background although magnetic resonance spectroscopy (mrs) has been shown as an effective diagnostic tool in distinguishing inflammation from neoplasm in cystic brain lesions, the optimum approach in selecting the portions of lesions in mrs and the possible effects of different times of echoes (tes) remains unknown. objectives to determine the most effective te in diagnosing neoplastic lesions b...

A new NMR experiment which allows a measurement of the chemical shift anisotropy (CSA) tensor under magic angle spinning (MAS) is described. This correlates a fast MAS spectrum in the omega2 dimension with a sideband pattern in omega1 in which the intensities mimic those for a sample spinning at a fraction of the rate omega r/N, and these sidebands result from an amplification by a factor N of ...

We have obtained the 13CR chemical shift tensors for each amino acid in the protein GB1. We then developed a CST force field and incorporated this into the Xplor-NIH structure determination program. GB1 structures obtained by using CST restraints had improved precision over those obtained in the absence of CST restraints and were also more accurate. When combined with isotropic chemical shifts,...

Several inconsistencies have been noted during recent systematic studies of the validity of additivity relationships (1-6) in the C chemical shifts of substituted pyridines. These showed that substantial errors could be introduced if care is not taken to use, for a given solvent, approximately the same concentration for all solutes; in our case this applied to monosubstituted and polysubstitute...

The monitoring of antibody-directed enzyme-prodrug therapies re quires evaluation of drug activation within the tissues of interest. We have demonstrated the feasibility of noninvasive magnetic resonance spectroscopy and spectroscopic imaging (chemical shift imaging) to detect activa tion of the prodrug 5-fluorocytosine (5-FCyt) to the cytotoxic species 5-fluorouracil (5-FU) by monoclonal antib...

Neuroethics addresses moral, legal, and social questions created or highlighted by theoretical and practical developments in neuroscience. Practices in need of scrutiny currently include at least brain imaging with new techniques, chemical attempts to shift exceptional brain function toward normality, chemical attempts to enhance ordinary brain function beyond normality, and brain manipulation ...

Lipid characterization of bone marrow in vivo with proton magnetic resonance spectroscopy was performed using Spin-Echo Planar Spectroscopic Imaging sequences. The methods are shown capable of rapidly generating two-dimensional chemical shift imaging data sets suitable for measuring lipid indices that reflect unsaturation levels among triglycerides, as demonstrated in oil phantoms and bone marr...

Introduction: Water-fat separation is of interest in several MRI applications including fat suppression and fat quantification. Chemical shift imaging allows robust water-fat separation [1, 2], however the acquisition of multiple images results in prolonged scan time. Accelerated water-fat separation using compressed sensing (CS) was partly addressed in [3] by considering the separation as a sp...

Introduction Rapid chemical shift imaging (CSI) techniques are of considerable interest for hyperpolarized C metabolic imaging [1,2]. Undersampled spiral CSI (spCSI) using a free induction decay (FID) acquisition mode has been applied to real-time metabolic imaging with acquisition times of less than 1 s per slice [3]. The FID acquisition necessitates phase correction during reconstruction for ...

A new scheme for the excitation of spins according to the joint values of their heteronuclear or homonuclear J couplings and of their chemical shifts, is proposed and demonstrated. The principles of the new pulses involved derive from those employed in NMR imaging for exciting arbitrary 2D spatial shapes, using so-called "multidimensional" RF pulses. It is shown that if recast in a suitable spe...