is maximized at the blood-entering slic...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25215
更新日期:2015-03-01 00:00:00
abstract::Trifluoroacetate and trifluoroacetamide, when added to a suspension of human red blood cells, give rise to separate 19F NMR signals from the intra- and extracellular species. This phenomenon has recently been exploited for measuring the membrane potential of erythrocytes. However, the separation of the peaks was incor...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910180119
更新日期:1991-03-01 00:00:00
abstract:PURPOSE:Within multiple sclerosis (MS) lesions iron is present in chronically activated microglia. Thus, iron detection with MRI might provide a biomarker for chronic inflammation within lesions. Here, we examine contributions of iron and myelin to magnetic susceptibility of lesions on quantitative susceptibility mappi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25420
更新日期:2015-08-01 00:00:00
abstract:PURPOSE:High angular resolution diffusion imaging (HARDI) is a well-established method to help reveal the architecture of nerve bundles, but long scan times and geometric distortions inherent to echo planar imaging (EPI) have limited its integration into clinical protocols. METHODS:A fast imaging method is proposed he...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26163
更新日期:2017-02-01 00:00:00
abstract::Image contrast with gradient-recalled echo sequences (GRE) used for fMRI can have both blood oxygen level-dependent (BOLD) and inflow components, and the latter is often undesirable. A dual-echo technique can be used to differentiate these mechanisms, because modulation of signal from inflow is common to both echoes, ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910350306
更新日期:1996-03-01 00:00:00
abstract::In in vivo (1)H spectroscopy, the signal at 1.32 ppm is usually assigned to lactate. This resonance position is shared with threonine at physiological pH. The similarity of spectral patterns of lactate and threonine renders the separate measurement of either threonine or lactate without and even with editing technical...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21492
更新日期:2008-02-01 00:00:00
abstract::Elastase-induced changes in lung morphology and function were detected in spontaneously breathing rats using conventional proton MRI at 4.7 T. A single dose of porcine pancreatic elastase (75 U/100 g body weight) or vehicle (saline) was administered intratracheally (i.t.) to male Brown Norway (BN) rats. MRI fluid sign...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21051
更新日期:2006-12-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910340202
更新日期:1995-08-01 00:00:00
abstract:PURPOSE:The aim of this study was to develop a technique for rapid collection of chemical exchange saturation transfer images with the saturation varied to modulate signal loss transfer and enhance contrast. METHODS:Multi-echo Length and Offset VARied Saturation (MeLOVARS) divides the saturation pulse of length Tsat i...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25567
更新日期:2015-02-01 00:00:00
abstract::We describe a doubly tuned radiofrequency (RF) local coil probe designed specifically for performing in vivo image-localized spectroscopy. The probe was designed using principles developed in connection with the counter-rotating-current (CRC) and planar-pair loop gap resonators for magnetic resonance imaging (MRI). Th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910060303
更新日期:1988-03-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910040203
更新日期:1987-02-01 00:00:00
abstract::A simple iterative algorithm, termed deconvolution-interpolation gridding (DING), is presented to address the problem of reconstructing images from arbitrarily-sampled k-space. The new algorithm solves a sparse system of linear equations that is equivalent to a deconvolution of the k-space with a small window. The dec...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21095
更新日期:2006-12-01 00:00:00
abstract::This note considers the anomolous contrast in inversion recovery images produced by NMR scanners if a map of [My] is reconstructed, rather than a map of My'. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910020110
更新日期:1985-02-01 00:00:00