Magnetic Resonance Insights[JOURNAL]
Sun
47 papers
Safety and efficacy of gadobutrol-enhanced MRI in patients aged under 2 years-a single-center, observational study.
Bhargava R, Noga M
Magn Reson Insights · 2013 · PMID 25114540 · Full text
Gadobutrol is a 1-molar gadolinium-based contrast agent with well-characterized safety and efficacy for magnetic resonance imaging (MRI) in adults and children ≥ 2 years old. This observational study assessed gadobutrol-...
Gadobutrol is a 1-molar gadolinium-based contrast agent with well-characterized safety and efficacy for magnetic resonance imaging (MRI) in adults and children ≥ 2 years old. This observational study assessed gadobutrol-enhanced MRI in children < 2 years of age. Sixty infants (mean age 11.1 months) underwent MRI using gadobutrol at standard dose of 0.1 mL/kg (0.1 mmol/kg) body weight. MRI examinations included brain, spine, and neck (n = 24), subcutaneous soft tissues (n = 14), chest, abdomen, and pelvis (n = 12), musculoskeletal system (n = 7) and vascular system (n = 3). No patients experienced adverse events related to gadobutrol injection. In 57 patients with confirmed diagnoses, gadobutrol-enhanced MRI provided findings consistent with confirmed pathologies. This study indicates that gadobutrol at a standard dose for MRI is safe in patients aged < 2 years and provides diagnostic information for multiple pathologies.
Improvements in a Mouse Model of Alzheimer's Disease Through SOD2 Overexpression are Due to Functional and Not Structural Alterations.
Bitner BR, Perez-Torres CJ, Hu L … +2 more , Inoue T, Pautler RG
Magn Reson Insights · 2012 Mar · PMID 22639527 · Full text
Oxidative stress and mitochondrial dysfunction have been implicated in the pathogenesis of Alzheimer's disease. We and others have shown that over expression of the mitochondrial antioxidant superoxide dismutase 2 (SOD-2...
Oxidative stress and mitochondrial dysfunction have been implicated in the pathogenesis of Alzheimer's disease. We and others have shown that over expression of the mitochondrial antioxidant superoxide dismutase 2 (SOD-2) can improve many of the pathologies in the Tg2576 mouse model of Alzheimer's disease that harbors the Swedish mutation in the amyloid precursor protein. However, it is not clear if these improvements are due to functional improvements or structural/anatomical changes. To answer this question, we used diffusion tensor imaging (DTI) to assess the structural integrity of white matter tracts in the control mice, Tg2576 mouse and Tg2576 mice over expressing SOD-2. We observed minimal differences in diffusion parameters with SOD-2 over expression in this model indicating that the improvements we previously reported are due to functional changes and not any alterations to the white matter tractography.
Detection of Amide and Aromatic Proton Resonances of Human Brain Metabolites Using Localized Correlated Spectroscopy Combined with Two Different Water Suppression Schemes.
Nagarajan R, Ramadan S, Thomas MA
Magn Reson Insights · 2010 Jun · PMID 21546981 · Full text
The purpose of the study was to demonstrate the J-coupling connectivity network between the amide, aliphatic, and aromatic proton resonances of metabolites in human brain using two-dimensional (2D) localized correlated s...
The purpose of the study was to demonstrate the J-coupling connectivity network between the amide, aliphatic, and aromatic proton resonances of metabolites in human brain using two-dimensional (2D) localized correlated spectroscopy (L-COSY). Two different global water suppression techniques were combined with L-COSY, one before and another after localizing the volume of interest (VOI). Phantom solutions containing several cerebral metabolites at physiological concentrations were evaluated initially for sequence optimization. Nine healthy volunteers were scanned using a 3T whole body MRI scanner. The VOI for 2D L-COSY was placed in the right occipital white/gray matter region. The 2D cross and diagonal peak volumes were measured for several metabolites such as N-acetyl aspartate (NAA), creatine (Cr), free choline (Ch), glutamate/glutamine (Glx), aspartate (Asp), myo-inositol (mI), GABA, glutathione (GSH), phosphocholine (PCh), phosphoethanolamine (PE), tyrosine (Tyr), lactate (Lac), macromolecules (MM) and homocarnosine (Car). Using the pre-water suppression technique with L-COSY, the above mentioned metabolites were clearly identifiable and the relative ratios of metabolites were calculated. In addition to detecting multitude of aliphatic resonances in the high field region, we have demonstrated that the amide and aromatic resonances can also be detected using 2D L-COSY by pre water suppression more reliably than the post-water suppression.
Increased Human Wildtype Tau Attenuates Axonal Transport Deficits Caused by Loss of APP in Mouse Models.
Smith KD, Peethumnongsin E, Lin H … +2 more , Zheng H, Pautler RG
Magn Reson Insights · 2010 · PMID 20798780 · Full text
Amyloid precursor protein (APP) is implicated in axonal elongation, synaptic plasticity, and axonal transport. However, the role of APP on axonal transport in conjunction with the microtubule associated protein tau conti...
