ZnO:Gd nanocrystals for fluorescent applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Divya, N. K., E-mail: divyank90@gmail.com; Pradyumnan, P. P.

2016-05-23

Gadolinium doped ZnO crystals within the solubility limit of gadolinium in ZnO matrix were prepared by solid state reaction technique. The method is relatively less expense and enables the production in large scale. The samples were characterised by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), UV/Vis diffuse reflectance spectroscopy and photoluminescence techniques. Fluorescent property studies of gadolinium doped ZnO at room temperature show enhanced visible light emission due to the defects and oxygen vacancies produced via doping. This work reports the impact of gadolinium doping in the structural, optical and luminescent properties of ZnO inmore » detail.« less

Coronary wave energy: a novel predictor of functional recovery after myocardial infarction.

PubMed

De Silva, Kalpa; Foster, Paul; Guilcher, Antoine; Bandara, Asela; Jogiya, Roy; Lockie, Tim; Chowiencyzk, Phil; Nagel, Eike; Marber, Michael; Redwood, Simon; Plein, Sven; Perera, Divaka

2013-04-01

Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery. Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (r=-0.81; P<0.0001) and strongly predicted regional left ventricular recovery (r=0.68; P=0.001). By receiver operating characteristic analysis, a backward-traveling (microcirculatory) expansion wave threshold of 2.8 W m(-2) s(-2)×10(5) predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (r=0.48; P=0.03) but not left ventricular recovery (r=-0.34; P=0.07). The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.

Density of Gadolinium Nitrate Solutions for the High Flux Isotope Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Paul Allen; Lee, Denise L

2009-05-01

In late 1992, the High Flux Isotope Reactor (HFIR) was planning to switch the solution contained in the poison injection tank from cadmium nitrate to gadolinium nitrate. The poison injection system is an emergency system used to shut down the reactor by adding a neutron poison to the cooling water. This system must be able to supply a minimum of 69 pounds of gadolinium to the reactor coolant system in order to guarantee that the reactor would become subcritical. A graph of the density of gadolinium nitrate solutions over a concentration range of 5 to 30 wt% and a temperaturemore » range of 15 to 40{sup o}C was prepared. Routine density measurements of the solution in the poison injection tank are made by HFIR personnel, and an adaptation of the original graph is used to determine the gadolinium nitrate concentration. In late 2008, HFIR personnel decided that the heat tracing that was present on the piping for the poison injection system could be removed without any danger of freezing the solution; however, the gadolinium nitrate solution might get as cold as 5{sup o}C. This was outside the range of the current density-concentration correlation, so the range needed to be expanded. This report supplies a new density-concentration correlation that covers the extended temperature range. The correlation is given in new units, which greatly simplifies the calculation that is required to determine the pounds of gadolinium in the tank solution. The procedure for calculating the amount of gadolinium in the HFIR poison injection system is as follows: (1) Calculate the usable volume in the system; (2) Measure the density of the solution; (3) Calculate the gadolinium concentration using the following equation: Gd(lb/ft{sup 3}) = measured density (g/mL) x 34.681 - 34.785; (4) Calculate the amount of gadolinium in the system using the following equation: Amount of Gd(lb) = Gd concentration (lb/ft{sup 3}) x usable volume (ft{sup 3}). The equation in step 3 is exact for a temperature of 5{sup o}C, and overestimates the gadolinium concentration at all higher temperatures. This guarantees that the calculation is conservative, in that the actual concentration will be at least as high as that calculated. If an additional safety factor is desired, it is recommended that an administrative control limit be set that is higher than the required minimum amount of gadolinium.« less

Hepatic Hemangiomas: Factors Associated with Pseudo Washout Sign on Gd-EOB-DTPA-enhanced MR Imaging.

PubMed

Tateyama, Akihiro; Fukukura, Yoshihiko; Takumi, Koji; Shindo, Toshikazu; Kumagae, Yuichi; Nakamura, Fumihiko

2016-01-01

Our study aim was to clarify the characteristics of hemangiomas with pseudo washout sign (PWS) by comparing their features with those of hemangiomas without PWS on gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging. We evaluated the features of hemangiomas on Gd-EOB-DTPA-enhanced MR imaging of 70 hepatic hemangiomas in 31 patients, investigating the presence of peripheral or central nodular enhancement, diffuse enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and PWS, which is low signal intensity during the late phase. We visually assessed the intensity of contrast enhancement of the lesion during the arterial, portal venous, late, and hepatobiliary phases using a 4-grade scale and used the Fisher exact and Mann-Whitney U tests to compare hemangiomas with and without PWS. We observed PWS in 33 (47%) of 70 hemangiomas, which were significantly smaller than the hemangiomas without PWS (17.4 mm ± 20.3 versus 30.1 mm ± 28.5; P = 0.005); more frequent diffuse enhancement in hemangiomas with PWS than those without (21.2% versus 2.7%; P = 0.026); and no significant differences in nodular enhancement (P = 0.231), arterioportal shunt (P = 0.403), or fill-in enhancement (P = 0.357) between hemangiomas with and without PWS. Visually determined grades of tumor contrast enhancement were significantly lower in hemangiomas with PWS during the portal venous (P = 0.007) and late (P < 0.001) phases. Small hemangiomas tend to decrease in signal intensity during the portal venous phase and show PWS during the late phase.

Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins.

PubMed

Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F

2017-11-01

The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.

Intracranial solitary fibrous tumor: imaging findings.

PubMed

Clarençon, Frédéric; Bonneville, Fabrice; Rousseau, Audrey; Galanaud, Damien; Kujas, Michèle; Naggara, Olivier; Cornu, Philippe; Chiras, Jacques

2011-11-01

To study the neuroimaging features of intracranial solitary fibrous tumors (ISFTs). Retrospective study of neuroimaging features of 9 consecutive histopathologically proven ISFT cases. Location, size, shape, density, signal intensity and gadolinium uptake were studied at CT and MRI. Data collected from diffusion-weighted imaging (DWI) (3 patients), perfusion imaging and MR spectroscopy (2 patients), and DSA (4 patients) were also analyzed. The tumors most frequently arose from the intracranial meninges (7/9), while the other lesions were intraventricular. Tumor size ranged from 2.5 to 10 cm (mean=6.6 cm). They presented multilobular shape in 6/9 patients. Most ISFTs were heterogeneous (7/9) with areas of low T2 signal intensity that strongly enhanced after gadolinium administration (6/8). Erosion of the skull was present in about half of the cases (4/9). Components with decreased apparent diffusion coefficient were seen in 2/3 ISFTs on DWI. Spectroscopy revealed elevated peaks of choline and myo-inositol. MR perfusion showed features of hyperperfusion. ISFT should be considered in cases of extra-axial, supratentorial, heterogeneous, hypervascular tumor. Areas of low T2 signal intensity that strongly enhance after gadolinium injection are suggestive of this diagnosis. Restricted diffusion and elevated peak of myo-inositol may be additional valuable features. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Assessment of myocardial fibrosis with T1 mapping MRI.

PubMed

Everett, R J; Stirrat, C G; Semple, S I R; Newby, D E; Dweck, M R; Mirsadraee, S

2016-08-01

Myocardial fibrosis can arise from a range of pathological processes and its presence correlates with adverse clinical outcomes. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of cardiac structure, function, and tissue characteristics, which includes late gadolinium enhancement (LGE) techniques to identify focal irreversible replacement fibrosis with a high degree of accuracy and reproducibility. Importantly the presence of LGE is consistently associated with adverse outcomes in a range of common cardiac conditions; however, LGE techniques are qualitative and unable to detect diffuse myocardial fibrosis, which is an earlier form of fibrosis preceding replacement fibrosis that may be reversible. Novel T1 mapping techniques allow quantitative CMR assessment of diffuse myocardial fibrosis with the two most common measures being native T1 and extracellular volume (ECV) fraction. Native T1 differentiates normal from infarcted myocardium, is abnormal in hypertrophic cardiomyopathy, and may be particularly useful in the diagnosis of Anderson-Fabry disease and amyloidosis. ECV is a surrogate measure of the extracellular space and is equivalent to the myocardial volume of distribution of the gadolinium-based contrast medium. It is reproducible and correlates well with fibrosis on histology. ECV is abnormal in patients with cardiac failure and aortic stenosis, and is associated with functional impairment in these groups. T1 mapping techniques promise to allow earlier detection of disease, monitor disease progression, and inform prognosis; however, limitations remain. In particular, reference ranges are lacking for T1 mapping values as these are influenced by specific CMR techniques and magnetic field strength. In addition, there is significant overlap between T1 mapping values in healthy controls and most disease states, particularly using native T1, limiting the clinical application of these techniques at present. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Nephrogenic systemic fibrosis (NSF): a late adverse reaction to some of the gadolinium based contrast agents

PubMed Central

Marckmann, Peter; Logager, Vibeke B.

2007-01-01

Abstract Until recently it was believed that extracellular gadolinium based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium based contrast agents may trigger the development of nephrogenic systemic fibrosis, a generalised fibrotic disorder, in renal failure patients. Accordingly, the use of gadodiamide and gadopentate dimeglumine for renal failure patients was banned in Europe in spring 2007. The same two compounds should only be used cautiously in patients with moderate renal dysfunction. The current paper reviews the situation (July 2007) regarding gadolinium based contrast agent and the severe delayed reaction to some of these agents. The fear of nephrogenic systemic fibrosis should not lead to a denial of a well indicated enhanced magnetic resonance imaging examination. PMID:17905680

Atypical patterns of cardiac involvement in Fabry disease.

PubMed

Coughlan, J J; Elkholy, K; O'Brien, J; Kiernan, T

2016-03-17

A 58-year-old woman was referred to our cardiology service with chest pain, exertional dyspnoea and palpitations on a background of known Fabry disease diagnosed with genetic testing in 1994. ECG showed sinus rhythm, shortened PR interval, widespread t wave inversion, q waves in the lateral leads and left ventricular hypertrophy (LVH). Coronary angiogram showed only mild atheroma. Transthoracic echocardiogram showed anterolateral LVH and reduced left ventricular cavity size in keeping with Fabry cardiomyopathy. Cardiac MRI demonstrated asymmetric hypertrophy with evidence of diffuse myocardial fibrosis in the maximally hypertrophied segments from base to apex with late gadolinium enhancement in the anterior and anteroseptal walls. This was quite an atypical appearance for Fabry cardiomyopathy. This case highlights the heterogeneity of patterns of cardiac involvement that may be associated with this rare X-linked lysosomal disorder. 2016 BMJ Publishing Group Ltd.

Quantification and significance of diffuse myocardial fibrosis and diastolic dysfunction in childhood hypertrophic cardiomyopathy.

PubMed

Hussain, Tarique; Dragulescu, Andreea; Benson, Lee; Yoo, Shi-Joon; Meng, Howard; Windram, Jonathan; Wong, Derek; Greiser, Andreas; Friedberg, Mark; Mertens, Luc; Seed, Michael; Redington, Andrew; Grosse-Wortmann, Lars

2015-06-01

The purpose of this study was to evaluate the presence of diffuse myocardial fibrosis in children and adolescents with hypertrophic cardiomyopathy (HCM) and to assess associations with echocardiographic and clinical parameters of disease. While a common end point in adults with HCM, it is unclear whether diffuse myocardial fibrosis occurs early in the disease. Cardiac magnetic resonance (CMR) estimation of myocardial post-contrast longitudinal relaxation time (T1) is an increasingly used method to estimate diffuse fibrosis. T1 measurements were taken using standard multi-breath-hold spoiled gradient echo phase-sensitive inversion-recovery CMR before and 15 min after the injection of gadolinium. The tissue-blood partition coefficient was calculated as a function of the ratio of T1 change of myocardium compared with blood. An echocardiogram and blood brain natriuretic peptide (BNP) levels were obtained on the day of the CMR. Twelve controls (mean age 12.8 years; 7 male) and 28 patients with HCM (mean age 12.8 years; 21 male) participated. The partition coefficient for both septal (0.27 ± 0.17 vs. 0.13 ± 0.09; p = 0.03) and lateral walls (0.22 ± 0.09 vs. 0.07 ± 0.10; p < 0.001) was increased in patients compared with controls. Eight patients had overt areas of late gadolinium enhancement (LGE). These patients did not show increased partition coefficient compared with those without LGE (0.27 ± 0.15 vs. 0.27 ± 0.19 and 0.22 ± 0.09 vs. 0.22 ± 0.09; p = 0.95 and 0.98, respectively). However, patients who were symptomatic (dyspnea, arrhythmia and/or chest pain) had higher lateral wall partition coefficient than asymptomatic HCM patients (0.27 ± 0.08 vs. 0.17 ± 0.08; p = 0.006). Similarly, patients with raised BNP (>100 pg/ml) had raised lateral wall coefficients (0.27 ± 0.07 vs. 0.20 ± 0.07; p = 0.03), as did those with traditional risk factors for sudden death (0.27 ± 0.06 vs. 0.18 ± 0.08; p = 0.007). Diffuse fibrosis, measured by the partition coefficient technique, is demonstrable in children and adolescents with HCM. Markers of fibrosis show an association with symptoms and raised serum BNP. Further study of the prognostic implication of this technique in young patients with HCM is warranted.

Quantification of fibrosis in infarcted swine hearts by ex vivo late gadolinium-enhancement and diffusion-weighted MRI methods

NASA Astrophysics Data System (ADS)

Pop, Mihaela; Ghugre, Nilesh R.; Ramanan, Venkat; Morikawa, Lily; Stanisz, Greg; Dick, Alexander J.; Wright, Graham A.

2013-08-01

Many have speculated that MRI signal characteristics can be used to identify regions of heterogeneous infarct associated with an arrhythmogenic substrate; however, direct evidence of this relationship is limited. The aim of this study was to demonstrate the remodelling characteristics of fibrosis by means of histology and high-resolution MR imaging. For this purpose, we performed whole-mount histology in heart samples (n = 9) collected from five swine at six weeks post-infarction and compared the extent of fibrosis in the infarcted areas delineated in these histological images with that obtained ex vivo by MRI using late gadolinium-enhancement (LGE) and diffusion-weighted imaging (DWI) methods. All MR images were obtained at a submillimetre resolution (i.e., voxel size of 0.6×0.6×1.2 mm3). Specifically, in the histology images, we differentiated moderate fibrosis (consisting of a mixture of viable and non-viable myocytes, known as border zone, BZ) from severe fibrosis (i.e., the dense scar). Correspondingly, tissue heterogeneities in the MR images were categorized by a Gaussian mixture model into healthy, BZ and scar. Our results showed that (a) both MRI methods were capable of qualitatively distinguishing sharp edges between dense scar and healthy tissue from regions of heterogeneous BZ; (b) the BZ and dense scar areas had intermediate-to-high increased values of signal intensity in the LGE images and of apparent diffusion coefficient in the DWI, respectively. In addition, as demonstrated by the Picrosirius Red and immunohistochemistry stains, the viable bundles in the BZ were clearly separated by thin collagen strands and had reduced expression of Cx43, whereas the core scar was composed of dense fibrosis. A quantitative analysis demonstrated that the comparison between BZ/scar extent in LGE and DWI to the corresponding areas identified in histology yielded very good correlations (i.e., for the scar identified by LGE, R2 was 0.96 compared to R2 = 0.93 for the scar identified in ADC maps, whereas the BZ had R2 = 0.95 for the correlation between LGE and histology compared to R2 = 0.91 obtained for ADC). This novel study represents an intermediate step in translating such research to the in vivo stages, as well as in establishing the best and most accurate MR method to help identify arrhythmia substrate in patients with structural heart disease.

Heterogeneous intratumoral distribution of gadolinium nanoparticles within U87 human glioblastoma xenografts unveiled by micro-PIXE imaging.

PubMed

Carmona, Asuncion; Roudeau, Stéphane; L'Homel, Baptiste; Pouzoulet, Frédéric; Bonnet-Boissinot, Sarah; Prezado, Yolanda; Ortega, Richard

2017-04-15

Metallic nanoparticles have great potential in cancer radiotherapy as theranostic drugs since, they serve simultaneously as contrast agents for medical imaging and as radio-therapy sensitizers. As with other anticancer drugs, intratumoral diffusion is one of the main limiting factors for therapeutic efficiency. To date, a few reports have investigated the intratumoral distribution of metallic nanoparticles. The aim of this study was to determine the quantitative distribution of gadolinium (Gd) nanoparticles after direct intratumoral injection within U87 human glioblastoma tumors grafted in mice, using micro-PIXE (Particle Induced X-ray Emission) imaging. AGuIX (Activation and Guiding of Irradiation by X-ray) 3 nm particles composed of a polysiloxane network surrounded by gadolinium chelates were used. PIXE results indicate that the direct injection of Gd nanoparticles in tumors results in their heterogeneous diffusion, probably related to variations in tumor density. All tumor regions contain Gd, but with markedly different concentrations, with a more than 250-fold difference. Also Gd can diffuse to the healthy adjacent tissue. This study highlights the usefulness of mapping the distribution of metallic nanoparticles at the intratumoral level, and proposes PIXE as an imaging modality to probe the quantitative distribution of metallic nanoparticles in tumors from experimental animal models with micrometer resolution. Copyright © 2017 Elsevier Inc. All rights reserved.

Diffuse fibrosis is common in the left, but not in the right ventricle in patients with transposition of the great arteries late after atrial switch operation.

PubMed

Shehu, Nerejda; Meierhofer, Christian; Messroghli, Daniel; Mkrtchyan, Naira; Martinoff, Stefan; Ewert, Peter; Stern, Heiko

2018-03-29

In adult patients with transposition of the great arteries (TGA) late after atrial switch operation (AtSO), each of the ventricles is faced with a profoundly different pressure regimen from the one they are meant to support in normal conditions. The extent of diffuse fibrosis of the right ventricle (RV) and left ventricle (LV) in these patients remains incompletely investigated. Aim of this study was to quantify the degree of fibrosis of the unloaded LV and of the overloaded RV by determining the myocardial extracellular volume (ECV) with non-invasive techniques as T1 mapping. We determined ECV by cardiac magnetic resonance (CMR) in 10 patients (36.8 ± 5.3 years old) with TGA late after AtSO, without relevant pulmonary stenosis, by acquiring T1-maps of the myocardium before and 10 min after injection of Gadolinium-based contrast agent. ECV of the inferior wall (36% (33-41%)) and of the lateral wall (37% (35-39%)) of the LV was significantly increased compared to the ECV of the RV (27% (25-29%)), in both comparisons P < 0.0001. Long-time LV unloading following atrial switch procedures leads to severe myocardial fibrosis of the subpulmonary LV. T1 mapping CMR might be useful for selection of patients with atrial switch operation, in whom reestablishment of the LV as a systemic ventricle by staged arterial switch operation is planned. However larger studies and newer higher resolution methods for T1-mapping are needed to determine the role of ECV in the decision of a surgical intervention in this kind of population.

High spatial resolution free-breathing 3D late gadolinium enhancement cardiac magnetic resonance imaging in ischaemic and non-ischaemic cardiomyopathy: quantitative assessment of scar mass and image quality.

PubMed

Bizino, Maurice B; Tao, Qian; Amersfoort, Jacob; Siebelink, Hans-Marc J; van den Bogaard, Pieter J; van der Geest, Rob J; Lamb, Hildo J

2018-04-06

To compare breath-hold (BH) with navigated free-breathing (FB) 3D late gadolinium enhancement cardiac MRI (LGE-CMR) MATERIALS AND METHODS: Fifty-one patients were retrospectively included (34 ischaemic cardiomyopathy, 14 non-ischaemic cardiomyopathy, three discarded). BH and FB 3D phase sensitive inversion recovery sequences were performed at 3T. FB datasets were reformatted into normal resolution (FB-NR, 1.46x1.46x10mm) and high resolution (FB-HR, isotropic 0.91-mm voxels). Scar mass, scar edge sharpness (SES), SNR and CNR were compared using paired-samples t-test, Pearson correlation and Bland-Altman analysis. Scar mass was similar in BH and FB-NR (mean ± SD: 15.5±18.0 g vs. 15.5±16.9 g, p=0.997), with good correlation (r=0.953), and no bias (mean difference ± SD: 0.00±5.47 g). FB-NR significantly overestimated scar mass compared with FB-HR (15.5±16.9 g vs 14.4±15.6 g; p=0.007). FB-NR and FB-HR correlated well (r=0.988), but Bland-Altman demonstrated systematic bias (1.15±2.84 g). SES was similar in BH and FB-NR (p=0.947), but significantly higher in FB-HR than FB-NR (p<0.01). SNR and CNR were lower in BH than FB-NR (p<0.01), and lower in FB-HR than FB-NR (p<0.01). Navigated free-breathing 3D LGE-CMR allows reliable scar mass quantification comparable to breath-hold. During free-breathing, spatial resolution can be increased resulting in improved sharpness and reduced scar mass. • Navigated free-breathing 3D late gadolinium enhancement is reliable for myocardial scar quantification. • High-resolution 3D late gadolinium enhancement increases scar sharpness • Ischaemic and non-ischaemic cardiomyopathy patients can be imaged using free-breathing LGE CMR.

Native T1 mapping of the heart - a pictorial review.

PubMed

Germain, Philippe; El Ghannudi, Soraya; Jeung, Mi-Young; Ohlmann, Patrick; Epailly, Eric; Roy, Catherine; Gangi, Afshin

2014-01-01

T1 mapping is now a clinically feasible method, providing pixel-wise quantification of the cardiac structure's T1 values. Beyond focal lesions, well depicted by late gadolinium enhancement sequences, it has become possible to discriminate diffuse myocardial alterations, previously not assessable by noninvasive means. The strength of this method includes the high reproducibility and immediate clinical applicability, even without the use of contrast media injection (native or pre-contrast T1). The two most important determinants of native T1 augmentation are (1) edema related to tissue water increase (recent infarction or inflammation) and (2) interstitial space increase related to fibrosis (infarction scar, cardiomyopathy) or to amyloidosis. Conversely, lipid (Anderson-Fabry) or iron overload diseases are responsible for T1 reduction. In this pictorial review, the main features provided by native T1 mapping are discussed and illustrated, with a special focus on the awaited clinical purpose of this unique, promising new method.

[Current practice in MR imaging of the liver].

PubMed

Kanematsu, M; Kondo, H; Matsuo, M; Hoshi, H

2001-12-01

MR imaging, which is able to evaluate T1- and T2-relaxation time, fat, hemorrhage, metal deposition, blood flow, perfusion, diffusion, and so on, has offered more information for the diagnosis of diffuse and focal hepatic diseases than CT. The spoiled-GRE sequence with high contrast resolution and ease of the aimed contrast capture derived from the k-space property, with the use of a phased-array multicoil, have remarkably increased the value of gadolinium-enhanced dynamic MR diagnosis of the liver. In recent years, the clinical use of ferumoxide has begun, and issues concerning the superiority or inferiority and combination of contrast media are being debated. This paper describes the value, role, and clinical practice of unenhanced, gadolinium-enhanced, and ferumoxide-enhanced MR imaging of the liver based on knowledge obtained in our institution, with some reference to the literature.

Apparent diffusion coefficient for molecular subtyping of non-gadolinium-enhancing WHO grade II/III glioma: volumetric segmentation versus two-dimensional region of interest analysis.

PubMed

Thust, S C; Hassanein, S; Bisdas, S; Rees, J H; Hyare, H; Maynard, J A; Brandner, S; Tur, C; Jäger, H R; Yousry, T A; Mancini, L

2018-03-23

To investigate if quantitative apparent diffusion coefficient (ADC) measurements can predict genetic subtypes of non-gadolinium-enhancing gliomas, comparing whole tumour against single slice analysis. Volumetric T2-derived masks of 44 gliomas were co-registered to ADC maps with ADC mean (ADC mean ) calculated. For the slice analysis, two observers placed regions of interest in the largest tumour cross-section. The ratio (ADC ratio ) between ADC mean in the tumour and normal appearing white matter was calculated for both methods. Isocitrate dehydrogenase (IDH) wild-type gliomas showed the lowest ADC values throughout (p < 0.001). ADC mean in the IDH-mutant 1p19q intact group was significantly higher than in the IDH-mutant 1p19q co-deleted group (p < 0.01). A volumetric ADC mean threshold of 1201 × 10 -6 mm 2 /s identified IDH wild-type with a sensitivity of 83% and a specificity of 86%; a volumetric ADC ratio cut-off value of 1.65 provided a sensitivity of 80% and a specificity of 92% (area under the curve (AUC) 0.9-0.94). A slice ADC ratio threshold for observer 1 (observer 2) of 1.76 (1.83) provided a sensitivity of 80% (86%), specificity of 91% (100%) and AUC of 0.95 (0.96). The intraclass correlation coefficient was excellent (0.98). ADC measurements can support the distinction of glioma subtypes. Volumetric and two-dimensional measurements yielded similar results in this study. • Diffusion-weighted MRI aids the identification of non-gadolinium-enhancing malignant gliomas • ADC measurements may permit non-gadolinium-enhancing glioma molecular subtyping • IDH wild-type gliomas have lower ADC values than IDH-mutant tumours • Single cross-section and volumetric ADC measurements yielded comparable results in this study.

Mass diffusion coefficient measurement for vitreous humor using FEM and MRI

NASA Astrophysics Data System (ADS)

Rattanakijsuntorn, Komsan; Penkova, Anita; Sadha, Satwindar S.

2018-01-01

In early studies, the ‘contour method’ for determining the diffusion coefficient of the vitreous humor was developed. This technique relied on careful injection of an MRI contrast agent (surrogate drug) into the vitreous humor of fresh bovine eyes, and tracking the contours of the contrast agent in time. In addition, an analytical solution was developed for the theoretical contours built on point source model for the injected surrogate drug. The match between theoretical and experimental contours as a least square fit, while floating the diffusion coefficient, led to the value of the diffusion coefficient. This method had its limitation that the initial injection of the surrogate had to be spherical or ellipsoidal because of the analytical result based on the point-source model. With a new finite element model for the analysis in this study, the technique is much less restrictive and handles irregular shapes of the initial bolus. The fresh bovine eyes were used for drug diffusion study in the vitreous and three contrast agents of different molecular masses: gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA, 938 Da), non-ionic gadoteridol (Prohance, 559 Da), and bovine albumin conjugated with gadolinium (Galbumin, 74 kDa) were used as drug surrogates to visualize the diffusion process by MRI. The 3D finite element model was developed to determine the diffusion coefficients of these surrogates with the images from MRI. This method can be used for other types of bioporous media provided the concentration profile can be visualized (by methods such as MRI or fluorescence).

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance

PubMed Central

van Geuns, Robert‐Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J.G.M.

2017-01-01

Abstract Aims Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast‐enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. Methods and results We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast‐enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non‐invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P < 0.001). Right ventricular enhancement correlated with systolic ventricular dysfunction (P < 0.001), hypertrophy (P = 0.001), and dilation (P < 0.001). Conclusions Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. PMID:29154434

The Utility of Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Sarcoidosis.

PubMed

Stanton, Kelly M; Ganigara, Madhusudan; Corte, Peter; Celermajer, David S; McGuire, Mark A; Torzillo, Paul J; Corte, Tamera J; Puranik, Rajesh

2017-11-01

Autopsy reports suggest that cardiac sarcoidosis occurs in 20 to 25% of patients with pulmonary sarcoidosis, yet the clinical ante-mortem diagnosis is made in only 5% of cases. Current diagnostic algorithms are complex and lack sensitivity. Cardiac Magnetic Resonance imaging (CMR) provides an opportunity to detect myocardial involvement in sarcoidosis. The aim of this study is to determine the prevalence and clinical significance of late gadolinium enhancement (LGE) on CMR in patients with sarcoidosis. Consecutive patients with biopsy-proven sarcoidosis undergoing CMR were retrospectively evaluated for cardiac sarcoidosis. Medical records were correlated with CMR. Forty-six patients were evaluated. Late gadolinium enhancement was present in 22%, indicating myocardial involvement, and 70% had corresponding hyper-intense T2 signal indicating active inflammation. Late gadolinium enhancement was 18%+/-9.7% of overall left ventricular (LV) mass and most commonly located in the basal to mid septum. There was no association between LGE and cardiovascular symptoms or pulmonary stage. Eighty per cent of patients with LGE did not fulfill conventional diagnostic criteria for cardiac sarcoidosis. However, LGE was associated with clinically significant arrhythmia (p<0.01) and a lower LVEF (p=0.04). Using CMR, we identified a higher prevalence of cardiac sarcoidosis than previously reported clinical studies, a prevalence which is more consistent with autopsy data. The presence of LGE was highly correlated with clinically significant arrhythmias and lower LVEF. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.

Late Gadolinium Enhancement Amount As an Independent Risk Factor for the Incidence of Adverse Cardiovascular Events in Patients with Stage C or D Heart Failure

PubMed Central

Liu, Tong; Ma, Xiaohai; Liu, Wei; Ling, Shukuan; Zhao, Lei; Xu, Lei; Song, Deli; Liu, Jie; Sun, Zhonghua; Fan, Zhanming; Luo, Taiyang; Kang, Junping; Liu, Xiaohui; Dong, Jianzeng

2016-01-01

Background: Myocardial fibrosis (MF) is a risk factor for poor prognosis in dilated cardiomyopathy (DCM). Late gadolinium enhancement (LGE) of the myocardium on cardiac magnetic resonance (CMR) represents MF. We examined whether the LGE amount increases the incidence of adverse cardiovascular events in patients with stage C or D heart failure (HF). Methods: Eighty-four consecutive patients with stage C or D HF, either ischemic or non-ischemic, were enrolled. Comprehensive clinical and CMR evaluations were performed. All patients were followed up for a composite endpoint of cardiovascular death, heart transplantation, and cardiac resynchronization therapy with defibrillator (CRT-D). Results: LGE was present in 79.7% of the end-stage HF patients. LGE distribution patterns were mid-wall, epi-myocardial, endo-myocardial, and the morphological patterns were patchy, transmural, and diffuse. During the average follow-up of 544 days, 13 (15.5%) patients had endpoint events: 7 patients cardiac death, 2 patients heart transplantation, and 4 patients underwent CRT-D implantation. On univariate analysis, LGE quantification on cardiac magnetic resonance, blood urine nitrogen, QRS duration on electrocardiogram, left ventricular end-diastolic diameter (LVEDD), and left ventricular end-diastolic volume (LVEDV) on CMR had the strongest associations with the composite endpoint events. However, on multivariate analysis for both Model I (after adjusting for age, sex, and body mass index) and Model II (after adjusting for age, sex, BMI, renal function, QRS duration, and atrial fibrillation on electrocardiogram, the etiology of HF, LVEF, CMR-LVEDD, and CMR-LVEDV), LGE amount was a significant risk factor for composite endpoint events (Model I 6SD HR 1.037, 95%CI 1.005–1.071, p = 0.022; Model II 6SD HR 1.045, 95%CI 1.001–1.084, p = 0.022). Conclusion: LGE amount from high-scale threshold on CMR increased the incidence of adverse cardiovascular events for patients in either stage C or D HF. PMID:27840608

Critical Questions Regarding Gadolinium Deposition in the Brain and Body After Injections of the Gadolinium-Based Contrast Agents, Safety, and Clinical Recommendations in Consideration of the EMA's Pharmacovigilance and Risk Assessment Committee Recommendation for Suspension of the Marketing Authorizations for 4 Linear Agents.

PubMed

Runge, Val M

2017-06-01

For magnetic resonance, the established class of intravenous contrast media is the gadolinium-based contrast agents. In the 3 decades since initial approval, these have proven in general to be very safe for human administration. However, in 2006, a devastating late adverse reaction to administration of the less stable gadolinium-based contrast agents was identified, nephrogenic systemic fibrosis. The result of actions taken by the European Medicines Agency and the US Food and Drug Administration, stratifying the agents by risk and contraindicating specific agents in severe renal dysfunction, has led to no new cases being identified in North America or Europe. Subsequently, in 2014, long-term deposition in the brain of gadolinium was first shown, after administration of 2 nonionic linear chelates, gadodiamide, and gadopentetate dimeglumine. This has led to an intense focus on the question of in vivo distribution, possible dechelation, and subsequent deposition of gadolinium, together with substantial clarification of the phenomenon as well as stratification of the agents on this basis. This review focuses on 8 critical questions regarding gadolinium deposition in the brain and body, with the answers and discussion therein important for future regulatory decisions and clinical practice. It is now clear that dechelation of gadolinium occurs in vivo with the linear agents and is responsible for this phenomenon, with key experts in the field recommending, except where there is no suitable alternative, a shift in clinical practice from the linear to macrocyclic agents. In addition, on March 10, 2017, the Pharmacovigilance and Risk Assessment Committee of the European Medicines Agency recommended suspension of the marketing authorization for 4 linear gadolinium contrast agents-specifically Omniscan, Optimark, Magnevist, and MultiHance (gadodiamide, gadoversetamide, gadopentetate dimeglumine, and gadobenate dimeglumine)-for intravenous injection. Cited in the report was convincing evidence of gadolinium deposition in the brain months after injection of these linear agents. Primovist/Eovist (gadoxetic acid disodium) will remain available, being used at a lower dose for liver imaging, because it meets an important diagnostic need. In addition, a formulation of Magnevist for intra-articular injection will remain available because of its very low gadolinium concentration.

Multiparametric Cardiac Magnetic Resonance Survey in Children With Thalassemia Major: A Multicenter Study.

PubMed

Casale, Maddalena; Meloni, Antonella; Filosa, Aldo; Cuccia, Liana; Caruso, Vincenzo; Palazzi, Giovanni; Gamberini, Maria Rita; Pitrolo, Lorella; Putti, Maria Caterina; D'Ascola, Domenico Giuseppe; Casini, Tommaso; Quarta, Antonella; Maggio, Aurelio; Neri, Maria Giovanna; Positano, Vincenzo; Salvatori, Cristina; Toia, Patrizia; Valeri, Gianluca; Midiri, Massimo; Pepe, Alessia

2015-08-01

Cardiovascular magnetic resonance (CMR) plays a key role in the management of thalassemia major patients, but few data are available in pediatric population. This study aims at a retrospective multiparametric CMR assessment of myocardial iron overload, function, and fibrosis in a cohort of pediatric thalassemia major patients. We studied 107 pediatric thalassemia major patients (61 boys, median age 14.4 years). Myocardial and liver iron overload were measured by T2* multiecho technique. Atrial dimensions and biventricular function were quantified by cine images. Late gadolinium enhancement images were acquired to detect myocardial fibrosis. All scans were performed without sedation. The 21.4% of the patients showed a significant myocardial iron overload correlated with lower compliance to chelation therapy (P<0.013). Serum ferritin ≥2000 ng/mL and liver iron concentration ≥14 mg/g/dw were detected as the best threshold for predicting cardiac iron overload (P=0.001 and P<0.0001, respectively). A homogeneous pattern of myocardial iron overload was associated with a negative cardiac remodeling and significant higher liver iron concentration (P<0.0001). Myocardial fibrosis by late gadolinium enhancement was detected in 15.8% of the patients (youngest children 13 years old). It was correlated with significant lower heart T2* values (P=0.022) and negative cardiac remodeling indexes. A pathological magnetic resonance imaging liver iron concentration was found in the 77.6% of the patients. Cardiac damage detectable by a multiparametric CMR approach can occur early in thalassemia major patients. So, the first T2* CMR assessment should be performed as early as feasible without sedation to tailor the chelation treatment. Conversely, late gadolinium enhancement CMR should be postponed in the teenager age. © 2015 American Heart Association, Inc.

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance.

PubMed

Smedema, Jan-Peter; van Geuns, Robert-Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J G M

2017-11-01

Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast-enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast-enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non-invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P < 0.001). Right ventricular enhancement correlated with systolic ventricular dysfunction (P < 0.001), hypertrophy (P = 0.001), and dilation (P < 0.001). Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Long-Term Outcomes of Catheter Ablation of Ventricular Tachycardia in Patients With Cardiac Sarcoidosis.

