Maghemite (gamma-Fe2O3) nanocrystals stable at neutral pH and in isotonic aqueous media were synthesized and encapsulated within large unilamellar vesicles of egg phosphatidylcholine (EPC) and distearoyl-SN-glycero-3-phosphoethanolamine-N-[methoxy(poly(ethylene glycol))-2000] (DSPE-PEG(2000), 5 mol %), formed by film hydration coupled with sequential extrusion. The nonentrapped particles were removed by flash gel exclusion chromatography. The ...

Changes in the magnetic resonance (MR) parameters of demyelinated neural tissue were measured in vitro using an experimental animal model. A tellurium (Te) diet was applied to weanling rats to induce the demyelination process in the sciatic nerve. The quantitative MR parameters, such as T(1), T(2) relaxation time constants and ...

The temporal magnetic resonance (MR) appearance of human brain tissue during formalin fixation was measured and modeled using a diffusion mathematical model of formalin fixation. Coronal MR images of three human brains before formalin fixation and at multiple time points thereafter were acquired. T1 relaxation, T2 relaxation, water apparent diffusion ...

The ability to differentiate noninvasively between the primary nuclear divisions of the thalamus has immediate clinical applicability for surgical planning and guidance of functional stereotactic procedures. Comparison of prior qualitative magnetic resonance imaging (MRI) studies carried out at field strengths of 1.5 and 4 Tesla have revealed contrast within the ...

Focal cerebral ischemia was induced in rats and followed with high-resolution MRI methods for a chronic period of 10 weeks. Two weeks after stroke induction and at the end of the observation period, conventional histological analysis was combined with immunohistochemical staining for macrophages and with Prussian blue staining for the ...

PURPOSE: Magnetic resonance imaging (MRI) can track labeled cells in the brain. The use of hemagglutinating virus of Japan envelopes (HVJ-Es) to effectively introduce the contrast agent to neural progenitor cells (NPCs) is limited to date despite their high NPC affinity. PROCEDURES: HVJ-Es and Lipofectamine 2000 were compared as transfection ...

OBJECTIVE: To evaluate by MRI the area size and the degree of iron accumulation in basal ganglia nuclei that are implicated in the pathogenesis of Parkinson's disease (PD). METHODS: 40 patients with idiopathic PD and 40 controls were examined on a 1. 5 Tesla MR imager, using a multiecho SE ...

Background: Iron accumulation in substantia nigra pars compacta (SNpc) and related intensity and volumetric changes in patients with idiopathic Parkinson’s disease (PD) has been reported previously. There are only a few studies evaluating the relation between neuroradiological findings and clinical scores, with contradictory results. Aims: In this study we aimed ...

A clinical strength MRI and intact bovine caudal intervertebral discs were used to test the hypotheses that (1) mechanical loading and trypsin treatment induce changes in NMR parameters, mechanical properties and biochemical contents; and (2) mechanical properties are quantitatively related to NMR parameters. MRI acquisitions, confined compression stress-relaxation experiments, and ...

BACKGROUND AND PURPOSE: Intraoperative MR imaging and sonography are used for navigation during neurosurgical procedures. The purpose of this experimental study was to evaluate the potential of high-resolution sonography using superparamagnetic iron oxide (SPIO) particles as a contrast medium to delineate brain tumors and to relate these findings with those ...

BACKGROUND: Blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) provides a measure of deoxyhemoglobin content and therefore an indirect measure of the partial oxygen pressure (pO(2)). The main purpose of this study was to examine the relationship between the apparent relaxation rate (R2*) in the pig kidney by BOLD ...

In order to establish a continuous hyperpolarized xenon-129 (HP-129Xe) gas delivery system for MR imaging, the effect of the metallic materials in the gas pipeline on the signal intensity was investigated. In the gas pipeline, an appropriate surface is needed to minimize wall relaxation by the HP-129Xe gas caused by ...

