Abstract:
:Regional values of fractional anisotropy (FA) and mean diffusivity (D(av)) of in vivo and excised rat spinal cords were measured using an iscosahedral encoding scheme that is based on 21 uniformly distributed and alternating gradient directions with an echo planar imaging (EPI) readout. Based on the water phantom studies, this scheme was shown to provide unbiased estimation of FA. The stability of the scanner during the acquisition of diffusion tensor imaging (DTI) data was evaluated. Repeated measurements of the FA values demonstrated excellent reproducibility, as assessed by the Bland-Altman analysis. These studies demonstrated a reduced anisotropy in excised samples relative to in vivo cords. Diffusion in the spinal cord gray matter was shown to be anisotropic. The FA value in the dorsal white matter (WM) was found to be higher relative to the ventral WM. Results from these studies should provide the necessary baseline data for serial in vivo DTI of injured spinal cord.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Madi S,Hasan KM,Narayana PAdoi
10.1002/mrm.20304subject
Has Abstractpub_date
2005-01-01 00:00:00pages
118-25issue
1eissn
0740-3194issn
1522-2594journal_volume
53pub_type
杂志文章abstract::T2 relaxation time is a promising MRI parameter for the detection of cartilage degeneration in osteoarthritis. However, the accuracy and precision of the measured T2 may be substantially impaired by the low signal-to-noise ratio of images available from clinical examinations. The purpose of this work was to assess the...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22178
更新日期:2010-01-01 00:00:00
abstract::The goal of this work was to develop and evaluate a numerically optimized inversion pulse to be used with a homonuclear editing sequence to measure human cerebral GABA in vivo at 4.1 T in the occipital lobe. The optimized pulse was constructed using pallindromic symmetry with 30 pulses and 29 delays. The optimized pul...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910390103
更新日期:1998-01-01 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
pub_type: 杂志文章
doi:10.1002/mrm.28401
更新日期:2021-01-01 00:00:00
abstract:PURPOSE:To determine the feasibility of employing the prior knowledge of well-separated chemical exchange saturation transfer (CEST) signals in the 9.4 T Z-spectrum to separate overlapping CEST signals acquired at 3 T, using a deep learning approach trained with 3 T and 9.4 T CEST spectral data from brains of the same ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27690
更新日期:2019-06-01 00:00:00
abstract::A modular, user-friendly computer simulation of NMR imaging was created for the DEC VAX computer. This simulation is novel in that complex imaging phenomena, such as chemical shifts and flow, may be easily studied. Other features include spin warp and backprojection imaging, movie generation, and simulation of image c...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910030302
更新日期:1986-06-01 00:00:00
abstract::Human intervertebral discs were investigated by 1H NMR in vitro. The measured parameters of samples differently located in discs give the "maps" of discs. The spin-lattice relaxation-time maps show similar structure to dry matter and bound water maps, which might mean the future possibility to detect certain disc proc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910030122
更新日期:1986-02-01 00:00:00
abstract::Optimal control theory has been applied in the past for the design of RF pulses for selective excitation. This was the outcome of having established the controllability of the MR spin system for the selective excitation problem. "Minimum distance" was the main formulation used for the solution. Because of their robust...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910360311
更新日期:1996-09-01 00:00:00
abstract:PURPOSE:MR-based quantification of liver magnetic susceptibility may enable field strength-independent measurement of liver iron concentration (LIC). However, susceptibility quantification is challenging, due to nonlocal effects of susceptibility on the B0 field. The purpose of this work is to demonstrate feasibility o...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24848
更新日期:2013-09-01 00:00:00
abstract::In this work a 3D fully balanced steady-state spin-echo sequence (bSSSE) was designed and implemented on a 3-Tesla whole-body MR scanner. In contrast to previously introduced nonbalanced SSSE (nbSSSE) sequences, bSSSE features fully rewound imaging gradients. Additionally, all phase encodings and the readout prephasin...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21037
更新日期:2006-11-01 00:00:00
abstract::Nuclear Overhauser effect (NOE) enhancements and relaxation times of 31P metabolites in human calf were measured in 12 volunteers (4 men and 8 women) at 1.5 T using a dual tuned four-ring birdcage. The NOE enhancements of inorganic phosphate (Pi), phosphocreatine (PCr), gamma-, alpha-, and beta-nucleoside triphosphate...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330316
更新日期:1995-03-01 00:00:00
abstract::Gadobutrol (Gd-Bt; Gadovist(R), Schering AG) is a 1-M Gadolinium (Gd)-based contrast agent. Its higher Gd concentration allows for reduction of injection volumes in first pass contrast-enhanced MR angiography (CE-MRA) and should increase bolus sharpness and image quality. However, ambivalent results were reported. In ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21345
更新日期:2008-01-01 00:00:00
abstract::The objective of this study is to evaluate the effect of MR image resolution on trabecular bone parameters and to determine the acceptable resolution that can be accurately analyzed to assess structural parameters. Ten distal femoral condyle specimens of 1 × 1 × 1 cm(3) were scanned with a 4.7-T Bruker BioSpec MRI sca...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22984