PubMed

Muser, Daniele; Santangeli, Pasquale; Pathak, Rajeev K; Castro, Simon A; Liang, Jackson J; Magnani, Silvia; Hayashi, Tatsuya; Garcia, Fermin C; Hutchinson, Mathew D; Supple, Gregory E; Frankel, David S; Riley, Michael P; Lin, David; Schaller, Robert D; Desjardins, Benoit; Dixit, Sanjay; Callans, David J; Zado, Erica S; Marchlinski, Francis E

2016-08-01

Catheter ablation (CA) of ventricular tachycardia (VT) in patients with cardiac sarcoidosis can be challenging because of the complex underlying substrate. We sought to determine the long-term outcome of CA of VT in patients with cardiac sarcoidosis. We enrolled 31 patients (age, 55±10 years) with diagnosis of cardiac sarcoidosis based on Heart Rhythm Society criteria and VT who underwent CA. In 23 (74%) patients, preprocedure cardiac magnetic resonance imaging and positron emission tomographic (PET) evaluation were performed. Preprocedure magnetic resonance imaging was positive for late gadolinium enhancement in 21 of 23 (91%) patients, whereas abnormal 18-fluorodeoxyglucose uptake was found in 15 of 23 (65%) cases. In 14 of 15 patients with positive PET at baseline, PET was repeated after 6.1±3.7-month follow-up. After a median follow-up of 2.5 (range, 0-10.5) years, 1 (3%) patient died and 4 (13%) underwent heart transplant. Overall VT-free survival was 55% at 2-year follow-up. Among the 16 (52%) patients with VT recurrences, CA resulted in a significant reduction of VT burden, with 8 (50%) having only isolated (1-3) VT episodes and only 1 patient with recurrent VT storm. The presence of late gadolinium enhancement at magnetic resonance imaging, a positive PET at baseline, and lack of PET improvement over follow-up were associated with increased risk of recurrent VT. In patients with cardiac sarcoidosis and VT, CA is effective in achieving long-term freedom from VT or improvement in VT burden in the majority of patients. The presence of late gadolinium enhancement at magnetic resonance imaging, a positive PET scan at baseline, or lack of improvement at repeat PET over follow-up predict worse arrhythmia-free survival. © 2016 American Heart Association, Inc.

Gadolinium enhanced cardiovascular magnetic resonance in Anderson-Fabry disease. Evidence for a disease specific abnormality of the myocardial interstitium.

PubMed

Moon, James C C; Sachdev, Bhavesh; Elkington, Andrew G; McKenna, William J; Mehta, Atul; Pennell, Dudley J; Leed, Philip J; Elliott, Perry M

2003-12-01

Anderson-Fabry Disease (AFD), an X-linked disorder of sphingolipid metabolism, is a cause of idiopathic left ventricular hypertrophy but the mechanism of hypertrophy is poorly understood. Gadolinium enhanced cardiovascular magnetic resonance can detect focal myocardial fibrosis. We hypothesised that hyperenhancement would be present in AFD. Eighteen males (mean 43+/-14 years) and eight female heterozygotes (mean 48+/-12 years) with AFD underwent cine and late gadolinium cardiovascular magnetic resonance. Nine male (50%) had myocardial hyperenhancement ranging from 3.4% to 20.6% (mean 7.7+/-5.7%) of total myocardium; in males, percentage hyperenhancement related to LV mass index (r=0.78, P=0.0002) but not to ejection fraction or left ventricular volumes. Lesser hyperenhancement was also found in four (50%) heterozygous females (mean 4.6%). In 12 (92%) patients with abnormal gadolinium uptake, hyperenhancement occurred in the basal infero-lateral wall where, unlike myocardial infarction, it was not sub-endocardial. In two male patients with severe LVH (left ventricular hypertrophy) and systolic impairment there was additional hyperenhancement in other myocardial segments. These observations suggests that myocardial fibrosis occurs in AFD and may contribute to the hypertrophy and the natural history of the disease.

Comparison of cardiogoniometry and electrocardiography with perfusion cardiac magnetic resonance imaging and late gadolinium enhancement.

PubMed

Birkemeyer, Ralf; Toelg, Ralph; Zeymer, Uwe; Wessely, Rainer; Jäckle, Sebastian; Hairedini, Bajram; Lübke, Mike; Aßfalg, Manfred; Jung, Werner

2012-12-01

Cardiogoniometry (CGM) is a spatio-temporal five-lead resting electrocardiographic method utilizing automated analysis. The purpose of this study was to determine CGM's and electrocardiography (ECG)'s accuracy for detecting myocardial ischaemia and/or lesions in comparison with perfusion cardiac magnetic resonance imaging (CMRI) and late gadolinium enhancement (LGE). Forty (n= 40) patients with suspected or known stable coronary artery disease were examined by CGM and resting ECG directly prior to CMRI including adenosine stress perfusion (ASP) and LGE. The investigators visually reading the CMRI were blinded to the CGM and ECG results. Half of the patients (n= 20) had a normal CMRI while the other half presented with either abnormal ASP and/or detectable LGE. Cardiogoniometry yielded an accuracy of 83% (sensitivity 70%) and ECG of 63% (sensitivity 35%) compared with CMRI. In this pilot study CGM compares more favourably than ECG with the detection of ischaemia and/or structural myocardial lesions on CMRI.

Effect of Contrast Media on Single Shot EPI: Implications for Abdominal Diffusion Imaging

PubMed Central

Gulani, Vikas; Willatt, Jonathan M.; Blaimer, Martin; Hussain, Hero K.; Duerk, Jeffrey L.; Griswold, Mark A.

2010-01-01

Purpose The goal of this study was to determine the effect of contrast media on the signal behavior of single shot echo planar imaging (ssEPI) used for abdominal diffusion imaging. Materials and Methods The signal of a ssEPI spin echo sequence in a water phantom with varying concentrations of gadolinium was modeled with Bloch equations and the predicted behavior validated on a phantom at 1.5 T. Six volunteers were given gadolinium contrast, and signal intensity (SI) time courses for regions of interest (ROIs) in the liver, pancreas, spleen, renal cortex and medulla were analyzed. The Student's t-test was used to compare pre-contrast SI to 0, 1, 4, 5, 10, and 13 minutes following contrast. Results The results show that following contrast, ssEPI SI goes through a nadir, recovering differently for each organ. Maximal contrast related signal losses relative to pre-contrast signal are 20%, 20%, 53%, and 67%, for the liver, pancreas, renal cortex and medulla respectively. The SIs remain statistically below the pre-contrast values for 5, 4, and 1 minutes for the pancreas, liver, and spleen, and for all times measured for the renal cortex and medulla. Conclusion Abdominal diffusion imaging should be performed prior to contrast due to adverse effects on the signal in ssEPI. PMID:19856456

Left ventricular hypertrophy: The relationship between the electrocardiogram and cardiovascular magnetic resonance imaging.

PubMed

Bacharova, Ljuba; Ugander, Martin

2014-11-01

Conventional assessment of left ventricular hypertrophy (LVH) using the electrocardiogram (ECG), for example, by the Sokolow-Lyon, Romhilt-Estes or Cornell criteria, have relied on assessing changes in the amplitude and/or duration of the QRS complex of the ECG to quantify LV mass. ECG measures of LV mass have typically been validated by imaging with echocardiography or cardiovascular magnetic resonance imaging (CMR). However, LVH can be the result of diverse etiologies, and LVH is also characterized by pathological changes in myocardial tissue characteristics on the genetic, molecular, cellular, and tissue level beyond a pure increase in the number of otherwise normal cardiomyocytes. For example, slowed conduction velocity through the myocardium, which can be due to diffuse myocardial fibrosis, has been shown to be an important determinant of conventional ECG LVH criteria regardless of LV mass. Myocardial tissue characterization by CMR has emerged to not only quantify LV mass, but also detect and quantify the extent and severity of focal or diffuse myocardial fibrosis, edema, inflammation, myocarditis, fatty replacement, myocardial disarray, and myocardial deposition of amyloid proteins (amyloidosis), glycolipids (Fabry disease), or iron (siderosis). This can be undertaken using CMR techniques including late gadolinium enhancement (LGE), T1 mapping, T2 mapping, T2* mapping, extracellular volume fraction (ECV) mapping, fat/water-weighted imaging, and diffusion tensor CMR. This review presents an overview of current and emerging concepts regarding the diagnostic possibilities of both ECG and CMR for LVH in an attempt to narrow gaps in our knowledge regarding the ECG diagnosis of LVH. © 2014 Wiley Periodicals, Inc.

T1 and T2 Mapping in Cardiology: "Mapping the Obscure Object of Desire".

PubMed

Mavrogeni, Sophie; Apostolou, Dimitris; Argyriou, Panayiotis; Velitsista, Stella; Papa, Lilika; Efentakis, Stelios; Vernardos, Evangelos; Kanoupaki, Mikela; Kanoupakis, George; Manginas, Athanassios

The increasing use of cardiovascular magnetic resonance (CMR) is based on its capability to perform biventricular function assessment and tissue characterization without radiation and with high reproducibility. The use of late gadolinium enhancement (LGE) gave the potential of non-invasive biopsy for fibrosis quantification. However, LGE is unable to detect diffuse myocardial disease. Native T1 mapping and extracellular volume fraction (ECV) provide knowledge about pathologies affecting both the myocardium and interstitium that is otherwise difficult to identify. Changes of myocardial native T1 reflect cardiac diseases (acute coronary syndromes, infarction, myocarditis, and diffuse fibrosis, all with high T1) and systemic diseases such as cardiac amyloid (high T1), Anderson-Fabry disease (low T1), and siderosis (low T1). The ECV, an index generated by native and post-contrast T1 mapping, measures the cellular and extracellular interstitial matrix (ECM) compartments. This myocyte-ECM dichotomy has important implications for identifying specific therapeutic targets of great value for heart failure treatment. On the other hand, T2 mapping is superior compared with myocardial T1 and ECM for assessing the activity of myocarditis in recent-onset heart failure. Although these indices can significantly affect the clinical decision making, multicentre studies and a community-wide approach (including MRI vendors, funding, software, contrast agent manufacturers, and clinicians) are still missing. © 2017 S. Karger AG, Basel.

Crystallization and preliminary X-ray diffraction studies of choline-binding protein F from Streptococcus pneumoniae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molina, Rafael; González, Ana; Moscoso, Miriam

2007-09-01

The modular choline-binding protein F (CbpF) from S. pneumoniae has been crystallized by the hanging-drop vapour-diffusion method. A SAD data set from a gadolinium-complex derivative has been collected to 2.1 Å resolution. Choline-binding protein F (CbpF) is a modular protein that is bound to the pneumococcal cell wall through noncovalent interactions with choline moieties of the bacterial teichoic and lipoteichoic acids. Despite being one of the more abundant proteins on the surface, along with the murein hydrolases LytA, LytB, LytC and Pce, its function is still unknown. CbpF has been crystallized using the hanging-drop vapour-diffusion method at 291 K. Diffraction-qualitymore » orthorhombic crystals belong to space group P2{sub 1}2{sub 1}2, with unit-cell parameters a = 49.13, b = 114.94, c = 75.69 Å. A SAD data set from a Gd-HPDO3A-derivatized CbpF crystal was collected to 2.1 Å resolution at the gadolinium L{sub III} absorption edge using synchrotron radiation.« less

Assessment of late cardiomyopathy by magnetic resonance imaging in patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and idarubicin.

PubMed

Rodríguez-Veiga, Rebeca; Igual, Begoña; Montesinos, Pau; Tormo, Mar; Sayas, Mª José; Linares, Mariano; Fernández, José María; Salvador, Antonio; Maceira-González, Alicia; Estornell, Jordi; Calabuig, Marisa; Pedreño, María; Roig, Mónica; Sanz, Jaime; Sanz, Guillermo; Carretero, Carlos; Boluda, Blanca; Martínez-Cuadrón, David; Sanz, Miguel Ángel

2017-07-01

Late cardiomyopathy CMP is regarded as a potential severe long-term complication after anthracycline-based regimens for acute promyelocitic leukaemia (APL). We assess by MRI the incidence and severity of clinical and subclinical long-term CMP in a cohort of adult APL patients in first complete remission with PETHEMA trials. Adult patients diagnosed with APL in first complete remission lasting ≥2 years underwent anamnesis and physical examination and were asked to perform a cardiac MRI. Clinical CMP was defined as radiographic and physical signs of heart failure accompanied by symptoms or by left ventricle ejection fraction (LVEF) <45% by MRI with or without symptoms. Subclinical CMP was defined as the following MRI abnormalities: LVEF 45-50% or late gadolinium enhancement or two or more of LVEF ≤55%, left ventricle end-diastolic volume index ≥98 ml/m 2 , left ventricle end-systolic volume index ≥38 ml/m 2 , right ventricle end-diastolic volume index ≥106 ml/m 2 and regional wall motion abnormalities. Of the 82 patients enrolled in the study, median cumulative dose of anthracyclines (doxorubicin equivalence) was 650 mg/m 2 , and median time from APL diagnosis to the study was 87 months (range, 24-195). Seven out of 57 patients with available MRI (12%) had subclinical CMP (all of them showed late gadolinium enhancement in MRI), and none had clinical CMP. Among the 25 patients without MRI, none had CMP by chest X-ray and physical assessment. In summary, we found 12% of subclinical and no clinical late CMP assessed by MRI in APL patients treated with PETHEMA protocols. Due to the low number of patients, we must interpret our results cautiously.

Complex imaging features of accidental cerebral intraventricular gadolinium administration.

PubMed

Nayak, Nita B; Huang, Jimmy C; Hathout, Gasser M; Shaba, Wisam; El-Saden, Suzie M

2013-05-01

Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) is a contrast agent commonly used for enhancing MRI. In this paper, the authors report on 2 cases of postoperative inadvertent administration of Gd-DTPA directly into a ventriculostomy tubing side port that was mistaken for intravenous tubing. Both cases demonstrated a low signal on MRI throughout the ventricular system and dependent portions of the subarachnoid spaces, which was originally believed to be CSF with areas of T1 shortening in the nondependent portions of the subarachnoid spaces, and misinterpreted as basal leptomeningeal enhancement and meningitis. The authors propose that the appearance of profound T1 hypointensity within the ventricles and diffuse susceptibility artifact along the ependyma is pathognomonic of intraventricular Gd-DTPA and should be recognized.

Impact of the Glymphatic System on the Kinetic and Distribution of Gadodiamide in the Rat Brain: Observations by Dynamic MRI and Effect of Circadian Rhythm on Tissue Gadolinium Concentrations.

PubMed

Taoka, Toshiaki; Jost, Gregor; Frenzel, Thomas; Naganawa, Shinji; Pietsch, Hubertus

2018-04-12

The glymphatic system is a recently hypothesized waste clearance system of the brain in which perivascular space constitutes a pathway similar to the lymphatic system in other body regions. Sleep and anesthesia are reported to influence the activity of the glymphatic system. Because rats are nocturnal animals, the glymphatic system is expected to be more active during the day. We attempted to elucidate the influence of the glymphatic system for intravenously injected gadodiamide in the rat brain by 2 experiments. One was a magnetic resonance imaging (MRI) experiment to evaluate the short-term dynamics of signal intensity changes after gadodiamide administration. The other was a quantification experiment to evaluate the concentration of retained gadolinium within the rat brain after repeated intravenous administration of gadodiamide at different times of day and levels of anesthesia. The imaging experiment was performed on 6 rats that received an intravenous injection of gadodiamide (1 mmol/kg) and dynamic MRI for 3 hours at 2.4-minute intervals. The time course of the signal intensity changes was evaluated for different brain structures. The tissue quantification experiment was performed on 24 rats divided into 4 groups by injection time (morning, late afternoon) and anesthesia (none, short, long) during administration. All animals received gadodiamide (1.8 mmol/kg, 8 times over 2 weeks). Gadolinium concentration of dissected brain tissues was quantified 5 weeks after the last administration by inductively coupled plasma mass spectrometry. In the imaging experiment, muscle and the fourth ventricle showed an instantaneous signal intensity increase immediately after gadodiamide injection. The signal curve of the cerebral cortex and deep cerebellar nuclei reached the peak signal intensity later than the fourth ventricle but earlier than that of the prepontine cistern. In the gadolinium quantification experiment, the concentration in the group with the morning injection showed a significantly lower concentration than the late afternoon injection group. The lowest tissue gadolinium concentrations were found in the groups injected in the morning during long anesthesia. Instantaneous transition of gadodiamide from blood to cerebrospinal fluid was indicated by dynamic MRI. The gadodiamide distribution to the cerebral cortex and deep cerebellar nuclei seemed to depend on both blood flow and cerebrospinal fluid. This confirms previous studies indicating that the cerebrospinal fluid is one potential pathway of gadolinium-based contrast agent entry into the brain. For the distribution and clearance of the gadodiamide from brain tissue, involvement of the glymphatic system seemed to be indicated in terms of the influence of sleep and anesthesia.

Progressing Toward a Cohesive Pediatric 18F-FDG PET/MR Protocol: Is Administration of Gadolinium Chelates Necessary?

PubMed

Klenk, Christopher; Gawande, Rakhee; Tran, Vy Thao; Leung, Jennifer Trinh; Chi, Kevin; Owen, Daniel; Luna-Fineman, Sandra; Sakamoto, Kathleen M; McMillan, Alex; Quon, Andy; Daldrup-Link, Heike E

2016-01-01

With the increasing availability of integrated PET/MR scanners, the utility and need for MR contrast agents for combined scans is questioned. The purpose of our study was to evaluate whether administration of gadolinium chelates is necessary for evaluation of pediatric tumors on (18)F-FDG PET/MR images. First, in 119 pediatric patients with primary and secondary tumors, we used 14 diagnostic criteria to compare the accuracy of several MR sequences: unenhanced T2-weighted fast spin-echo imaging; unenhanced diffusion-weighted imaging; and-before and after gadolinium chelate contrast enhancement-T1-weighted 3-dimensional spoiled gradient echo LAVA (liver acquisition with volume acquisition) imaging. Next, in a subset of 36 patients who had undergone (18)F-FDG PET within 3 wk of MRI, we fused the PET images with the unenhanced T2-weighted MR images (unenhanced (18)F-FDG PET/MRI) and the enhanced T1-weighted MR images (enhanced (18)F-FDG PET/MRI). Using the McNemar test, we compared the accuracy of the two types of fused images using the 14 diagnostic criteria. We also evaluated the concordance between (18)F-FDG avidity and gadolinium chelate enhancement. The standard of reference was histopathologic results, surgical notes, and follow-up imaging. There was no significant difference in diagnostic accuracy between the unenhanced and enhanced MR images. Accordingly, there was no significant difference in diagnostic accuracy between the unenhanced and enhanced (18)F-FDG PET/MR images. (18)F-FDG avidity and gadolinium chelate enhancement were concordant in 30 of the 36 patients and 106 of their 123 tumors. Gadolinium chelate administration is not necessary for accurate diagnostic characterization of most solid pediatric malignancies on (18)F-FDG PET/MR images, with the possible exception of focal liver lesions. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Multi-atlas propagation based left atrium segmentation coupled with super-voxel based pulmonary veins delineation in late gadolinium-enhanced cardiac MRI

NASA Astrophysics Data System (ADS)

Yang, Guang; Zhuang, Xiahai; Khan, Habib; Haldar, Shouvik; Nyktari, Eva; Li, Lei; Ye, Xujiong; Slabaugh, Greg; Wong, Tom; Mohiaddin, Raad; Keegan, Jennifer; Firmin, David

2017-02-01

Late Gadolinium-Enhanced Cardiac MRI (LGE CMRI) is a non-invasive technique, which has shown promise in detecting native and post-ablation atrial scarring. To visualize the scarring, a precise segmentation of the left atrium (LA) and pulmonary veins (PVs) anatomy is performed as a first step—usually from an ECG gated CMRI roadmap acquisition—and the enhanced scar regions from the LGE CMRI images are superimposed. The anatomy of the LA and PVs in particular is highly variable and manual segmentation is labor intensive and highly subjective. In this paper, we developed a multi-atlas propagation based whole heart segmentation (WHS) to delineate the LA and PVs from ECG gated CMRI roadmap scans. While this captures the anatomy of the atrium well, the PVs anatomy is less easily visualized. The process is therefore augmented by semi-automated manual strokes for PVs identification in the registered LGE CMRI data. This allows us to extract more accurate anatomy than the fully automated WHS. Both qualitative visualization and quantitative assessment with respect to manual segmented ground truth showed that our method is efficient and effective with an overall mean Dice score of 0.91.

Bone marrow with diffuse tumor infiltration in patients with lymphoproliferative diseases: dynamic gadolinium-enhanced MR imaging.

PubMed

Rahmouni, Alain; Montazel, Jean-Luc; Divine, Marine; Lepage, Eric; Belhadj, Karim; Gaulard, Philippe; Bouanane, Mohamed; Golli, Mondher; Kobeiter, Hicham

2003-12-01

To evaluate gadolinium enhancement of bone marrow in patients with lymphoproliferative diseases and diffuse bone marrow involvement. Dynamic contrast material-enhanced magnetic resonance (MR) imaging of the thoracolumbar spine was performed in 42 patients with histologically proved diffuse bone marrow involvement and newly diagnosed myeloma (n = 31), non-Hodgkin lymphoma (n = 8), or Hodgkin disease (n = 3). The maximum percentage of enhancement (Emax), enhancement slope, and enhancement washout were determined from enhancement time curves (ETCs). A three-grade system for scoring bone marrow involvement was based on the percentage of neoplastic cells in bone marrow samples. Quantitative ETC values for the 42 patients were compared with ETC values for healthy subjects and with grades of bone marrow involvement by using mean t test comparisons. Receiver operating characteristic (ROC) analysis was conducted by comparing Emax values between patients with and those without bone marrow involvement. Baseline and follow-up MR imaging findings were compared in nine patients. Significant differences in Emax (P <.001), slope (P <.001), and washout (P =.005) were found between subjects with normal bone marrow and patients with diffuse bone marrow involvement. ROC analysis results showed Emax values to have a diagnostic accuracy of 99%. Emax, slope, and washout values increased with increasing bone marrow involvement grade. The mean Emax increased from 339% to 737%. Contrast enhancement decreased after treatment in all six patients who responded to treatment but not in two of three patients who did not respond to treatment. Dynamic contrast-enhanced MR images can demonstrate increased bone marrow enhancement in patients with lymphoproliferative diseases and marrow involvement.

Influence of doping on thermal diffusivity of single crystals used in photonics: measurements based on thermal wave methods.

PubMed

Bodzenta, Jerzy; Kaźmierczak-Bałata, Anna; Wokulska, Krystyna B; Kucytowski, Jacek; Łukasiewicz, Tadeusz; Hofman, Władysław

2009-03-01

Three crystals used in solid-state lasers, namely, yttrium aluminum garnet (YAG), yttrium orthovanadate (YVO(4)), and gadolinium calcium oxoborate (GdCOB), were investigated to determine the influence of dopants on their thermal diffusivity. The thermal diffusivity was measured by thermal wave method with a signal detection based on mirage effect. The YAG crystals were doped with Yb or V, the YVO(4) with Nd or Ca and Tm, and the GdCOB crystals contained Nd or Yb. In all cases, the doping caused a decrease in thermal diffusivity. The analysis of complementary measurements of ultrasound velocity changes caused by dopants leads to the conclusion that impurities create phonon scattering centers. This additional scattering reduces the phonon mean free path and accordingly results in the decrease of the thermal diffusivity of the crystal. The influence of doping on lattice parameters was investigated, additionally.

Vanishing Parotid Tumors on MR Imaging

PubMed Central

Matsusue, Eiji; Fujihara, Yoshio; Matsuda, Eiken; Tokuyasu, Yusuke; Nakamoto, Shu; Nakamura, Kazuhiko; Ogawa, Toshihide

2018-01-01

Background Of all parotid gland tumors, only oncocytoma has been reported to appear isointense to the parotid gland, namely vanishing, on fat-saturated T2 and T1 postcontrast gadolinium-enhanced magnetic resonance imaging (MRI). The purpose of this study was to evaluate vanishing of parotid tumors on conventional MRI with and/or without postcontrast gadolinium-enhancement and on diffusion weighted imaging (DWI). Methods In 8 of 51 patients, ten parotid gland tumors had homogeneously enhanced lesions and were retrospectively analysed. Comparisons of signal intensity between those parotid tumors and parotid glands and evaluations of vanishing were performed on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fat-suppressed T2WI (FS-T2WI), postcontrast gadolinium-enhanced T1WI (CE-T1WI) and fat-suppressed CE-T1WI (FS-CE-T1WI), DWI as well as apparent diffusion coefficient (ADC). Results Ten parotid gland tumors consisted of five Warthin tumors, two pleomorphic adenomas, two parotid carcinomas (small cell carcinoma and adenoid cystic carcinoma) and one oncocytoma. All tumors showed hypointensity on T1WI and hyperintensity on DWI. Nine of ten tumors showed vanishing on the other MR sequences. All Warthin tumors showed vanishing on FS-T2WI, FS-CE-T1WI and the ADC map. One oncocytoma showed vanishing on FS-T2WI and the ADC map and hyperintensity on FS-CE-T1WI. All pleomorphic adenomas showed vanishing on T2WI and CE-T1WI. One adenoid cystic carcinoma showed vanishing only on CE-T1WI. Conclusion Vanishing of parotid tumors can be observed not only on FS-T2WI and FS-CE-T1WI but also on T2WI, CE-T1WI and ADC mapping. PMID:29599620

[Atrial fibrillation as consequence and cause of structural changes of atria].

PubMed

Aparina, O P; Chikhireva, L N; Stukalova, O V; Mironova, N A; Kashtanova, S Iu; Ternovoĭ, S K; Golitsyn, S P

2014-01-01

Changes of atrial structure and function are the contributors of atrial fibrillation clinical course, complications and treatment effectiveness. Effects of inflammation and mechanical stretch on atrial structural remodeling leading to atrial fibrillation are reviewed in the article. Contemporary invasive and non-invasive methods of evaluation (including late gadolinium enhancement magnetic resonance imaging) of patients with atrial structural remodeling in atrial fibrillation are also described.

Mechanistic insights and characterization of sickle cell disease-associated cardiomyopathy.

PubMed

Desai, Ankit A; Patel, Amit R; Ahmad, Homaa; Groth, John V; Thiruvoipati, Thejasvi; Turner, Kristen; Yodwut, Chattanong; Czobor, Peter; Artz, Nicole; Machado, Roberto F; Garcia, Joe G N; Lang, Roberto M

2014-05-01

Cardiovascular disease is an important cause of morbidity and mortality in sickle cell disease (SCD). We sought to characterize sickle cell cardiomyopathy using multimodality noninvasive cardiovascular testing and identify potential causative mechanisms. Stable adults with SCD (n=38) and healthy controls (n=13) prospectively underwent same day multiparametric cardiovascular magnetic resonance (cine, T2* iron, vasodilator first pass myocardial perfusion, and late gadolinium enhancement imaging), transthoracic echocardiography, and applanation tonometry. Compared with controls, patients with SCD had severe dilation of the left ventricle (124±27 vs 79±12 mL/m(2)), right ventricle (127±28 vs 83±14 mL/m(2)), left atrium (65±16 vs 41±9 mL/m(2)), and right atrium (78±17 vs 56±17 mL/m(2); P<0.01 for all). Patients with SCD also had a 21% lower myocardial perfusion reserve index than control subjects (1.47±0.34 vs 1.87±0.37; P=0.034). A significant subset of patients with SCD (25%) had evidence of late gadolinium enhancement, whereas only 1 patient had evidence of myocardial iron overload. Diastolic dysfunction was present in 26% of patients with SCD compared with 8% in controls. Estimated filling pressures (E/e', 9.3±2.7 vs 7.3±2.0; P=0.0288) were higher in patients with SCD. Left ventricular dilation and the presence of late gadolinium enhancement were inversely correlated to hepatic T2* times (ie, hepatic iron overload because of frequent blood transfusions; P<0.05 for both), whereas diastolic dysfunction and increased filling pressures were correlated to aortic stiffness (augmentation pressure and index, P<0.05 for all). Sickle cell cardiomyopathy is characterized by 4-chamber dilation and in some patients myocardial fibrosis, abnormal perfusion reserve, diastolic dysfunction, and only rarely myocardial iron overload. Left ventricular dilation and myocardial fibrosis are associated with increased blood transfusion requirements, whereas left ventricular diastolic dysfunction is predominantly correlated with increased aortic stiffness. http://www.clinicaltrials.gov. Unique identifier: NCT01044901. © 2014 American Heart Association, Inc.

Self-Gated Late Gadolinium Enhancement at 7T to Image Rats with Reperfused Acute Myocardial Infarction.

PubMed

Wang, Lei; Chen, Yushu; Zhang, Bing; Chen, Wei; Wang, Chunhua; Song, Li; Xu, Ziqian; Zheng, Jie; Gao, Fabao

2018-01-01

A failed electrocardiography (ECG)-trigger often leads to a long acquisition time (TA) and deterioration in image quality. The purpose of this study was to evaluate and optimize the technique of self-gated (SG) cardiovascular magnetic resonance (CMR) for cardiac late gadolinium enhancement (LGE) imaging of rats with myocardial infarction/reperfusion. Cardiovascular magnetic resonance images of 10 rats were obtained using SG-LGE or ECG with respiration double-gating (ECG-RESP-gating) method at 7T to compare differences in image interference and TA between the two methods. A variety of flip angles (FA: 10°-80°) and the number of repetitions (NR: 40, 80, 150, and 300) were investigated to determine optimal scan parameters of SG-LGE technique based on image quality score and contrast-to-noise ratio (CNR). Self-gated late gadolinium enhancement allowed successful scan in 10 (100%) rats. However, only 4 (40%) rats were successfully scanned with the ECG-RESP-gating method. TAs with SG-LGE varied depending on NR used (TA: 41, 82, 154, and 307 seconds, corresponding to NR of 40, 80, 150, and 300, respectively). For the ECG-RESP-gating method, the average TA was 220 seconds. For SG-LGE images, CNR (42.5 ± 5.5, 43.5 ± 7.5, 54 ± 9, 59.5 ± 8.5, 56 ± 13, 54 ± 8, and 41 ± 9) and image quality score (1.85 ± 0.75, 2.20 ± 0.83, 2.85 ± 0.37, 3.85 ± 0.52, 2.8 ± 0.51, 2.45 ± 0.76, and 1.95 ± 0.60) were achieved with different FAs (10°, 15°, 20°, 25°, 30°, 35°, and 40°, respectively). Optimal FAs of 20°-30° and NR of 80 were recommended. Self-gated technique can improve image quality of LGE without irregular ECG or respiration gating. Therefore, SG-LGE can be used an alternative method of ECG-RESP-gating.

Does Late Gadolinium Enhancement still have Value? Right Ventricular Internal Mechanical Work, Ea/Emax and Late Gadolinium Enhancement as Prognostic Markers in Patients with Advanced Pulmonary Hypertension via Cardiac MRI.

PubMed

Abouelnour, Amr Ei; Doyle, Mark; Thompson, Diane V; Yamrozik, June; Williams, Ronald B; Shah, Moneal B; Soma, Siva Kr; Murali, Srinivas; Benza, Raymond L; Biederman, Robert Ww

2017-01-01

Investigate the impact of Right Ventricular (RV) Internal Work (IW), ratio of arterial to ventricular end-systolic elastance (E a /E max ), and RV Insertion Point (IP) Late Gadolinium Enhancement (LGE) on outcome in Pulmonary Hypertension (PH) patients. LGE is well known to be present within the RVIPs and Inter Ventricular Septum (IVS) in PH patients, but its prognostic role remains complex and potentially overestimated via 2D qualitative relative to the 3D quantitative measures now available. However, E a /E max , a measure of ventricular-arterial coupling and IW, when added to external cardiac work i.e. the P-V loop area as correlates to the heart's energy demands, might fundamentally improve measures of prognosis as they interrogate physiology beyond just the RV. Cardiac Magnetic Resonance Imaging (CMR) of 124 PH patients (age = 60±13, 85F) referred to a large tertiary PH center, was retrospectively examined for RV volumetric and functional indices and RVIP LGE%. Right Heart Catheterizations (RHC) performed within 1±2 months of the CMR were reviewed. E a /E max was derived as RV End-Systolic Volume (ESV/RVSV). IW was estimated as RVESV ×(RV end-systolic pressure-RV diastolic pressure). Patients were followed from date of CMR for up to 5 years for MACE (death, hospitalized RV failure, initiation of parenteral prostacyclin, sustained ventricular arrhythmia or referral for lung transplantation). MACE was high; 48/124 (39%) patients had MACE by 1.6±1.3 years. Neither RVIP nor IVS LGE using visual assessment or even 3D quantization predicted MACE. The strongest predictor of MACE was RVIW (OR=1.00013, p<0.002), vs. mPAP, RV mass, RV EF and IP LGE. Surprisingly, neither a single time-point RVIP nor whole IVS LGE% can predict outcome in the largest cohort of PH patients studied to date when compared with conventional or contemporary metrics of disease progression. CMR-LGE appears to lose its' prognostic value in PH patients in stark contradistinction to all other left and right-sided human myocardial pathologies.

Rare complication characterized by late-onset transient neurological symptoms without hyperperfusion after carotid artery stenting: A report of three cases

PubMed Central

Nakahara, Ichiro; Ohta, Tsuyoshi; Matsumoto, Shoji; Ishibashi, Ryota; Gomi, Masanori; Miyata, Haruka; Nishi, Hidehisa; Watanabe, Sadayoshi

2015-01-01

We experienced a rare complication after carotid artery stenting (CAS) characterized by transient neurological symptoms with no evidence of distal emboli or hyperperfusion. Using neuroimaging, we investigated the pathogenesis of the complication that occurred after CAS in three patients who developed neurological symptoms over a period of ten hours after CAS and improved within two days. None of the three patients showed signs of fresh infarctions on diffusion-weighted imaging or hyperperfusion on single-photon emission computed tomography. However, high signal intensity was observed in the leptomeningeal zone of the cerebral hemisphere on the stent side in all three patients and in the leptomeningeal zone of the contralateral anterior cerebral artery territory in one patient. These areas were assessed using fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging without gadolinium administration. The high signal intensity in the leptomeningeal zone disappeared as the symptoms improved. Based on the transient nature of the neurological disorders and the normalization of FLAIR imaging findings in these patients, the pathogenesis of this complication might have been vasogenic edema due to vasoparalysis of the local vessels caused by the hemodynamic changes occurring after CAS. PMID:25934779

Comparison of Image Processing Techniques for Nonviable Tissue Quantification in Late Gadolinium Enhancement Cardiac Magnetic Resonance Images.

PubMed

Carminati, M Chiara; Boniotti, Cinzia; Fusini, Laura; Andreini, Daniele; Pontone, Gianluca; Pepi, Mauro; Caiani, Enrico G

2016-05-01

The aim of this study was to compare the performance of quantitative methods, either semiautomated or automated, for left ventricular (LV) nonviable tissue analysis from cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) images. The investigated segmentation techniques were: (i) n-standard deviations thresholding; (ii) full width at half maximum thresholding; (iii) Gaussian mixture model classification; and (iv) fuzzy c-means clustering. These algorithms were applied either in each short axis slice (single-slice approach) or globally considering the entire short-axis stack covering the LV (global approach). CMR-LGE images from 20 patients with ischemic cardiomyopathy were retrospectively selected, and results from each technique were assessed against manual tracing. All methods provided comparable performance in terms of accuracy in scar detection, computation of local transmurality, and high correlation in scar mass compared with the manual technique. In general, no significant difference between single-slice and global approach was noted. The reproducibility of manual and investigated techniques was confirmed in all cases with slightly lower results for the nSD approach. Automated techniques resulted in accurate and reproducible evaluation of LV scars from CMR-LGE in ischemic patients with performance similar to the manual technique. Their application could minimize user interaction and computational time, even when compared with semiautomated approaches.

Modified Wideband Three-Dimensional Late Gadolinium Enhancement MRI for Patients with Implantable Cardiac Devices

PubMed Central

Rashid, Shams; Rapacchi, Stanislas; Shivkumar, Kalyanam; Plotnik, Adam; Finn, J. Paul; Hu, Peng

2015-01-01

Purpose To study the effects of cardiac devices on three-dimensional (3D) late gadolinium enhancement (LGE) MRI and to develop a 3D LGE protocol for implantable cardioverter defibrillator (ICD) patients with reduced image artifacts. Theory and Methods The 3D LGE sequence was modified by implementing a wideband inversion pulse, which reduces hyperintensity artifacts, and by increasing bandwidth of the excitation pulse. The modified wideband 3D LGE sequence was tested in phantoms and evaluated in six volunteers and five patients with ICDs. Results Phantom and in vivo studies results demonstrated extended signal void and ripple artifacts in 3D LGE that were associated with ICDs. The reason for these artifacts was slab profile distortion and the subsequent aliasing in the slice-encoding direction. The modified wideband 3D LGE provided significantly reduced ripple artifacts than 3D LGE with wideband inversion only. Comparison of 3D and 2D LGE images demonstrated improved spatial resolution of the heart using 3D LGE. Conclusion Increased bandwidth of the inversion and excitation pulses can significantly reduce image artifacts associated with ICDs. Our modified wideband 3D LGE protocol can be readily used for imaging patients with ICDs given appropriate safety guidelines are followed. PMID:25772155

Electrocardiographic Impact of Myocardial Diffuse Fibrosis and Scar: MESA (Multi-Ethnic Study of Atherosclerosis)

PubMed Central

Inoue, Yuko Y.; Ambale-Venkatesh, Bharath; Mewton, Nathan; Volpe, Gustavo J.; Ohyama, Yoshiaki; Sharma, Ravi K.; Wu, Colin O.; Liu, Chia-Ying; Bluemke, David A.; Soliman, Elsayed Z.; Lima, João A. C.

