Role of magnetic resonance imaging and in vivo MR spectroscopy in clinical, experimental and biological research

Magnetic resonance imaging, a noninvasive imaging modality in clinical medicine produces soft tissue anatomical pictures in any desired plane that are exquisite representation of the spatial distribution of mobile protons present in human/animal tissues. In vivo magnetic resonance spectroscopy, on the other hand, is a useful technique for studying metabolic processes in biological systems. In the last decade, magnetic resonance imaging and in vivo spectroscopy methods have become an established tool in many areas of biomedical research for example, in understanding the physiology of several disease processes, tumor metabolism, and drug discovery process. In fact, in vivo magnetic resonance spectroscopy can be used for diagnosis of a specific disease pattern with biochemical/metabolic signature (marker), assessment of tumor response to different treatment regimens, drug concentrations in tissues, drug efficacy and metabolism. The advantage of in vivo magnetic resonance is its versatility and comprehensive characterization of normal and diseased tissues. In this article, a few examples of in vivo magnetic resonance methods and their utility in clinical, experimental and biological research are presented

Magnetic resonance spectroscopy in ring enhancing lesions

We report a 4 year old girl with ring enhancing lesions in brain CT, initially diagnosed as neurocysticercosis but did not respond to cysticidal therapy. A Magnetic resonance spectropscopy (MRS) revealed lipid peaks suggestive of tuberculoma which was successfully treated with antituberculosis therapy. This report highlights the role of MRS in the diagnosis of ring enhancing lesios

High-resolution solid-state carbon-13 nuclear magnetic resonance study of acetaminophen: a common analgesic drug

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Functional and pathophysiological study of disease processes in human and animal systems: role of magnetic resonance imaging and in vivo MR spectroscopy

Magnetic resonance imaging (MRI), a non-invasive imaging modality, has revolutionized the field of clinical medicine with its multiplanar imaging capability, high spatial resolution, excellent soft tissue contrast and absence of ionizing radiation. It covers a broad range of applications from fast noninvasive anatomical measurements to the study of tissue physiology and metabolism. MR images arise primarily from the protons of water and fat present in human and/or animal tissues. Several variants of MR methods have been developed for studying specific disease processes. Recently, diffusion and perfusion MRI have found widespread application in the evaluation of epilepsy, stroke and other brain disorders. Functional MRI, yet another advance, is useful for studying several brain functions and has immense potential in unravelling the mystery of the human brain. It has the capability of identifying specific anatomical sites involved in many cognitive processes. Another aspect of MR is the so-called in vivo MR spectroscopy of living systems. In vivo MRS of living systems are an extension of the traditional high-resolution NMR method used for studying structure of molecules but applied to more complex systems. Among the various nuclei that generate MR signal, proton (1H) and phosphorous (31P) are important in the study of the biochemistry of living systems. In vivo MRS can be used to observe different biochemicals (metabolites) from a particular specified region of a living system. Determination of the concentration and relative levels of these metabolites provides information on the normal and abnormal states of tissues and their response to various therapeutic modalities. In short, in vivo MRS can be used as a unique means for probing the biochemistry and physiology of living systems. In this article, a general overview of the basics, development and the applications of various MRI and MRS methodologies used in clinical and experimental research are presented to understand the pathophysiology of various disease processes

Quantum theory of magnetic electron lenses based on the Dirac equation

A quantum theory of magnetic electron lenses based on a convenient formulation of the Dirac theory is outlined. It is shown that the passage from the conventional scalar theory to the spinor theory can be accomplished through a simple algebraic rule in analogy with the passage from scalar to vector light optics

Magnetic resonance imaging: basic concepts and applications

Magnetic resonance imaging (MRl) is a state-of-the-art imaging modality that has gained consid­erable attention ill clinical medicine, particularly diagnostic radiology, because of its noninvasive nature and its sensitivity to the state of biological tissue. As an exquisite representation of the spatial distribution of mobile protons in the body, MRI presents the soft-tissue anatomical picture in any desired plane. This article reviews the historical development, the conceptual basics, and the diagnostic applications of various MRI techniques

Assessment of changes in brain metabolites in Indian patients with type-2 diabetes mellitus using proton magnetic resonance spectroscopy

BACKGROUND: The brain is a target for diabetic end-organ damage, though the pathophysiology of diabetic encephalopathy is still not well understood. The aim of the present study was to investigate the effect of diabetes on the metabolic profile of brain of patients having diabetes in comparison to healthy controls, using in-vivo magnetic resonance spectroscopy to get an insight into the pathophysiology of cerebral damages caused due to diabetes. METHODS: Single voxel proton magnetic resonance spectroscopy ((1)H-MRS) was performed at 1.5 T on right frontal, right parieto-temporal and right parieto-occipital white matter regions of the brain of 10 patients having type-2 diabetes along with 7 healthy controls. Absolute concentration of N-acetylaspartate (NAA), choline (cho), myo-inositol (mI), glutamate (Glu) and glutamine (Gln), creatine (Cr) and glucose were determined using the LC-Model and compared between the two groups. RESULTS: The concentration of N-acetylaspartate was significantly lower in the right frontal [4.35 ±0.69 vs. 5.23 ±0.74; p = 0.03] and right parieto-occipital region [5.44 ±0.52 vs.6.08 ±0.25; p = 0.02] of the brain of diabetics as compared to the control group. The concentrations of glutamate and glutamine were found to be significantly higher in the right frontal region of the brain [7.98 ±2.57 vs. 5.32 ±1.43; P = 0.01] in diabetics. Glucose levels were found significantly elevated in all the three regions of the brain in diabetics as compared to the control group. However, no significant changes in levels of choline, myo-inositol and creatine were observed in the three regions of the brain examined among the two groups. CONCLUSIONS: (1)H-MRS analysis indicates that type-2 diabetes mellitus may cause subtle changes in the metabolic profile of the brain. Decreased concentrations of NAA might be indicative of decreased neuronal viability in diabetics while elevated concentrations of Gln and Glu might be related to the fluid imbalance resulting from disruption of glucose homeostasis

The exponential map for representations of Up,q(gl(2))U_{p,q}(gl(2))

For the quantum group $GL_{p,q}(2)$ and the corresponding quantum algebra $U_{p,q}(gl(2))$ Fronsdal and Galindo explicitly constructed the so-called universal $T$-matrix. In a previous paper we showed how this universal $T$-matrix can be used to exponentiate representations from the quantum algebra to get representations (left comodules) for the quantum group. Here, further properties of the universal $T$-matrix are illustrated. In particular, it is shown how to obtain comodules of the quantum algebra by exponentiating modules of the quantum group. Also the relation with the universal $R$-matrix is discussed.Comment: LaTeX-file, 7 pages. Submitted for the Proceedings of the 4th International Colloquium ``Quantum Groups and Integrable Systems,'' Prague, 22-24 June 199

New connection formulae for the q-orthogonal polynomials via a series expansion of the q-exponential

Using a realization of the q-exponential function as an infinite multiplicative sereis of the ordinary exponential functions we obtain new nonlinear connection formulae of the q-orthogonal polynomials such as q-Hermite, q-Laguerre and q-Gegenbauer polynomials in terms of their respective classical analogs.Comment: 14 page