T(2)* relaxometry for quantitative MR imaging is strongly hampered by large-scale field inhomogeneities, which lead to signal losses and an overestimation of the relaxation rate R(2)*. This is of particular importance for the sensitive detection of iron oxide contrast agent distributions. To derive an accurate measurement of T(2)*, a main ...

A modified cellular ELISA (enzyme-linked immunosorbent assay), named cellular magnetic-linked immunosorbent assay (C-MALISA), has been developed as an application of magnetic resonance imaging (MRI) for in vitro clinical diagnosis. To validate the method, three contrast agents targeted to integrins were synthesized by grafting to USPIO (ultrasmall particles of iron oxide): ...

Measurements of hepatic iron concentration (HIC) are important predictors of transfusional iron burden and long-term outcome in patients with transfusion-dependent anemias. The goal of this work was to develop a readily available, noninvasive method for clinical HIC measurement. The relaxation rates R2 (1/T2) and R2* (1/T2*) measured by magnetic resonance ...

Pharmaceutical grade magnetic colloidal dispersions have been prepared from iron alloys synthesized by laser pyrolysis. The colloids were obtained by simultaneous dispersion and coating of the particles with dextran in a strong alkaline solution. Both powders and dispersions have been analyzed in terms of microstructural characteristics, chemical composition and magnetic ...

The application of stem cells as delivery vehicles opens up the opportunity for targeting therapeutic proteins to the damaged or degenerating central nervous system. Neural stem cell (NSC) lines have been shown to engraft, differentiate and correct certain central nervous system diseases. The present study was performed to test the ...

OBJECTIVES: Hepatic fibrosis is a complication of hereditary hemochromatosis. The aim of this study was to determine whether the product of the magnitude and duration of hepatic iron exposure is related to the risk of significant fibrosis. METHODS: Receiver-operating characteristic curve analysis to determine the utility of hepatic iron concentration ...

Compositional (non-magnetic) data can correlate strongly with particle size, which deems it appropriate as a particle size proxy and, therefore, a reliable means of normalising analytical data for particle size effects. Previous studies suggest magnetic concentration parameters represent an alternative means of normalising for these effects and, given the speed, ...

PURPOSE: To measure the transverse relaxation rate (1/T2) and magnetic susceptibility of the heart in conditions of iron overload by using magnetic resonance (MR) imaging and to correlate these with the tissue iron concentration in a gerbil model. MATERIALS AND METHODS: With prior approval by the institutional animal care and ...

MRI of superparamagnetic iron oxide (SPIO)-labeled cells has become a valuable tool for studying the in vivo trafficking of transplanted cells. Cellular detection with MRI is generally considered to be orders of magnitude less sensitive than other techniques, such as positron emission tomography (PET), single photon emission-computed tomography (SPECT), or ...

PURPOSE: To estimate the relationship between R2 = 1/T2 as measured with a double echo spin echo sequence and total iron concentration in gray matter structures in the brains of aging rhesus monkeys. MATERIALS AND METHODS: Using a 1.5-T magnetic resonance (MR) imager, we collected double echo spin echo images ...

Hydration and drying coupling effect monitoring with single point imaging profiles allowed us to evaluate "free" pore and "bounded" chemical water quantity. White cement pastes inverse Laplace analysis of T1 measurements shown original results with two components during setting. After hardening, we found three components. Single point imaging measures were ...

The current systems are unable to control and predict the cured meat composition nondestructively and in a reasonable time for production needs. In this work, T1 and T2 maps were obtained, with a monoexponential model, on internal sections of Longissimus dorsi muscle at increasing salting times. The maps allow one ...

For the last century, there has been great physiological interest in brain iron and its role in brain function and disease. It is well known that iron accumulates in the brain for people with Huntington's disease, Parkinson's disease, Alzheimer's disease, multiple sclerosis, chronic hemorrhage, cerebral infarction, anemia, thalassemia, hemochromatosis, Hallervorden-Spatz, ...