2017-01-01

Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging. In individuals without a late gadolinium enhancement–defined myocardial scar (n = 1131), T1 mapping was used to assess left ventricular (LV) interstitial diffuse fibrosis. The associations of LV diffuse fibrosis or myocardial scar with ECG parameters (QRS voltage, QRS duration, and corrected QT interval [QTc]) were evaluated by using multivariable regression analyses adjusted for demographic data, risk factors for scar, LV end-diastolic volume, and LV mass. Results The mean age of the 1669 participants was 67.4 years ± 8.7 (standard deviation); 49.8% were women. Lower postcontrast T1 time at 12 minutes was significantly associated with lower QRS Sokolow-Lyon voltage (β = 15.1 µV/10 msec, P = .004), lower QRS Cornell voltage (β = 9.2 µV/10 msec, P = .031), and shorter QRS duration (β = 0.16 msec/10 msec, P = .049). Greater extracellular volume (ECV) fraction was also significantly associated with lower QRS Sokolow-Lyon voltage (β = −35.2 µV/1% ECV increase, P < .001) and Cornell voltage (β = −23.7 µV/1% ECV increase, P < .001), independent of LV structural indexes. In contrast, the presence of LV scar (n = 106) was associated with longer QTc (β = 4.3 msec, P = .031). Conclusion In older adults without prior coronary heart disease, underlying greater LV diffuse fibrosis is associated with lower QRS voltage and shorter QRS duration at surface ECG, whereas clinically unrecognized myocardial scar is associated with a longer QT interval. © RSNA, 2016 Online supplemental material is available for this article. PMID:27740904

[The Role of Imaging in Central Nervous System Infections].

PubMed

Yokota, Hajime; Tazoe, Jun; Yamada, Kei

2015-07-01

Many infections invade the central nervous system. Magnetic resonance imaging (MRI) is the main tool that is used to evaluate infectious lesions of the central nervous system. The useful sequences on MRI are dependent on the locations, such as intra-axial, extra-axial, and spinal cord. For intra-axial lesions, besides the fundamental sequences, including T1-weighted images, T2-weighted images, and fluid-attenuated inversion recovery (FLAIR) images, advanced sequences, such as diffusion-weighted imaging, diffusion tensor imaging, susceptibility-weighted imaging, and MR spectroscopy, can be applied. They are occasionally used as determinants for quick and correct diagnosis. For extra-axial lesions, understanding the differences among 2D-conventional T1-weighted images, 2D-fat-saturated T1-weighted images, 3D-Spin echo sequences, and 3D-Gradient echo sequence after the administration of gadolinium is required to avoid wrong interpretations. FLAIR plus gadolinium is a useful tool for revealing abnormal enhancement on the brain surface. For the spinal cord, the sequences are limited. Evaluating the distribution and time course of the spinal cord are essential for correct diagnoses. We summarize the role of imaging in central nervous system infections and show the pitfalls, key points, and latest information in them on clinical practices.

Analysis of a simulation algorithm for direct brain drug delivery

PubMed Central

Rosenbluth, Kathryn Hammond; Eschermann, Jan Felix; Mittermeyer, Gabriele; Thomson, Rowena; Mittermeyer, Stephan; Bankiewicz, Krystof S.

2011-01-01

Convection enhanced delivery (CED) achieves targeted delivery of drugs with a pressure-driven infusion through a cannula placed stereotactically in the brain. This technique bypasses the blood brain barrier and gives precise distributions of drugs, minimizing off-target effects of compounds such as viral vectors for gene therapy or toxic chemotherapy agents. The exact distribution is affected by the cannula positioning, flow rate and underlying tissue structure. This study presents an analysis of a simulation algorithm for predicting the distribution using baseline MRI images acquired prior to inserting the cannula. The MRI images included diffusion tensor imaging (DTI) to estimate the tissue properties. The algorithm was adapted for the devices and protocols identified for upcoming trials and validated with direct MRI visualization of Gadolinium in 20 infusions in non-human primates. We found strong agreement between the size and location of the simulated and gadolinium volumes, demonstrating the clinical utility of this surgical planning algorithm. PMID:21945468

High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meux, Susan C.; Datta, Ankona; Hooker, Jacob M.

2007-08-29

High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) theremore » is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups.« less

Eosinophilic myocarditis due to Churg-Strauss syndrome with markedly elevated eosinophil cationic protein.

PubMed

Hara, Tomoya; Yamaguchi, Koji; Iwase, Takashi; Kadota, Muneyuki; Bando, Mika; Ogasawara, Kozue; Bando, Sachiko; Ise, Takayuki; Niki, Toshiyuki; Ueda, Yuka; Tomita, Noriko; Taketani, Yoshio; Yamada, Hirotsugu; Soeki, Takeshi; Wakatsuki, Tetsuzo; Sata, Masataka

2013-01-01

A 67-year-old woman with asthma visited our hospital with increasing dyspnea and new-onset paresthesia and purpura in her legs. Physical examination showed a wheeze, pretibial edema, and surrounding purpura. Chest X-rays showed cardiac decompensation and an electrocardiogram revealed a new ST-T change. Laboratory data showed leukocytosis, hypereosinophilia (10,450/μL), troponin T(+), elevated BNP, and markedly elevated eosinophil cationic protein (ECP) (> 150 ng/mL). Echocardiography revealed diffuse left ventricular hypokinesis (ejection fraction 30%) with increased wall thickness. Coronary angiography was normal. Cardiac magnetic resonance imaging implied diffuse myocardial edema and subendocardial late gadolinium enhancement. Skin biopsy of purpura showed superfi cial perivascular dermatitis with remarkable eosinophilic infiltrations. No evidence of drug allergies, parasitic infection, or myeloproliferative disorder was detected. Based on these findings, a diagnosis of eosinophilic myocarditis due to Churg-Strauss syndrome was considered. She was administered prednisolone at a dose of 1 mg/kg, cyclophosphamide, and diuretics. Several markers of eosinophilic myocarditis and heart failure gradually improved, including ECP. She was discharged 30 days later with no cardiac event. Eosinophilic myocarditis is characterized by predominantly eosinophilic infi ltration. Eosinophilic granule proteins, such as ECP and major basic protein, play important roles in the pathogenesis of eosinophilic myocarditis. We experienced a rare case of eosinophilic myocarditis due to Churg-Strauss syndrome. Markedly elevated ECP played an important role in the early diagnosis and subsequent reduction in ECP served as a marker of monitoring. In an asthmatic patient with dyspnea, hypereosinophilia, and vasculitis, Churg-Strauss syndrome with eosinophilic myocarditis should be considered.

Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

PubMed Central

Fontana, Marianna; Pica, Silvia; Reant, Patricia; Abdel-Gadir, Amna; Treibel, Thomas A.; Banypersad, Sanjay M.; Maestrini, Viviana; Barcella, William; Rosmini, Stefania; Bulluck, Heerajnarain; Sayed, Rabya H.; Patel, Ketna; Mamhood, Shameem; Bucciarelli-Ducci, Chiara; Whelan, Carol J.; Herrey, Anna S.; Lachmann, Helen J.; Wechalekar, Ashutosh D.; Manisty, Charlotte H.; Schelbert, Eric B.; Kellman, Peter; Gillmore, Julian D.; Hawkins, Philip N.

2015-01-01

Background— The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. Methods and Results— Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1–13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E′, and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3–13.1; P<0.05). Conclusions— There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after adjustment for known prognostic factors. PMID:26362631

Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis.

PubMed

Fontana, Marianna; Pica, Silvia; Reant, Patricia; Abdel-Gadir, Amna; Treibel, Thomas A; Banypersad, Sanjay M; Maestrini, Viviana; Barcella, William; Rosmini, Stefania; Bulluck, Heerajnarain; Sayed, Rabya H; Patel, Ketna; Mamhood, Shameem; Bucciarelli-Ducci, Chiara; Whelan, Carol J; Herrey, Anna S; Lachmann, Helen J; Wechalekar, Ashutosh D; Manisty, Charlotte H; Schelbert, Eric B; Kellman, Peter; Gillmore, Julian D; Hawkins, Philip N; Moon, James C

2015-10-20

The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1-13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E', and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3-13.1; P<0.05). There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after adjustment for known prognostic factors. © 2015 The Authors.

T1 mapping using saturation recovery single-shot acquisition at 3-tesla magnetic resonance imaging in hypertrophic cardiomyopathy: comparison to late gadolinium enhancement.

PubMed

Ogawa, Ryo; Kido, Tomoyuki; Nakamura, Masashi; Kido, Teruhito; Kurata, Akira; Uetani, Teruyoshi; Ogimoto, Akiyoshi; Miyagawa, Masao; Mochizuki, Teruhito

2017-03-01

We evaluated the T1 values of segments and slices and the reproducibility in healthy controls, using saturation recovery single-shot acquisition (SASHA) at 3T magnetic resonance imaging. Moreover, we examined the difference in T1 values between hypertrophic cardiomyopathy (HCM) and healthy controls, and compared those with late gadolinium enhancement (LGE). Twenty-one HCM patients and 10 healthy controls underwent T1 mapping before and after contrast administration. T1 values were measured in 12 segments. Native T1 values were significantly longer in HCM than in healthy controls [1373 ms (1312-1452 ms) vs. 1279 ms (1229-1326 ms); p < 0.0001]. Even in HCM segments without LGE, native T1 values were significantly longer than in healthy control segments [1366 ms (1300-1439 ms) vs. 1279 ms (1229-1326 ms); p < 0.0001]. Using a cutoff value of 1327 ms for septal native T1 values, we differentiated between HCM and healthy controls with 95% sensitivity, 90% specificity, 94% accuracy, and an area under the curve of 0.95. Native T1 values using a SASHA at 3T could differentiate HCM from healthy controls. Moreover, native T1 values have the potential to detect abnormal myocardium that cannot be identified adequately by LGE in HCM.

Magnetic resonance imaging (MRI) of the renal sinus.

PubMed

Krishna, Satheesh; Schieda, Nicola; Flood, Trevor A; Shanbhogue, Alampady Krishna; Ramanathan, Subramaniyan; Siegelman, Evan

2018-04-09

This article presents methods to improve MR imaging approach of disorders of the renal sinus which are relatively uncommon and can be technically challenging. Multi-planar Single-shot T2-weighted (T2W) Fast Spin-Echo sequences are recommended to optimally assess anatomic relations of disease. Multi-planar 3D-T1W Gradient Recalled Echo imaging before and after Gadolinium administration depicts the presence and type of enhancement and relation to arterial, venous, and collecting system structures. To improve urographic phase MRI, concentrated Gadolinium in the collecting systems should be diluted. Diffusion-Weighted Imaging (DWI) should be performed before Gadolinium administration to minimize T2* effects. Renal sinus cysts are common but can occasionally be confused for dilated collecting system or calyceal diverticula, with the latter communicating with the collecting system and filling on urographic phase imaging. Vascular lesions (e.g., aneurysm, fistulas) may mimic cystic (or solid) lesions on non-enhanced MRI but can be suspected by noting similar signal intensity to the blood pool and diagnosis can be confirmed with MR angiogram/venogram. Multilocular cystic nephroma commonly extends to the renal sinus, however, to date are indistinguishable from cystic renal cell carcinoma (RCC). Solid hilar tumors are most commonly RCC and urothelial cell carcinoma (UCC). Hilar RCC are heterogeneous, hypervascular with epicenter in the renal cortex compared to UCC which are centered in the collecting system, homogeneously hypovascular, and show profound restricted diffusion. Diagnosis of renal sinus invasion in RCC is critically important as it is the most common imaging cause of pre-operative under-staging of disease. Fat is a normal component of the renal sinus; however, amount of sinus fat correlates with cardiovascular disease and is also seen in lipomatosis. Fat-containing hilar lesions include lipomas, angiomyolipomas, and less commonly other tumors which engulf sinus fat. Mesenchymal hilar tumors are rare. MR imaging diagnosis is generally not possible, although anatomic relations should be described to guide diagnosis by percutaneous biopsy or surgery.

[Role of cardiac magnetic resonance in cardiac involvement of Fabry disease].

PubMed

Serra, Viviana M; Barba, Miguel Angel; Torrá, Roser; Pérez De Isla, Leopoldo; López, Mónica; Calli, Andrea; Feltes, Gisela; Torras, Joan; Valverde, Victor; Zamorano, José L

2010-09-04

Fabry disease is a hereditary disorder. Clinical manifestations are multisystemic. The majority of the patients remain undiagnosed until late in life, when alterations could be irreversible. Early detection of cardiac symptoms is of major interest in Fabry's disease (FD) in order to gain access to enzyme replacement therapy. Echo-Doppler tissular imaging (TDI) has been used as a cardiologic early marker in FD. This study is intended to determine whether the cardiac magnetic resonance is as useful tool as TDI for the early detection of cardiac affectation in FD. Echocardiography, tissue Doppler and Cardio magnetic resonance was performed in 20 patients with confirmed Fabry Disease. Left ventricular hypertrophy was defined as septum and left ventricular posterior wall thickness ≥12 mm. An abnormal TDI velocity was defined as (Sa), (Ea) and/or (Aa) velocities <8 cm/s at either the septal or lateral corner. Late phase gadolinium-enhanced images sequences were obtained using magnetic resonance. Twenty patients included in the study were divided into three groups: 1. Those without left ventricular hypertrophy nor tissue Doppler impairment 2. Those without left ventricular hypertrophy and tissue Doppler impairment 3. Those with left ventricular hypertrophy and Tissue Doppler impairment. Late gadolinium enhancement was found in only one patient, who has already altered DTI and LVH. Tissue Doppler imaging (TDI) is the only diagnostic tool able to provide early detection of cardiac affectation in patients with FD. Magnetic resonance provides information of the disease severity in patients with LVH, but can not be used as an early marker of cardiac disease in patients with FD. However MRI could be of great value for diagnostic stratification. Copyright © 2009 Elsevier España, S.L. All rights reserved.

Comparison of gadolinium-EOB-DTPA-enhanced and diffusion-weighted liver MRI for detection of small hepatic metastases.

PubMed

Shimada, Kotaro; Isoda, Hiroyoshi; Hirokawa, Yuusuke; Arizono, Shigeki; Shibata, Toshiya; Togashi, Kaori

2010-11-01

To compare the accuracy of gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI with that of diffusion-weighted MRI (DWI) in the detection of small hepatic metastases (2 cm or smaller). Forty-five patients underwent abdominal MRI at 3 T, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI (HASTE), DWI with a b-value of 500 s/mm(2) and contrast-enhanced MRI with Gd-EOB-DTPA. Two groups were assigned and compared: group A (T1WI, T2WI, HASTE and contrast-enhanced study with Gd-EOB-DTPA), and group B (T1WI, T2WI, HASTE and DWI). Two observers independently interpreted the images obtained in a random order. For all hepatic metastases, the diagnostic performance using each imaging set was evaluated by receiver-operating characteristic (ROC) curve analysis. A total of 51 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B, and the difference in the mean Az values between the two image sets was statistically significant, whereas, there were three metastases that lay near thin vessels or among multiple cysts and were better visualised in group B than in group A. Gd-EOB-DTPA-enhanced MRI showed higher accuracy in the detection of small metastases than DWI.

Distinguishing liver haemangiomas from metastatic tumours using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced diffusion-weighted imaging at 1.5T MRI.

PubMed

Saito, Kazuhiro; Yoshimura, Nobutaka; Shirota, Natsuhiko; Saguchi, Toru; Sugimoto, Katsutoshi; Tokuuye, Koichi

2016-10-01

The aim of this study to evaluate the effectiveness of enhanced diffusion-weighted imaging (DWI) for distinguishing liver haemangiomas from metastatic tumours (mets). This study included 23 patients with 27 haemangiomas and 26 patients with 46 mets. Breath-holding diffusion-weighted imaging (DWI) (b-values of 0, 50, 100, 150, 200, 400 and 800 s/mm 2 ) were obtained before and 20 min after injection of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Lesion contrast-to-noise ratios (CNRs) were calculated. The data were processed using the bi-exponential model of intravoxel incoherent motion (IVIM). Receiver operating characteristic analysis was performed to compare the diagnostic performance when distinguishing haemangioma from mets. The CNRs of haemangioma and mets at post-contrast enhancement increased. All IVIM parameters for liver haemangioma and mets showed no significant differences between pre- and post-contrast enhancement. The highest A z value of CNR and IVIM parameters occurred at a post-contrast b-value of 0 s/mm 2 and true diffusion (D). The highest qualitative evaluation occurred at a b-value of 800 s/mm 2 . The sensitivity and specificity, with a CNR of 100 or higher at a post-contrast b-value of 0 s/mm 2 and considered to be haemangioma, were 89% and 67% (<10 mm, 91%, 77%) respectively. The sensitivity and specificity, when D was higher than 1.4 × 10 -3 mm 2 /s, were 74% and 83% (<10 mm, 64%, 77%) respectively. The sensitivity and specificity of qualitative evaluation by enhanced DWI were 74% and 76% (<10 mm, 64%, 80%) respectively. The accuracy of the CNR was highest with b = 0; however, examination at high b-values had advantages in the qualitative evaluation of some small-size lesions. © 2016 The Royal Australian and New Zealand College of Radiologists.

Effect of intravenous gadolinium-DTPA on diffusion tensor MR imaging for the evaluation of brain tumors.

PubMed

Bae, Min Sun; Jahng, Geon-Ho; Ryu, Chang Woo; Kim, Eui Jong; Choi, Woo Suk; Yang, Dal Mo

2009-12-01

The aim of this study was to investigate whether indices of diffusion tensor MRI (DT-MRI) are altered after contrast medium injection in patients with brain tumors. DT-MRIs at a 3-T unit before and 6 min after gadolinium-diethylenetriamine penta-acetic acid injection were obtained in nine patients (five women, four men) with histologically confirmed brain tumors (four metastases, one glioblastoma multiforme, three meningiomas, and one lymphoma). Fractional anisotropy (FA), trace and mean raw DT-MRI data without (DT_b0, b value = 0 s/mm(2)) and with (DT_b800, b value = 800 s/mm(2)) diffusion-encoded gradients were calculated. Regions of interest (ROIs) were placed in the tumor, peritumoral edema, and normal-appearing symmetric contralateral brain tissue for each patient. The Kruskal-Wallis rank sum test was used to determine the effects of contrast medium and ROI for all of the maps, and the Wilcoxon signed-rank test was performed for either paired t test between pre- and post-contrast values of DTI indices for the ROIs or the post hoc test. Statistically significant differences between pre-contrast and post-contrast DT-MRI are shown in the trace value of the peritumoral edema area (p = 0.0195) and the FA value of the tumor area (p = 0.0273). Trace and FA values of the other areas show no statistically significant differences between pre- and post-contrast (p > 0.05). In addition, we find a significant ROI effect for both FA (chi (2) = 26.514, df = 2, p = 0.0001) and trace (chi (2) = 21.218, df = 2, p = 0.0001). DT-MRI obtained after contrast medium injection of 6 min results in significant changes in diffusion isotropic and anisotropic values. Therefore, clinical applications of DT-MRI after administrating a contrast medium require caution in interpretation.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging of brain tumors: a short temporal interval assessment.

PubMed

Li, Xiang; Qu, Jin-Rong; Luo, Jun-Peng; Li, Jing; Zhang, Hong-Kai; Shao, Nan-Nan; Kwok, Keith; Zhang, Shou-Ning; Li, Yan-le; Liu, Cui-Cui; Zee, Chi-Shing; Li, Hai-Liang

2014-09-01

To determine the effect of intravenous administration of gadolinium (Gd) contrast medium (Gd-DTPA) on diffusion-weighted imaging (DWI) for the evaluation of normal brain parenchyma vs. brain tumor following a short temporal interval. Forty-four DWI studies using b values of 0 and 1000 s/mm(2) were performed before, immediately after, 1 min after, 3 min after, and 5 min after the administration of Gd-DTPA on 62 separate lesions including 15 meningioma, 17 glioma and 30 metastatic lesions. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values of the brain tumor lesions and normal brain tissues were measured on pre- and postcontrast images. Statistical analysis using paired t-test between precontrast and postcontrast data were obtained on three brain tumors and normal brain tissue. The SNR and CNR of brain tumors and the SNR of normal brain tissue showed no statistical differences between pre- and postcontrast (P > 0.05). The ADC values on the three cases of brain tumors demonstrated significant initial increase on the immediate time point (P < 0.01) and decrease on following the 1 min time point (P < 0.01) after contrast. Significant decrease of ADC value was still found at 3min and 5min time point in the meningioma group (P < 0.01) with gradual normalization over time. The ADC values of normal brain tissues demonstrated significant initial elevation on the immediately postcontrast DWI sequence (P < 0.01). Contrast medium can cause a slight but statistically significant change on the ADC value within a short temporal interval after the contrast administration. The effect is both time and lesion-type dependent. © 2013 Wiley Periodicals, Inc.

Cardiac T1 mapping in congenital heart disease: bolus vs. infusion protocols for measurements of myocardial extracellular volume fraction.

PubMed

Al-Wakeel-Marquard, Nadya; Rastin, Sanaz; Muench, Frédéric; O H-Ici, Darach; Yilmaz, Sevim; Berger, Felix; Kuehne, Titus; Messroghli, Daniel R

2017-12-01

Myocardial extracellular volume fraction (ECV) reflecting diffuse myocardial fibrosis can be measured with T1 mapping cardiovascular magnetic resonance (CMR) before and after the application of a gadolinium-based extracellular contrast agent. The equilibrium between blood and myocardium contrast concentration required for ECV measurements can be obtained with a primed contrast infusion (equilibrium contrast-CMR). We hypothesized that equilibrium can also be achieved with a single contrast bolus to accurately measure diffuse myocardial fibrosis in patients with congenital heart disease (CHD). Healthy controls (n = 17; median age 24.0 years) and patients with CHD (n = 19; 25.0 years) were prospectively enrolled. Using modified Look-Locker inversion recovery T1 mapping before, 15 min after bolus injection, and during constant infusion of gadolinium-DOTA, T1 values were obtained for blood pool and myocardium of the left ventricle (LV), the interventricular septum (IVS), and the right ventricle (RV) in a single midventricular plane in short axis or in transverse orientation. ECV of LV, IVS and RV by bolus-only and bolus-infusion correlated significantly in CHD patients (r = 0.94, 0.95, and 0.74; p < 0.01, respectively) and healthy controls (r = 0.96, 0.89, and 0.64; p < 0.05, respectively). Bland-Altman plots revealed no significant bias between the techniques for any of the analyzed regions. ECV of LV and RV myocardium measured by bolus-only T1 mapping agrees well with bolus-infusion measurements in patients with CHD. The use of a bolus-only approach facilitates the integration of ECV measurements into existing CMR imaging protocols, allowing for assessment of diffuse myocardial fibrosis in CHD in clinical routine.

Postural headache in a patient with Marfan's syndrome.

PubMed

Ferrante, E; Citterio, A; Savino, A; Santalucia, P

2003-09-01

A 26-year-old man with Marfan's syndrome had postural headache. Brain MRI with gadolinium showed diffuse pachymeningeal enhancement. MRI myelography revealed bilateral multiple large meningeal diverticula at sacral nerve roots level. He was suspected to have spontaneous intracranial hypotension syndrome. Eight days later headache improved with bed rest and hydration. One month after the onset he was asymptomatic and 3 months later brain MRI showed no evidence of diffuse pachymeningeal enhancement. The 1-year follow-up revealed no neurological abnormalities. The intracranial hypotension syndrome likely resulted from a CSF leak from one of the meningeal diverticula. In conclusion patients with spinal meningeal diverticula (frequently seen in Marfan's syndrome) might be at increased risk of developing CSF leaks, possibly secondary to Valsalva maneuver or minor unrecognized trauma.

Cardiovascular magnetic resonance imaging (CMR) reveals characteristic pattern of myocardial damage in patients with mitochondrial myopathy.

PubMed

Yilmaz, Ali; Gdynia, Hans-Jürgen; Ponfick, Matthias; Rösch, Sabine; Lindner, Alfred; Ludolph, Albert C; Sechtem, Udo

2012-04-01

Mitochondrial myopathy comprises various clinical subforms of neuromuscular disorders that are characterised by impaired mitochondrial energy metabolism due to dysfunction of the mitochondrial respiratory chain. No comprehensive and targeted cardiovascular magnetic resonance (CMR) studies have been performed so far in patients with mitochondrial disorders. The present study aimed at characterising cardiac disease manifestations in patients with mitochondrial myopathy and elucidating the in vivo cardiac damage pattern of patients with different subforms of mitochondrial disease by CMR studies. In a prospective study, 37 patients with mitochondrial myopathy underwent comprehensive neurological and cardiac evaluations including physical examination, resting ECG and CMR. The CMR studies comprised cine-CMR, T2-weighted "edema" imaging and T1-weighted late-gadolinium-enhancement (LGE) imaging. Various patterns and degrees of skeletal myopathy were present in the participants of this study, whereas clinical symptoms such as chest pain symptoms (in eight (22%) patients) and various degrees of dyspnea (in 16 (43%) patients) were less frequent. Pathological ECG findings were documented in eight (22%) patients. T2-weighted "edema" imaging was positive in one (3%) patient with MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) only. LGE imaging demonstrated the presence of non-ischemic LGE in 12 (32%) patients: 10 out of 24 (42%) patients with CPEO (chronic progressive external ophthalmoplegia) or KSS (Kearns-Sayre syndrome) and 2 of 3 (67%) patients with MELAS were LGE positive. All 10 LGE-positive patients with CPEO or KSS demonstrated a potentially typical pattern of diffuse intramural LGE in the left-ventricular (LV) inferolateral segments. Cardiac involvement is a frequent finding in patients with mitochondrial myopathy. A potentially characteristic pattern of diffuse intramural LGE in the LV inferolateral segments was identified in patients suffering from the subforms CPEO or KSS.

Cardiac involvement in ANCA (+) and ANCA (-) Churg-Strauss syndrome evaluated by cardiovascular magnetic resonance.

PubMed

Mavrogeni, Sophie; Karabela, Georgia; Gialafos, Elias; Stavropoulos, Efthymios; Spiliotis, George; Katsifis, Gikas; Kolovou, Genovefa

2013-10-01

The cardiovascular magnetic resonance (CMR) pattern of Churg-Strauss syndrome (CSS) includes myopericarditis, diffuse subendocardial vasculitis or myocardial infarction with or without cardiac symptoms and is usually associated with lack of antineutrophil cytoplasmic antibodies (ANCA). To correlate the CMR pattern with ANCA in CSS, compare it with healthy controls and systemic lupus erythematosus (SLE) patients and re-evaluate 2 yrs after the first CMR. 28 consecutive CSS, aged 42±7 yrs, were referred for CMR and 2 yrs re-evaluation. The CMR included left ventricular ejection fraction (LVEF), T2-weighted (T2-W), early (EGE) and late gadolinium enhanced (LGE) imaging. Their results were compared with 28 systemic lupus erythematosus (SLE) under remission and 28 controls with normal myocardial perfusion, assessed by scintigraphy. CMR revealed acute cardiac lesions in all ANCA (-) CSS with active disease and acute cardiac symptoms and only in one asymptomatic ANCA (+) CSS, with active disease. Diffuse subendocardial fibrosis (DSF) or past myocarditis was identified in both ANCA(+) and ANCA (-) CSS, but with higher incidence and fibrosis amount in ANCA (-) CSS (p<0.05). In comparison to SLE, both ANCA (+) and ANCA (-) CSS had higher incidence of DSF, lower incidence of myocarditis and no evidence of myocardial infarction, due to coronary artery disease (p<0.05). In 2 yrs CMR follow up, 1/3 of CSS with DSF presented LV function deterioration and one died, although immunosuppressive treatment was given early after CSS diagnosis. Cardiac involvement either as DSF or myocarditis, can be detected in both ANCA (+) and ANCA (-) CSS, although more clinically overt in ANCA (-). DSF carries an ominous prognosis for LV function. CMR, due to its capability to detect disease severity, before cardiac dysfunction takes place, is an excellent tool for CSS risk stratification and treatment individualization.

Diffusion MRI: literature review in salivary gland tumors.

PubMed

Attyé, A; Troprès, I; Rouchy, R-C; Righini, C; Espinoza, S; Kastler, A; Krainik, A

2017-07-01

Surgical resection is currently the best treatment for salivary gland tumors. A reliable magnetic resonance imaging mapping, encompassing tumor grade, location, and extension may assist safe and effective tumor resection and provide better information for patients regarding potential risks and morbidity after surgical intervention. However, direct examination of the tumor grade and extension using conventional morphological MRI remains difficult, often requiring contrast media injection and complex algorithms on perfusion imaging to estimate the degree of malignancy. In addition, contrast-enhanced MRI technique may be problematic due to the recently demonstrated gadolinium accumulation in the dentate nucleus of the cerebellum. Significant developments in magnetic resonance diffusion imaging, involving voxel-based quantitative analysis through the measurement of the apparent diffusion coefficient, have enhanced our knowledge on the different histopathological salivary tumor grades. Other diffusion imaging-derived techniques, including high-order tractography models, have recently demonstrated their usefulness in assessing the facial nerve location in parotid tumor context. All of these imaging techniques do not require contrast media injection. Our review starts by outlining the physical basis of diffusion imaging, before discussing findings from diagnostic studies testing its usefulness in assessing salivary glands tumors with diffusion MRI. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Gadolinium toxicity and treatment.

PubMed

Ramalho, Joana; Ramalho, Miguel; Jay, Michael; Burke, Lauren M; Semelka, Richard C

2016-12-01

Gadolinium based contrast agents (GBCAs) play an important role in the diagnostic evaluation of many patients. The safety of these agents has been once again questioned after gadolinium deposits were observed and measured in brain and bone of patients with normal renal function. This retention of gadolinium in the human body has been termed "gadolinium storage condition". The long-term and cumulative effects of retained gadolinium in the brain and elsewhere are not as yet understood. Recently, patients who report that they suffer from chronic symptoms secondary to gadolinium exposure and retention created gadolinium-toxicity on-line support groups. Their self-reported symptoms have recently been published. Bone and joint complaints, and skin changes were two of the most common complaints. This condition has been termed "gadolinium deposition disease". In this review we will address gadolinium toxicity disorders, from acute adverse reactions to GBCAs to gadolinium deposition disease, with special emphasis on the latter, as it is the most recently described and least known. Copyright © 2016 Elsevier Inc. All rights reserved.

The Prognostic Value of Late Gadolinium-Enhanced Cardiac Magnetic Resonance Imaging in Nonischemic Dilated Cardiomyopathy: A Review and Meta-Analysis.

PubMed

Becker, Marthe A J; Cornel, Jan H; van de Ven, Peter M; van Rossum, Albert C; Allaart, Cornelis P; Germans, Tjeerd

2018-04-13

This review and meta-analysis reviews the prognostic value of cardiac magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (DCM). Late gadolinium-enhanced (LGE) CMR is a noninvasive method to determine the underlying cause of DCM and previous studies reported the prognostic value of the presence of LGE to identify patients at risk of major adverse cardiovascular events. PubMed was searched for studies describing the prognostic implication of LGE in patients with DCM for the specified endpoints cardiovascular mortality, major ventricular arrhythmic events including appropriate implantable cardioverter-defibrillator therapy, rehospitalization for heart failure, and left ventricular reverse remodeling. Data from 34 studies were included, with a total of 4,554 patients. Contrast enhancement was present in 44.8% of DCM patients. Patients with LGE had increased cardiovascular mortality (odds ratio [OR]: 3.40; 95% confidence interval [CI]: 2.04 to 5.67), ventricular arrhythmic events (OR: 4.52; 95% CI: 3.41 to 5.99), and rehospitalization for heart failure (OR: 2.66; 95% CI: 1.67 to 4.24) compared with those without LGE. Moreover, the absence of LGE predicted left ventricular reverse remodeling (OR: 0.15; 95% CI: 0.06 to 0.36). The presence of LGE on CMR substantially worsens prognosis for adverse cardiovascular events in DCM patients, and the absence indicates left ventricular reverse remodeling. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

[Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

PubMed

Ishimoto, Takeshi; Ishihara, Masaru; Ikeda, Takayuki; Kawakami, Momoe

2008-12-20

Cardiac late Gadolinium enhancement MR imaging has been shown to allow assessment of myocardial viability in patients with ischemic heart disease. The current standard approach is a 3D inversion recovery sequence at 1.5 Tesla. The aims of this study were to evaluate the technique feasibility and clinical utility of MR viability imaging at 3.0 Tesla in patients with myocardial infarction and cardiomyopathy. In phantom and volunteer studies, the inversion time required to suppress the signal of interests and tissues was prolonged at 3.0 Tesla. In the clinical study, the average inversion time to suppress the signal of myocardium at 3.0 Tesla with respect to MR viability imaging at 1.5 Tesla was at 15 min after the administration of contrast agent (304.0+/-29.2 at 3.0 Tesla vs. 283.9+/-20.9 at 1.5 Tesla). The contrast between infarction and viable myocardium was equal at both field strengths (4.06+/-1.30 at 3.0 Tesla vs. 4.42+/-1.85 at 1.5 Tesla). Even at this early stage, MR viability imaging at 3.0 Tesla provides high quality images in patients with myocardial infarction. The inversion time is significantly prolonged at 3.0 Tesla. The contrast between infarction and viable myocardium at 3.0 Tesla are equal to 1.5 Tesla. Further investigation is needed for this technical improvement, for clinical evaluation, and for limitations.

Differentiation of pre-ablation and post-ablation late gadolinium-enhanced cardiac MRI scans of longstanding persistent atrial fibrillation patients

NASA Astrophysics Data System (ADS)

Yang, Guang; Zhuang, Xiahai; Khan, Habib; Haldar, Shouvik; Nyktari, Eva; Li, Lei; Ye, Xujiong; Slabaugh, Greg; Wong, Tom; Mohiaddin, Raad; Keegan, Jennifer; Firmin, David

2017-03-01

Late Gadolinium-Enhanced Cardiac MRI (LGE CMRI) is an emerging non-invasive technique to image and quantify preablation native and post-ablation atrial scarring. Previous studies have reported that enhanced image intensities of the atrial scarring in the LGE CMRI inversely correlate with the left atrial endocardial voltage invasively obtained by electro-anatomical mapping. However, the reported reproducibility of using LGE CMRI to identify and quantify atrial scarring is variable. This may be due to two reasons: first, delineation of the left atrium (LA) and pulmonary veins (PVs) anatomy generally relies on manual operation that is highly subjective, and this could substantially affect the subsequent atrial scarring segmentation; second, simple intensity based image features may not be good enough to detect subtle changes in atrial scarring. In this study, we hypothesized that texture analysis can provide reliable image features for the LGE CMRI images subject to accurate and objective delineation of the heart anatomy based on a fully-automated whole heart segmentation (WHS) method. We tested the extracted texture features to differentiate between pre-ablation and post-ablation LGE CMRI studies in longstanding persistent atrial fibrillation patients. These patients often have extensive native scarring and differentiation from post-ablation scarring can be difficult. Quantification results showed that our method is capable of solving this classification task, and we can envisage further deployment of this texture analysis based method for other clinical problems using LGE CMRI.

