Development Of Magnetic Resonance Spectroscopy Research Articles

Recent advances in understanding brain cancer metabolomics: a review.

Regardless of the significant progress made in surgical techniques and adjuvant therapies, brain tumors are a major contributor to cancer-related morbidity and mortality in both pediatric and adult populations. Gliomas represent a significant proportion of cerebral neoplasms, exhibiting diverse levels of malignancy. The etiology and mechanisms of resistance of this malignancy are inadequately comprehended, and the optimization of patient diagnosis and prognosis is a challenge due to the diversity of the disease and the restricted availability of therapeutic options. Metabolomics refers to the comprehensive analysis of endogenous and exogenous small molecules, both in a targeted and untargeted manner, that enables the characterization of an individual's phenotype and offers valuable insights into cellular activity, particularly in the context of cancer biology, including brain tumor biology. Metabolomics has garnered attention in current years due to its potential to facilitate comprehension of the dynamic spatiotemporal regulatory network of enzymes and metabolites that enables cancer cells to adapt to their environment and foster the development of tumors. Metabolic changes are widely acknowledged as a significant characteristic for tracking the advancement of diseases, treatment efficacy, and identifying novel molecular targets for successful medical management. Metabolomics has emerged as an exciting area for personalized medicine and drug discovery, utilizing advanced analytical techniques such as nuclear magnetic resonance spectroscopy (MRS) and mass spectrometry (MS) to achieve high-throughput analysis. This review examines and highlights the latest developments in MRS, MS, and other technologies in studying human brain tumor metabolomics.

MR-Nucleomics: The study of pathological cellular processes with multinuclear magnetic resonance spectroscopy and imaging in vivo.

Clinical medicine has experienced a rapid development in recent decades, during which therapies targeting specific cellular signaling pathways, or specific cell surface receptors, have been increasingly adopted. While these developments in clinical medicine call for improved precision in diagnosis and treatment monitoring, modern medical imaging methods are restricted mainly to anatomical imaging, lagging behind the requirements of precision medicine. Although positron emission tomography and single photon emission computed tomography have been used clinically for studies of metabolism, their applications have been limited by the exposure risk to ionizing radiation, the subsequent limitation in repeated and longitudinal studies, and the incapability in assessing downstream metabolism. Magnetic resonance spectroscopy (MRS) or spectroscopic imaging (MRSI) are, in theory, capable of assessing molecular activities in vivo, although they are often limited by sensitivity. Here, we review some recent developments in MRS and MRSI of multiple nuclei that have potential as molecular imaging tools in the clinic.

Magnetic resonance spectroscopy ex vivo: A short historical review.

Over the last half century, there have been several periods during which magnetic resonance spectroscopy (MRS) has been used ex vivo, for a variety of reasons, on samples such as microorganisms, cells, animal or human tissue, tissue extracts or biological fluids. These studies began in the days before the acronym MRS had been invented, when all such methods were still called nuclear magnetic resonance (NMR), and have extended to the present day. I will describe the historical development of NMR methods used ex vivo, their influences on the development of MRS in vivo, and their longer-term uses. All the interpretations will be personal, based on what I saw, or discussed with colleagues at the time.

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Major depression and bipolar disorder are common conditions with substantial negative consequences for sufferers. Understanding the biological changes associated with these conditions is a major research priority, and a better understanding of their biological basis could lead to improved diagnosis and treatment. There is growing interest in the development of precision medicine algorithms with the aim of tailoring treatment strategies to individual patients according to unique biological signatures. This biomarker-based approach to precision prescribing has the potential to improve therapeutic response, minimize adverse reactions, and reduce time to symptomatic relief. However, few validated biological targets for treatment response prediction in depression have been identified to date. Biomarkers derived from neuroimaging data are potentially important contributors to the goal of guiding treatment selection using clinical and bio-typing data. Information on brain structure and function may be used to predict response versus non-response to various treatments. Ignited by the observation of a rapid antidepressant effect of the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine, the glutamate system has emerged as a leading focus for novel drug discovery for depression and other mood disorders. Over the last two decades, neuroimaging has brought a deeper understanding of neurobiological alterations associated with these conditions, and researchers are moving towards developing these methods to diagnose and treat affective disorders. This research has been aided by developments in magnetic resonance spectroscopy (MRS), a method that allows non-invasive measurement of glutamate and glutamine levels in vivo. Glutamate and glutamine levels are typically found to be reduced in unipolar depression, most notably in prefrontal regions such as the anterior cingulate cortex, while studies in bipolar disorder suggests an increase in glutamate in this region.