To determine the amount of iron deposits in the basal ganglia, we examined 13 healthy volunteers with a 1.5 T MRI system using three transverse relaxation rates measured with two sequences. The transverse relaxation rates comprise the reversible contribution (R2') and irreversible contribution (R2) to a phase-reversal 180 degrees -pulse ...

The ability to visualize the cellular inflammatory responses after experimental spinal cord injury (SCI) was investigated using a clinical 1.5-T magnetic resonance imaging scanner, a custom-built, high-strength gradient coil insert, a 3-D fast imaging employing steady-state acquisition (FIESTA) imaging sequence and a superparamagnetic iron oxide (SPIO) contrast agent. An "active ...

The aim of this study was to optimize MRI conventional protocols for BMD measurements using MR-Relaxometry in systems not facilitated with special multi echo protocols. Since, cortical and trabecular bone separation can not be performed in DEXA, so the results might lead to erroneous interpretation of BMD values. One method ...

BACKGROUND: Efficient techniques to noninvasively monitor stem cell transplants will accelerate the development of stem cell therapies. Magnetic resonance (MR) imaging of labeled stem cells is a noninvasive approach that can provide images with high spatial resolution. In this report, we have evaluated the ability of a commercially available, FDA-approved ...

Panoramic Camera (Pancam) images from Meridiani Planum reveal a low-albedo, generally flat, and relatively rock-free surface. Within and around impact craters and fractures, laminated outcrop rocks with higher albedo are observed. Fine-grained materials include dark sand, bright ferric iron-rich dust, angular rock clasts, and millimeter-size spheroidal granules that are eroding ...

The aim of this study was to detect late radiation effects in the rat spinal cord using MR imaging with ultra-small particles of iron oxide (USPIO) contrast agent to better understand the development of late radiation damage with emphasis on the period preceding neurological signs. Additionally, the role of an ...

BACKGROUND: Magnetic resonance imaging (MRI) of magnetically labeled stem cells is a non-invasive approach that can provide images with high spatial resolution. We evaluated the ability of a commercially available, Food and Drug Administration (FDA) approved contrast agent to allow the monitoring of myoblast transplants in the rodent heart. METHODS ...

BACKGROUND AND PURPOSE: The present studies were undertaken to determine whether 19F MRS could be used to quantify the binding of the pentafluorinated derivative of etanidazole (EF5) in hypoxic cells of solid tumors. MATERIALS AND METHODS: A 4.7 T imaging magnet was used for the in situ and in vitro ...

A magnetic resonance (MR) imaging method with the potential for assessing hepatic iron overload from measurements of hepatic magnetic susceptibility in vivo is described. Using the blood in the portal and hepatic veins as an internal reference, this technique uses the orientation dependence of signal phase to measure the susceptibility ...

OBJECTIVES: Following the empiric observation of a significant decrease of signal intensity of both myometrium and cervical stroma on ultrasmall superparamagnetic iron oxide (USPIO)-enhanced images, the aim of our study was to evaluate whether USPIO-enhanced T2*-weighted gradient echo (GRE) images might provide any potential advantage on T-staging of uterine malignancies ...

Magnetic resonance imaging (MRI) is a powerful method for in vivo quantification of tissue properties. It has been previously proposed that the index Q identical with Delta R2/(Delta R2*)2/3, where Delta R2 and Delta R2* are the spin echo and gradient echo relaxation rate shifts caused by the injection of ...

The hippocampal formation (HF) of healthy control subjects and schizophrenic patients was examined using an MRI experiment that implements sequences for relaxometry and magnetization transfer (MT) quantification. In addition to the semi-quantitative magnetization transfer ratio (MTR), all of the observable properties of the binary spin bath model were included. The ...

Myoblast transplantation is a promising means of restoring cardiac function in infarcted areas. For optimization of transplant protocols, tracking the location and fate of the injected cells is necessary. An attractive imaging modality for this is magnetic resonance imaging (MRI) as it is noninvasive and as iron-labeled myoblasts provide a ...