3D Late Gadolinium Enhancement in a Single Prolonged Breath-hold using Supplemental Oxygenation and Hyperventilation

PubMed Central

Roujol, Sébastien; Basha, Tamer A.; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H.; Kissinger, Kraig V.; Goddu, Beth; Berg, Sophie; Manning, Warren J.; Nezafat, Reza

2013-01-01

Purpose: To evaluate the feasibility of 3D single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Methods: Breath-hold metrics (breath-hold duration, diaphragmatic/LV position drift, and maximum variation of RR interval) without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (FOV=320×320×100 mm3, resolution=1.6×1.6×5.0 mm3, acceleration rate of 4) and a free breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semi-quantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Results: Supplemental oxygenation and hyperventilation increased the breath-hold duration (35±11 s to 58±21 s, p<0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both p>0.01). LGE images were of similar quality when compared to free breathing acquisitions but with reduced total scan time (85±22 s to 35±6 s, p<0.001). Conclusions: Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. PMID:24186772

Experience-Related Structural Changes of Degenerated Occipital White Matter in Late-Blind Humans – A Diffusion Tensor Imaging Study

PubMed Central

Dietrich, Susanne; Hertrich, Ingo; Kumar, Vinod; Ackermann, Hermann

2015-01-01

Late-blind humans can learn to understand speech at ultra-fast syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. Thus, the observed functional cross-modal recruitment of occipital cortex might facilitate ultra-fast speech processing in these individuals. To further elucidate the structural prerequisites of this skill, diffusion tensor imaging (DTI) was conducted in late-blind subjects differing in their capability of understanding ultra-fast speech. Fractional anisotropy (FA) was determined as a quantitative measure of the directionality of water diffusion, indicating fiber tract characteristics that might be influenced by blindness as well as the acquired perceptual skills. Analysis of the diffusion images revealed reduced FA in late-blind individuals relative to sighted controls at the level of the optic radiations at either side and the right-hemisphere dorsal thalamus (pulvinar). Moreover, late-blind subjects showed significant positive correlations between FA and the capacity of ultra-fast speech comprehension within right-hemisphere optic radiation and thalamus. Thus, experience-related structural alterations occurred in late-blind individuals within visual pathways that, presumably, are linked to higher order frontal language areas. PMID:25830371

Subcellular SIMS imaging of gadolinium isotopes in human glioblastoma cells treated with a gadolinium containing MRI agent

NASA Astrophysics Data System (ADS)

Smith, Duane R.; Lorey, Daniel R.; Chandra, Subhash

2004-06-01

Neutron capture therapy is an experimental binary radiotherapeutic modality for the treatment of brain tumors such as glioblastoma multiforme. Recently, neutron capture therapy with gadolinium-157 has gained attention, and techniques for studying the subcellular distribution of gadolinium-157 are needed. In this preliminary study, we have been able to image the subcellular distribution of gadolinium-157, as well as the other six naturally abundant isotopes of gadolinium, with SIMS ion microscopy. T98G human glioblastoma cells were treated for 24 h with 25 mg/ml of the metal ion complex diethylenetriaminepentaacetic acid Gd(III) dihydrogen salt hydrate (Gd-DTPA). Gd-DTPA is a contrast enhancing agent used for MRI of brain tumors, blood-brain barrier impairment, diseases of the central nervous system, etc. A highly heterogeneous subcellular distribution was observed for gadolinium-157. The nuclei in each cell were distinctly lower in gadolinium-157 than in the cytoplasm. Even within the cytoplasm the gadolinium-157 was heterogeneously distributed. The other six naturally abundant isotopes of gadolinium were imaged from the same cells and exhibited a subcellular distribution consistent with that observed for gadolinium-157. These observations indicate that SIMS ion microscopy may be a viable approach for subcellular studies of gadolinium containing neutron capture therapy drugs and may even play a major role in the development and validation of new gadolinium contrast enhancing agents for diagnostic MRI applications.

Extracellular diffusion quantified by magnetic resonance imaging during rat C6 glioma cell progression.

PubMed

Song, G; Luo, T; Dong, L; Liu, Q

2017-07-03

Solution reflux and edema hamper the convection-enhanced delivery of the standard treatment for glioma. Therefore, a real-time magnetic resonance imaging (MRI) method was developed to monitor the dosing process, but a quantitative analysis of local diffusion and clearance parameters has not been assessed. The objective of this study was to compare diffusion into the extracellular space (ECS) at different stages of rat C6 gliomas, and analyze the effects of the extracellular matrix (ECM) on the diffusion process. At 10 and 20 days, after successful glioma modeling, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was introduced into the ECS of rat C6 gliomas. Diffusion parameters and half-life of the reagent were then detected using MRI, and quantified according to the mathematical model of diffusion. The main ECM components [chondroitin sulfate proteoglycans (CSPGs), collagen IV, and tenascin C] were detected by immunohistochemical and immunoblot analyses. In 20-day gliomas, Gd-DTPA diffused more slowly and derived higher tortuosity, with lower clearance rate and longer half-life compared to 10-day gliomas. The increased glioma ECM was associated with different diffusion and clearance parameters in 20-day rat gliomas compared to 10-day gliomas. ECS parameters were altered with C6 glioma progression from increased ECM content. Our study might help better understand the glioma microenvironment and provide benefits for interstitial drug delivery to treat brain gliomas.

Idiopathic and diabetic skeletal muscle necrosis: evaluation by magnetic resonance imaging.

PubMed

Kattapuram, Taj M; Suri, Rajeev; Rosol, Michael S; Rosenberg, Andrew E; Kattapuram, Susan V

2005-04-01

Idiopathic and diabetic-associated muscle necrosis are similar, uncommon clinical entities requiring conservative management and minimal intervention to avoid complications and prolonged hospitalization. An early noninvasive diagnosis is therefore essential. We evaluated the magnetic resonance imaging (MRI) characteristics of muscle necrosis in 14 patients, in eight of whom the diagnoses were confirmed histologically. Two experienced musculoskeletal radiologists performed retrospective evaluations of the MRI studies of 14 patients with the diagnoses of skeletal muscle infarction. In 10 cases gadolinium-enhanced (T1-weighted fat-suppressed) sequences were available along with T1-weighted, T2-weighted images and STIR sequences, while in four cases contrast-enhanced images were not available. Eight patients had underlying diabetes and in six patients the cause of the myonecrosis was considered idiopathic. T1-weighted images demonstrated isointense swelling of the involved muscle, with mildly displaced fascial planes. There was effacement of the fat signal intensity within the muscle. Fat-suppressed T2-weighted images showed diffuse heterogeneous high signal intensity in the muscles suggestive of edema. Perifascial fluid collection was seen in eight cases. Subcutaneous edema was present in seven patients. Following intravenous gadolinium administration, MRI demonstrated a focal area of heterogeneously enhancing mass with peripheral enhancement. Within this focal lesion, linear dark areas were seen with serpentine enhancing streaks separating them in eight cases. In two cases, a central relatively nonenhancing mass with irregular margins and peripheral enhancement was noted. The peripheral enhancement involved a significant part of the muscle. No focal fluid collection was noted. We believe that the constellation of imaging findings on T1- and T2-weighted images and post-gadolinium sequences is highly suggestive of muscle necrosis. We consider certain specific findings on gadolinium-enhanced images to be characteristic. The findings reported here should provide radiologists with useful information in making the diagnosis of skeletal muscle necrosis without resorting to invasive procedures.

Spectral Diffusion: An Algorithm for Robust Material Decomposition of Spectral CT Data

PubMed Central

Clark, Darin P.; Badea, Cristian T.

2014-01-01

Clinical successes with dual energy CT, aggressive development of energy discriminating x-ray detectors, and novel, target-specific, nanoparticle contrast agents promise to establish spectral CT as a powerful functional imaging modality. Common to all of these applications is the need for a material decomposition algorithm which is robust in the presence of noise. Here, we develop such an algorithm which uses spectrally joint, piece-wise constant kernel regression and the split Bregman method to iteratively solve for a material decomposition which is gradient sparse, quantitatively accurate, and minimally biased. We call this algorithm spectral diffusion because it integrates structural information from multiple spectral channels and their corresponding material decompositions within the framework of diffusion-like denoising algorithms (e.g. anisotropic diffusion, total variation, bilateral filtration). Using a 3D, digital bar phantom and a material sensitivity matrix calibrated for use with a polychromatic x-ray source, we quantify the limits of detectability (CNR = 5) afforded by spectral diffusion in the triple-energy material decomposition of iodine (3.1 mg/mL), gold (0.9 mg/mL), and gadolinium (2.9 mg/mL) concentrations. We then apply spectral diffusion to the in vivo separation of these three materials in the mouse kidneys, liver, and spleen. PMID:25296173

Spectral diffusion: an algorithm for robust material decomposition of spectral CT data.

PubMed

Clark, Darin P; Badea, Cristian T

2014-11-07

Clinical successes with dual energy CT, aggressive development of energy discriminating x-ray detectors, and novel, target-specific, nanoparticle contrast agents promise to establish spectral CT as a powerful functional imaging modality. Common to all of these applications is the need for a material decomposition algorithm which is robust in the presence of noise. Here, we develop such an algorithm which uses spectrally joint, piecewise constant kernel regression and the split Bregman method to iteratively solve for a material decomposition which is gradient sparse, quantitatively accurate, and minimally biased. We call this algorithm spectral diffusion because it integrates structural information from multiple spectral channels and their corresponding material decompositions within the framework of diffusion-like denoising algorithms (e.g. anisotropic diffusion, total variation, bilateral filtration). Using a 3D, digital bar phantom and a material sensitivity matrix calibrated for use with a polychromatic x-ray source, we quantify the limits of detectability (CNR = 5) afforded by spectral diffusion in the triple-energy material decomposition of iodine (3.1 mg mL(-1)), gold (0.9 mg mL(-1)), and gadolinium (2.9 mg mL(-1)) concentrations. We then apply spectral diffusion to the in vivo separation of these three materials in the mouse kidneys, liver, and spleen.

Effect of intravenous FX06 as an adjunct to primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction results of the F.I.R.E. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury) trial.

PubMed

Atar, Dan; Petzelbauer, Peter; Schwitter, Jürg; Huber, Kurt; Rensing, Benno; Kasprzak, Jaroslaw D; Butter, Christian; Grip, Lars; Hansen, Peter R; Süselbeck, Tim; Clemmensen, Peter M; Marin-Galiano, Marcos; Geudelin, Bernard; Buser, Peter T

2009-02-24

The purpose of this study was to investigate whether FX06 would limit infarct size when given as an adjunct to percutaneous coronary intervention. FX06, a naturally occurring peptide derived from human fibrin, has been shown to reduce myocardial infarct size in animal models by mitigating reperfusion injury. In all, 234 patients presenting with acute ST-segment elevation myocardial infarction were randomized in 26 centers. FX06 or matching placebo was given as intravenous bolus at reperfusion. Infarct size was assessed 5 days after myocardial infarction by late gadolinium enhanced cardiac magnetic resonance imaging. Secondary outcomes included size of necrotic core zone and microvascular obstruction at 5 days, infarct size at 4 months, left ventricular function, troponin I levels, and safety. There were no baseline differences between groups. On day 5, there was no significant difference in total late gadolinium enhanced zone in the FX06 group compared with placebo (reduction by 21%; p = 0.207). The necrotic core zone, however, was significantly reduced by 58% (median 1.77 g [interquartile range 0.0, 9.09 g] vs. 4.20 g [interquartile range 0.3, 9.93 g]; p < 0.025). There were no significant differences in troponin I levels (at 48 h, -17% in the FX06 group). After 4 months, there were no longer significant differences in scar size. There were numerically fewer serious cardiac events in the FX06-treated group, and no differences in adverse events. In this proof-of-concept trial, FX06 reduced the necrotic core zone as one measure of infarct size on magnetic resonance imaging, while total late enhancement was not significantly different between groups. The drug appears safe and well tolerated. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury [F.I.R.E.]; NCT00326976).

Diffusion of new drugs in Danish general practice.

PubMed

Steffensen, F H; Sørensen, H T; Olesen, F

1999-08-01

There is a large variation in implementing research findings in clinical practice. We examined whether the concept of early or late adopters is universal for the diffusion of all new drugs, and whether it is associated with non-scientific factors in general practice. We identified all prescriptions for five new drugs from the population-based prescription database in North Jutland County, Denmark (490000 inhabitants) from 1993 to 1996, and calculated the period from release of the drugs to the issuing of the first prescription by each GP. Logistic regression was performed to predict early or late prescribing from physician characteristics, practice activity and the number of prescriptions, adjusted for age and sex. The distributions of the diffusion time of the drugs by 95 solo practitioners were asymmetrical, with a long upper tail representing the late prescribers. The shape and slope of the diffusion curve were highly drug dependent. There was poor agreement of the three adopter categories (early, intermediate and late prescribers) between the five drugs (kappa < 0.35), but being a late prescriber was the most consistent condition. Late prescribing of tramadol, compared with intermediate prescribing, was associated with female physicians (odds ratio (OR) 5.7; 95% CI 1.5-21.3), smaller list size (OR 0.1; 95% CI 0.0-0.8), a strong general restrictive attitude to pharmacotherapy (OR 0.07; 95% CI 0.01-0.68) and a tendency to lower diagnostic activity per patient (OR 0.4; 95% CI 0.1-1.9). The slope and shape of the diffusion curve are both dependent on physician and drug characteristics, but late prescribers share some common characteristics.

Diffusion Tensor Imaging of Normal-Appearing White Matter as Biomarker for Radiation-Induced Late Delayed Cognitive Decline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Christopher H., E-mail: chchap@umich.edu; Nagesh, Vijaya; Sundgren, Pia C.

Purpose: To determine whether early assessment of cerebral white matter degradation can predict late delayed cognitive decline after radiotherapy (RT). Methods and Materials: Ten patients undergoing conformal fractionated brain RT participated in a prospective diffusion tensor magnetic resonance imaging study. Magnetic resonance imaging studies were acquired before RT, at 3 and 6 weeks during RT, and 10, 30, and 78 weeks after starting RT. The diffusivity variables in the parahippocampal cingulum bundle and temporal lobe white matter were computed. A quality-of-life survey and neurocognitive function tests were administered before and after RT at the magnetic resonance imaging follow-up visits. Results:more » In both structures, longitudinal diffusivity ({lambda}{sub Double-Vertical-Line }) decreased and perpendicular diffusivity ({lambda}{sub Up-Tack }) increased after RT, with early changes correlating to later changes (p < .05). The radiation dose correlated with an increase in cingulum {lambda}{sub Up-Tack} at 3 weeks, and patients with >50% of cingula volume receiving >12 Gy had a greater increase in {lambda}{sub Up-Tack} at 3 and 6 weeks (p < .05). The post-RT changes in verbal recall scores correlated linearly with the late changes in cingulum {lambda}{sub Double-Vertical-Line} (30 weeks, p < .02). Using receiver operating characteristic curves, early cingulum {lambda}{sub Double-Vertical-Line} changes predicted for post-RT changes in verbal recall scores (3 and 6 weeks, p < .05). The neurocognitive test scores correlated significantly with the quality-of-life survey results. Conclusions: The correlation between early diffusivity changes in the parahippocampal cingulum and the late decline in verbal recall suggests that diffusion tensor imaging might be useful as a biomarker for predicting late delayed cognitive decline.« less

Automatic classification of scar tissue in late gadolinium enhancement cardiac MRI for the assessment of left-atrial wall injury after radiofrequency ablation

PubMed Central

Morris, Alan; Burgon, Nathan; McGann, Christopher; MacLeod, Robert; Cates, Joshua

2013-01-01

Radiofrequency ablation is a promising procedure for treating atrial fibrillation (AF) that relies on accurate lesion delivery in the left atrial (LA) wall for success. Late Gadolinium Enhancement MRI (LGE MRI) at three months post-ablation has proven effective for noninvasive assessment of the location and extent of scar formation, which are important factors for predicting patient outcome and planning of redo ablation procedures. We have developed an algorithm for automatic classification in LGE MRI of scar tissue in the LA wall and have evaluated accuracy and consistency compared to manual scar classifications by expert observers. Our approach clusters voxels based on normalized intensity and was chosen through a systematic comparison of the performance of multivariate clustering on many combinations of image texture. Algorithm performance was determined by overlap with ground truth, using multiple overlap measures, and the accuracy of the estimation of the total amount of scar in the LA. Ground truth was determined using the STAPLE algorithm, which produces a probabilistic estimate of the true scar classification from multiple expert manual segmentations. Evaluation of the ground truth data set was based on both inter- and intra-observer agreement, with variation among expert classifiers indicating the difficulty of scar classification for a given a dataset. Our proposed automatic scar classification algorithm performs well for both scar localization and estimation of scar volume: for ground truth datasets considered easy, variability from the ground truth was low; for those considered difficult, variability from ground truth was on par with the variability across experts. PMID:24236224

Influence of pacing site characteristics on response to cardiac resynchronization therapy.

PubMed

Wong, Jorge A; Yee, Raymond; Stirrat, John; Scholl, David; Krahn, Andrew D; Gula, Lorne J; Skanes, Allan C; Leong-Sit, Peter; Klein, George J; McCarty, David; Fine, Nowell; Goela, Aashish; Islam, Ali; Thompson, Terry; Drangova, Maria; White, James A

2013-07-01

Transmural scar occupying left ventricular (LV) pacing regions has been associated with reduced response to cardiac resynchronization therapy (CRT). However, spatial influences of lead tip delivery relative to scar at both pacing sites remain poorly explored. This study evaluated scar distribution relative to LV and right ventricular (RV) lead tip placement through coregistration of late gadolinium enhancement MRI and cardiac computed tomographic (CT) findings. Influences on CRT response were assessed by serial echocardiography. Sixty patients receiving CRT underwent preimplant late gadolinium enhancement MRI, postimplant cardiac CT, and serial echocardiography. Blinded segmental evaluations of mechanical delay, percentage scar burden, and lead tip location were performed. Response to CRT was defined as a reduction in LV end-systolic volume ≥15% at 6 months. The mean age and LV ejection fraction were 64±9 years and 25±7%, respectively. Mean scar volume was higher among CRT nonresponders for both the LV (23±23% versus 8±14% [P=0.01]) and RV pacing regions (40±32% versus 24±30% [P=0.04]). Significant pacing region scar was identified in 13% of LV pacing regions and 37% of RV pacing regions. Absence of scar in both regions was associated with an 81% response rate compared with 55%, 25%, and 0%, respectively, when the RV, LV, or both pacing regions contained scar. LV pacing region dyssynchrony was not predictive of response. Myocardial scar occupying the LV pacing region is associated with nonresponse to CRT. Scar occupying the RV pacing region is encountered at higher frequency and seems to provide a more intermediate influence on CRT response.

Automatic classification of scar tissue in late gadolinium enhancement cardiac MRI for the assessment of left-atrial wall injury after radiofrequency ablation

NASA Astrophysics Data System (ADS)

Perry, Daniel; Morris, Alan; Burgon, Nathan; McGann, Christopher; MacLeod, Robert; Cates, Joshua

2012-03-01

Radiofrequency ablation is a promising procedure for treating atrial fibrillation (AF) that relies on accurate lesion delivery in the left atrial (LA) wall for success. Late Gadolinium Enhancement MRI (LGE MRI) at three months post-ablation has proven effective for noninvasive assessment of the location and extent of scar formation, which are important factors for predicting patient outcome and planning of redo ablation procedures. We have developed an algorithm for automatic classification in LGE MRI of scar tissue in the LA wall and have evaluated accuracy and consistency compared to manual scar classifications by expert observers. Our approach clusters voxels based on normalized intensity and was chosen through a systematic comparison of the performance of multivariate clustering on many combinations of image texture. Algorithm performance was determined by overlap with ground truth, using multiple overlap measures, and the accuracy of the estimation of the total amount of scar in the LA. Ground truth was determined using the STAPLE algorithm, which produces a probabilistic estimate of the true scar classification from multiple expert manual segmentations. Evaluation of the ground truth data set was based on both inter- and intra-observer agreement, with variation among expert classifiers indicating the difficulty of scar classification for a given a dataset. Our proposed automatic scar classification algorithm performs well for both scar localization and estimation of scar volume: for ground truth datasets considered easy, variability from the ground truth was low; for those considered difficult, variability from ground truth was on par with the variability across experts.

3D late gadolinium enhancement in a single prolonged breath-hold using supplemental oxygenation and hyperventilation.

PubMed

Roujol, Sébastien; Basha, Tamer A; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

2014-09-01

To evaluate the feasibility of three-dimensional (3D) single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Breath-hold metrics [breath-hold duration, diaphragmatic/LV position drift, and maximum variation of R wave to R wave (RR) interval] without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real-time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (field of view = 320 × 320 × 100 mm(3) , resolution = 1.6 × 1.6 × 5.0 mm(3) , acceleration rate of 4) and a free-breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semiquantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Supplemental oxygenation and hyperventilation increased the breath-hold duration (35 ± 11 s to 58 ± 21 s; P < 0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both P > 0.01). LGE images were of similar quality when compared with free-breathing acquisitions, but with reduced total scan time (85 ± 22 s to 35 ± 6 s; P < 0.001). Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. Copyright © 2013 Wiley Periodicals, Inc.

Myocardial impairment detected by late gadolinium enhancement in hypertrophic cardiomyopathy: comparison with 99mTc-MIBI/tetrofosmin and 123I-BMIPP SPECT.

PubMed

Hashimura, Hiromi; Kiso, Keisuke; Yamada, Naoaki; Kono, Atsushi; Morita, Yoshiaki; Fukushima, Kazuto; Higashi, Masahiro; Noguchi, Teruo; Ishibashi-Ueda, Hatsue; Naito, Hiroaki; Sugimura, Kazuro

2013-06-17

Myocardial fibrosis is considered to be an important factor in myocardial dysfunction and sudden cardiac death in hypertrophic cardiomyopathy (HCM). The purpose of this study was to compare myocardial fibrosis detected by late gadolinium enhancement (LGE) on cardiac MRI with myocardial perfusion and fatty acid metabolism assessed by single photon emission computed tomography in HCM. We retrospectively evaluated 20 consecutive HCM patients (female, 7; mean age, 53.4 years) who underwent LGE, technetium-99m methoxyisobutylisonitrile/tetrofosmin (99mTc-MIBI/tetrofosmin), and iodine-123 beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP) imaging. We calculated the myocardium-to-lumen signal ratio (M/L) for LGE in 17 segments based on the American Heart Association statement. Scoring of 99mTc-MIBI/tetrofosmin (PI) and 123I-BMIPP (BM) was performed for each segment using a 5-point scale (0, normal; 4, highly decreased). Nineteen of 20 patients (95%) and 153 of 340 segments (45%) showed LGE. M/Ls were 0.42±0.16, 0.55±0.17, and 0.65±0.24 in PI0/BM0, PI0/BM1-4 and PI1-4/BM1-4, respectively. All M/Ls were significantly higher than that of a normal control (0.34±0.14) (p<0.001). Myocardial fibrosis in HCM can occur despite normal perfusion and fatty acid metabolism, and is more strongly associated with disorders of fatty acid metabolism than with perfusion abnormalities. M/L may be a useful indicator of disease severity.

The prognostic value of T1 mapping and late gadolinium enhancement cardiovascular magnetic resonance imaging in patients with light chain amyloidosis.

PubMed

Lin, Lu; Li, Xiao; Feng, Jun; Shen, Kai-Ni; Tian, Zhuang; Sun, Jian; Mao, Yue-Ying; Cao, Jian; Jin, Zheng-Yu; Li, Jian; Selvanayagam, Joseph B; Wang, Yi-Ning

2018-01-03

Cardiac impairment is associated with high morbidity and mortality in immunoglobulin light chain (AL) type amyloidosis, for which early identification and risk stratification is vital. For myocardial tissue characterization, late gadolinium enhancement (LGE) is a classic and most commonly performed cardiovascular magnetic resonance (CMR) parameter. T1 mapping with native T1 and extracellular volume (ECV) are recently developed quantitative parameters. We aimed to investigate the prognostic value of native T1, ECV and LGE in patients with AL amyloidosis. Eighty-two patients (55.5 ± 8.5 years; 52 M) and 20 healthy subjects (53.2 ± 11.7 years; 10 M) were prospectively recruited. All subjects underwent CMR with LGE imaging and T1 mapping using a Modified Look-Locker Inversion-recovery (MOLLI) sequence on a 3 T scanner. Native T1 and ECV were measured semi-automatically using a dedicated CMR software. The left ventricular (LV) LGE pattern was classified as none, patchy, and global groups. Global LGE was considered when there was diffuse, transmural LGE in more than half of the short axis images. Follow-up was performed for all-cause mortality using Cox proportional hazards regression analysis and Kaplan-Meier survival curves. The patients demonstrated an increase in native T1 (1438 ± 120 ms vs. 1283 ± 46 ms, P = 0.001) and ECV (43.9 ± 10.9% vs. 27.0 ± 1.7%, P = 0.001) compared to healthy controls. Native T1, ECV and LGE showed significant correlation with Mayo Stage, and ECV and LGE showed significant correlation with echocardiographic E/E' and LV ejection fraction. During the follow-up for a median time of 8 months, 21 deaths occurred. ECV ≥ 44.0% (hazard ratio [HR] 7.249, 95% confidence interval (CI) 1.751-13.179, P = 0.002) and global LGE (HR 4.804, 95% CI 1.971-12.926, P = 0.001) were independently prognostic for mortality over other clinical and imaging parameters. In subgroups with the same LGE pattern, ECV ≥ 44.0% remained prognostic (log rank P = 0.029). Median native T1 (1456 ms) was not prognostic for mortality (Tarone-Ware, P = 0.069). During a short-term follow-up, both ECV and LGE are independently prognostic for mortality in AL amyloidosis. In patients with a similar LGE pattern, ECV remained prognostic. Native T1 was not found to be a prognostic factor.

Use of gadolinium-based magnetic resonance imaging contrast agents and awareness of brain gadolinium deposition among pediatric providers in North America.

PubMed

Mithal, Leena B; Patel, Payal S; Mithal, Divakar; Palac, Hannah L; Rozenfeld, Michael N

2017-05-01

Numerous recent articles have reported brain gadolinium deposition when using linear but not macrocyclic gadolinium-based contrast agents (GBCAs). To determine the current landscape of gadolinium use among pediatric institutions and the knowledge base of radiologists and referring providers with regard to GBCAs and brain gadolinium deposition. We e-mailed voluntary closed surveys to 5,390 physicians in various pediatric professional societies between January 2016 and March 2016. We used chi-square and Fisher exact tests to compare response distributions among specialties. We found that 80% of surveyed pediatric hospitals use macrocyclic contrast agents. In the last year, 58% switched their agent, most commonly to gadoterate meglumine, with the most common reason being brain gadolinium deposition. Furthermore, surveys indicated that 23% of hospitals are considering switching, and, of these, 83% would switch to gadoterate meglumine; the most common reasons were brain gadolinium deposition and safety. Radiologists were more aware of brain gadolinium deposition than non-radiologist physicians (87% vs. 26%; P<0.0001). Radiologists and referring providers expressed similar levels of concern (95% and 89%). Twelve percent of radiologists and 2% of referring providers reported patients asking about brain gadolinium deposition. Radiologists were significantly more comfortable addressing patient inquiries than referring pediatric physicians (48% vs. 6%; P<0.0001). The number of MRIs requested by referring pediatric physicians correlated with their knowledge of brain gadolinium deposition, contrast agent used by their hospital, and comfort discussing brain gadolinium deposition with patients (P<0.0001). Since the discovery of brain gadolinium deposition, many pediatric hospitals have switched to or plan to switch to a more stable macrocyclic MR contrast agent, most commonly gadoterate meglumine. Despite this, there is need for substantial further education of radiologists and referring pediatric providers regarding GBCAs and brain gadolinium deposition.

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

DOE PAGES

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; ...

2014-11-07

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

NASA Astrophysics Data System (ADS)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

2014-10-01

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Sm-type → dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GPa and a temperature of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.

Gadolinium-based contrast agent toxicity: a review of known and proposed mechanisms.

PubMed

Rogosnitzky, Moshe; Branch, Stacy

2016-06-01

Gadolinium chelates are widely used as contrast media for magnetic resonance imaging. The approved gadolinium-based contrast agents (GBCAs) have historically been considered safe and well tolerated when used at recommended dosing levels. However, for nearly a decade, an association between GBCA administration and the development of nephrogenic systemic fibrosis (NSF) has been recognized in patients with severe renal impairment. This has led to modifications in clinical practices aimed at reducing the potential and incidence of NSF development. Newer reports have emerged regarding the accumulation of gadolinium in various tissues of patients who do not have renal impairment, including bone, brain, and kidneys. Despite the observations of gadolinium accumulation in tissues regardless of renal function, very limited clinical data regarding the potential for and mechanisms of toxicity is available. This significant gap in knowledge warrants retrospective cohort study efforts, as well as prospective studies that involve gadolinium ion (Gd(3+)) testing in patients exposed to GBCA. This review examines the potential biochemical and molecular basis of gadolinium toxicity, possible clinical significance of gadolinium tissue retention and accumulation, and methods that can limit gadolinium body burden.

Associations of electrocardiographic P-wave characteristics with left atrial function, and diffuse left ventricular fibrosis defined by cardiac magnetic resonance: The PRIMERI Study.

PubMed

Tiffany Win, Theingi; Ambale Venkatesh, Bharath; Volpe, Gustavo J; Mewton, Nathan; Rizzi, Patricia; Sharma, Ravi K; Strauss, David G; Lima, Joao A; Tereshchenko, Larisa G

2015-01-01

Abnormal P-terminal force in lead V1 (PTFV1) is associated with an increased risk of heart failure, stroke, atrial fibrillation, and death. Our goal was to explore associations of left ventricular (LV) diffuse fibrosis with left atrial (LA) function and electrocardiographic (ECG) measures of LA electrical activity. Patients without atrial fibrillation (n = 91; mean age 59.5 years; 61.5% men; 65.9% white) with structural heart disease (spatial QRS-T angle ≥105° and/or Selvester QRS score ≥5 on ECG) but LV ejection fraction >35% underwent clinical evaluation, cardiac magnetic resonance, and resting ECG. LA function indices were obtained by multimodality tissue tracking using 2- and 4-chamber long-axis images. T1 mapping and late gadolinium enhancement were used to assess diffuse LV fibrosis and presence of scar. P-prime in V1 amplitude (PPaV1) and duration (PPdV1), averaged P-wave-duration, PR interval, and P-wave axis were automatically measured using 12 SLTM algorithm. PTFV1 was calculated as a product of PPaV1 and PPdV1. In linear regression after adjustment for demographic characteristics, body mass index, maximum LA volume index, presence of scar, and LV mass index, each decile increase in LV interstitial fibrosis was associated with 0.76 mV*ms increase in negative abnormal PTFV1 (95% confidence interval [CI] -1.42 to -0.09; P = .025), 15.3 ms prolongation of PPdV1 (95% CI 6.9 to 23.8; P = .001) and 5.4 ms prolongation of averaged P-duration (95% CI 0.9-10.0; P = .020). LV fibrosis did not affect LA function. PPaV1 and PTFV1 were associated with an increase in LA volumes and decrease in LA emptying fraction and LA reservoir function. LV interstitial fibrosis is associated with abnormal PTFV1, prolonged PPdV1, and P-duration, but does not affect LA function. Copyright © 2015 Heart Rhythm Society. All rights reserved.

Unusual scarring patterns on cardiac magnetic resonance imaging: A potentially treatable etiology not to be missed.

PubMed

Jordan, Andrew; Lyne, Jonathan; Wong, Tom

2010-04-01

A case of cardiomyopathy and ventricular tachycardia previously assumed to be idiopathic in origin is described. Investigation with cardiac magnetic resonance imaging prompted the diagnosis and successful treatment of an underlying disorder based on typical scarring patterns seen with late gadolinium enhancement. The present report suggests that clinicians should have a low threshold for actively excluding this condition in patients presenting with cardiomyopathy, even in the absence of other disease features, particularly if typical scarring patterns are found on cardiac magnetic resonance imaging because disease-specific therapy appears to significantly improve both symptoms and prognosis.

Removal of gadolinium by peritoneal dialysis.

PubMed

Murashima, M; Drott, H R; Carlow, D; Shaw, L M; Milone, M; Bachman, M; Tsai, D E; Yang, S-L; Bloom, R D

2008-05-01

An association between gadolinium-containing contrast and the development of nephrogenic systemic fibrosis (NSF) has been increasingly recognized. For patients receiving hemodialysis (HD) who are exposed to gadolinium, the Federal Drug Administration (FDA) recommends HD to remove this contrast agent in order to minimize the risk of NSF. This study examines if gadolinium can be removed by frequent exchanges by peritoneal dialysis (PD). Following administration of 0.1 mmol/kg of gadodiamide to a patient with end-stage renal disease, the serum clearance of this contrast agent by automated PD was examined. 10 and 15 exchanges of PD using an automated cycler were respectively performed during the first and second 24-hour periods after gadolinium exposure. Serum gadolinium levels were measured 1 hour after the gadolinium administration, then at 24 and 48 hours after PD was initiated. 90% of the gadolinium was removed from the circulation in 2 days with a regimen of 10-15 exchanges per day of PD. For patients on chronic maintenance PD who receive gadolinium, our case suggests that a temporary intensive automated PD regimen, aimed at maximizing clearance of this contrast agent immediately after exposure, could be an effective alternative when institution of HD is problematic.

Universal time-dependent dispersion properties for diffusion in a one-dimensional critically tilted potential

NASA Astrophysics Data System (ADS)

Guérin, T.; Dean, D. S.

2017-01-01

We consider the time-dependent dispersion properties of overdamped tracer particles diffusing in a one-dimensional periodic potential under the influence of an additional constant tilting force F . The system is studied in the region where the force is close to the critical value Fc at which the barriers separating neighboring potential wells disappear. We show that, when F crosses the critical value, the shape of the mean-square displacement (MSD) curves is strongly modified. We identify a diffusive regime at intermediate-time scales with an effective diffusion coefficient which is much larger than the late-time diffusion coefficient for F >Fc , whereas for F

Synthesis and evaluation of gadolinium complexes based on PAMAM as MRI contrast agents.

PubMed

Yan, Guo-Ping; Hu, Bin; Liu, Mai-Li; Li, Li-Yun

2005-03-01

Diethylenetriaminepentaacetic acid (DTPA) and pyridoxamine (PM) were incorporated into the amine groups on the surface of ammonia-core poly(amidoamine) dendrimers (PAMAM, Generation 2.0-5.0) to obtain dendritic ligands. These dendritic ligands were reacted with gadolinium chloride to yield the corresponding dendritic gadolinium (Gd) complexes. The dendritic ligands and their gadolinium complexes were characterized by(1)HNMR, IR, UV and elemental analysis. Relaxivity studies showed that the dendritic gadolinium complexes possessed higher relaxation effectiveness compared with the clinically used Gd-DTPA. After administration of the dendritic gadolinium complexes (0.09 mmol kg(-1) ) to rats, magnetic resonance imaging of the liver indicated that the dendritic gadolinium complexes containing pyridoxamine groups enhanced the contrast of the MR images of the liver, provided prolonged intravascular duration and produced highly contrasted visualization of blood vessels.

Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys

NASA Astrophysics Data System (ADS)

Maltsev, Dmitry S.; Volkovich, Vladimir A.; Yamshchikov, Leonid F.; Chukin, Andrey V.

2016-09-01

Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys were studied. Temperature dependences of gadolinium activity in the studied alloys were determined at 573-1073 K employing the EMF method. Solubility of gadolinium in the Ga-Sn and Ga-Zn alloys was measured at 462-1073 K using IMCs sedimentation method. Activity coefficients as well as partial and excess thermodynamic functions of gadolinium in the studied alloys were calculated on the basis of the obtained experimental data.

Gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres for gadolinium neutron-capture therapy.

PubMed

Saha, Tapan Kumar; Ichikawa, Hideki; Fukumori, Yoshinobu

2006-12-11

In order to provide a suitable device that would contain water-soluble drugs, highly water-soluble gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres (CMS-Gd-DTPA) were prepared by the emulsion method using glutaraldehyde as a cross-linker and Span 80 as a surfactant for gadolinium neutron-capture therapy of cancer. The gadolinium content and the mass median diameter of CMS-Gd-DTPA were estimated. The size and morphology of the CMS-Gd-DTPA were strongly influenced by the initial applied weight ratio of Gd-DTPA:chitosan. FTIR spectra showed that the electrostatic interaction between chitosan and Gd-DTPA accelerated the formation of gadolinium-enriched chitosan microspheres. Sufficient amounts of glutaraldehyde and Span 80 were necessary for producing discrete CMS-Gd-DTPA. The CMS-Gd-DTPA having a mass median diameter 11.7microm and 11.6% of gadolinium could be used in Gd-NCT following intratumoral injection.

Nephrogenic Systemic Fibrosis Manifesting a Decade After Exposure to Gadolinium.

PubMed

Larson, Krista N; Gagnon, Amy L; Darling, Melissa D; Patterson, James W; Cropley, Thomas G

2015-10-01

Nephrogenic systemic fibrosis (NSF) is a fibrosing skin disorder that develops in patients with kidney failure and has been linked to exposure to gadolinium-containing contrast agents. The time between exposure to gadolinium and the initial presentation of NSF is typically weeks to months but has been documented to be as long as 3½ years. We report a case of NSF developing 10 years after exposure to gadolinium. A long-term hemodialysis patient was exposed to gadolinium several times between 1998 and 2004 during magnetic resonance angiography of his abdominal vessels and arteriovenous fistula. In 2014, he was seen at our clinic with new dermal papules and plaques. Biopsy of affected skin showed thickening of collagen, CD34+ spindle cells, and increased mucin in the dermis, supporting the diagnosis of NSF. The clinical history and histopathological features of this case support the diagnosis of NSF 10 years after exposure to gadolinium. Although the use of gadolinium contrast agents in patients with kidney failure has markedly decreased, patients with exposure to gadolinium years to decades previously may manifest the disease.