Amyloid precursor protein (APP) is implicated in axonal elongation, synaptic plasticity, and axonal transport. However, the role of APP on axonal transport in conjunction with the microtubule associated protein tau continues to be debated. Here we measured in vivo axonal transport in APP knockout mice with Manganese Enhanced MRI (MEMRI) to determine whether APP is necessary for maintaining normal axonal transport. We also tested how overexpression and mutations of tau affect axonal transport in the presence or absence of APP. In vivo axonal transport reduced significantly in the absence of functional APP. Overexpression of human wildtype tau maintained normal axonal transport and resulted in a transient compensation of axonal transport deficits in the absence of APP. Mutant R406Wtau in combination with the absence of APP compounded axonal transport deficits and these deficits persisted with age. These results indicate that APP is necessary for axonal transport, and overexpression of human wildtype tau can compensate for the absence of APP at an early age.
DANCING WITH THE ELECTRONS: TIME-DOMAIN AND CW IN VIVO EPR IMAGING.
Subramanian S, Krishna MC
Magn Reson Insights · 2008 Sep · PMID 22025900 · Full text
The progress in the development of imaging the distribution of unpaired electrons in living systems and the functional and the potential diagnostic dimensions of such an imaging process, using Electron Paramagnetic Reson...
The progress in the development of imaging the distribution of unpaired electrons in living systems and the functional and the potential diagnostic dimensions of such an imaging process, using Electron Paramagnetic Resonance Imaging (EPRI), is traced from its origins with emphasis on our own work. The importance of EPR imaging stems from the fact that many paramagnetic probes show oxygen dependent spectral broadening. Assessment of in vivo oxygen concentration is an important factor in radiation oncology in treatment-planning and monitoring treatment-outcome. The emergence of narrow-line trairylmethyl based, bio-compatible spin probes has enabled the development of radiofrequency time-domain EPRI. Spectral information in time-domain EPRI can be achieved by generating a time sequence of T(2)* or T(2) weighted images. Progress in CW imaging has led to the use of rotating gradients, more recently rapid scan with direct detection, and a combination of all the three. Very low field MRI employing Dynamic Nuclear polarization (Overhauser effect) is also employed for monitoring tumor hypoxia, and re-oxygenation in vivo. We have also been working on the co-registration of MRI and time domain EPRI on mouse tumor models at 300 MHz using a specially designed resonator assembly. The mapping of the unpaired electron distribution and unraveling the spectral characteristics by using magnetic resonance in presence of stationary and rotating gradients in indeed 'dancing with the (unpaired) electrons', metaphorically speaking.
Gender Differences in Musculoskeletal Lipid Metabolism as Assessed by Localized Two-Dimensional Correlation Spectroscopy.
Velan SS, Said N, Narasimhan K … +8 more , Papan C, Bahu A, Vargo JA, Raylman RR, Thomas MA, Rajendran VM, Spencer RG, Alway SE
Magn Reson Insights · 2008 Sep · PMID 25371653
Gender differences in lipid metabolism are poorly understood and difficult to study using conventional approaches. Magnetic resonance spectroscopy (MRS) permits non-invasive investigation of lipid metabolism. We employed...
Gender differences in lipid metabolism are poorly understood and difficult to study using conventional approaches. Magnetic resonance spectroscopy (MRS) permits non-invasive investigation of lipid metabolism. We employed novel two-dimensional MRS techniques to quantify intramyocellular (IMCL) and extramyocellular (EMCL) lipid compartments and their degree of unsaturation in normal weight adult male and female subjects. Using muscle creatine (Cr) for normalization, a statistically significant (p < 0.05) increase in IMCL/Cr (7.8 ± 1.6) and EMCL/Cr (22.5 ± 3.6) for female subjects was observed (n=8), as compared to IMCL/Cr (5.9 ± 1.7) and EMCL/Cr (18.4 ± 2.64) for male subjects. The degree of unsaturation within IMCL and EMCL was lower in female subjects, 1.3 ± 0.075 and 1.04 ± 0.06, respectively, as compared to that observed in males (n=8), 1.5 ± 0.08 and 1.12 ± 0.03, respectively (p < 0.05 male vs female for both comparisons). We conclude that certain salient gender differences in lipid metabolism can be assessed noninvasively by advanced MRS approaches.
Role of Magnetic Resonance in Understanding the Pathogenesis of Hepatic Encephalopathy.
Huda A, Gupta RK, Rajakumar N … +1 more , Thomas MA
Magn Reson Insights · 2008 · PMID 20890387 · Full text
A spectrum of neuropsychiatric abnormalities caused by portosystemic venous shunting occurs in hepatic encephalopathy (HE) patients with or without liver dysfunction. It is not completely clear how the astrocyte swelling...
A spectrum of neuropsychiatric abnormalities caused by portosystemic venous shunting occurs in hepatic encephalopathy (HE) patients with or without liver dysfunction. It is not completely clear how the astrocyte swelling leads to glial-neuronal dysfunction, and how the symptoms are manifested in HE. A major goal of this work is to review the current status of information available from the existing magnetic resonance (MR) modalities including MR imaging (MRI) and MR Spectroscopy (MRS) as well as other modalities in the understanding the pathogenesis of HE. First, we discuss briefly neuron-histopathology, neurotoxins, neuropsychological and neurophysiological tests. A short review on the progress with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) is then presented. In the remaining part of the manuscript, the following topics pertinent to understanding the pathogenesis of HE are discussed: MRI, diffusion tensor imaging (DTI), one-dimensional MRS based single- and multi-voxel based spectroscopic imaging techniques and two-dimensional MRS.
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