更新日期:2012-01-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910180204
更新日期:1991-04-01 00:00:00
abstract:PURPOSE:The objective of this study was to determine whether a sodium phased array would improve sodium breast MRI at 3 T. The secondary objective was to create acceptable proton images with the sodium phased array in place. METHODS:A novel composite array for combined proton/sodium 3 T breast MRI is compared with a c...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24860
更新日期:2014-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.24807
更新日期:2014-04-01 00:00:00
abstract:PURPOSE:To present a time-efficient technique for banding reduction in balanced steady-state free precession (bSSFP) imaging using phase-cycled simultaneous multislice (SMS) acquisition with CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration). THEORY:The proposed technique exploits the ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26076
更新日期:2016-12-01 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
pub_type: 杂志文章
doi:10.1002/mrm.22038
更新日期:2009-09-01 00:00:00
abstract:PURPOSE:Structure-guided total variation is a recently introduced prior that allows reconstruction of images using knowledge of the location and orientation of edges in a reference image. In this work, we demonstrate the advantages of a variant of structure-guided total variation known as directional total variation (D...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28245
更新日期:2020-10-01 00:00:00
abstract:PURPOSE:The diseased myocardium lacks metabolic flexibility and responds to stimuli differently compared with healthy hearts. Here, we report the use of hyperpolarized 13C NMR spectroscopy to detect sudden changes in cardiac metabolism in isolated, perfused rat hearts in response to adrenergic stimulation. METHODS:Met...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25419
更新日期:2015-08-01 00:00:00
abstract::This review reports data on the general and renal tolerance of the paramagnetic contrast agent Gd-DTPA after intravenous administration. Gd-DTPA was administered usually at a dose level of 0.1-0.2 mmol/kg body wt (range: 0.005-0.25 mmol/kg body wt) in cranial, spinal and body MR indications. In phase I-IIIa studies a ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章,评审
doi:10.1002/mrm.1910220212
更新日期:1991-12-01 00:00:00
abstract::This study presents the detection of [2-(13)C]glucose metabolism in the carboxylic/amide region in the human brain, and demonstrates that the cerebral metabolism of [2-(13)C]glucose can be studied in human subjects in the presence of severe hardware constraints of widely available 3 T clinical scanners and with low-po...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22044
更新日期:2009-09-01 00:00:00
abstract::The spin-lattice relaxation time T1 of multicomponent tissues is often determined by fitting relaxation data to monoexponential functions. This process can lead to large errors in the relaxation time. We describe a procedure using chemical-shift imaging (CSI) which separates the NMR signal into water and lipid compone...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910130307
更新日期:1990-03-01 00:00:00
abstract::A type of local coil (or surface coil) for magnetic resonance imaging and spectroscopy is described in which two circular loops of the same diameter are disposed axially with respect to each other and in which counter rotating currents (CRC) are supported in the two loops. This type of coil has been used for localized...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910030412
更新日期:1986-08-01 00:00:00
abstract::The feasibility of MR subtraction imaging of lung ventilation using air against oxygen using a multiple inversion recovery half-Fourier single-shot turbo spin echo (MIR-HASTE) sequence was investigated. Eight healthy, nonsmoking volunteers (3 males, 5 females; from 27 to 48 years of age) were studied on a 1.5 T MR uni...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/1522-2594(200006)43:6<913::aid-mrm21>3.0.c
更新日期:2000-06-01 00:00:00
abstract:PURPOSE:To propose and evaluate a deep learning model for rapid and accurate calculation of myocardial T1 /T2 values based on a previously proposed Bloch equation simulation with slice profile correction (BLESSPC) method. METHODS:Deep learning Bloch equation simulations (DeepBLESS) models are proposed for rapid and ac...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28321
更新日期:2020-11-01 00:00:00
abstract:PURPOSE:To determine whether neurochemical concentrations obtained at two MRI sites using clinical 3T scanners can be pooled when a highly optimized, nonvendor short-echo, single-voxel proton MRS pulse sequence is used in conjunction with identical calibration and quantification procedures. METHODS:A modified semi-LAS...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25295
更新日期:2015-05-01 00:00:00
abstract:PURPOSE:This study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs). METHODS:MRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two-po...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25725
更新日期:2016-04-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910060212
更新日期:1988-02-01 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
pub_type: 杂志文章
doi:10.1002/mrm.27938
更新日期:2020-02-01 00:00:00
abstract:PURPOSE:To improve signal-to-noise ratio (SNR) for high-resolution spectroscopic imaging using a subspace-based technique known as SPectroscopic Imaging by exploiting spatiospectral CorrElation (SPICE). METHODS:The proposed method is based on a union-of-subspaces model of MRSI signals, which exploits the partial separ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26130
更新日期:2017-02-01 00:00:00