Structural, optical and magnetic properties of gadolinium sesquioxide nanobars synthesized via thermal decomposition of gadolinium oxalate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manigandan, R.; Giribabu, K.; Suresh, R.

2013-10-15

Graphical abstract: - Highlights: • The cubic Gd{sub 2}O{sub 3} nanobars are synthesized by decomposition of C{sub 6}H{sub 20}Gd{sub 2}O{sub 22}. • The nanoparticles are rectangular bar shape with high porous surface. • The combination of magnetic and optical properties within a single particle. • The Gd{sub 2}O{sub 3} nanobars have tailorable nanostructure, wide bandgap and are paramagnetic. - Abstract: Gadolinium oxide nanobars were obtained by thermal decomposition of gadolinium oxalate, which was synthesized by the chemical precipitation method along with glycerol. The functional group analysis and formation of gadolinium oxide from gadolinium oxalate were characterized by the Fourier transformmore » infrared spectroscopy and thermo gravimetric analyzer. The crystal structure, average crystallite size, and lattice parameter were analyzed by X-ray diffraction technique. Moreover, Raman shifts, elemental composition and morphology of the gadolinium oxide was widely investigated by the laser Raman microscope, X-ray photoelectron spectroscopy, FE-SEM-EDAX and HR-TEM, respectively. Furthermore, the optical properties like band gap, absorbance measurement of the gadolinium oxide were extensively examined. In addition, the paramagnetic property of gadolinium oxide nanobars was explored by the vibrating sample magnetometer.« less

Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study.

PubMed

van Hamersvelt, Robbert W; Willemink, Martin J; de Jong, Pim A; Milles, Julien; Vlassenbroek, Alain; Schilham, Arnold M R; Leiner, Tim

2017-09-01

The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P < 0.001; ICCs > 0.99, CI 0.99-1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. • Gadolinium quantification may be useful in patients with contraindication to iodine. • Dual-layer spectral detector CT allows for overall accurate quantification of gadolinium. • Interscan variability of gadolinium quantification using SDCT material decomposition is excellent.

The dosimetric impact of gadolinium-based contrast media in GBM brain patient plans for a MRI-Linac

NASA Astrophysics Data System (ADS)

Bilal Ahmad, Syed; Paudel, Moti Raj; Sarfehnia, Arman; Kim, Anthony; Pang, Geordi; Ruschin, Mark; Sahgal, Arjun; Keller, Brian M.

2017-08-01

Dosimetric effects of gadolinium based contrast media (Gadovist) were evaluated for the Elekta MRI linear accelerator using the research version of the Monaco treatment planning system (TPS). In order to represent a gadolinium uptake, the contrast was manually assigned to a phantom as well as to the gross tumour volume (GTV) of 6 glioblastoma multiforme (GBM) patients. A preliminary estimate of the dose enhancement, due to gadolinium, was performed using the phantom irradiated with a single beam. A more complicated assessment was performed for the GBM patients using a 7 field IMRT technique. The material table in Monaco was modified in order to identify the presence of a non-biological material. The dose distribution was modelled using GPUMCD (MC algorithm in Monaco) for an unmodified (or default) material table (DMT) as well as for a modified (or custom) material table (CMT) for both the phantom and patients. Various concentrations ranging between 8 and 157 mg ml-1 were used to represent the gadolinium uptake in the patient’s GTV. It was assumed that the gadolinium concentration remained the same for the entire course of radiation treatment. Results showed that at the tissue-Gadovist interface, inside the phantom, dose scored using the DMT was 7% lower compared to that using the CMT for 157 mg ml-1 concentration of gadolinium. Dosimetric differences in the case of the patient study were measured using the DVH parameters. D 50% was higher by 6% when the DMT was used compared to the CMT for dose modelling for a gadolinium concentration of 157 mg ml-1. This difference decreased gradually with decreasing concentration of gadolinium. It was concluded that dosimetric differences can be quantified in Monaco if the tumour-gadolinium concentration is more than 23 mg ml-1. If the gadolinium concentration is lower than 23 mg ml-1, then a correction for the presence of gadolinium may not be necessary in the TPS.

The dosimetric impact of gadolinium-based contrast media in GBM brain patient plans for a MRI-Linac.

PubMed

Ahmad, Syed Bilal; Paudel, Moti Raj; Sarfehnia, Arman; Kim, Anthony; Pang, Geordi; Ruschin, Mark; Sahgal, Arjun; Keller, Brian M

2017-08-01

Dosimetric effects of gadolinium based contrast media (Gadovist) were evaluated for the Elekta MRI linear accelerator using the research version of the Monaco treatment planning system (TPS). In order to represent a gadolinium uptake, the contrast was manually assigned to a phantom as well as to the gross tumour volume (GTV) of 6 glioblastoma multiforme (GBM) patients. A preliminary estimate of the dose enhancement, due to gadolinium, was performed using the phantom irradiated with a single beam. A more complicated assessment was performed for the GBM patients using a 7 field IMRT technique. The material table in Monaco was modified in order to identify the presence of a non-biological material. The dose distribution was modelled using GPUMCD (MC algorithm in Monaco) for an unmodified (or default) material table (DMT) as well as for a modified (or custom) material table (CMT) for both the phantom and patients. Various concentrations ranging between 8 and 157 mg ml -1 were used to represent the gadolinium uptake in the patient's GTV. It was assumed that the gadolinium concentration remained the same for the entire course of radiation treatment. Results showed that at the tissue-Gadovist interface, inside the phantom, dose scored using the DMT was 7% lower compared to that using the CMT for 157 mg ml -1 concentration of gadolinium. Dosimetric differences in the case of the patient study were measured using the DVH parameters. D 50% was higher by 6% when the DMT was used compared to the CMT for dose modelling for a gadolinium concentration of 157 mg ml -1 . This difference decreased gradually with decreasing concentration of gadolinium. It was concluded that dosimetric differences can be quantified in Monaco if the tumour-gadolinium concentration is more than 23 mg ml -1 . If the gadolinium concentration is lower than 23 mg ml -1 , then a correction for the presence of gadolinium may not be necessary in the TPS.

Pediatric Patients Demonstrate Progressive T1-Weighted Hyperintensity in the Dentate Nucleus following Multiple Doses of Gadolinium-Based Contrast Agent.

PubMed

Roberts, D R; Chatterjee, A R; Yazdani, M; Marebwa, B; Brown, T; Collins, H; Bolles, G; Jenrette, J M; Nietert, P J; Zhu, X

2016-12-01

While there have been recent reports of brain retention of gadolinium following gadolinium-based contrast agent administration in adults, a retrospective series of pediatric patients has not previously been reported, to our knowledge. We investigated the relationship between the number of prior gadolinium-based contrast agent doses and increasing T1 signal in the dentate nucleus on unenhanced T1-weighted MR imaging. We hypothesized that despite differences in pediatric physiology and the smaller gadolinium-based contrast agent doses that pediatric patients are typically administered based on weighted-adjusted dosing, the pediatric brain would also demonstrate dose-dependent increasing T1 signal in the dentate nucleus. We included children with multiple gadolinium-based contrast agent administrations at our institution. A blinded reader placed ROIs within the dentate nucleus and adjacent cerebellar white matter. To eliminate reader bias, we also performed automated ROI delineation of the dentate nucleus, cerebellar white matter, and pons. Dentate-to-cerebellar white matter and dentate-to pons ratios were compared with the number of gadolinium-based contrast agent administrations. During 20 years at our institution, 280 patients received at least 5 gadolinium-based contrast agent doses, with 1 patient receiving 38 doses. Sixteen patients met the inclusion/exclusion criteria for ROI analysis. Blinded reader dentate-to-cerebellar white matter ratios were significantly associated with gadolinium-based contrast agent doses (r s = 0.77, P = .001). The dentate-to-pons ratio and dentate-to-cerebellar white matter ratios based on automated ROI placement were also significantly correlated with gadolinium-based contrast agent doses (t = 4.98, P < .0001 and t = 2.73, P < .02, respectively). In pediatric patients, the number of prior gadolinium-based contrast agent doses is significantly correlated with progressive T1-weighted dentate hyperintensity. Definitive confirmation of gadolinium deposition requires tissue analysis. Any potential clinical sequelae of gadolinium retention in the developing brain are unknown. Given this uncertainty, we suggest taking a cautious stance, including the use, in pediatric patients, of higher stability, macrocyclic agents, which in both human and animal studies have been shown to be associated with lower levels of gadolinium deposition, and detailed documentation of dosing. Most important, a patient should not be deprived of a well-indicated contrasted MR examination. © 2016 by American Journal of Neuroradiology.

Phenotypic expression in hypertrophic cardiomyopathy and late gadolinium enhancement on cardiac magnetic resonance.

PubMed

Caetano, Francisca; Botelho, Ana; Trigo, Joana; Silva, Joana; Almeida, Inês; Venâncio, Margarida; Pais, João; Sanches, Conceição; Leitão Marques, António

2014-05-01

The prognostic value of late gadolinium enhancement (LGE) for risk stratification of hypertrophic cardiomyopathy (HCM) patients is the subject of disagreement. We set out to examine the association between clinical and morphological variables, risk factors for sudden cardiac death and LGE in HCM patients. From a population of 78 patients with HCM, we studied 53 who underwent cardiac magnetic resonance. They were divided into two groups according to the presence or absence of LGE. Ventricular arrhythmias and morbidity and mortality during follow-up were analyzed. Patients with LGE were younger at the time of diagnosis (p=0.046) and more often had a family history of sudden death (p=0.008) and known coronary artery disease (p=0.086). On echocardiography they had greater maximum wall thickness (p=0.007) and left atrial area (p=0.037) and volume (p=0.035), and more often presented a restrictive pattern of diastolic dysfunction (p=0.011) with a higher E/É ratio (p=0.003) and left ventricular systolic dysfunction (p=0.038). Cardiac magnetic resonance supported the association between LGE and previous echocardiographic findings: greater left atrial area (p=0.029) and maximum wall thickness (p<0.001) and lower left ventricular ejection fraction (p=0.056). Patients with LGE more often had an implantable cardioverter-defibrillator (ICD) (p=0.015). At follow-up, no differences were found in the frequency of ventricular arrhythmias, appropriate ICD therapies or mortality. The presence of LGE emerges as a risk marker, associated with the classical predictors of sudden cardiac death in this population. However, larger studies are required to confirm its independent association with clinical events. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Effectiveness of late gadolinium enhancement to improve outcomes prediction in patients referred for cardiovascular magnetic resonance after echocardiography

PubMed Central

2013-01-01

Background Echocardiography (echo) is a first line test to assess cardiac structure and function. It is not known if cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) ordered during routine clinical practice in selected patients can add additional prognostic information after routine echo. We assessed whether CMR improves outcomes prediction after contemporaneous echo, which may have implications for efforts to optimize processes of care, assess effectiveness, and allocate limited health care resources. Methods and results We prospectively enrolled 1044 consecutive patients referred for CMR. There were 38 deaths and 3 cardiac transplants over a median follow-up of 1.0 years (IQR 0.4-1.5). We first reproduced previous survival curve strata (presence of LGE and ejection fraction (EF) < 50%) for transplant free survival, to support generalizability of any findings. Then, in a subset (n = 444) with contemporaneous echo (median 3 days apart, IQR 1–9), EF by echo (assessed visually) or CMR were modestly correlated (R2 = 0.66, p < 0.001), and 30 deaths and 3 transplants occurred over a median follow-up of 0.83 years (IQR 0.29-1.40). CMR EF predicted mortality better than echo EF in univariable Cox models (Integrated Discrimination Improvement (IDI) 0.018, 95% CI 0.008-0.034; Net Reclassification Improvement (NRI) 0.51, 95% CI 0.11-0.85). Finally, LGE further improved prediction beyond EF as determined by hazard ratios, NRI, and IDI in all Cox models predicting mortality or transplant free survival, adjusting for age, gender, wall motion, and EF. Conclusions Among those referred for CMR after echocardiography, CMR with LGE further improves risk stratification of individuals at risk for death or death/cardiac transplant. PMID:23324403

Does stress perfusion imaging improve the diagnostic accuracy of late gadolinium enhanced cardiac magnetic resonance for establishing the etiology of heart failure?

PubMed

Gulsin, Gaurav S; Shetye, Abishek; Khoo, Jeffrey; Swarbrick, Daniel J; Levelt, Eylem; Lai, Florence Y; Squire, Iain B; Arnold, Jayanth R; McCann, Gerry P

2017-04-08

Late gadolinium enhanced cardiovascular magnetic resonance (LGE-CMR) has excellent specificity, sensitivity and diagnostic accuracy for differentiating between ischemic cardiomyopathy (ICM) and non-ischemic dilated cardiomyopathy (NICM). CMR first-pass myocardial perfusion imaging (perfusion-CMR) may also play role in distinguishing heart failure of ischemic and non-ischemic origins, although the utility of additional of stress perfusion imaging in such patients is unclear. The aim of this retrospective study was to assess whether the addition of adenosine stress perfusion imaging to LGE-CMR is of incremental value for differentiating ICM and NICM in patients with severe left ventricular systolic dysfunction (LVSD) of uncertain etiology. We retrospectively identified 100 consecutive adult patients (median age 69 years (IQR 59-73)) with severe LVSD (mean LV EF 26.6 ± 7.0%) referred for perfusion-CMR to establish the underlying etiology of heart failure. The cause of heart failure was first determined on examination of CMR cine and LGE images in isolation. Subsequent examination of complete adenosine stress perfusion-CMR studies (cine, LGE and perfusion images) was performed to identify whether this altered the initial diagnosis. On LGE-CMR, 38 patients were diagnosed with ICM, 46 with NICM and 16 with dual pathology. With perfusion-CMR, there were 39 ICM, 44 NICM and 17 dual pathology diagnoses. There was excellent agreement in diagnoses between LGE-CMR and perfusion-CMR (κ 0.968, p<0.001). The addition of adenosine stress perfusion images to LGE-CMR altered the diagnosis in only two of the 100 patients. The addition of adenosine stress perfusion-CMR to cine and LGE-CMR provides minimal incremental diagnostic yield for determining the etiology of heart failure in patients with severe LVSD.

Evaluation of state-of-the-art segmentation algorithms for left ventricle infarct from late Gadolinium enhancement MR images.

PubMed

Karim, Rashed; Bhagirath, Pranav; Claus, Piet; James Housden, R; Chen, Zhong; Karimaghaloo, Zahra; Sohn, Hyon-Mok; Lara Rodríguez, Laura; Vera, Sergio; Albà, Xènia; Hennemuth, Anja; Peitgen, Heinz-Otto; Arbel, Tal; Gonzàlez Ballester, Miguel A; Frangi, Alejandro F; Götte, Marco; Razavi, Reza; Schaeffter, Tobias; Rhode, Kawal

2016-05-01

Studies have demonstrated the feasibility of late Gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging for guiding the management of patients with sequelae to myocardial infarction, such as ventricular tachycardia and heart failure. Clinical implementation of these developments necessitates a reproducible and reliable segmentation of the infarcted regions. It is challenging to compare new algorithms for infarct segmentation in the left ventricle (LV) with existing algorithms. Benchmarking datasets with evaluation strategies are much needed to facilitate comparison. This manuscript presents a benchmarking evaluation framework for future algorithms that segment infarct from LGE CMR of the LV. The image database consists of 30 LGE CMR images of both humans and pigs that were acquired from two separate imaging centres. A consensus ground truth was obtained for all data using maximum likelihood estimation. Six widely-used fixed-thresholding methods and five recently developed algorithms are tested on the benchmarking framework. Results demonstrate that the algorithms have better overlap with the consensus ground truth than most of the n-SD fixed-thresholding methods, with the exception of the Full-Width-at-Half-Maximum (FWHM) fixed-thresholding method. Some of the pitfalls of fixed thresholding methods are demonstrated in this work. The benchmarking evaluation framework, which is a contribution of this work, can be used to test and benchmark future algorithms that detect and quantify infarct in LGE CMR images of the LV. The datasets, ground truth and evaluation code have been made publicly available through the website: https://www.cardiacatlas.org/web/guest/challenges. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Wideband late gadolinium enhanced magnetic resonance imaging for imaging myocardial scar without image artefacts induced by implantable cardioverter-defibrillator: a feasibility study at 3 T

PubMed Central

Ranjan, Ravi; McGann, Christopher J.; Jeong, Eun-Kee; Hong, KyungPyo; Kholmovski, Eugene G.; Blauer, Josh; Wilson, Brent D.; Marrouche, Nassir F.; Kim, Daniel

2015-01-01

Aim Late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) is a useful tool for facilitating ventricular tachycardia (VT) ablation. Unfortunately, most VT ablation candidates often have prophylactic implantable cardioverter-defibrillator (ICD) and do not undergo cardiac MRI largely due to image artefacts generated by ICD. A prior study has reported success of ‘wideband’ LGE MRI for imaging myocardial scar without image artefacts induced by ICD at 1.5T. The purpose of this study was to widen the availability of wideband LGE MRI to 3T, since it has the potential to achieve higher spatial resolution than 1.5T. Methods and results We compared the performance of standard and wideband LGE MRI pulse sequences in phantoms and canines with myocardial lesions created by radiofrequency ablation. Standard LGE MRI produced image artefacts induced by ICD and 49% accuracy in detecting 97 myocardial scars examined in this study, whereas wideband LGE MRI produced artefact-free images and 94% accuracy in detecting scars. The mean image quality score (1 = nondiagnostic, 2 = poor, 3 = adequate, 4 = good, 5 = excellent) was significantly (P < 0.001) higher for wideband (3.7 ± 0.8) than for standard LGE MRI (2.1 ± 0.7). The mean artefact level score (1 = minimal, 2 = mild, 3 = moderate, 4 = severe, 5 = nondiagnostic) was significantly (P < 0.001) lower for wideband (2.1 ± 0.8) than for standard LGE MRI (4.0 ± 0.6). Wideband LGE MRI agreed better with gross pathology than standard LGE MRI. Conclusion This study demonstrates the feasibility of wideband LGE MRI for suppression of image artefacts induced by ICD at 3T. PMID:25336666

Improved dark blood late gadolinium enhancement (DB-LGE) imaging using an optimized joint inversion preparation and T2 magnetization preparation.

PubMed

Basha, Tamer A; Tang, Maxine C; Tsao, Connie; Tschabrunn, Cory M; Anter, Elad; Manning, Warren J; Nezafat, Reza

2018-01-01

To develop a dark blood-late gadolinium enhancement (DB-LGE) sequence that improves scar-blood contrast and delineation of scar region. The DB-LGE sequence uses an inversion pulse followed by T 2 magnetization preparation to suppress blood and normal myocardium. Time delays inserted after preparation pulses and T 2 -magnetization-prep duration are used to adjust tissue contrast. Selection of these parameters was optimized using numerical simulations and phantom experiments. We evaluated DB-LGE in 9 swine and 42 patients (56 ± 14 years, 33 male). Improvement in scar-blood contrast and overall image quality was subjectively evaluated by two independent readers (1 = poor, 4 = excellent). The signal ratios among scar, blood, and myocardium were compared. Simulations and phantom studies demonstrated that simultaneous nulling of myocardium and blood can be achieved by selecting appropriate timing parameters. The scar-blood contrast score was significantly higher for DB-LGE (P < 0.001) with no significant difference in overall image quality (P > 0.05). Scar-blood signal ratios for DB-LGE versus LGE were 5.0 ± 2.8 versus 1.5 ± 0.5 (P < 0.001) for patients, and 2.2 ± 0.7 versus 1.0 ± 0.4 (P = 0.0023) for animals. Scar-myocardium signal ratios were 5.7 ± 2.9 versus 6.3 ± 2.6 (P = 0.35) for patients, and 3.7 ± 1.1 versus 4.1 ± 2.0 (P = 0.60) for swine. The DB-LGE sequence simultaneously reduces normal myocardium and blood signal intensity, thereby enhancing scar-blood contrast while preserving scar-myocardium contrast. Magn Reson Med 79:351-360, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Incremental prognostic value of the SYNTAX score to late gadolinium-enhanced magnetic resonance images for patients with stable coronary artery disease.

PubMed

Kato, Shingo; Saito, Naka; Kirigaya, Hidekuni; Gyotoku, Daiki; Iinuma, Naoki; Kusakawa, Yuka; Iguchi, Kohei; Nakachi, Tatsuya; Fukui, Kazuki; Futaki, Masaaki; Iwasawa, Tae; Taguri, Masataka; Kimura, Kazuo; Umemura, Satoshi

2016-06-01

The prognostic significance of the SYNTAX (Synergy between PCI with Taxus and cardiac surgery) score has recently been demonstrated in patients with stable multivessel or left main coronary artery disease (CAD). The present study determines whether adding the SYNTAX score to Framingham risk score (FRS), left ventricular ejection fraction (LVEF) and presence of myocardial infarction (MI) by late gadolinium enhancement (LGE) magnetic resonance imaging can improve the risk stratification in patients with stable CAD. We calculated the SYNTAX score in 161 patients with stable CAD (mean age: 66 ± 10 years old). During a mean follow-up of 2.3 years, 56 (35 %) of 161 patients developed cardiovascular events defined as cardiovascular death, non-fatal MI, cerebral infarction, unstable angina pectoris, hospitalization due to heart failure and revascularization. Multivariate Cox regression analysis selected triglycerides [hazard ratio (HR): 1.005 (95 % confidence interval (CI): 1.001-1.008), p < 0.008], presence of LGE [HR: 6.329 (95 % CI: 2.662-15.05), p < 0.001] and the SYNTAX score [HR: 1.085 (95 % CI: 1.044-1.127), p < 0.001] as risk factors for future cardiovascular events. Adding the SYNTAX score to FRS, EF and LGE significantly improved the net reclassification index (NRI) [40.4 % (95 % CI: 18.1-54.8 %), p < 0.05] with an increase in C-statistics of 0.089 (from 0.707 to 0.796). An increase in C-statistics and significant improvement of NRI showed that adding the SYNTAX score to the FRS, LVEF and LGE incrementally improved risk stratification in patient with stable CAD.

High mass (>18g) of late gadolinium enhancement on CMR imaging is associated with major cardiac events on long-term outcome in patients with biopsy-proven extracardiac sarcoidosis.

PubMed

Agoston-Coldea, Lucia; Kouaho, Sylvain; Sacre, Karim; Dossier, Antoine; Escoubet, Brigitte; Chillon, Sylvie; Laissy, Jean-Pierre; Rouzet, François; Kutty, Shelby; Extramiana, Fabrice; Leenhardt, Antoine; Borie, Raphael; Crestani, Bruno; Ou, Phalla

2016-11-01

Cardiac involvement is the most important cause of mortality in patients with systemic sarcoidosis. Late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging (CMR) has been shown to be a predictor of major cardiovascular adverse events (MACE) in the setting of systemic sarcoidosis. We sought to evaluate the relationship between LGE mass and adverse long-term outcome in patients with biopsy-proven extracardiac sarcoidosis. Between 2001 and 2013, 197 consecutive patients with suspected cardiac sarcoidosis were identified in our institution database. Of them, 56 patients have had biopsy-proven extracardiac sarcoidosis and represented our studied population. Patients were divided into two groups based on LGE mass by a median value (mild LGE<18g, high LGE>18g) for comparison of MACE. Twenty-eight patients had a high mass of LGE. Of them, 15 (54%) experienced MACE (OR=31.15, 95% CI 3.7-262). Except for 1 patient, no patient with mild LGE presented with any MACE during follow-up (median of 32months). Patients with high LGE had lower CMR-derived left (53.6±14.9 vs. 62.2±6.7, p<0.01) and right (49.1±11.5 vs. 56.4±9.2, p<0.05) ventricular ejection fractions. LGE mass of 18g discriminated patients with and without MACE (93% sensitivity, 88% specificity, AUC=0.972). LGE mass was the only independent predictor of MACE on multivariate Cox analysis adjusted (OR=1.7, 95% CI 1.06 to 2.72, p=0.03). In biopsy-proven extracardiac sarcoidosis patients, a high mass of LGE >18g was associated with MACE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Later Onset Fabry Disease, Cardiac Damage Progress in Silence: Experience With a Highly Prevalent Mutation.

PubMed

Hsu, Ting-Rong; Hung, Sheng-Che; Chang, Fu-Pang; Yu, Wen-Chung; Sung, Shih-Hsien; Hsu, Chia-Lin; Dzhagalov, Ivan; Yang, Chia-Feng; Chu, Tzu-Hung; Lee, Han-Jui; Lu, Yung-Hsiu; Chang, Sheng-Kai; Liao, Hsuan-Chieh; Lin, Hsiang-Yu; Liao, Tsan-Chieh; Lee, Pi-Chang; Li, Hsing-Yuan; Yang, An-Hang; Ho, Hui-Chen; Chiang, Chuan-Chi; Lin, Ching-Yuang; Desnick, Robert J; Niu, Dau-Ming

2016-12-13

Recently, several studies revealed a much higher prevalence of later onset Fabry disease (FD) than previously expected. It suggested that later onset FD might present as an important hidden health issue in certain ethnic or demographic populations in the world. However, the natural history of its phenotype has not been systemically investigated, especially the cardiac involvement. The study analyzed a large-scale newborn screening program for FD to understand the natural course of later onset FD. To date, 916,383 newborns have been screened for FD in Taiwan, including more than 1,200 individuals with the common, later onset IVS4+919G>A (IVS4) mutation. Echocardiography was performed in 620 adults with the IVS4 mutation to analyze the prevalence of left ventricular hypertrophy (LVH), and gadolinium-enhanced cardiac magnetic resonance imaging was performed in 129 patients with FD, including 100 IVS4 adults. LVH was observed in 67% of men and 32% of women older than 40 years. Imaging evidenced significant late gadolinium enhancement in 38.1% of IVS4 men and 16.7% of IVS4 women with the IVS4 mutation but without LVH. Seventeen patients underwent endomyocardial biopsies, which revealed significant globotriaosylceramide substrate accumulation in their cardiomyocytes. Significant cardiomyocyte substrate accumulation in IVS4 patients led to severe and irreversible cardiac fibrosis before development of LVH or other significant cardiac manifestations. Thus, it might be too late to start enzyme replacement therapy after the occurrence of LVH or other significant cardiac manifestations in patients with later onset FD. This study also indicated the importance of newborn screening for early detection of the insidious, ongoing, irreversible cardiac damage in patients with later onset FD. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Clinical predictors of cardiac magnetic resonance late gadolinium enhancement in patients with atrial fibrillation.

PubMed

Chrispin, Jonathan; Ipek, Esra Gucuk; Habibi, Mohammadali; Yang, Eunice; Spragg, David; Marine, Joseph E; Ashikaga, Hiroshi; Rickard, John; Berger, Ronald D; Zimmerman, Stefan L; Calkins, Hugh; Nazarian, Saman

2017-03-01

This study aims to examine the association of clinical co-morbidities with the presence of left atrial (LA) late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). Previous studies have established the severity of LA LGE to be associated with atrial fibrillation (AF) recurrence following AF ablation. We sought to determine whether baseline clinical characteristics were associated with LGE extent among patients presenting for an initial AF ablation. The cohort consisted of 179 consecutive patients with no prior cardiac ablation procedures who underwent pre-procedure LGE-CMR. The extent of LA LGE for each patient was calculated using the image intensity ratio, normalized to the mean blood pool intensity, corresponding to a bipolar voltage ≤0.3 mV. The association of LGE extent with baseline clinical characteristics was examined using non-parametric and multivariable models. The mean age of the cohort was 60.9 ± 9.6 years and 128 (72%) were male. In total, 56 (31%) patients had persistent AF. The mean LA volume was 118.4 ± 41.6 mL, and the mean LA LGE extent was 14.1 ± 10.4%. There was no association with any clinical variables with LGE extent by quartiles in the multivariable model. Extent of LGE as a continuous variable was positively, but weakly associated with LA volume in a multivariable model adjusting for age, body mass index, AF persistence, and left ventricular ejection fraction (1.5% scar/mL, P = 0.038). In a cohort of patients presenting for initial AF ablation, the presence of pre-ablation LA LGE extent was weakly, but positively associated with increasing LA volume. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Universal time-dependent dispersion properties for diffusion in a one-dimensional critically tilted potential.

PubMed

Guérin, T; Dean, D S

2017-01-01

We consider the time-dependent dispersion properties of overdamped tracer particles diffusing in a one-dimensional periodic potential under the influence of an additional constant tilting force F. The system is studied in the region where the force is close to the critical value F_{c} at which the barriers separating neighboring potential wells disappear. We show that, when F crosses the critical value, the shape of the mean-square displacement (MSD) curves is strongly modified. We identify a diffusive regime at intermediate-time scales with an effective diffusion coefficient which is much larger than the late-time diffusion coefficient for F>F_{c}, whereas for F

Pathophysiology of gadolinium-associated systemic fibrosis

PubMed Central

Drel, Viktor; Gorin, Yves

2016-01-01

Systemic fibrosis from gadolinium-based magnetic resonance imaging contrast is a scourge for the afflicted. Although gadolinium-associated systemic fibrosis is a rare condition, the threat of litigation has vastly altered clinical practice. Most theories concerning the etiology of the fibrosis are grounded in case reports rather than experiment. This has led to the widely accepted conjecture that the relative affinity of certain contrast agents for the gadolinium ion inversely correlates with the risk of succumbing to the disease. How gadolinium-containing contrast agents trigger widespread and site-specific systemic fibrosis and how chronicity is maintained are largely unknown. This review highlights experimentally-derived information from our laboratory and others that pertain to our understanding of the pathophysiology of gadolinium-associated systemic fibrosis. PMID:27147669

Progression of Hypertrophy and Myocardial Fibrosis in Aortic Stenosis: A Multicenter Cardiac Magnetic Resonance Study.

PubMed

Everett, Russell J; Tastet, Lionel; Clavel, Marie-Annick; Chin, Calvin W L; Capoulade, Romain; Vassiliou, Vassilios S; Kwiecinski, Jacek; Gomez, Miquel; van Beek, Edwin J R; White, Audrey C; Prasad, Sanjay K; Larose, Eric; Tuck, Christopher; Semple, Scott; Newby, David E; Pibarot, Philippe; Dweck, Marc R

2018-06-01

Aortic stenosis is accompanied by progressive left ventricular hypertrophy and fibrosis. We investigated the natural history of these processes in asymptomatic patients and their potential reversal post-aortic valve replacement (AVR). Asymptomatic and symptomatic patients with aortic stenosis underwent repeat echocardiography and magnetic resonance imaging. Changes in peak aortic-jet velocity, left ventricular mass index, diffuse fibrosis (indexed extracellular volume), and replacement fibrosis (late gadolinium enhancement [LGE]) were quantified. In 61 asymptomatic patients (43% mild, 34% moderate, and 23% severe aortic stenosis), significant increases in peak aortic-jet velocity, left ventricular mass index, indexed extracellular volume, and LGE mass were observed after 2.1±0.7 years, with the most rapid progression observed in patients with most severe stenosis. Patients with baseline midwall LGE (n=16 [26%]; LGE mass, 2.5 g [0.8-4.8 g]) demonstrated particularly rapid increases in scar burden (78% [50%-158%] increase in LGE mass per year). In 38 symptomatic patients (age, 66±8 years; 76% men) who underwent AVR, there was a 19% (11%-25%) reduction in left ventricular mass index ( P <0.0001) and an 11% (4%-16%) reduction in indexed extracellular volume ( P =0.003) 0.9±0.3 years after surgery. By contrast midwall LGE (n=10 [26%]; mass, 3.3 g [2.6-8.0 g]) did not change post-AVR (n=10; 3.5 g [2.1-8.0 g]; P =0.23), with no evidence of regression even out to 2 years. In patients with aortic stenosis, cellular hypertrophy and diffuse fibrosis progress in a rapid and balanced manner but are reversible after AVR. Once established, midwall LGE also accumulates rapidly but is irreversible post valve replacement. Given its adverse long-term prognosis, prompt AVR when midwall LGE is first identified may improve clinical outcomes. URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01755936 and NCT01679431. © 2018 The Authors.

Using late arriving photons for diffuse optical tomography of biological objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Proskurin, S G

2011-05-31

The issues of detecting the inhomogeneities are studied aimed at mapping the distribution of absorption and scattering in soft tissues. A modification of the method of diffuse optical tomography is proposed for detecting directly and determining the region of spatial localisation of such absorbing and scattering inhomogeneities as a cyst, a hematoma, a tumour, as well as for measuring the degree of oxygenation or deoxygenation of blood, in which the late arriving photons that diffuse through the scattering object are used. (optical technologies in biophysics and medicine)

Diffusion properties of conventional and calcium-sensitive MRI contrast agents in the rat cerebral cortex.

PubMed

Hagberg, Gisela E; Mamedov, Ilgar; Power, Anthony; Beyerlein, Michael; Merkle, Hellmut; Kiselev, Valerij G; Dhingra, Kirti; Kubìček, Vojtĕch; Angelovski, Goran; Logothetis, Nikos K

2014-01-01

Calcium-sensitive MRI contrast agents can only yield quantitative results if the agent concentration in the tissue is known. The agent concentration could be determined by diffusion modeling, if relevant parameters were available. We have established an MRI-based method capable of determining diffusion properties of conventional and calcium-sensitive agents. Simulations and experiments demonstrate that the method is applicable both for conventional contrast agents with a fixed relaxivity value and for calcium-sensitive contrast agents. The full pharmacokinetic time-course of gadolinium concentration estimates was observed by MRI before, during and after intracerebral administration of the agent, and the effective diffusion coefficient D* was determined by voxel-wise fitting of the solution to the diffusion equation. The method yielded whole brain coverage with a high spatial and temporal sampling. The use of two types of MRI sequences for sampling of the diffusion time courses was investigated: Look-Locker-based quantitative T(1) mapping, and T(1) -weighted MRI. The observation times of the proposed MRI method is long (up to 20 h) and consequently the diffusion distances covered are also long (2-4 mm). Despite this difference, the D* values in vivo were in agreement with previous findings using optical measurement techniques, based on observation times of a few minutes. The effective diffusion coefficient determined for the calcium-sensitive contrast agents may be used to determine local tissue concentrations and to design infusion protocols that maintain the agent concentration at a steady state, thereby enabling quantitative sensing of the local calcium concentration. Copyright © 2014 John Wiley & Sons, Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, Ranu, E-mail: ranu.dutta16@gmail.com; NanoeRA Medicare Private Limited, Uttar Pradesh; Pandey, Avinash C.

Gadolinium chelates and gadolinium based inorganic nanoparticles have been extensively studied, because of the high magnetic moment of gadolinium. Here, metallic gadolinium nanocongregates have been developed. Upon injecting these nanoparticles in the mice, they initially circulate in the blood stream and are localized at the cancer site, which could be visualized upon application of magnetic field hence acting as small magnetic nanosensors searching for even small cancers, detecting cancers at a very early stage.

Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

PubMed

Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K; Varani, James

2012-12-01

Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

Technical aspects of MRI signal change quantification after gadolinium-based contrast agents' administration.

PubMed

Ramalho, Joana; Ramalho, Miguel; AlObaidy, Mamdoh; Semelka, Richard C

2016-12-01

Over the last 2years several studies have been published regarding gadolinium deposition in brain structures in patients with normal renal function after repeated administrations of gadolinium-based contrast agents (GBCAs). Most of the publications are magnetic resonance imaging (MRI) based retrospective studies, where gadolinium deposition may be indirectly measured by evaluating changes in T1 signal intensity (SI) in brain tissue, particularly in the dentate nucleus (DN) and/or globus pallidi (GP). The direct correlation between T1 signal changes and gadolinium deposition was validated by human pathology studies. However, the variability of the MR equipment and parameters used across different publications, along with the inherent limitations of MRI to assess gadolinium in human tissues should be acknowledged when interpreting those studies. Nevertheless, MRI studies remain essential regarding gadolinium bio-distribution knowledge. The aim of this paper is to overview current knowledge of technical aspects of T1 signal intensity evaluation by MRI and describe confounding factors, with the intention to achieve higher accuracy and maximize reproducibility. Copyright © 2016 Elsevier Inc. All rights reserved.

Solute Transport of Negatively Charged Contrast Agents Across Articular Surface of Injured Cartilage.