BACKGROUND AND PURPOSE: Although the subthalamic nucleus is the most frequently used target for surgical treatment of Parkinson's disease, the criteria on which it can be identified on T2-weighted images have never been clearly defined. This study was conducted to characterize the precise anatomic distribution of T2-weighted hyposignal in the ...

PURPOSE: To study in vitro the proton relaxation induced in tissues by ferritin, the iron-storing protein of mammals. MATERIALS AND METHODS: Nuclear magnetic relaxation dispersion (NMRD) profiles of liver and spleen from control and iron-overloaded mice are compared with NMRD profiles of ferritin and Fercayl-a ferritin-like akaganeite particle-in aqueous solutions ...

Binding of annexin V or the C2A domain of synaptotagmin I to phosphatidylserine expressed on the surface of apoptotic cells can, when labeled with appropriate probe molecules, be used to detect the presence of apoptosis using radionuclide, magnetic resonance, and optical imaging techniques. The preparation of a biotinylated C2A-GST fusion ...

Magnetic resonance imaging (MRI) is often divided into structural MRI and functional MRI (fMRI). The former is a widely used imaging technique in research as well as in clinical practice. This review describes the more important developments in structural MRI in recent years, including high resolution imaging, T2 relaxation measurement, ...

A phantom has previously been developed containing carrageenan, agarose and gadolinium chloride (called CAG phantom) for MRI with 1.5 T. T(1) and T(2) relaxation times of this phantom are independently changeable by varying concentrations of relaxation-time modifiers to simulate relaxation times of the various types of human tissues. The CAG ...

BACKGROUND/PURPOSE: Quantitative assessments in skin layers using images obtained with standard magnetic resonance imaging (MRI) sequences are limited, since the stratum corneum and dermis, the layers of most clinical interest, have low signal due to their short spin-spin relaxation, T2. METHODS: In the present work, different methods of MRI contrast, ...

Functional magnetic resonance imaging (MRI) with a new intravascular contrast agent, monocrystalline iron oxide nanoparticles (MION), was applied to assess the effect of transpupillary thermotherapy in a rabbit model of choroidal melanoma. 3D-spoiled gradient recalled sequences were used for quantitative assessment of blood volume. The MRI-parameters were 5/22/35 degrees (time ...

The aim of this study was to evaluate the feasibility, the safety, and the usefulness of T2*-weighted magnetic resonance (MR) for neuronavigational guidance in patients with cerebral cavernomas. Eight patients with intracerebral cavernomas were operated assisted by T2*-weighted MR image-guidance. The cavernomas were either deep-seated or in eloquent regions. Image ...

PURPOSE: To measure lumbar spine T2*, T2, T2' and T1 MR relaxometry parameters and compare them with lumbar spine bone mineral density (BMD) in a group of postmenopausal women. MATERIALS AND METHODS: Lumbar spine T2*, T2, T2' and T1 MR relaxometry parameters and BMD values were assessed in 101 postmenopausal ...

Brain inflammation contributes to the tissue injury caused by ischemic stroke. Macrophages as the most abundant inflammatory cell population in stroke lesions can be visualized using ultrasmall superparamagnetic iron oxide (USPIO) as a cell-specific contrast agent for magnetic resonance imaging (MRI). The aim of our present study was to delineate ...

Background- It has been suggested that inflammatory cells within vulnerable plaques may be visualized by superparamagnetic iron oxide particle-enhanced MRI. The purpose of this study was to determine the time course for macrophage visualization with in vivo contrast-enhanced MRI using an ultrasmall superparamagnetic iron oxide (USPIO) agent in symptomatic human ...

We describe a novel missense mutation of ceruloplasmin in a patient with aceruloplasminaemia causing the replacement of a neutral amino acid (phenylalanine) with a polar one (serine) at position 198, probably leading to abnormal folding and secretion of the protein. The patient showed mild microcytic anaemia, mild hepatic iron overload, ...