Advanced magnetic resonance spectroscopy and imaging techniques applied to brain development and animal models of perinatal injury

Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) are widely used in the field of brain development and perinatal brain injury. Due to technical progress the magnetic field strength (B0) of MR systems has continuously increased, favoring 1H-MRS with quantification of up to 18 metabolites in the brain and short echo time (TE) MRI sequences including phase and susceptibility imaging. For longer TE techniques including diffusion imaging modalities, the benefits of higher B0 have not been clearly established. Nevertheless, progress has also been made in new advanced diffusion models that have been developed to enhance the accuracy and specificity of the derived diffusion parameters. In this review, we will describe the latest developments in MRS and MRI techniques, including high-field 1H-MRS, phase and susceptibility imaging, and diffusion imaging, and discuss their application in the study of cerebral development and perinatal brain injury.

Quantitative metabolic profiles of 2nd and 3rd trimester human amniotic fluid using 1H HR-MAS spectroscopy

ObjectTo establish and compare normative metabolite concentrations in 2nd and 3rd trimester human amniotic fluid samples in an effort to reveal metabolic biomarkers of fetal health and development.Materials and methodsTwenty-one metabolite concentrations were compared between 2nd (15–27 weeks gestation, N = 23) and 3rd (29–39 weeks gestation, N = 27) trimester amniotic fluid samples using 1H high resolution magic angle spinning (HR-MAS) spectroscopy. Data were acquired using the electronic reference to access in vivo concentrations method and quantified using a modified semi-parametric quantum estimation algorithm modified for high-resolution ex vivo data.ResultsSixteen of 21 metabolite concentrations differed significantly between 2nd and 3rd trimester groups. Betaine (0.00846±0.00206 mmol/kg vs. 0.0133±0.0058 mmol/kg, P <0.002) and creatinine (0.0124±0.0058 mmol/kg vs. 0.247±0.011 mmol/kg, P <0.001) concentrations increased significantly, while glucose (5.96±1.66 mmol/kg vs. 2.41±1.69 mmol/kg, P <0.001), citrate (0.740±0.217 mmol/kg vs. 0.399±0.137 mmol/kg, P <0.001), pyruvate (0.0659±0.0103 mmol/kg vs. 0.0299±0.286 mmol/kg, P <0.001), and numerous amino acid (e.g. alanine, glutamate, isoleucine, leucine, lysine, and valine) concentrations decreased significantly with advancing gestation. A stepwise multiple linear regression model applied to 50 samples showed that gestational age can be accurately predicted using combinations of alanine, glucose and creatinine concentrations.ConclusionThese results provide key normative data for 2nd and 3rd trimester amniotic fluid metabolite concentrations and provide the foundation for future development of magnetic resonance spectroscopy (MRS) biomarkers to evaluate fetal health and development.

MAGNETIC RESONANCE IN SURGICAL ONCOLOGY: I – ON THE ORIGIN OF THE SPECTRUM

The discovery of the phenomenon of nuclear magnetic resonance occurred just 60 years ago. The profusion of subsequent discoveries in this domain has led to the development of magnetic resonance spectroscopy - refined as an analytical tool to discern molecular structure - and magnetic resonance imaging, a cornerstone of modern radiology. Observable alterations in cellular structure and metabolism can be discerned using the non-destructive chemical analysis of magnetic resonance spectroscopy in vitro or in vivo. Differences may thus be discerned between malignant and normal tissues.

Spectroscopy and image texture analysis

Acoustic spectroscopy concerns the estimation of acoustic parameters of tissue by means of analysis of the frequency (spectral) contents of ultrasonographic signals (or images). Conventional echographic imaging is based on signals that are processed within the equipment in such a way that the spectral information is distorted. For this reason, the radiofrequency (RF) signals have to be used after linear amplification (i.e., prior to demodulation and logarithmic compression). A further prerequisite is the removal of the influence of beam formation, at transmission and at reception, on the spectral information. This influence becomes evident in echographic images by the depth dependence of the speckle pattern, both in the apparent echo level and in the size of individual speckles (Oosterveld et al. 1985). When all these influences are appropriately accounted for, it becomes possible to estimate the attenuation coefficient and the backscattering coefficient, and their frequency dependence, of parenchymal tissues. A further step is to perform the estimation locally and to construct two-dimensional (2-D) parametric images. The analogy to current developments in magnetic resonance spectroscopy may be evident.