PubMed

Kokkonen, H T; Chin, H C; Töyräs, J; Jurvelin, J S; Quinn, T M

2017-04-01

Solute transport through the extracellular matrix (ECM) is crucial to chondrocyte metabolism. Cartilage injury affects solute transport in cartilage due to alterations in ECM structure and solute-matrix interactions. Therefore, cartilage injury may be detected by using contrast agent-based clinical imaging. In the present study, effects of mechanical injury on transport of negatively charged contrast agents in cartilage were characterized. Using cartilage plugs injured by mechanical compression protocol, effective partition coefficients and diffusion fluxes of iodine- and gadolinium-based contrast agents were measured using high resolution microCT imaging. For all contrast agents studied, effective diffusion fluxes increased significantly, particularly at early times during the diffusion process (38 and 33% increase after 4 min, P < 0.05 for iodine and Gd-DTPA; and 76% increase after 10 min for diatrizoate, P < 0.05). Effective partition coefficients were unaffected in mechanically injured cartilage. Mechanical injury reduced PG content and collagen integrity in cartilage superficial zone. This study suggests that alterations in contrast agent diffusion flux, a non-equilibrium transport parameter, provides a more sensitive indicator for assessment of cartilage matrix integrity than partition coefficient and the equilibrium distribution of solute. These findings may help in developing clinical methods of contrast agent-based imaging to detect cartilage injury.

Magnetic resonance and confocal imaging of solute penetration into the lens reveals a zone of restricted extracellular space diffusion.

PubMed

Vaghefi, Ehsan; Walker, Kerry; Pontre, Beau P; Jacobs, Marc D; Donaldson, Paul J

2012-06-01

It has been proposed that in the absence of blood supply, the ocular lens operates an internal microcirculation system that delivers nutrients to internalized fiber cells faster and more efficiently than would occur by passive diffusion alone. To visualize the extracellular space solute fluxes potentially generated by this system, bovine lenses were organ cultured in artificial aqueous humor (AAH) for 4 h in the presence or absence of two gadolinium-based contrast agents, ionic Gd(3+), or a chelated form of Gd(3+), Gd-diethylenetriamine penta-acetic acid (Gd-DTPA; mol mass = 590 Da). Contrast reagent penetration into the lens core was monitored in real time using inversion recovery-spin echo (IR-SE) magnetic resonance imaging (MRI), while steady-state accumulation of [Gd-DTPA](-2) was also determined by calculating T1 values. After incubation, lenses were fixed and cryosectioned, and sections were labeled with the membrane marker wheat germ agglutinin (WGA). Sections were imaged by confocal microscopy using standard and reflectance imaging modalities to visualize the fluorescent WGA label and gadolinium reagents, respectively. Real-time IR-SE MRI showed rapid penetration of Gd(3+) into the outer cortex of the lens and a subsequent bloom of signal in the core. These two areas of signal were separated by an area in the inner cortex that limited entry of Gd(3+). Similar results were obtained for Gd-DTPA, but the penetration of the larger negatively charged molecule into the core could only be detected by calculating T1 values. The presence of Gd-DTPA in the extracellular space of the outer cortex and core, but its apparent absence from the inner cortex was confirmed using reflectance imaging of equatorial sections. In axial sections, Gd-DTPA was associated with the sutures, suggesting these structures provide a pathway from the surface, across the inner cortex barrier to the lens core. Our studies have revealed inner and outer boundaries of a zone within which a narrowing of the extracellular space restricts solute diffusion and acts to direct fluxes into the lens core via the sutures.

Growth Control in Colon Epithelial Cells: Gadolinium Enhances Calcium-Mediated Growth Regulation

PubMed Central

Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K.

2013-01-01

Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1–5 µM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet. PMID:23008064

Gadolinium Deposition in Human Brain Tissues after Contrast-enhanced MR Imaging in Adult Patients without Intracranial Abnormalities.

PubMed

McDonald, Robert J; McDonald, Jennifer S; Kallmes, David F; Jentoft, Mark E; Paolini, Michael A; Murray, David L; Williamson, Eric E; Eckel, Laurence J

2017-11-01

Purpose To determine whether gadolinium deposits in neural tissues of patients with intracranial abnormalities following intravenous gadolinium-based contrast agent (GBCA) exposure might be related to blood-brain barrier integrity by studying adult patients with normal brain pathologic characteristics. Materials and Methods After obtaining antemortem consent and institutional review board approval, the authors compared postmortem neuronal tissue samples from five patients who had undergone four to 18 gadolinium-enhanced magnetic resonance (MR) examinations between 2005 and 2014 (contrast group) with samples from 10 gadolinium-naive patients who had undergone at least one MR examination during their lifetime (control group). All patients in the contrast group had received gadodiamide. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy with energy-dispersive x-ray spectroscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Results Tissues from the four neuroanatomic regions of gadodiamide-exposed patients contained 0.1-19.4 μg of gadolinium per gram of tissue in a statistically significant dose-dependent relationship (globus pallidus: ρ = 0.90, P = .04). In contradistinction, patients in the control group had undetectable levels of gadolinium with ICP-MS. All patients had normal brain pathologic characteristics at autopsy. Three patients in the contrast group had borderline renal function (estimated glomerular filtration rate <45 mL/min/1.73 m 2 ) and hepatobiliary dysfunction at MR examination. Gadolinium deposition in the contrast group was localized to the capillary endothelium and neuronal interstitium and, in two cases, within the nucleus of the cell. Conclusion Gadolinium deposition in neural tissues after GBCA administration occurs in the absence of intracranial abnormalities that might affect the permeability of the blood-brain barrier. These findings challenge current understanding of the biodistribution of these contrast agents and their safety. © RSNA, 2017.

Two cases of traumatic head injury mimicking acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Nishiyama, Masahiro; Fujita, Kyoko; Maruyama, Azusa; Nagase, Hiroaki

2014-11-01

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) presents a distinct clinical course of biphasic seizures and impaired consciousness. These symptoms are followed by reduced diffusion in the subcortical white matter on magnetic resonance imaging that is typically observed between 3 and 9 days after illness onset. Here, we report two cases of traumatic head injury with clinical and radiological features similar to those for AESD. The similarities between our cases and AESD may be useful in understanding the pathogenesis of AESD. Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

In vitro comparison of intracranial stent visibility using various concentrations of gadolinium contrast agent under 1.5 T and 3 T MR angiography.

PubMed

Chiang, Chen-Hua; Tseng, Ying-Chi; Chen, Ai-Chi; Huang, Yen-Lin; Chen, David Yen-Ting; Chen, Chi-Jen; Lin, Yen-Kuang; Hsu, Hui-Ling

2017-04-01

MR angiography (MRA) is an increasingly used evaluation method following intracranial stenting. However, the various artifacts created by the stent limit this technique. The purpose of this study was to investigate the effects of various concentrations of gadolinium contrast agent on the visibility and signal characteristics of two stents using the a contrast enhanced MRA technique. Two intracranial stents (Enterprise and Helistent) were placed in polyvinyl chloride tubes as vascular phantoms. They were filled with six different doses of gadolinium contrast agent (1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 mmol/L dimeglumine gadopentetate, respectively) and imaged using 3 T and 1.5 T MR systems. Relative in-stent signal (RIS) was calculated and artificial luminal narrowing (ALN) was obtained using pixel by pixel analysis. The Enterprise stent, performed in both 1.5 T and 3 T MR systems, showed mean RIS values much less than those for the Helistent for all different doses of gadolinium solution. Increased gadolinium concentration resulted in a gradual reduction in RIS values in the Enterprise group. Also, ALN in the Enterprise group showed no or little change with various gadolinium doses. The Enterprise stent demonstrated good luminal visibility regardless of gadolinium concentration. The relative in-stent signals were more predictable in the Enterprise stent with various doses of gadolinium. Therefore, the Enterprise stent has been shown to provide better in-stent visibility compared with the Helistent using various gadolinium doses. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Gadolinium Use in Spine Pain Management Procedures for Patients with Contrast Allergies: Results in 527 Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safriel, Yair; Ang, Roberto; Ali, Muhammed

2008-03-15

Introduction. To review the safety and efficacy of gadolinium in spine pain management procedures in patients at high risk for a contrast reaction and who are not suitable candidates for the use of standard non-ionic contrast. Methods. We reviewed records over a 61-month period of all image-guided spinal pain management procedures where patients had allergies making them unsuitable candidates for standard non-ionic contrast and where gadolinium was used to confirm needle tip placement prior to injection of medication. Results. Three hundred and four outpatients underwent 527 procedures. A spinal needle was used in all but 41 procedures. Gadolinium was visualizedmore » using portable C-arm fluoroscopy in vivo allowing for confirmation of needle tip location. The gadolinium dose ranged from 0.2 to 10 ml per level. The highest dose received by one patient was 15.83 ml intradiscally during a three-level discogram. Three hundred and one patients were discharged without complication or known delayed complications. One patient had documented intrathecal injection but without sequelae and 2 patients who underwent cervical procedures experienced seizures requiring admission to the intensive care unit. Both the latter patients were discharged without any further complications. Conclusion. Based on our experience we recommend using gadolinium judiciously for needle tip confirmation. We feel more confident using gadolinium in the lumbar spine and in cervical nerve blocks. Gadolinium should probably not be used as an injectate volume expander. The indications for gadolinium use in cervical needle-guided spine procedures are less clear and use of a blunt-tipped needle should be considered.« less

Kubo formulas for dispersion in heterogeneous periodic nonequilibrium systems.

PubMed

Guérin, T; Dean, D S

2015-12-01

We consider the dispersion properties of tracer particles moving in nonequilibrium heterogeneous periodic media. The tracer motion is described by a Fokker-Planck equation with arbitrary spatially periodic (but constant in time) local diffusion tensors and drifts, eventually with the presence of obstacles. We derive a Kubo-like formula for the time-dependent effective diffusion tensor valid in any dimension. From this general formula, we derive expressions for the late time effective diffusion tensor and drift in these systems. In addition, we find an explicit formula for the late finite-time corrections to these transport coefficients. In one dimension, we give a closed analytical formula for the transport coefficients. The formulas derived here are very general and provide a straightforward method to compute the dispersion properties in arbitrary nonequilibrium periodic advection-diffusion systems.

Coronary microvascular function and myocardial fibrosis in women with angina pectoris and no obstructive coronary artery disease: the iPOWER study.

PubMed

Mygind, Naja Dam; Michelsen, Marie Mide; Pena, Adam; Qayyum, Abbas Ali; Frestad, Daria; Christensen, Thomas Emil; Ghotbi, Adam Ali; Dose, Nynne; Faber, Rebekka; Vejlstrup, Niels; Hasbak, Philip; Kjaer, Andreas; Prescott, Eva; Kastrup, Jens

2016-11-04

Even in absence of obstructive coronary artery disease women with angina pectoris have a poor prognosis possibly due to coronary microvascular disease. Coronary microvascular disease can be assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve (CFVR) and by positron emission tomography measuring myocardial blood flow reserve (MBFR). Diffuse myocardial fibrosis can be assessed by cardiovascular magnetic resonance (CMR) T1 mapping. We hypothesized that coronary microvascular disease is associated with diffuse myocardial fibrosis. Women with angina, a clinically indicated coronary angiogram with <50 % stenosis and no diabetes were included. CFVR was measured using dipyridamole (0.84 mg/kg) and MBFR using adenosine (0.84 mg/kg). Focal fibrosis was assessed by 1.5 T CMR late gadolinium enhancement (0.1 mmol/kg) and diffuse myocardial fibrosis by T1 mapping using a modified Look-Locker pulse sequence measuring T1 and extracellular volume fraction (ECV). CFVR and CMR were performed in 64 women, mean (SD) age 62.5 (8.3) years. MBFR was performed in a subgroup of 54 (84 %) of these women. Mean native T1 was 1023 (86) and ECV (%) was 33.7 (3.5); none had focal fibrosis. Median (IQR) CFVR was 2.3 (1.9; 2.7), 23 (36 %) had CFVR < 2 indicating coronary microvascular disease, and median MBFR was 2.7 (2.2; 3.0) and 19 (35 %) had a MBFR value below 2.5. No significant correlations were found between CFVR and ECV or native T1 (R 2  = 0.02; p = 0.27 and R 2  = 0.004; p = 0.61, respectively). There were also no correlations between MBFR and ECV or native T1 (R 2  = 0.1; p = 0.13 and R 2  = 0.004, p = 0.64, respectively). CFVR and MBFR were correlated to hypertension and heart rate. In women with angina and no obstructive coronary artery disease we found no association between measures of coronary microvascular disease and myocardial fibrosis, suggesting that myocardial ischemia induced by coronary microvascular disease does not elicit myocardial fibrosis in this population. The examined parameters seem to provide independent information about myocardial and coronary disease.

Thermal, spectroscopic and laser properties of Nd3+ in gadolinium scandium gallium garnet crystal produced by optical floating zone method

NASA Astrophysics Data System (ADS)

Tian, Li; Wang, Shuxian; Wu, Kui; Wang, Baolin; Yu, Haohai; Zhang, Huaijin; Cai, Huaqiang; Huang, Hui

2013-12-01

A neodymium-doped gadolinium scandium gallium garnet (Nd:GSGG) single crystal with dimensions of Φ 5 × 20 mm2 has been grown by means of optical floating zone (OFZ). X-ray powder diffraction (XRPD) result shows that the as-grown Nd:GSGG crystal possesses a cubic structure with space group Ia3d and a cell parameter of a = 1.2561 nm. Effective elemental segregation coefficients of the Nd:GSGG as-grown crystal were calculated by using X-ray fluorescence (XRF). The thermal properties of the Nd:GSGG crystal were systematically studied by measuring the specific heat, thermal expansion and thermal diffusion coefficient, and the thermal conductivity of this crystal was calculated. The absorption and luminescence spectra of Nd:GSGG were measured at room temperature (RT). By using the Judd-Ofelt (J-O) theory, the theoretical radiative lifetime was calculated and compared with the experimental result. Continuous wave (CW) laser performance was achieved with the Nd:GSGG at the wavelength of 1062 nm when it was pumped by a laser diode (LD). A maximum output power of 0.792 W at 1062 nm was obtained with a slope efficiency of 11.89% under a pump power of 7.36 W, and an optical-optical conversion efficiency of 11.72%.

Identification and characterization of gadolinium(III) complexes in biological tissue extracts.

PubMed

Kahakachchi, Chethaka L; Moore, Dennis A

2010-07-01

The gadolinium species present in a rat kidney following intravenous administration of a gadolinium-based magnetic resonance contrast agent (Optimark™, Gadoversetamide injection) to a rat was examined in the present study. The major gadolinium species in the supernatant of the rat kidney tissue extracts was determined by reversed-phase liquid chromatography with online inductively coupled plasma optical emission spectrometry (HPLC-ICP-OES). The identity of the compound was established by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) detection. The principal gadolinium(III) complex in a rat kidney tissue extract was identified as Gd-DTPA-BMEA 24 Hrs and 7 days after a single intravenous injection of Optimark™ (gadoversetamide; Gd-DTPA-BMEA) at a dose of 5 mmol Gd/kg body weight. The study demonstrated for the first time the feasibility of the use of two complementary techniques, HPLC-ICP-OES and HPLC-ESI-MS to study the in vivo behavior of gadolinium-based magnetic resonance contrast media.

Proton Relaxivity and Magnetic Hyperthermia Evaluation of Gadolinium Doped Nickel Ferrite Nanoparticles as Potential Theranostic Agents.

PubMed

Yadavalli, Tejabhiram; Raja, Paradeep; Ramaswamy, Shivaraman; Chandrasekharan, Gopalakrishnan; Chennakesavulu, Ramasamy

2017-02-01

This paper outlines the preparation of gadolinium doped nickel ferrite nanoparticles as potential magnetic carriers and longitudinal magnetic resonance imaging contrast agents using hydrothermal method with gadolinium concentration varying from 10% to 40%. A concise effect on the crystal structure was observed at 10% and 20% gadolinium doping, while gadolinium oxide was observed to leach at concentrations exceeding 20%. Further, gadolinium doped nickel ferrites were analyzed for their morphological, magnetic, proton relaxation and magnetic hyperthermia heating properties to understand their potential role as magnetic carrier agents. Low temperature and room temperature magnetic studies conducted on the samples showed comparatively high magnetic saturation with low remanent magnetization. Further, relaxometry studies revealed a high relaxation rate of 6.63 s−1 at a concentration of 0.1 mg/mL. Magnetic hyperthermia studies of the samples at a concentration of 1 mg/mL, assessed that the samples attained a temperature of 68 °C in 240 seconds.

[Unclassified cardiomyopathy or Lyme carditis? A three year follow-up].

PubMed

Konopka, Marcin; Kuch, Marek; Braksator, Wojciech; Walczak, Ewa; Jakuciński, Maciej; Lipowski, Dariusz; Dłużniewski, Mirosław

2013-01-01

Lyme carditis can be a clinical manifestation of the early disseminated stage of Lyme disease caused by the tick-transmitted pathogen Borrelia burgdorferi. We present the case of a 41 year-old Caucasian woman referred to our hospital with symptoms of fatigue, progressive exertional dyspnoea, supraventricular cardiac arrhythmia, and an enlarged heart revealed on chest radiography. Following an untypical result of transthoracic echocardiography, cardiac magnetic resonance was performed. This showed structural cardiac changes and focus of late gadolinium enhancement in the midwall of the apex region. Further diagnostic processes, including endomyocardial biopsy and serology tests, made it possible to diagnose Lyme carditis. Clinical observation was followed-up for three years.

Longitudinal evidence for anterograde trans-synaptic degeneration after optic neuritis

PubMed Central

Goodkin, Olivia; Altmann, Daniel R.; Jenkins, Thomas M.; Miszkiel, Katherine; Mirigliani, Alessia; Fini, Camilla; Gandini Wheeler-Kingshott, Claudia A. M.; Thompson, Alan J.; Ciccarelli, Olga; Toosy, Ahmed T.

2016-01-01

Abstract In multiple sclerosis, microstructural damage of normal-appearing brain tissue is an important feature of its pathology. Understanding these mechanisms is vital to help develop neuroprotective strategies. The visual pathway is a key model to study mechanisms of damage and recovery in demyelination. Anterograde trans-synaptic degeneration across the lateral geniculate nuclei has been suggested as a mechanism of tissue damage to explain optic radiation abnormalities seen in association with demyelinating disease and optic neuritis, although evidence for this has relied solely on cross-sectional studies. We therefore aimed to assess: (i) longitudinal changes in the diffusion properties of optic radiations after optic neuritis suggesting trans-synaptic degeneration; (ii) the predictive value of early optic nerve magnetic resonance imaging measures for late optic radiations changes; and (iii) the impact on visual outcome of both optic nerve and brain post-optic neuritis changes. Twenty-eight consecutive patients with acute optic neuritis and eight healthy controls were assessed visually (logMAR, colour vision, and Sloan 1.25%, 5%, 25%) and by magnetic resonance imaging, at baseline, 3, 6, and 12 months. Magnetic resonance imaging sequences performed (and metrics obtained) were: (i) optic nerve fluid-attenuated inversion-recovery (optic nerve cross-sectional area); (ii) optic nerve proton density fast spin-echo (optic nerve proton density-lesion length); (iii) optic nerve post-gadolinium T 1 -weighted (Gd-enhanced lesion length); and (iv) brain diffusion-weighted imaging (to derive optic radiation fractional anisotropy, radial diffusivity, and axial diffusivity). Mixed-effects and multivariate regression models were performed, adjusting for age, gender, and optic radiation lesion load. These identified changes over time and associations between early optic nerve measures and 1-year global optic radiation/clinical measures. The fractional anisotropy in patients’ optic radiations decreased ( P = 0.018) and radial diffusivity increased ( P = 0.002) over 1 year following optic neuritis, whereas optic radiation measures were unchanged in controls. Also, smaller cross-sectional areas of affected optic nerves at 3 months post-optic neuritis predicted lower fractional anisotropy and higher radial diffusivity at 1 year ( P = 0.007) in the optic radiations, whereas none of the inflammatory measures of the optic nerve predicted changes in optic radiations. Finally, greater Gd-enhanced lesion length at baseline and greater optic nerve proton density-lesion length at 1 year were associated with worse visual function at 1 year ( P = 0.034 for both). Neither the cross-sectional area of the affected optic nerve after optic neuritis nor the damage in optic radiations was associated with 1-year visual outcome. Our longitudinal study shows that, after optic neuritis, there is progressive damage to the optic radiations, greater in patients with early residual optic nerve atrophy, even after adjusting for optic radiation lesions. These findings provide evidence for trans-synaptic degeneration. PMID:26912640

Role of MRI and added value of diffusion-weighted and gadolinium-enhanced MRI for the diagnosis of local recurrence from rectal cancer.

PubMed

Molinelli, Valeria; Angeretti, Maria Gloria; Duka, Ejona; Tarallo, Nicola; Bracchi, Elena; Novario, Raffaele; Fugazzola, Carlo

2018-03-14

To evaluate whether the addition of gadolinium-enhanced MRI and diffusion-weighted imaging (DWI) improves T2 sequence performance for the diagnosis of local recurrence (LR) from rectal cancer and to assess which approach is better at formulating this diagnosis among readers with different experience. Forty-three patients with suspected LR underwent pelvic MRI with T2 weighted (T2) sequences, gadolinium fat-suppressed T1 weighted sequences (post-contrast T1), and DWI sequences. Three readers (expert: G, intermediate: E, resident: V) scored the likelihood of LR on T2, T2 + post-contrast T1, T2 + DWI, and T2 + post-contrast T1 + DWI. In total, 18/43 patients had LR; on T2 images, the expert reader achieved an area under the ROC curve (AUC) of 0.916, sensitivity of 88.9%, and specificity of 76%; the intermediate reader achieved values of 0.890, 88.9%, and 48%, respectively, and the resident achieved values of 0.852, 88.9%, and 48%, respectively. DWI significantly improved the AUC value for the expert radiologist by up to 0.999 (p = 0.04), while post-contrast T1 significantly improved the AUC for the resident by up to 0.950 (p = 0.04). For the intermediate reader, both the T2 + DWI AUC and T2 + post-contrast T1 AUC were better than the T2 AUC (0.976 and 0.980, respectively), but with no statistically significant difference. No statistically significant difference was achieved by any of the three readers by comparing either the T2 + DWI AUCs to the T2 + post-contrast T1 AUCs or the AUCs of the two pairs of sequences to those of the combined three sequences. Furthermore, using the T2 sequences alone, all of the readers achieved a fair number of "equivocal" cases: they decreased with the addition of either DWI or post-contrast T1 sequences and, for the two less experienced readers, they decreased even more with the three combined sequences. Both DWI and T1 post-contrast MRI increased diagnostic performance for LR diagnosis compared to T2; however, no significant difference was observed by comparing the two different pairs of sequences with the three combined sequences.

Application of Paramagnetically Tagged Molecules for Magnetic Resonance Imaging of Biofilm Mass Transport Processes▿

PubMed Central

Ramanan, B.; Holmes, W. M.; Sloan, W. T.; Phoenix, V. R.

2010-01-01

Molecules become readily visible by magnetic resonance imaging (MRI) when labeled with a paramagnetic tag. Consequently, MRI can be used to image their transport through porous media. In this study, we demonstrated that this method could be applied to image mass transport processes in biofilms. The transport of a complex of gadolinium and diethylenetriamine pentaacetic acid (Gd-DTPA), a commercially available paramagnetic molecule, was imaged both in agar (as a homogeneous test system) and in a phototrophic biofilm. The images collected were T1 weighted, where T1 is an MRI property of the biofilm and is dependent on Gd-DTPA concentration. A calibration protocol was applied to convert T1 parameter maps into concentration maps, thus revealing the spatially resolved concentrations of this tracer at different time intervals. Comparing the data obtained from the agar experiment with data from a one-dimensional diffusion model revealed that transport of Gd-DTPA in agar was purely via diffusion, with a diffusion coefficient of 7.2 × 10−10 m2 s−1. In contrast, comparison of data from the phototrophic biofilm experiment with data from a two-dimensional diffusion model revealed that transport of Gd-DTPA inside the biofilm was by both diffusion and advection, equivalent to a diffusion coefficient of 1.04 × 10−9 m2 s−1. This technology can be used to further explore mass transport processes in biofilms, either by using the wide range of commercially available paramagnetically tagged molecules and nanoparticles or by using bespoke tagged molecules. PMID:20435773

High specific heat superconducting composite

DOEpatents

Steyert, Jr., William A.

1979-01-01

A composite superconductor formed from a high specific heat ceramic such as gadolinium oxide or gadolinium-aluminum oxide and a conventional metal conductor such as copper or aluminum which are insolubly mixed together to provide adiabatic stability in a superconducting mode of operation. The addition of a few percent of insoluble gadolinium-aluminum oxide powder or gadolinium oxide powder to copper, increases the measured specific heat of the composite by one to two orders of magnitude below the 5.degree. K. level while maintaining the high thermal and electrical conductivity of the conventional metal conductor.

Gadolinium-based magnetic resonance imaging contrast agents in interventional radiology.

PubMed

Atar, Eli

2004-07-01

Gadolinium-based agents are widely used in magnetic resonance imaging as contrast agents. These agents are radio-opaque enough for diagnostic imaging of the vascular tree by using digitally subtracted images as well as for imaging of the biliary system and the urinary tract. The recommended doses for gadolinium do not impair renal function or cause adverse reactions in patients with iodine sensitivity; thus patients with such conditions can safely undergo diagnostic angiography, either by MRI angiography or by catheterization using gadolinium as contrast agent, for diagnostic and therapeutic purposes.

Rare-Earth Ion-Host Lattice Interactions: 15. Analysis of the Spectra of Nd3+ in Gd3Sc2Ga3O12.

DTIC Science & Technology

1984-05-01

Luminescence of Cr3+ Ions in Gadolinium Gallium and Gadolinium Scandium Gallium Garnet CT’stals, Soy. J. Quant. Electron. 12 (1982), 1124. 6M. Dutoit, J. C...Shcherbakov, Absolute Quantum Efficiency of the Luminescence of Cr3+ Ions in Gadolinium Gallium and Gadolinium Scandium Gallium Garnet Crystals, Soy. J...HDL Project: 324332 19. KEY WORDS (Continue on reverse side it necessary end Identify by block number) Rare earth Mixed garnet Spectra Laser Judd-Ofelt

Theoretical study of structure and stability of small gadolinium carboxylate complexes in liquid scintillator solvents.

PubMed

Huang, Pin-Wen

2014-09-01

The structural properties of three small gadolinium carboxylate complexes in three liquid scintillator solvents (pseudocumene, linear alkylbenzene, and phenyl xylylethane) were theoretically investigated using density functional theory (B3LYP/LC-RECP) and polarizable continuum model (PCM). The average interaction energy between gadolinium atom and carboxylate ligand (E(int)) and the energy difference of the highest singly occupied molecular orbital and lowest unoccupied molecular orbital (Δ(SL)) were calculated to evaluate and compare the relative stability of these complexes in solvents. The calculation results show that the larger (with a longer alkyl chain) gadolinium carboxylate complex has greater stability than the smaller one, while these gadolinium carboxylates in linear alkylbenzene were found to have greater stability than those in the other two solvents.

The Effect of Pressure and Temperature on Separation of Free Gadolinium(III) From Gd-DTPA Complex by Nanofiltration-Complexation Method

NASA Astrophysics Data System (ADS)

Rahayu, Iman; Anggraeni, Anni; Ukun, MSS; Bahti, Husein H.

2017-05-01

Nowdays, the utilization of rare earth elements has been carried out widely in industry and medicine, one of them is gadolinium in Gd-DTPA complex is used as a contrast agent in a magnetic resonance imaging (MRI) diagnostic to increase the visual contrast between normal tissue and diseased. Although the stability of a given complex may be high enough, the complexation step couldnot have been completed, so there is possible to gadolinium(III) in the complex compound. Therefore, the function of that compounds should be dangerous because of the toxicity of gadolinium(III) in human body. So, it is necessarry to separate free gadolinium(III) from Gd-DTPA complex by nanofiltration-complexation. The method of this study is complexing of Gd2O3 with DTPA ligand by reflux and separation of Gd-DTPA complex from gadolinium(III) with a nanofiltration membrane on the variation of pressures(2, 3, 4, 5, 6 bars) and temperature (25, 30, 35, 40 °C) and determined the flux and rejection. The results of this study are the higher of pressures and temperatures, permeation flux are increasing and ion rejections are decreasing and gave the free gadolinium(III) rejection until 86.26%.

Helium defectoscopy of cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the impurity disorder region

NASA Astrophysics Data System (ADS)

Koromyslov, A. V.; Zhiganov, A. N.; Kovalenko, M. A.; Kupryazhkin, A. Ya.

2013-12-01

The concentration of impurity anion vacancies formed upon the dissociation of gadolinium-vacancy complexes has been determined using helium defectoscopy of the cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the temperature range T = 740-1123 K and at saturation pressures ranging from 0.05 to 15 MPa. It has been found that the energy of dissociation of gadoliniumvacancy complexes is E {eff/ D }= 0.26 ± 0.06 eV, and the energy of dissolution of helium in anion vacancies in the impurity disorder region is E P = -0.31 ± 0.09 eV. The proposed mechanism of dissolution has been confirmed by the investigation of the electrical conductivity of the cerium gadolinium ceramics, as well as by the high-speed molecular dynamics simulation of the dissociation of gadolinium-vacancy complexes. It has been assumed that a decrease in the effective dissolution energy in comparison with the results of the previously performed low-temperature investigations is caused by the mutual repulsion of vacancies formed upon the dissociation of gadolinium-vacancy complexes in highly concentrated solutions of gadolinium in CeO2 with increasing temperature.

LGE Provides Incremental Prognostic Information Over Serum Biomarkers in AL Cardiac Amyloidosis.

PubMed

Boynton, Samuel J; Geske, Jeffrey B; Dispenzieri, Angela; Syed, Imran S; Hanson, Theodore J; Grogan, Martha; Araoz, Philip A

2016-06-01

This study sought to determine the prognostic value of cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) in amyloid light chain (AL) cardiac amyloidosis. Cardiac involvement is the major determinant of mortality in AL amyloidosis. CMR LGE is a marker of amyloid infiltration of the myocardium. The purpose of this study was to evaluate retrospectively the prognostic value of CMR LGE for determining all-cause mortality in AL amyloidosis and to compare the prognostic power with the biomarker stage. Seventy-six patients with histologically proven AL amyloidosis underwent CMR LGE imaging. LGE was categorized as global, focal patchy, or none. Global LGE was considered present if it was visualized on LGE images or if the myocardium nulled before the blood pool on a cine multiple inversion time (TI) sequence. CMR morphologic and functional evaluation, echocardiographic diastolic evaluation, and cardiac biomarker staging were also performed. Subjects' charts were reviewed for all-cause mortality. Cox proportional hazards analysis was used to evaluate survival in univariate and multivariate analysis. There were 40 deaths, and the median study follow-up period was 34.4 months. Global LGE was associated with all-cause mortality in univariate analysis (hazard ratio = 2.93; p < 0.001). In multivariate modeling with biomarker stage, global LGE remained prognostic (hazard ratio = 2.43; p = 0.01). Diffuse LGE provides incremental prognosis over cardiac biomarker stage in patients with AL cardiac amyloidosis. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The Effect of gadolinium on the ESR response of alanine and ammonium tartrate exposed to thermal neutrons.

PubMed

Marrale, Maurizio; Brai, Maria; Gennaro, Gaetano; Bartolotta, Antonio; D'Oca, Maria Cristina

2008-02-01

Many efforts have been made to develop neutron capture therapy (NCT) for cancer treatment. Among the challenges in using NCT is the characterization of the features of the mixed radiation field and of its components. In this study, we examined the enhancement of the ESR response of pellets of alanine and ammonium tartrate with gadolinium oxide exposed to a thermal neutron beam. In particular, the ESR response of these dosimeters as a function of the gadolinium content inside the dosimeter was analyzed. We found that the addition of gadolinium improves the sensitivity of both alanine and ammonium tartrate. However, the use of gadolinium reduces or abolishes tissue equivalence because of its high atomic number (Z(Gd) = 64). Therefore, it is necessary to find the optimum compromise between the sensitivity to thermal neutrons and the reduction of tissue equivalence. Our analysis showed that a low concentration of gadolinium oxide (of the order of 5% of the total mass of the dosimeter) can enhance the thermal neutron sensitivity more than 13 times with an insignificant reduction of tissue equivalence.

Speckle-Tracking Layer-Specific Analysis of Myocardial Deformation and Evaluation of Scar Transmurality in Chronic Ischemic Heart Disease.

PubMed

Tarascio, Michela; Leo, Laura Anna; Klersy, Catherine; Murzilli, Romina; Moccetti, Tiziano; Faletra, Francesco Fulvio

2017-07-01

Identification of the extent of scar transmurality in chronic ischemic heart disease is important because it correlates with viability. The aim of this retrospective study was to evaluate whether layer-specific two-dimensional speckle-tracking echocardiography allows distinction of scar presence and transmurality. A total of 70 subjects, 49 with chronic ischemic cardiomyopathy and 21 healthy subjects, underwent two-dimensional speckle-tracking echocardiography and late gadolinium-enhanced cardiac magnetic resonance. Scar extent was determined as the relative amount of hyperenhancement using late gadolinium-enhanced cardiac magnetic resonance in an 18-segment model (0% hyperenhancement = normal; 1%-50% = subendocardial scar; 51%-100% = transmural scar). In the same 18-segment model, peak systolic circumferential strain and longitudinal strain were calculated separately for the endocardial and epicardial layers as well as the full-wall myocardial thickness. All strain parameters showed cutoff values (area under the curve > 0.69) that allowed the discrimination of normal versus scar segments but not of transmural versus subendocardial scars. This was true for all strain parameters analyzed, without differences in efficacy between longitudinal and circumferential strain and subendocardial, subepicardial, and full-wall-thickness strain values. Circumferential and longitudinal strain in normal segments showed transmural and basoapical gradients (greatest values at the subendocardial layer and apex). In segments with scar, transmural gradient was maintained, whereas basoapical gradient was lost because the reduction of strain values in the presence of the scar was greater at the apex. The two-dimensional speckle-tracking echocardiographic values distinguish scar presence but not transmurality; thus, they are not useful predictors of scar segment viability. It remains unclear why there is a greater strain value reduction in the presence of a scar at the apical level. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Is Associated With Subsequent Hospitalization for Heart Failure

PubMed Central

Wong, Timothy C.; Piehler, Kayla M.; Zareba, Karolina M.; Lin, Kathie; Phrampus, Ashley; Patel, Agam; Moon, James C.; Ugander, Martin; Valeti, Uma; Holtz, Jonathan E.; Fu, Bo; Chang, Chung‐Chou H.; Mathier, Michael; Kellman, Peter; Butler, Javed; Gheorghiade, Mihai; Schelbert, Erik B.

2013-01-01

Background Hospitalization for heart failure (HHF) is among the most important problems confronting medicine. Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) robustly identifies intrinsic myocardial damage. LGE may indicate inherent vulnerability to HHF, regardless of etiology, across the spectrum of heart failure stage or left ventricular ejection fraction (LVEF). Methods and Results We enrolled 1068 consecutive patients referred for CMR where 448 (42%) exhibited LGE. After a median of 1.4 years (Q1 to Q3: 0.9 to 2.0 years), 57 HHF events occurred, 15 deaths followed HHF, and 43 deaths occurred without antecedent HHF (58 total deaths). Using multivariable Cox regression adjusting for LVEF, heart failure stage, and other covariates, LGE was associated with first HHF after CMR (HR: 2.70, 95% CI: 1.32 to 5.50), death (HR: 2.13, 95% CI: 1.08 to 4.21), or either death or HHF (HR: 2.52, 95% CI: 1.49 to 4.25). Quantifying LGE extent yielded similar results; more LGE equated higher risks. LGE improved model discrimination (IDI: 0.016, 95% CI: 0.005 to 0.028, P=0.002) and reclassification of individuals at risk (continuous NRI: 0.40, 95% CI: 0.05 to 0.70, P=0.024). Adjustment for competing risks of death that shares common risk factors with HHF strengthened the LGE and HHF association (HR: 4.85, 95% CI: 1.40 to 16.9). Conclusions The presence and extent of LGE is associated with vulnerability for HHF, including higher risks of HHF across the spectrum of heart failure stage and LVEF. Even when LVEF is severely decreased, those without LGE appear to fare reasonably well. LGE may enhance risk stratification for HHF and may enhance both clinical and research efforts to reduce HHF through targeted treatment. PMID:24249712

Role of late gadolinium enhancement cardiovascular magnetic resonance in the risk stratification of hypertrophic cardiomyopathy.

PubMed

Ismail, Tevfik F; Jabbour, Andrew; Gulati, Ankur; Mallorie, Amy; Raza, Sadaf; Cowling, Thomas E; Das, Bibek; Khwaja, Jahanzaib; Alpendurada, Francisco D; Wage, Ricardo; Roughton, Michael; McKenna, William J; Moon, James C; Varnava, Amanda; Shakespeare, Carl; Cowie, Martin R; Cook, Stuart A; Elliott, Perry; O'Hanlon, Rory; Pennell, Dudley J; Prasad, Sanjay K

2014-12-01

Myocardial fibrosis identified by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM) is associated with adverse cardiovascular events, but its value as an independent risk factor for sudden cardiac death (SCD) is unknown. We investigated the role of LGE-CMR in the risk stratification of HCM. We conducted a prospective cohort study in a tertiary referral centre. Consecutive patients with HCM (n=711, median age 56.3 years, IQR 46.7-66.6; 70.0% male) underwent LGE-CMR and were followed for a median 3.5 years. The primary end point was SCD or aborted SCD. Overall, 471 patients (66.2%) had myocardial fibrosis (median 5.9% of left ventricular mass, IQR: 2.2-13.3). Twenty-two (3.1%) reached the primary end point. The extent but not the presence of fibrosis was a significant univariable predictor of the primary end point (HR per 5% LGE: 1.24, 95% CI 1.06 to 1.45; p=0.007 and HR for LGE: 2.69, 95% CI 0.91 to 7.97; p=0.073, respectively). However, on multivariable analysis, only LV-EF remained statistically significant (HR: 0.92, 95% CI 0.89 to 0.95; p<0.001). For the secondary outcome of cardiovascular mortality/aborted SCD, the presence and the amount of fibrosis were significant predictors on univariable but not multivariable analysis after adjusting for LV-EF and non-sustained ventricular tachycardia. The amount of myocardial fibrosis was a strong univariable predictor of SCD risk. However, this effect was not maintained after adjusting for LV-EF. Further work is required to elucidate the interrelationship between fibrosis and traditional predictors of outcome in HCM. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Presence of Late Gadolinium Enhancement by Cardiac Magnetic Resonance Among Patients With Suspected Cardiac Sarcoidosis Is Associated With Adverse Cardiovascular Prognosis: A Systematic Review and Meta-Analysis.

PubMed

Hulten, Edward; Agarwal, Vikram; Cahill, Michael; Cole, Geoff; Vita, Tomas; Parrish, Scott; Bittencourt, Marcio Sommer; Murthy, Venkatesh L; Kwong, Raymond; Di Carli, Marcelo F; Blankstein, Ron

2016-09-01

Individuals with cardiac sarcoidosis have an increased risk of ventricular arrhythmia and death. Several small cohort studies have evaluated the ability of late gadolinium enhancement (LGE) by cardiac magnetic resonance imaging (MRI) to predict adverse cardiovascular events. However, studies have yielded inconsistent results, and some analyses were underpowered. Therefore, we sought to systematically review and perform meta-analysis of the prognostic value of cardiac MRI for patients with known or suspected cardiac sarcoidosis. We systematically searched for cohort studies of patients with known sarcoidosis with suspected cardiac involvement who underwent cardiac MRI with LGE with at least 12 months of either prospective or retrospective follow-up data regarding post-MRI adverse cardiovascular outcomes. We identified 7 studies of 694 subjects (mean age 53; 42% men).One hundred and ninety-nine patients (29%) were LGE positive. All-cause mortality occurred in 19 LGE-positive versus 17 LGE-negative subjects (annualized incidence, 3.1% versus 0.6%). The pooled relative risk was 3.38 (95% confidence interval, 1.07-10.7; P=0.04). Cardiovascular mortality occurred in 10 LGE-positive versus 2 LGE-negative subjects (annualized incidence, 1.9% versus 0.3%; relative risk 10.7 [95% confidence interval, 1.34-86.3]; P=0.03). Ventricular arrhythmia occurred in 41 LGE-positive versus 0 LGE-negative subjects (annualized incidence, 5.9% versus 0%; relative risk 19.5 [95% confidence interval, 2.68-143]; P=0.003). A combined end point of death or ventricular arrhythmia occurred in 64 LGE-positive versus 18 LGE-negative subjects (annualized incidence, 8.8% versus 0.6%; relative risk 6.20 [95% confidence interval, 2.47-15.6]; P<0.001). There was no significant heterogeneity for any outcomes. LGE is associated with future cardiovascular death and ventricular arrhythmia among patients referred to MRI for known or suspected cardiac sarcoidosis. © 2016 American Heart Association, Inc.

Cardiac Phenotype of Prehypertrophic Fabry Disease.

PubMed

Nordin, Sabrina; Kozor, Rebecca; Baig, Shanat; Abdel-Gadir, Amna; Medina-Menacho, Katia; Rosmini, Stefania; Captur, Gabriella; Tchan, Michel; Geberhiwot, Tarekegn; Murphy, Elaine; Lachmann, Robin; Ramaswami, Uma; Edwards, Nicola C; Hughes, Derralynn; Steeds, Richard P; Moon, James C

2018-06-01

Fabry disease (FD) is a rare and treatable X-linked lysosomal storage disorder. Cardiac involvement determines outcomes; therefore, detecting early changes is important. Native T1 by cardiovascular magnetic resonance is low, reflecting sphingolipid storage. Early phenotype development is familiar in hypertrophic cardiomyopathy but unexplored in FD. We explored the prehypertrophic cardiac phenotype of FD and the role of storage. A prospective, international multicenter observational study of 100 left ventricular hypertrophy-negative FD patients (mean age: 39±15 years; 19% male) and 35 age- and sex-matched healthy volunteers (mean age: 40±14 years; 25% male) who underwent cardiovascular magnetic resonance, including native T1 and late gadolinium enhancement, and 12-lead ECG. In FD, 41% had a low native T1 using a single septal region of interest, but this increased to 59% using a second slice because early native T1 lowering was patchy. ECG abnormalities were present in 41% and twice as common with low native T1 (53% versus 24%; P =0.005). When native T1 was low, left ventricular maximum wall thickness, indexed mass, and ejection fraction were higher (maximum wall thickness 9±1.5 versus 8±1.4 mm, P <0.005; indexed left ventricular mass 63±10 versus 58±9 g/m 2 , P <0.05; and left ventricular ejection fraction 73±8% versus 69±7%, P <0.01). Late gadolinium enhancement was more likely when native T1 was low (27% versus 6%; P =0.01). FD had higher maximal apical fractal dimensions compared with healthy volunteers (1.27±0.06 versus 1.24±0.04; P <0.005) and longer anterior mitral valve leaflets (23±2 mm versus 21±3 mm; P <0.005). There is a detectable prehypertrophic phenotype in FD consisting of storage (low native T1), structural, functional, and ECG changes. © 2018 The Authors.

Quantitative comparison of 2D and 3D late gadolinium enhancement MR imaging in patients with Fabry disease and hypertrophic cardiomyopathy.

PubMed

Morsbach, F; Gordic, S; Gruner, C; Niemann, M; Goetti, R; Gotschy, A; Kozerke, S; Alkadhi, H; Manka, R

2016-08-15

This study aims to determine whether the quantification of myocardial fibrosis in patients with Fabry disease (FD) and hypertrophic cardiomyopathy (HCM) using a late gadolinium enhancement (LGE) singlebreath-hold three-dimensional (3D) inversion recovery magnetic resonance (MR) imaging sequence is comparable with a clinically established two-dimensional (2D) multi-breath-hold sequence. In this retrospective, IRB-approved study, 40 consecutive patients (18 male; mean age 50±17years) with Fabry disease (n=18) and HCM (n=22) underwent MR imaging at 1.5T. Spatial resolution was the same for 3D and 2D images (field-of-view, 350×350mm(2); in-plane-resolution, 1.2×1.2mm(2); section-thickness, 8mm). Datasets were analyzed for subjective image quality; myocardial and fibrotic mass, and total fibrotic tissue percentage were quantified. There was no significant difference in subjective image quality between 3D and 2D acquisitions (P=0.1 and P=0.3) for either disease. In patients with Fabry disease there were no significant differences between 3D and 2D acquisitions for myocardial mass (P=0.55), fibrous tissue mass (P=0.89), and total fibrous percentage (P=0.67), with good agreement between acquisitions according to Bland-Altman analyses. In patients with HCM there were also no significant differences between acquisitions for myocardial mass (P=0.48), fibrous tissue mass (P=0.56), and total fibrous percentage (P=0.67), with good agreement according to Bland-Altman analyses. Acquisition time was significantly shorter for 3D (25±5s) as compared to the 2D sequence (349±62s, P<0.001). In patients with Fabry disease and HCM, 3D LGE imaging provides equivalent diagnostic information in regard to quantification of myocardial fibrosis as compared with a standard 2D sequence, but at superior acquisition speed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

PubMed

Reddy, Sahadev T; Thai, Ngoc L; Fakhri, Asghar A; Oliva, Jose; Tom, Kusum B; Dishart, Michael K; Doyle, Mark; Yamrozik, June A; Williams, Ronald B; Grant, Saundra B; Poydence, Jacqueline; Shah, Moneal; Singh, Anil; Nathan, Swami; Biederman, Robert W W

2013-11-15

Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a "one-stop shop" in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6-40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. In this proof-of-concept study, it appears feasible to perform a comprehensive, efficient, and safe preoperative liver transplant imaging in a CMR suite-a one-stop shop, even in seriously ill patients.

Therapy response assessment after radioembolization of patients with hepatocellular carcinoma--comparison of MR imaging with gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid and gadobutrol.

PubMed

Schelhorn, Juliane; Best, Jan; Reinboldt, Marcus P; Gerken, Guido; Ruhlmann, Marcus; Lauenstein, Thomas C; Antoch, Gerald; Kinner, Sonja

2015-07-01

To compare the utility of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA), a liver-specific magnetic resonance (MR) imaging contrast agent, versus gadobutrol for treatment response evaluation of hepatocellular carcinoma (HCC) after radioembolization. This prospective study included 50 patients with HCC undergoing radioembolization. All patients underwent contrast-enhanced computed tomography (CT) and MR imaging with gadobutrol and Gd-EOB-DTPA on 2 consecutive days before radioembolization and 30 days, 90 days, 180 days, and 270 days after radioembolization. The standard of reference indicating tumor progression was CT combined with either α-fetoprotein or γ-glutamyltransferase. Gadobutrol-enhanced MR imaging, Gd-EOB-DTPA-enhanced MR imaging without late phase imaging (Gd-EOB-DTPA-), and Gd-EOB-DTPA-enhanced MR imaging with late phase imaging (Gd-EOB-DTPA+) were evaluated by 2 radiologists in consensus using a 4-point scale: 1 = definitely no tumor progression; 2 = probably no tumor progression; 3 = probably tumor progression; 4 = definitely tumor progression. Diagnostic accuracy was assessed with receiver operating characteristic analysis. Tumor progression was detected in 14 of 82 study visits according to the reference standard. Pairwise comparison of the area under the curve showed a tendency toward a larger area under the curve for Gd-EOB-DTPA+ compared with gadobutrol (P = .056). Sensitivity and specificity were higher in Gd-EOB-DTPA+ (0.929 and 0.971) than in Gd-EOB-DTPA- (0.786 and 0.941) or gadobutrol (0.643 and 0.956). In 2 cases, tumor progression was detected by Gd-EOB-DTPA+ and by an increase in α-fetoprotein, but not by CT, gadobutrol, or Gd-EOB-DTPA-. Gd-EOB-DTPA+ MR imaging was not inferior to gadobutrol-enhanced MR imaging in therapy response evaluation after radioembolization and may allow a more accurate detection of early HCC recurrence in single cases. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

Retention of Gadolinium-Based Contrast Agents in Multiple Sclerosis: Retrospective Analysis of an 18-Year Longitudinal Study.

PubMed

Forslin, Y; Shams, S; Hashim, F; Aspelin, P; Bergendal, G; Martola, J; Fredrikson, S; Kristoffersen-Wiberg, M; Granberg, T

2017-07-01

Gadolinium-based contrast agents have been associated with lasting high T1-weighted signal intensity in the dentate nucleus and globus pallidus, with histopathologically confirmed gadolinium retention. We aimed to longitudinally investigate the relationship of multiple gadolinium-based contrast agent administrations to the Signal Intensity Index in the dentate nucleus and globus pallidus and any associations with cognitive function in multiple sclerosis. The Signal Intensity Index in the dentate nucleus and globus pallidus was retrospectively evaluated on T1-weighted MR imaging in an 18-year longitudinal cohort study of 23 patients with MS receiving multiple gadolinium-based contrast agent administrations and 23 healthy age- and sex-matched controls. Participants also underwent comprehensive neuropsychological testing. Patients with MS had a higher Signal Intensity Index in the dentate nucleus ( P < .001), but not in the globus pallidus ( P = .19), compared with non-gadolinium-based contrast agent-exposed healthy controls by an unpaired t test. Increasing numbers of gadolinium-based contrast agent administrations were associated with an increased Signal Intensity Index in the dentate nucleus (β = 0.45, P < .001) and globus pallidus (β = 0.60, P < .001). This association remained stable with corrections for the age, disease duration, and physical disability for both the dentate nucleus (β = 0.43, P = .001) and globus pallidus (β = 0.58, P < .001). An increased Signal Intensity Index in the dentate nucleus among patients with MS was associated with lower verbal fluency scores, which remained significant after correction for several aspects of disease severity (β = -0.40 P = .013). Our data corroborate previous reports of lasting gadolinium retention in brain tissues. An increased Signal Intensity Index in the dentate nucleus and globus pallidus was associated with lower verbal fluency, which does not prove causality but encourages further studies on cognition and gadolinium-based contrast agent administration. © 2017 by American Journal of Neuroradiology.

Brain morphological and microstructural features in cryptogenic late-onset temporal lobe epilepsy: a structural and diffusion MRI study.

PubMed

Sone, Daichi; Sato, Noriko; Kimura, Yukio; Watanabe, Yutaka; Okazaki, Mitsutoshi; Matsuda, Hiroshi

2018-06-01

Although epilepsy in the elderly has attracted attention recently, there are few systematic studies of neuroimaging in such patients. In this study, we used structural MRI and diffusion tensor imaging (DTI) to investigate the morphological and microstructural features of the brain in late-onset temporal lobe epilepsy (TLE). We recruited patients with TLE and an age of onset > 50 years (late-TLE group) and age- and sex-matched healthy volunteers (control group). 3-Tesla MRI scans, including 3D T1-weighted images and 15-direction DTI, showed normal findings on visual assessment in both groups. We used Statistical Parametric Mapping 12 (SPM12) for gray and white matter structural normalization and comparison and used Tract-Based Spatial Statistics (TBSS) for fractional anisotropy and mean diffusivity comparisons of DTI. In both methods, p < 0.05 (family-wise error) was considered statistically significant. In total, 30 patients with late-onset TLE (mean ± SD age, 66.8 ± 8.4; mean ± SD age of onset, 63.0 ± 7.6 years) and 40 healthy controls (mean ± SD age, 66.6 ± 8.5 years) were enrolled. The late-onset TLE group showed significant gray matter volume increases in the bilateral amygdala and anterior hippocampus and significantly reduced mean diffusivity in the left temporofrontal lobe, internal capsule, and brainstem. No significant changes were evident in white matter volume or fractional anisotropy. Our findings may reflect some characteristics or mechanisms of cryptogenic TLE in the elderly, such as inflammatory processes.

Fundamental Flux Equations for Fracture-Matrix Interactions with Linear Diffusion

NASA Astrophysics Data System (ADS)

Oldenburg, C. M.; Zhou, Q.; Rutqvist, J.; Birkholzer, J. T.

2017-12-01

The conventional dual-continuum models are only applicable for late-time behavior of pressure propagation in fractured rock, while discrete-fracture-network models may explicitly deal with matrix blocks at high computational expense. To address these issues, we developed a unified-form diffusive flux equation for 1D isotropic (spheres, cylinders, slabs) and 2D/3D rectangular matrix blocks (squares, cubes, rectangles, and rectangular parallelepipeds) by partitioning the entire dimensionless-time domain (Zhou et al., 2017a, b). For each matrix block, this flux equation consists of the early-time solution up until a switch-over time after which the late-time solution is applied to create continuity from early to late time. The early-time solutions are based on three-term polynomial functions in terms of square root of dimensionless time, with the coefficients dependent on dimensionless area-to-volume ratio and aspect ratios for rectangular blocks. For the late-time solutions, one exponential term is needed for isotropic blocks, while a few additional exponential terms are needed for highly anisotropic blocks. The time-partitioning method was also used for calculating pressure/concentration/temperature distribution within a matrix block. The approximate solution contains an error-function solution for early times and an exponential solution for late times, with relative errors less than 0.003. These solutions form the kernel of multirate and multidimensional hydraulic, solute and thermal diffusion in fractured reservoirs.

Distribution and chemical forms of gadolinium in the brain: a review.

PubMed

Kanda, Tomonori; Nakai, Yudai; Hagiwara, Akifumi; Oba, Hiroshi; Toyoda, Keiko; Furui, Shigeru

2017-11-01

In the 3 years since residual gadolinium-based contrast agent (GBCA) in the brain was first reported, much has been learned about its accumulation, including the pathway of GBCA entry into the brain, the brain distribution of GBCA and its excretion. Here we review recent progress in understanding the routes of gadolinium deposition in brain structures.

Gadolinium Distribution in Cerebrospinal Fluid after Administration of a Gadolinium-based MR Contrast Agent in Humans.

PubMed

Berger, Florian; Kubik-Huch, Rahel A; Niemann, Tilo; Schmid, Hans Ruedi; Poetzsch, Michael; Froehlich, Johannes M; Beer, Jürg H; Thali, Michael J; Kraemer, Thomas

2018-05-08

Purpose To evaluate whether gadolinium penetrates human cerebrospinal fluid (CSF) after MR imaging (MRI) with a gadolinium-based contrast agent (GBCA). Materials and Methods For this retrospective study, the authors analyzed 60 CSF samples from 57 patients (median age, 50 years; range, 3-92 years) who underwent one contrast material-enhanced MRI examination with gadoterate meglumine within 60 days of CSF extraction between January and December 2016. CSF samples from patients who underwent MRI without contrast material administration (n = 22) or those who underwent contrast-enhanced MRI at least 1 year before extraction (n = 2) were analyzed and used as control samples. CSF measurements were performed with inductively coupled plasma mass spectrometry by monitoring the gadolinium 158 isotope. Statistical analyses were performed by using a preliminary Kruskal-Wallis test. Results Higher CSF gadolinium concentrations were detected within the first 8 hours after GBCA administration (mean concentration, 1152 ng/mL ± 734.6). Concentrations were lower between 8 and 48 hours (872 ng/mL ± 586). After 48 hours, gadolinium was almost completely cleared from CSF (121 ng/mL ± 296.3). All but two samples from the 24 control patients (median age, 60.5 years; range, 19-79 years) were negative for the presence of gadolinium. Those samples were from patients who had undergone GBCA-enhanced MRI examination more than a year before CSF extraction (0.1 and 0.2 ng/mL after 1 and 3 years, respectively). The concentrations in patients with chronic renal insufficiency (n = 3), cerebral toxoplasmosis (n = 1), and liver cirrhosis (n = 1) were higher than the mean concentrations. Conclusion Gadoterate meglumine can be detected in human CSF after intravenous administration. © RSNA, 2018.

Traumatic head injury mimicking acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Inoue, Hirofumi; Hasegawa, Shunji; Kajimoto, Madoka; Matsushige, Takeshi; Ichiyama, Takashi

2014-10-01

Many studies have reported acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) associated with viral infection at onset, but few studies have reported AESD without infection. We report the case of a 9-month-old boy who had a clinical course mimicking AESD after a traffic accident. The traffic accident caused a mild subdural hematoma without neurological abnormalities on admission. The boy became unconscious on the second day, and he was diagnosed with non-convulsive status epilepticus on the third day. Diffusion-weighted imaging showed reduced water diffusion in the subcortical white matter. On laboratory analysis interleukin (IL)-6 was elevated in the cerebrospinal fluid (CSF), but not in the serum. He had severe neurological sequelae with mental retardation, spastic tetraplegia, and epilepsy. We suggest that brain damage mimicking AESD was caused by the traffic accident and the prolonged seizure during infancy. © 2014 Japan Pediatric Society.

Alkali metal and alkali earth metal gadolinium halide scintillators

DOEpatents

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

2016-08-02

The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Compensated gadolinium-loaded plastic scintillators for thermal neutron detection (and counting)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.

2015-07-01

Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon partmore » of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of a neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes. (authors)« less

Differential diagnosis of left ventricular hypertrophy: usefulness of multimodality imaging and tissue characterization with cardiac magnetic resonance.

PubMed

Izgi, Cemil; Vassiliou, Vassilis; Baksi, A John; Prasad, Sanjay K

2016-11-01

Differential diagnosis of asymmetrical left ventricular hypertrophy may be challenging, particularly in patients with history of hypertension. A middle-aged man underwent an echocardiographic examination during workup for hypertension, which unexpectedly showed significant asymmetrical septal hypertrophy and raised suspicion for hypertrophic cardiomyopathy. Cardiovascular magnetic resonance confirmed the asymmetrical hypertrophy. No myocardial late gadolinium contrast enhancement was seen. However, precontrast T1 mapping revealed a low native myocardial T1 value. This was highly suggestive of Anderson-Fabry disease, which was subsequently proved with very low alpha galactosidase enzyme levels and mutation analysis. The case illustrates clinical usefulness of multimodality imaging and the novel tissue characterization techniques for assessment of left ventricular hypertrophy. © 2016, Wiley Periodicals, Inc.

Risk stratification for therapeutic management and prognosis.

PubMed

Coelho-Filho, Otavio R; Nallamshetty, Leelakrishna; Kwong, Raymond Y

2009-07-01

In coronary artery disease (CAD), cardiac magnetic resonance (CMR) imaging can integrate several types of pulse-sequence examinations (eg, myocardial perfusion, cine wall motion, T2-weighted imaging for myocardial edema, late gadolinium enhancement, and CMR angiography) that can provide anatomic, functional, and physiologic information about the heart in a single imaging session. Because of this ability to interrogate myocardial physiology using different pulse sequence techniques within a single CMR session, this technique has been recognized increasingly in many centers as the test of choice for assessing patients who present with cardiomyopathy of undetermined cause. This article first reviews the current evidence supporting the prognosticating role of CMR in assessing CAD and then discusses CMR applications and prognostication in many non-coronary cardiac conditions.

11C-4DST PET/CT Imaging of Cardiac Sarcoidosis: Comparison With 18F-FDG and Cardiac MRI.

PubMed

Hotta, Masatoshi; Minamimoto, Ryogo; Kubota, Shuji; Awaya, Toru; Hiroi, Yukio

2018-06-01

A 75-year-old woman with a history of sarcoidosis presenting with low cardiac output and complete right bundle-branch block underwent 4'-[methyl-C]-thiothymidine (4DST) PET/CT after cardiac MRI and FDG PET/CT for the evaluation of suspected cardiac sarcoidosis (CS) before treatment. Cardiac MRI revealed late gadolinium enhancement on the anterior-to-lateral and posterior wall, indicating CS. FDG uptake was shown on the anterior-to-lateral wall, but not on the posterior wall. In contrast, 4DST uptake was demonstrated on both anterior-to-lateral and posterior walls. Use of 4DST appears promising for detecting CS without dietary restriction, due to the lack of physiological uptake in myocardium.

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

PubMed

Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

2018-06-01

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P < 0.05) and no correlation for the remaining six [ 18 F]FDG-avid tumors. APT imaging can be used to increase diagnostic accuracy with no need to administer gadolinium chelates. APT imaging may provide an added value to [ 18 F]FDG PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

Advantages of high b-value diffusion-weighted imaging to diagnose pseudo-responses in patients with recurrent glioma after bevacizumab treatment.

PubMed

Yamasaki, Fumiyuki; Kurisu, Kaoru; Aoki, Tomokazu; Yamanaka, Masami; Kajiwara, Yoshinori; Watanabe, Yosuke; Takayasu, Takeshi; Akiyama, Yuji; Sugiyama, Kazuhiko

2012-10-01

The diagnosis of pseudo-responses after bevacizumab treatment is difficult. Because diffusion-weighted imaging (DWI) is associated with cell density, it may facilitate the differentiation between true- and pseudo-responses. Furthermore, as high b-value DWI is even more sensitive to diffusion, it has been reported to be diagnostically useful in various clinical settings. Between September 2008 and May 2011, 10 patients (5 males, 5 females; age range 6-65 years) with recurrent glioma were treated with bevacizumab. All underwent pre- and post-treatment MRI including T2- or FLAIR imaging, post-gadolinium contrast T1-weighted imaging, and DWI with b-1000 and b-4000. Response rates were evaluated by MacDonald- and by response assessment in neuro-oncology working group (RANO) criteria. We also assessed the response rate by calculating the size of high intensity areas using high b-value diffusion-weighted criteria. Prognostic factors were evaluated using Kaplan-Meier survival curves (log-rank test). It was easier to identify pseudo-responses with RANO- than MacDonald criteria, however the reduction of edema by bevacizumab rendered the early diagnosis of tumor progression difficult by RANO criteria. In some patients with recurrent glioma treated with bevacizumab, high b-value diffusion-weighted criteria did, while MacDonald- and RANO criteria did not identify pseudo-responses at an early point after the start of therapy. High b-value DWI reflects cell density more accurately than regular b-value DWI. Our findings suggest that in patients with recurrent glioma, high b-value diffusion-weighted criteria are useful for the differentiation between pseudo- and true responses to treatment with bevacizumab. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Gadolinium-conjugated PLA-PEG nanoparticles as liver targeted molecular MRI contrast agent.

PubMed

Chen, Zhijin; Yu, Dexin; Liu, Chunxi; Yang, Xiaoyan; Zhang, Na; Ma, Chunhong; Song, Jibin; Lu, Zaijun

2011-09-01

A nanoparticle magnetic resonance imaging (MRI) contrast agent targeted to liver was developed by conjugation of gadolinium (Gd) chelate groups onto the biocompatible poly(l-lactide)-block-poly (ethylene glycol) (PLA-PEG) nanoparticles. PLA-PEG conjugated with diethylenetriaminopentaacetic acid (DTPA) was used to formulate PLA-PEG-DTPA nanoparticles by solvent diffusion method, and then Gd was loaded onto the nanoparticles by chelated with the unfolding DTPA on the surface of the PLA-PEG-DTPA nanoparticles. The mean size of the nanoparticles was 265.9 ± 6.7 nm. The relaxivity of the Gd-labeled nanoparticles was measured, and the distribution in vivo was evaluated in rats. Compared with conventional contrast agent (Magnevist), the Gd-labeled PLA-PEG nanoparticles showed significant enhancement both on liver targeting ability and imaging signal intensity. The T(1) and T(2) relaxivities per [Gd] of the Gd-labeled nanoparticles was 18.865 mM(-1) s(-1) and 24.863 mM(-1) s(-1) at 3 T, respectively. In addition, the signal intensity in vivo was stronger comparing with the Gd-DTPA and the T(1) weight time was lasting for 4.5 h. The liver targeting efficiency of the Gd-labeled PLA-PEG nanoparticles in rats was 14.57 comparing with Magnevist injection. Therefore, the Gd-labeled nanoparticles showed the potential as targeting molecular MRI contrast agent for further clinical utilization.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging for prostate lesions and normal tissue at 3.0-Tesla magnetic resonance imaging.

PubMed

Liu, Xiaohang; Zhou, Liangping; Peng, Weijun; Qian, Min

2011-06-01

Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined. To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI). Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm(2) before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test. No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm(2)/s Vs 0.89 ± 0.12 mm(2)/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm(2)/s vs. 1.2 ± 0.29 mm(2)/s, p < 0.0001). No significant differences were detected for normal tissue. The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in interpretation.

Analysis of Blood Gadolinium in an Isotope Geochemist Following Contrast MRI

NASA Astrophysics Data System (ADS)

Wasylenki, L. E.

2011-12-01

Normal brain tissue does not have blood flowing throughout it; instead oxygen diffuses across a blood-brain barrier in order to oxygenate brain cells. Brain tumors, however, do grow blood supplies, so an abnormal distribution of blood in the brain is a key indicator of abnormal cell growth. But how is the distribution of blood in inside the brain observed? The lanthanide ion gadolinium(III) has unpaired 5f-shell electrons and is thus paramagnetic. As such, the presence of Gd causes the nuclei of nearby atoms to relax more quickly when excited to high-energy spin states by pulses of radio-frequency energy than they would without Gd nearby. The signal in magnetic resonance imaging correlates with this nuclear spin relaxation time, so gadolinium's presence in certain body tissues makes those tissues appear as bright areas on MRI images. Gadolinium is therefore commonly injected intravenously just prior to MRI imaging, so that the distribution of blood in and around the brain can be mapped. Gadolinium as a free ion is toxic, so it is injected in a relatively inert form, often as gadoversetamide, in which Gd is tightly bound in nine-fold coordination with N, C, and O. This compound is removed from the blood by the kidneys at a rate that is fast compared to the rate of breakdown of this compound in the blood, thus preventing release of toxic Gd in the bloodstream. But how quickly can the kidneys of an isotope geochemist remove Gd from blood? In this experiment, a single isotope geochemist's wristwatch was synchronized with that of the MRI technician and then left in a dressing room with all other magnetically susceptible objects until after the MRI. The time of intravenous injection of gadoversetamide into the isotopist was recorded by the technician and later transmitted verbally to the isotopist. Following the MRI session, blood samples were collected by self-fingerprick, in a Class 100 trace metal clean lab, from 47 to 281 minutes after intravenous injection. For each timepoint, approximately 300 microliters of blood were transferred by acid-washed pipette to an acid-washed, Teflon, screw-cap vial and weighed. Samples were digested with hot, concentrated nitric acid and 30% hydrogen peroxide, dried down, and redissolved in 0.32 M nitric acid. Gd concentrations were measured by quadrupole ICP-MS, at masses 152, 154, 155, 156, 157, 158, and 160, using yttrium (mass 89) and bismuth (mass 209) as internal standards to normalize plasma variations during the run. Results indicate decreasing blood Gd concentrations, from 35.8 parts per million by weight at 47 minutes after injection to 7.5 parts per million at 281 minutes. The data have a near-perfect fit to an exponential decay curve with half-life of 105 minutes, demonstrating that renal filtration of gadoversetamide is a first-order reaction in at least one isotope geochemist.

Acute encephalopathy with biphasic seizures and late reduced diffusion associated with hemophagocytic syndrome.

PubMed

Tadokoro, Rieko; Okumura, Akihisa; Nakazawa, Tomoyuki; Hara, Satoshi; Yamakawa, Yoko; Kamata, Ayako; Kinoshita, Keiji; Obinata, Kaoru; Shimizu, Toshiaki

2010-06-01

We reported a girl with HHV-6 infection associated with both acute encephalopathy with biphasic seizures and late reduced diffusion, and hemophagocytic syndrome. She had a prolonged convulsion after a one-day history of febrile illness. Cerebrospinal fluid or brain CT showed no abnormalities on admission and her consciousness was recovered on the next day. However, a prolonged seizure and deterioration of consciousness appeared on the sixth day of illness. Diffusion-weighted images revealed marked reduction of water diffusion in the bilateral frontal areas. HHV-6 infection was virologically proven by polymerase chain reaction. She was treated with gamma-globulin, steroid pulse therapy, and brain hypothermia. In addition, decrease in white blood cells and platelet counts, and elevation of liver enzymes and ferritin were noted on the fourth day of illness. Hemophagocytic macrophages were revealed by bone marrow aspiration on the sixth day. Her hematological and blood chemistry abnormalities recovered gradually after steroid pulse therapy. An elevation of interleukin-6, -8, and -10, and tumor necrosis factor in the serum and that of interleukin-4, -6, and-8 in the cerebrospinal fluid were observed at the onset of a late seizure. These facts suggested that hypercytokinemia will be related to the pathogenesis of acute encephalopathy of our patient. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Isolated Cortical Vein Thrombosis - The Cord Sign

PubMed Central

Sharma, Vijay K.; Teoh, Hock L

2009-01-01

Isolated cortical vein thrombosis is an uncommon condition and often difficult to diagnose, both clinically and radiologically. We report a case of a 38 years old man who presented with headache of new onset and clinical examination was unremarkable. The unenhanced brain CT did not reveal any abnormality. In view of unrelenting headache and partial seizures, we performed magnetic resonance imaging (with axial T1, T2 and gradient echo sequences, coronal FLAIR, diffusion weighted imaging as well as Gadolinium contrast-enhanced images) and magnetic resonance venography of the brain that revealed an isolated parietal cortical vein thrombosis with the rarely reported 'cord sign'. We report the clinical and radiological findings in our patient with isolated parietal cortical vein thrombosis. PMID:22470649

Are gadolinium-based contrast media nephrotoxic? A renal biopsy study.

PubMed

Akgun, Hulya; Gonlusen, Gulfiliz; Cartwright, Joiner; Suki, Wadi N; Truong, Luan D

2006-09-01

Gadolinium-based contrast media were originally introduced as alternatives to iodinated media for magnetic resonance imaging. Although originally thought to be nonnephrotoxic, gadolinium-based contrast media have recently been reported to be associated with acute renal failure; the mechanism and the underlying renal injury are not completely understood. We report what is, to our knowledge, the first renal biopsy in this context. A 56-year-old patient underwent 2 consecutive vascular imaging procedures in conjunction with gadolinium-based contrast medium administration. A few days later, the patient developed acute renal failure. A renal biopsy showed acute tubular cell injury including patchy tubular cell necrosis, tubular cell degeneration, and marked proliferation of tubular cells, together with mild interstitial edema and interstitial inflammation, but without significant glomerular or vascular changes. During supportive therapy, renal function was partially regained. This case emphasizes the potential nephrotoxicity of gadolinium-based contrast media and suggests that the nephrotoxicity is related to potentially reversible acute tubular cell injury.

Improved Peritoneal Cavity and Abdominal Organ Imaging Using a Biphasic Contrast Agent Protocol and Spectral Photon Counting Computed Tomography K-Edge Imaging.

PubMed

Si-Mohamed, Salim; Thivolet, Arnaud; Bonnot, Pierre-Emmanuel; Bar-Ness, Daniel; Képénékian, Vahan; Cormode, David P; Douek, Philippe; Rousset, Pascal

2018-05-23

To validate in vitro the capability of a high-spatial-resolution prototype spectral photon-counting computed tomography (SPCCT) scanner to differentiate between 2 contrast agents and to assess in vivo the image quality and the feasibility to image the peritoneal cavity in rats using the 2 contrast agents simultaneously within the vascular and peritoneal compartments. The authors performed SPCCT imaging (100 mAs, 120 kVp) with energy bin thresholds set to 30, 51, 64, 72, and 85 keV in vitro on a custom-made polyoxymethylene cylindrical phantom consisting of tubes with dilutions of both contrast agents and in vivo on 2 groups of adult rats using 2 injection protocols. Approval from the institutional animal ethics committee was obtained. One group received macrocylic gadolinium chelate intraperitoneal (IP) and iodine intravenous (IV) injections (protocol A, n = 3), whereas the second group received iodine IP and gadolinium IV (protocol B, n = 3). Helical scans were performed 35 minutes after IP injection and 20 seconds after IV injection. The SPCCT and contrast material images, that is, iodine and gadolinium maps, were reconstructed with a field of view of 160 mm, an isotropic voxel size of 250 μm, and a matrix size of 640 × 640 pixels using a soft reconstruction kernel. The SPCCT images were reconstructed with 2 different spatial resolutions to compare the image quality (sharpness, diagnostic quality, and organ visualization) of SPCCT (250 μm) with single-energy computed tomography (CT) (600 μm). Two radiologists evaluated the peritoneal opacification index in 13 regions (score = 0-3 per region) on each type of image. Concentrations of contrast agents were measured in the organs of interest. In vitro, the concentration measurements correlated well with the expected concentrations. The linear regressions both had R values of 0.99, slopes of 0.84 and 0.87, and offsets at -0.52 and -0.38 mg/mL for iodine and gadolinium, respectively. In vivo, the SPCCT images were of better diagnostic quality, with increased sharpness compared with the CT-like images (P < 0.0001). Intraperitoneal diffusion was excellent, with similar peritoneal opacification index on SPCCT images and overlay of contrast material maps (P = 1) without a significant difference between protocol A (37.0 ± 1.7) and protocol B (35.3 ± 1.5) (P = 0.34). Only the contrast material maps demonstrated clear visual separation of the contrast agents, allowing specific quantification of the physiological enhancement in the liver, spleen, and kidney and the urinary clearance in the renal pelvis and bladder. Renal excretion of the contrast agents injected IP was observed and was consistent with blood diffusion. Spectral photon-counting CT can be used to perform a complete peritoneal dual-contrast protocol, enabling a good assessment of the peritoneal cavity and abdominal organs in rats.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

PubMed

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

Tracing gadolinium-based contrast agents from surface water to drinking water by means of speciation analysis.