Magnetic resonance spectroscopy and near-infrared spectroscopy in the assessment of the asphyxiated term infant

Magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS) are capable of providing detailed information on cerebral oxidative metabolism in infants who have been resuscitated following an acute asphyxial episode. In severely affected infants studied by phosphorus and proton MRS, a consistent observation has been the development of deranged cerebral energy metabolism 12–48 hours after resuscitation, despite the maintenance of cardiovascular and respiratory homeostasis. Follow-up studies have indicated that the development of delayed energy failure is closely associated with the development of microcephaly and an adverse neurodevelopmental outcome. This pathophysiologic sequence has been modelled in newborn animals, allowing the mechanisms of delayed energy failure to be elucidated and cerebroprotective treatments to be tested. New developments in MRS and magnetic resonance imaging will enable quantitative and highly localised information on cerebral metabolism to be obtained in asphyxiated infants, increasing the accuracy of early clinical assessment. Significant cerebral vasodilatation and vasoparalysis of the cerebral circulation have been observed by NIRS in asphyxiated infants following resuscitation, but the prognostic value of this observation remains uncertain. Technical advances in NIRS are likely to improve the reproducibility and accuracy of the technique, allowing the assessment of regional cerebral haemodynamics and metabolism at the bedside. MRDD Research Reviews 3:42–48, 1997. © 1997 Wiley-Liss, Inc.

Book reviews

This concise book summarizes an extensive range of presentations on developments in magnetic resonance spectroscopy and relevant magnetic resonance imaging as of 1987. At the time of review (1990) it is evident that there has been an unfortunately long delay between the verbal presentations and the appearance of the public proceedings. This clearly limits the value of the book as an up-todate account of recent developments in the field. It does, however, represent a valuable compendium of physical principles underlying the clinical applications of MR spectroscopy.

Magnetic resonance and near infrared spectroscopy for investigation of perinatal hypoxic-ischaemic brain injury.

Hypoxic-ischaemic injury to the brain is an important cause of perinatal death and seems to be the commonest cause of permanent neurodevelopmental disability in newborn infants who survive after intensive care. If this type of brain injury is to be prevented and treatment put on a rational basis, non-invasive methods are required for defining its mechanisms. This review has considered two such methods: magnetic resonance spectroscopy and near infrared spectroscopy. Magnetic resonance spectroscopy is used to measure, in brain tissue, the concentrations of the 'high energy' phosphorus metabolites that are dependent for their synthesis on the processes of oxidative phosphorylation. Intracellular pH can also be measured. Normal maturational changes in the brain have been defined and abnormalities detected in a range of conditions where hypoxic-ischaemic injury was suspected to have occurred. In laboratory animals the acute effects of curtailment of oxygen supply to the brain ('primary' energy failure) have been observed, and the effects of two commonly used treatments, infusions of sodium bicarbonate and glucose, have been tested. After resuscitation of newborn infants from severe intrapartum asphyxia, a latent period has often been noted before energy failure became detectable. This 'secondary' energy failure is due to a variety of damaging reactions initiated by the acute hypoxicischaemic episode and reperfusion of the brain. It is possible that in the future irreversible injury to brain cells following the episode may be prevented or ameliorated by the prompt use of cerebroprotective agents. The extent of abnormalities detected by magnetic resonance spectroscopy has prognostic implications: evidence of severe energy failure in the first days of life was regularly associated with subsequent death or with severe neurodevelopmental impairments. Many technical developments in magnetic resonance spectroscopy are under way, particularly employing proton (1H) spectroscopy, which will allow the intracerebral concentrations of a wide range of metabolites, including neurotransmitters, to be measured. The combination of spectroscopy with magnetic resonance imaging will permit quantitative data to be obtained from selected volumes within the brain. Near infrared spectroscopy is used to make observations at the cotside of the intracerebral concentrations of the chromophores oxyhaemoglobin, deoxyhaemoglobin, and oxidised cytochrome aa3, and it therefore provides information complementary to that obtained by magnetic resonance spectroscopy. Measurements can also be made of cerebral blood flow, cerebral blood volume, and other haemodynamic indices; in addition, the rea