PubMed

Birka, Marvin; Wehe, Christoph A; Hachmöller, Oliver; Sperling, Michael; Karst, Uwe

2016-04-01

In recent decades, a significant amount of anthropogenic gadolinium has been released into the environment as a result of the broad application of contrast agents for magnetic resonance imaging (MRI). Since this anthropogenic gadolinium anomaly has also been detected in drinking water, it has become necessary to investigate the possible effect of drinking water purification on these highly polar microcontaminats. Therefore, a novel highly sensitive method for speciation analysis of gadolinium is presented. For that purpose, the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma-mass spectrometry (ICP-MS) was employed. In order to enhance the detection power, sample introduction was carried out by ultrasonic nebulization. In combination with a novel HILIC method using a diol-based stationary phase, it was possible to achieve superior limits of detection for frequently applied gadolinium-based contrast agents below 20pmol/L. With this method, the contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were determined in concentrations up to 159pmol/L in samples from several waterworks in a densely populated region of Germany alongside the river Ruhr as well as from a waterworks near a catchment lake. Thereby, the direct impact of anthropogenic gadolinium species being present in the surface water on the amount of anthropogenic gadolinium in drinking water was shown. There was no evidence for the degradation of contrast agents, the release of Gd(3+) or the presence of further Gd species. Copyright © 2016 Elsevier B.V. All rights reserved.

Gadolinium Chelate Safety in Pregnancy: Barely Detectable Gadolinium Levels in the Juvenile Nonhuman Primate after in Utero Exposure.

PubMed

Prola-Netto, Joao; Woods, Mark; Roberts, Victoria H J; Sullivan, Elinor L; Miller, Christina Ann; Frias, Antonio E; Oh, Karen Y

2018-01-01

Purpose To determine whether gadolinium remains in juvenile nonhuman primate tissue after maternal exposure to intravenous gadoteridol during pregnancy. Materials and Methods Gravid rhesus macaques and their offspring (n = 10) were maintained, as approved by the institutional animal care and utilization committee. They were prospectively studied as part of a pre-existing ongoing research protocol to evaluate the effects of maternal malnutrition on placental and fetal development. On gestational days 85 and 135, they underwent placental magnetic resonance imaging after intravenous gadoteridol administration. Amniocentesis was performed on day 135 prior to administration of the second dose of gadoteridol. After delivery, the offspring were followed for 7 months. Tissue samples from eight different organs and from blood were harvested from each juvenile macaque. Gadolinium levels were measured by using inductively coupled plasma mass spectrometry. Results Gadolinium concentration in the amniotic fluid was 0.028 × 10 -5 %ID/g (percentage injected dose per gram of tissue) 50 days after administration of one gadoteridol dose. Gadolinium was most consistently detected in the femur (mean, 2.5 × 10 -5 %ID/g; range, [0.81-4.1] × 10 -5 %ID/g) and liver (mean, 0.15 × 10 -5 %ID/g; range, [0-0.26] × 10 -5 %ID/g). Levels were undetectable in the remaining sampled tissues, with the exception of one juvenile skin sample (0.07 × 10 -5 %ID/g), one juvenile spleen sample (0.039 × 10 -5 %ID/g), and one juvenile brain (0.095 × 10 -5 %ID/g) and kidney (0.13 × 10 -5 %ID/g) sample. Conclusion The presence of gadoteridol in the amniotic fluid after maternal injection enables confirmation that it crosses the placenta. Extremely low levels of gadolinium are found in juvenile macaque tissues after in utero exposure to two doses of gadoteridol, indicating that a very small amount of gadolinium persists after delivery. © RSNA, 2017.

Gadolinium accumulation in organs of Sprague-Dawley® rats after implantation of a biodegradable magnesium-gadolinium alloy.

PubMed

Myrissa, Anastasia; Braeuer, Simone; Martinelli, Elisabeth; Willumeit-Römer, Regine; Goessler, Walter; Weinberg, Annelie Martina

2017-01-15

Biodegradable magnesium implants are under investigation because of their promising properties as medical devices. For enhancing the mechanical properties and the degradation resistance, rare earth elements are often used as alloying elements. In this study Mg10Gd pins were implanted into Sprague-Dawley® rats. The pin volume loss and a possible accumulation of magnesium and gadolinium in the rats' organs and blood were investigated in a long-term study over 36weeks. The results showed that Mg10Gd is a fast disintegrating material. Already 12weeks after implantation the alloy is fragmented to smaller particles, which can be found within the intramedullary cavity and the cortical bones. They disturbed the bone remodeling until the end of the study. The results concerning the elements' distribution in the animals' bodies were even more striking, since an accumulation of gadolinium could be observed in the investigated organs over the whole time span. The most affected tissue was the spleen, with up to 3240μgGd/kg wet mass, followed by the lung, liver and kidney (up to 1040, 685 and 207μgGd/kg). In the brain, muscle and heart, the gadolinium concentrations were much smaller (less than 20μg/kg), but an accumulation could still be detected. Interestingly, blood serum samples showed no accumulation of magnesium and gadolinium. This is the first time that an accumulation of gadolinium in animal organs was observed after the application of a gadolinium-containing degradable magnesium implant. These findings demonstrate the importance of future investigations concerning the distribution of the constituents of new biodegradable materials in the body, to ensure the patients' safety. In the last years, biodegradable Mg alloys are under investigation due to their promising properties as orthopaedic devices used for bone fracture stabilization. Gadolinium as Rare Earth Element enhances the mechanical properties of Mg-Gd alloys but its toxicity in humans is still questionable. Up to now, there is no study investigating the elements' metabolism of a REE-containing Magnesium alloy in an animal model. In this study, we examined the gadolinium distribution and accumulation in rat organs during the degradation of Mg10Gd. Our findings showed that Gd is accumulating in the animal organs, especially in spleen, liver and kidney. This study is of crucial benefit regarding a safe application of REE-containing Magnesium alloys in humans. Copyright © 2016. Published by Elsevier Ltd.

Measuring the supernova unknowns at the next-generation neutrino telescopes through the diffuse neutrino background

NASA Astrophysics Data System (ADS)

MØller, Klaes; Suliga, Anna M.; Tamborra, Irene; Denton, Peter B.

2018-05-01

The detection of the diffuse supernova neutrino background (DSNB) will preciously contribute to gauge the properties of the core-collapse supernova population. We estimate the DSNB event rate in the next-generation neutrino detectors, Hyper-Kamiokande enriched with Gadolinium, JUNO, and DUNE. The determination of the supernova unknowns through the DSNB will be heavily driven by Hyper-Kamiokande, given its higher expected event rate, and complemented by DUNE that will help in reducing the parameters uncertainties. Meanwhile, JUNO will be sensitive to the DSNB signal over the largest energy range. A joint statistical analysis of the expected rates in 20 years of data taking from the above detectors suggests that we will be sensitive to the local supernova rate at most at a 20‑33% level. A non-zero fraction of supernovae forming black holes will be confirmed at a 90% CL, if the true value of that fraction is gtrsim20%. On the other hand, the DSNB events show extremely poor statistical sensitivity to the nuclear equation of state and mass accretion rate of the progenitors forming black holes.

T1 and T2 mapping for evaluation of myocardial involvement in patients with ANCA-associated vasculitides.

PubMed

Greulich, Simon; Mayr, Agnes; Kitterer, Daniel; Latus, Joerg; Henes, Joerg; Steubing, Hannah; Kaesemann, Philipp; Patrascu, Alexandru; Greiser, Andreas; Groeninger, Stefan; Braun, Niko; Alscher, M Dominik; Sechtem, Udo; Mahrholdt, Heiko

2017-01-06

Myocardial involvement in AAV patients might be silent, presenting with no or nonspecific symptoms, normal ECG, and preserved left-ventricular ejection fraction (LV-EF). Since up to 50% of deaths in these patients may be due to myocardial involvement, a reliable diagnostic tool is warranted. In contrast to LGE-CMR, which has its strengths in detecting focal inflammatory or fibrotic processes, recent mapping techniques are able to detect even subtle, diffuse inflammatory or fibrotic processes. Our study sought to investigate ANCA (antineutrophil cytoplasmic antibody) associated vasculitides (AAV) patients for myocardial involvement by a cardiovascular magnetic resonance (CMR) protocol, including late gadolinium enhancement (LGE) and mapping sequences. Thirty seven AAV patients were prospectively enrolled and underwent CMR imaging. Twenty healthy volunteers served as controls. Mean LV-EF was 64%; LGE prevalence of the AAV patients was 43%. AAV patients had higher median native T1 (988 vs. 952 ms, p < 0.001), lower post-contrast T1 (488 vs. 524 ms, p = 0.03), expanded extracellular volume (ECV) (27.5 vs. 24.5%, p < 0.001), and higher T2 (53 vs. 49 ms, p < 0.001) compared to controls, with most parameters independent of the LGE status. Native T1 and T2 in AAV patients showed the highest prevalence of abnormally increased values beyond the 95% percentile of controls. AAV patients demonstrated increased T1, ECV, and T2 values, with native T1 and T2 showing the highest prevalence of values beyond the 95% percentile of normal. Since these findings seem to be independent of LGE, mapping techniques may provide complementary information to LGE-CMR in the assessment of myocardial involvement in patients with AAV.

Stress Cardiac MRI in Women With Myocardial Infarction and Nonobstructive Coronary Artery Disease.

PubMed

Mauricio, Rina; Srichai, Monvadi B; Axel, Leon; Hochman, Judith S; Reynolds, Harmony R

2016-10-01

In a prospective study, cardiac MRI (CMR) and intravascular ultrasound were performed in women with myocardial infarction (MI) and nonobstructive coronary artery disease (MINOCA). Forty participants underwent adenosine-stress CMR (sCMR). Abnormal perfusion may co-localize with ischemic late gadolinium enhancement (LGE) and T2-weighted signal hyperintensity (T2+), suggesting microvascular dysfunction contributed to MI. Qualitative perfusion analysis was performed by 2 independent readers. Abnormal myocardial perfusion reserve index (MPRI) was defined as global average ≤1.84. Abnormal rest perfusion was present in 10 patients (25%) and stress perfusion abnormalities in 25 (63%). Abnormal stress perfusion was not associated with LGE but tended to occur with T2+. Among patients with abnormal perfusion and LGE, the LGE pattern was ischemic in half. The locations of abnormal perfusion and LGE matched in 75%, T2+ in 100%. Abnormal stress perfusion was not associated with plaque disruption and matched in location in 63%. MPRI was abnormal in 10 patients (25%) and was not associated with LGE, T2+ or plaque disruption. Abnormal perfusion on sCMR is common among women with MINOCA. Abnormal perfusion usually co-localized with LGE and/or T2+ when present. Variability in LGE pattern leads to uncertainty about whether the finding of abnormal perfusion was cause or consequence of the tissue state leading to LGE. Low MPRI, possibly indicating diffuse microvascular disease, was observed with and without LGE and T2+. Multiple mechanisms may lead to abnormal perfusion on sCMR. Microvascular dysfunction may contribute to the pathogenesis of and coexist with other causes of MINOCA. © 2016 Wiley Periodicals, Inc.

Cardiac fibrosis detected by magnetic resonance imaging on predicting time course diversity of left ventricular reverse remodeling in patients with idiopathic dilated cardiomyopathy.

PubMed

Ikeda, Yuki; Inomata, Takayuki; Fujita, Teppei; Iida, Yuichiro; Nabeta, Takeru; Ishii, Shunsuke; Maekawa, Emi; Yanagisawa, Tomoyoshi; Mizutani, Tomohiro; Naruke, Takashi; Koitabashi, Toshimi; Takeuchi, Ichiro; Ako, Junya

2016-11-01

This study aimed to identify the association between the time course of left ventricular reverse remodeling (LVRR) and late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-cMRI) in patients with idiopathic dilated cardiomyopathy (IDCM). We identified 214 IDCM patients treated by optimal pharmacotherapies. LVRR was defined as ≥10 % increment in LV ejection fraction along with ≥10 % reduction in LV end-diastolic dimension. Findings of LGE-cMRI focusing on presence and extent of LGE were evaluated at baseline. Echocardiographic evaluation for detecting LVRR was performed in all patients for 3 years. The primary endpoint was defined as composite events (CEs) including readmission for heart failure, detection of major ventricular arrhythmia, and all-cause mortality. LVRR was found at <1 year in 59 patients (28 %, early responder), ≥1 year in 56 patients (26 %, late responder), and was absent in 99 patients (46 %, non-responder). Multivariate Cox-proportional hazards analysis revealed that both early responders (P = 0.02) and late responders (P < 0.001) had lower incidence of CEs than non-responders. Among 66 subjects (23 %) with complete cMRI evaluation, LGE was detected more often in late and non- than early responders (65, 83 vs. 23 % P < 0.001, respectively), whereas the LGE area was smaller in both early and late than non-responders (2 ± 3, 4 ± 3 vs. 12 ± 10 %, P < 0.001, respectively). In conclusion, evaluating the presence and the extent of LGE is useful for predicting the clinical differences of LVRR time course and subsequent long-term outcomes.

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

NASA Astrophysics Data System (ADS)

Cronin, M. F.; Pelland, N.; Emerson, S. R.; Crawford, W. R.

2015-12-01

Data from two National Oceanographic and Atmospheric Administration (NOAA) surface moorings in the North Pacific, in combination with data from satellite, Argo floats and glider (when available), are used to evaluate the residual diffusive flux of heat across the base of the mixed layer from the surface mixed layer heat budget. The diffusion coefficient (i.e., diffusivity) is then computed by dividing the diffusive flux by the temperature gradient in the 20-m transition layer just below the base of the mixed layer. At Station Papa in the NE Pacific subpolar gyre, this diffusivity is 1×10-4 m2/s during summer, increasing to ~3×10-4 m2/s during fall. During late winter and early spring, diffusivity has large errors. At other times, diffusivity computed from the mixed layer salt budget at Papa correlate with those from the heat budget, giving confidence that the results are robust for all seasons except late winter-early spring and can be used for other tracers. In comparison, at the Kuroshio Extension Observatory (KEO) in the NW Pacific subtropical recirculation gyre, somewhat larger diffusivity are found based upon the mixed layer heat budget: ~ 3×10-4 m2/s during the warm season and more than an order of magnitude larger during the winter, although again, wintertime errors are large. These larger values at KEO appear to be due to the increased turbulence associated with the summertime typhoons, and weaker wintertime stratification.

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

NASA Astrophysics Data System (ADS)

Cronin, Meghan F.; Pelland, Noel A.; Emerson, Steven R.; Crawford, William R.

2015-11-01

Data from two National Oceanographic and Atmospheric Administration (NOAA) surface moorings in the North Pacific, in combination with data from satellite, Argo floats and glider (when available), are used to evaluate the residual diffusive flux of heat across the base of the mixed layer from the surface mixed layer heat budget. The diffusion coefficient (i.e., diffusivity) is then computed by dividing the diffusive flux by the temperature gradient in the 20 m transition layer just below the base of the mixed layer. At Station Papa in the NE Pacific subpolar gyre, this diffusivity is 1 × 10-4 m2/s during summer, increasing to ˜3 × 10-4 m2/s during fall. During late winter and early spring, diffusivity has large errors. At other times, diffusivity computed from the mixed layer salt budget at Papa correlate with those from the heat budget, giving confidence that the results are robust for all seasons except late winter-early spring and can be used for other tracers. In comparison, at the Kuroshio Extension Observatory (KEO) in the NW Pacific subtropical recirculation gyre, somewhat larger diffusivities are found based upon the mixed layer heat budget: ˜ 3 × 10-4 m2/s during the warm season and more than an order of magnitude larger during the winter, although again, wintertime errors are large. These larger values at KEO appear to be due to the increased turbulence associated with the summertime typhoons, and weaker wintertime stratification.

Silica nanoparticle-based dual imaging colloidal hybrids: cancer cell imaging and biodistribution

PubMed Central

Lee, Haisung; Sung, Dongkyung; Kim, Jinhoon; Kim, Byung-Tae; Wang, Tuntun; An, Seong Soo A; Seo, Soo-Won; Yi, Dong Kee

2015-01-01

In this study, fluorescent dye-conjugated magnetic resonance (MR) imaging agents were investigated in T mode. Gadolinium-conjugated silica nanoparticles were successfully synthesized for both MR imaging and fluorescence diagnostics. Polyamine and polycarboxyl functional groups were modified chemically on the surface of the silica nanoparticles for efficient conjugation of gadolinium ions. The derived gadolinium-conjugated silica nanoparticles were investigated by zeta potential analysis, transmission electron microscopy, inductively coupled plasma mass spectrometry, and energy dispersive x-ray spectroscopy. MR equipment was used to investigate their use as contrast-enhancing agents in T1 mode under a 9.4 T magnetic field. In addition, we tracked the distribution of the gadolinium-conjugated nanoparticles in both lung cancer cells and organs in mice. PMID:26357472

A study on the imaging characteristics of Gold nanoparticles as a contrast agent in X-ray computed tomography

NASA Astrophysics Data System (ADS)

Mesbahi, Asghar; Famouri, Fatemeh; Ahar, Mohammad Johari; Ghaffari, Maryam Olade; Ghavami, Seyed Mostafa

2017-03-01

Aim: In the current study, some imaging characteristics of AuNPs were quantitatively analyzed and compared with two conventional contrast media (CM) including Iodine and Gadolinium by using of a cylindrical phantom. Methods: AuNPs were synthesized with the mean diameter of 16 nm and were equalized to the concentration of 0.5, 1, 2 and 4 mg/mL in the same volumes. A cylindrical phantom resembling the head and neck was fabricated and drilled to contain small tubes filled with Iodine, Gadolinium, and AuNPs as contrast media. The phantom was scanned in different exposure techniques and CT numbers of three studied contrast media inside test tubes were measured in terms of Hounsfield Unit (HU). The imaging parameters of the noise and contrast to noise ratios (CNR) were calculated for all studied CMs. Results: AuNPs showed 128% and 166% higher CT number in comparison with Iodine and Gadolinium respectively. Also, Iodine had a greater CT number than Gadolinium for the same exposure techniques and concentration. The maximum CT number for AuNPs and studied contrast materials was obtained at the highest mAs and the lowest tube potential. The maximum CT number were 1033±11 (HU) for AuNP, 565±10 (HU) for Iodine, 458±11 for Gadolinium. Moreover, the maximum CNRs of 433±117, 203±53, 145±37 were found for AuNPs, Iodine and Gadolinium respectively. Conclusion: The contrast agent based on AuNPs showed higher imaging quality in terms of contrast and noise relative to other iodine and gadolinium based contrast media in X-ray computed tomography. Application of the AuNPs as a contrast medium in x-ray CT is recommended.

Polythermal investigation of viscosity of solution of metal carboxylates in VIK-grade mixed carboxylic acids: Yttrium and gadolinium carboxylates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mezhov, E.A.; Samatov, A.V.; Troyanovskii, L.V.

Kinematic viscosities have been measured for solutions of yttrium and gadolinium carboxylates in grade VIK mixed carboxylic acids (MCA). It has been established that the optimal fluidity of these metal carboxylate solutions for application to articles is reached at 333 K. A regression model has been developed to describe the concentration and temperature dependences of the viscosity of yttrium- and gadolinium-containing MCA solutions. 2 refs., 3 tabs.

Inverse Relationship between Serum VEGF Levels and Late In-Stent Restenosis of Drug-Eluting Stents

PubMed Central

Shen, Li; Ji, Meng; Cai, Sishi; Chen, Jiahui; Yao, Zhifeng

2017-01-01

Late in-stent restenosis (ISR) has raised concerns regarding the long-term efficacy of drug-eluting stents (DES). The role of vascular endothelial growth factor (VEGF) in the pathological process of ISR is controversial. This retrospective study aimed to investigate the relationship between serum VEGF levels and late ISR in patients with DES implantation. A total of 158 patients who underwent angiography follow-up beyond 1 year after intervention were included. The study population was classified into ISR and non-ISR groups. The ISR group was further divided according to follow-up duration and Mehran classification. VEGF levels were significantly lower in the ISR group than in the non-ISR group [96.34 (48.18, 174.14) versus 179.14 (93.59, 307.74) pg/mL, p < 0.0001]. Multivariate regression revealed that VEGF level, procedure age, and low-density lipoprotein cholesterol were independent risk factors for late ISR formation. Subgroup analysis demonstrated that VEGF levels were even lower in the very late (≥5 years) and diffuse ISR group (Mehran patterns II, III, and IV) than in the late ISR group (1–4 years) and the focal ISR group (Mehran pattern I), respectively. Furthermore, significant difference was found between diffuse and focal ISR groups. Serum VEGF levels were inversely associated with late ISR after DES implantation. PMID:28373989

Gadolinium deposition disease: Initial description of a disease that has been around for a while.

PubMed

Semelka, Richard C; Ramalho, Joana; Vakharia, Ami; AlObaidy, Mamdoh; Burke, Lauren M; Jay, Michael; Ramalho, Miguel

2016-12-01

To describe the clinical manifestations of presumed gadolinium toxicity in patients with normal renal function. Participants were recruited from two online gadolinium toxicity support groups. The survey was anonymous and individuals were instructed to respond to the survey only if they had evidence of normal renal function, evidence of gadolinium in their system beyond 30days of this MRI, and no pre-existent clinical symptoms and/or signs of this type. 42 subjects responded to the survey (age: 28-69, mean 49.1±22.4years). The most common findings were: central pain (n=15), peripheral pain (n=26), headache (n=28), and bone pain (n=26). Only subjects with distal leg and arm distribution described skin thickening (n=22). Clouded mentation and headache were the symptoms described as persistent beyond 3months in 29 subjects. Residual disease was present in all patients. Twenty-eight patients described symptoms following administration of one brand of Gadolinium-Based Contrast Agent (GBCA), 21 after a single GBCA administration and 7 after multiple GBCA administrations, including: gadopentetate dimeglumine, n=9; gadodiamide, n=4; gadoversetamide, n=4; gadobenate dimeglumine, n=4; gadobutrol, n=1; gadoteridol, n=2; and unknown, n=4. Gadolinium toxicity appears to arise following GBCA administration, which appears to contain clinical features seen in Nephrogenic Systemic Fibrosis, but also features not observed in that condition. Copyright © 2016 Elsevier Inc. All rights reserved.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

PubMed Central

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N′-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor. PMID:26316749

Acute encephalopathy with biphasic seizures and late reduced diffusion associated with staphylococcal toxic shock syndrome caused by burns.

PubMed

Yokochi, Takaoki; Sakanishi, Shinpei; Ishidou, Yuuki; Kawano, Go; Matsuishi, Toyojiro; Akita, Yukihiro; Obu, Keizo

2016-10-01

We report a case of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) associated with toxic shock syndrome caused by burns. A one-year-old girl was admitted to our hospital for treatment of severe burns. On day 3, she exhibited a fever, generalized rash and multiple organ failure. She was diagnosed with toxic shock syndrome after burns. She had seizures with fever twice on the same day, followed by secondary seizures on day 8 and transient deterioration of the gross motor functions involved in sitting alone and rolling over. On day 9, MRI diffusion-weighted images showed bright tree appearance (BTA). We conclude that she developed AESD. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

A polymeric fastener can easily functionalize liposome surfaces with gadolinium for enhanced magnetic resonance imaging.

PubMed

Smith, Cartney E; Shkumatov, Artem; Withers, Sarah G; Yang, Binxia; Glockner, James F; Misra, Sanjay; Roy, Edward J; Wong, Chun-Ho; Zimmerman, Steven C; Kong, Hyunjoon

2013-11-26

Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization and, therefore, has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication.

Removal of gadolinium, a neutron poison from the moderator system of nuclear reactors.

PubMed

Rufus, A L; Kumar, Padma S; Jeena, K; Velmurugan, S

2018-01-15

Gadolinium as gadolinium nitrate is used as neutron poison in the moderator system for regulating and controlling the power generation of Pressurized Heavy Water Reactors (PHWR) and proposed to be used in Advanced Heavy Water Reactors (AHWR) owing to its high neutron absorption cross section. Removal of the added gadolinium nitrate (Gd 3+ and NO 3 - ) from the system after its intended use is done using ion exchange resins. In the present investigation, attempts have been made to optimize the ion exchange process for generation of low radioactive waste and maximize utilization of the ion exchange resins by employing different types of resins and different modes of operation. The investigations revealed that use of mixed bed (MB) resin column consisting of Strong Acid Cation (SAC) resin and Strong Base Anion (SBA) resin followed by SAC resin column is efficient in removing the Gd 3+ and NO 3 - from the system besides maintaining the pH of the moderator system in the desirable regime, where gadolinium does not get precipitated as its hydroxide. Copyright © 2017 Elsevier B.V. All rights reserved.

A Polymeric Fastener can Easily Functionalize Liposome Surfaces with Gadolinium for Enhanced Magnetic Resonance Imaging

PubMed Central

Smith, Cartney E.; Shkumatov, Artem; Withers, Sarah G.; Glockner, James F.; Misra, Sanjay; Roy, Edward J.; Wong, Chun-Ho; Zimmerman, Steven C.; Kong, Hyunjoon

2013-01-01

Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization, and therefore has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication. PMID:24083377

A case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Hazama, Kyoko; Shiihara, Takashi; Tsukagoshi, Hiroyuki; Hasegawa, Shunji; Dowa, Yuri; Watanabe, Mio

2017-10-01

Mumps is a common childhood viral disease characterized by fever and swelling of the parotid gland. The prognosis is generally good, although some complications, such as encephalitis (0.1%), exist. Acute encephalopathy with biphasic seizures and late reduced diffusion is the most common type of acute encephalopathy. However, this type of encephalopathy has not been reported in association with mumps infection. A previously healthy 3-year-old Japanese boy had a brief convulsion after fever for 3days, and then had conscious disturbance and parotitis. After several days, he had a second brief convulsion and was admitted. Increased serum amylase levels and presence of anti-mumps immunoglobulin M antibody confirmed mumps parotitis. The patient had another brief seizure later the day of admission. He did not have status or cluster seizures, although the biphasic nature of his seizures, conscious disturbance between the seizures, no pleocytosis in cerebrospinal fluid, and brain magnetic resonance images were consistent with acute encephalopathy with biphasic seizures and late reduced diffusion. In Japan, the mumps vaccine is not administered as a part of routine immunizations. It thus has low coverage (30-40%), and as a result, mumps infections are still common. However, this is the first case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion. This case may be representative of only a minority of patients with mumps-associated central nervous system involvement. Nevertheless, this diagnostic possibility may be considered. In order to prevent mumps-related complications, routine mumps vaccination might be warranted. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Geographical structures and the cholera epidemic in modern Japan: Fukushima prefecture in 1882 and 1895.

PubMed

Kuo, Chun-Lin; Fukui, Hiromichi

2007-06-30

Disease diffusion patterns can provide clues for understanding geographical change. Fukushima, a rural prefecture in northeast Japan, was chosen for a case study of the late nineteenth century cholera epidemic that occurred in that country. Two volumes of Cholera Ryu-ko Kiji (Cholera Epidemic Report), published by the prefectural government in 1882 and 1895, provide valuable records for analyzing and modelling diffusion. Text descriptions and numerical evidence culled from the reports were incorporated into a temporal-spatial study framework using geographic information system (GIS) and geo-statistical techniques. Changes in diffusion patterns between 1882 and 1895 reflect improvements in the Fukushima transportation system and growth in social-economic networks. The data reveal different diffusion systems in separate regions in which residents of Fukushima and neighboring prefectures interacted. Our model also shows that an area in the prefecture's northern interior was dominated by a mix of diffusion processes (contagious and hierarchical), that the southern coastal region was affected by a contagious process, and that other infected areas experienced relocation diffusion. In addition to enhancing our understanding of epidemics, the spatial-temporal patterns of cholera diffusion offer opportunities for studying regional change in modern Japan. By highlighting the dynamics of regional reorganization, our findings can be used to better understand the formation of an urban hierarchy in late nineteenth century Japan.

Gadolinium-Conjugated Gold Nanoshells for Multimodal Diagnostic Imaging and Photothermal Cancer Therapy

PubMed Central

Coughlin, Andrew J.; Ananta, Jeyarama S.; Deng, Nanfu; Larina, Irina V.; Decuzzi, Paolo

2014-01-01

Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated gold nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation. PMID:24115690

Gadolinium Scandium Gallium Garnet (GSGG) as a Solid-State Laser Host

DTIC Science & Technology

1987-07-01

o*SATI CODSi1.SBEC EM (otne nrvrs fnceayad dniy nb)k ubr ~~~~~~~~ Gadolinium Scandium Gallium Garnet (GSGG)asaSldtteLerHt 17. ABSTRACT 6.SUJCTTEM...certain other garnet materials for replacement. It also addresses the solid-state laser host material Gadolinium Scandium Gal- lium Garnet (GSGG) and its...by neodymium-doped yttrium aluminum garnet (Nd:YAG) or other mate- rials for most applications. In the years after the invention of the ruby laser, in

Dynamic aggregation of the mid-sized gadolinium complex {Ph4[Gd(DTTA)(H2O)2](-)3}.

PubMed

Jaccard, Hugues; Miéville, Pascal; Cannizzo, Caroline; Mayer, Cédric R; Helm, Lothar

2014-02-01

A compound binding three Gd(3+) ions, {Ph4[Gd(DTTA)(H2O)2](-) 3} (where H5DTTA is diethylenetriaminetetraacetic acid), has been synthesized around a hydrophobic center made up of four phenyl rings. In aqueous solution the molecules start to self-aggregate at concentrations well below 1 mM as shown by the increase of rotational correlation times and by the decrease of the translational self-diffusion constant. NMR spectra recorded in aqueous solution of the diamagnetic analogue {Ph4[Y(DTTA)(H2O)2](-)3} show that the aggregation is dynamic and due to intermolecular π-stacking interactions between the hydrophobic aromatic centers. From estimations of effective radii, it can be concluded that the aggregates are composed of two to three monomers. The paramagnetic {Ph4[Gd(DTTA)(H2O)2](-)3} exhibits concentration-dependent (1)H NMR relaxivities with high values of approximately 50 mM(-1) s(-1) (30 MHz, 25 °C) at gadolinium concentrations above 20 mM. A combined analysis of (1)H NMR dispersion profiles measured at different concentrations of the compound and (17)O NMR data measured at various temperatures was performed using different theoretical approaches. The fitted parameters showed that the increase in relaxivity with increasing concentration of the compound is due to slower global rotational motion and an increase of the Lipari-Szabo order parameter S(2).

Nuclear spin relaxation in ligands outside of the first coordination sphere in a gadolinium (III) complex: Effects of intermolecular forces

NASA Astrophysics Data System (ADS)

Kruk, Danuta; Kowalewski, Jozef

2002-07-01

This article describes paramagnetic relaxation enhancement (PRE) in systems with high electron spin, S, where there is molecular interaction between a paramagnetic ion and a ligand outside of the first coordination sphere. The new feature of our treatment is an improved handling of the electron-spin relaxation, making use of the Redfield theory. Following a common approach, a well-defined second coordination sphere is assumed, and the PRE contribution from these more distant and shorter-lived ligands is treated in a way similar to that used for the first coordination sphere. This model is called "ordered second sphere," OSS. In addition, we develop here a formalism similar to that of Hwang and Freed [J. Chem. Phys. 63, 4017 (1975)], but accounting for the electron-spin relaxation effects. We denote this formalism "diffuse second sphere," DSS. The description of the dynamics of the intermolecular dipole-dipole interaction is based on the Smoluchowski equation, with a potential of mean force related to the radial distribution function. We have used a finite-difference method to calculate numerically a correlation function for translational motion, taking into account the intermolecular forces leading to an arbitrary radial distribution of the ligand protons. The OSS and DSS models, including the Redfield description of the electron-spin relaxation, were used to interpret the PRE in an aqueous solution of a slowly rotating gadolinium (III) complex (S=7/2) bound to a protein.

Activated microglia in acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Fujita, Yuji; Takanashi, Jun-Ichi; Takei, Haruka; Ota, Setsuo; Fujii, Katsunori; Sakuma, Hiroshi; Hayashi, Masaharu

2016-07-15

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype of infectious pediatric encephalopathy in Japan. The exact pathogenesis of and the best therapeutic strategy for AESD are uncertain. We firstly performed a brain biopsy in a 2-year-old boy with AESD associated with RS viral infection, which revealed activated ameoboid microglia accumulation around degenerated neuron, and astrogliosis in the affected cortex. Glutamate released from activated microglia may play an important role in the pathogenesis of AESD, which is compatible with the previous report of magnetic resonance spectroscopy showing elevated glutamate. Copyright © 2016 Elsevier B.V. All rights reserved.

Compressed sensing for rapid late gadolinium enhanced imaging of the left atrium: A preliminary study.

PubMed

Kamesh Iyer, Srikant; Tasdizen, Tolga; Burgon, Nathan; Kholmovski, Eugene; Marrouche, Nassir; Adluru, Ganesh; DiBella, Edward

2016-09-01

Current late gadolinium enhancement (LGE) imaging of left atrial (LA) scar or fibrosis is relatively slow and requires 5-15min to acquire an undersampled (R=1.7) 3D navigated dataset. The GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) based parallel imaging method is the current clinical standard for accelerating 3D LGE imaging of the LA and permits an acceleration factor ~R=1.7. Two compressed sensing (CS) methods have been developed to achieve higher acceleration factors: a patch based collaborative filtering technique tested with acceleration factor R~3, and a technique that uses a 3D radial stack-of-stars acquisition pattern (R~1.8) with a 3D total variation constraint. The long reconstruction time of these CS methods makes them unwieldy to use, especially the patch based collaborative filtering technique. In addition, the effect of CS techniques on the quantification of percentage of scar/fibrosis is not known. We sought to develop a practical compressed sensing method for imaging the LA at high acceleration factors. In order to develop a clinically viable method with short reconstruction time, a Split Bregman (SB) reconstruction method with 3D total variation (TV) constraints was developed and implemented. The method was tested on 8 atrial fibrillation patients (4 pre-ablation and 4 post-ablation datasets). Blur metric, normalized mean squared error and peak signal to noise ratio were used as metrics to analyze the quality of the reconstructed images, Quantification of the extent of LGE was performed on the undersampled images and compared with the fully sampled images. Quantification of scar from post-ablation datasets and quantification of fibrosis from pre-ablation datasets showed that acceleration factors up to R~3.5 gave good 3D LGE images of the LA wall, using a 3D TV constraint and constrained SB methods. This corresponds to reducing the scan time by half, compared to currently used GRAPPA methods. Reconstruction of 3D LGE images using the SB method was over 20 times faster than standard gradient descent methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Improved multimodality data fusion of late gadolinium enhancement MRI to left ventricular voltage maps in ventricular tachycardia ablation.

PubMed

Roujol, Sebastien; Basha, Tamer A; Tan, Alex; Khanna, Varun; Chan, Raymond H; Moghari, Mehdi H; Rayatzadeh, Hussein; Shaw, Jaime L; Josephson, Mark E; Nezafat, Reza

2013-05-01

Electroanatomical voltage mapping (EAVM) is commonly performed prior to catheter ablation of scar-related ventricular tachycardia (VT) to locate the arrhythmic substrate and to guide the ablation procedure. EAVM is used to locate the position of the ablation catheter and to provide a 3-D reconstruction of left-ventricular anatomy and scar. However, EAVM measurements only represent the endocardial scar with no transmural or epicardial information. Furthermore, EAVM is a time-consuming procedure, with a high operator dependence and has low sampling density, i.e., spatial resolution. Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) allows noninvasive assessment of scar morphology that can depict 3-D scar architecture. Despite the potential use of LGE as a roadmap for VT ablation for identification of arrhythmogenic substrate, its utility has been very limited. To allow for identification of VT substrate, a correlation is needed between the substrates identified by EAVM as the gold standard and LGE-MRI scar characteristics. To do so, a system must be developed to fuse the datasets from these modalities. In this study, a registration pipeline for the fusion of LGE-MRI and EAVM data is presented. A novel surface registration algorithm is proposed, integrating the matching of global scar areas as an additional constraint in the registration process. A preparatory landmark registration is initially performed to expedite the convergence of the algorithm. Numerical simulations were performed to evaluate the accuracy of the registration in the presence of errors in identifying landmarks in EAVM or LGE-MRI datasets as well as additional errors due to respiratory or cardiac motion. Subsequently, the accuracy of the proposed fusion system was evaluated in a cohort of ten patients undergoing VT ablation where both EAVM and LGE-MRI data were available. Compared to landmark registration and surface registration, the presented method achieved significant improvement in registration error. The proposed data fusion system allows the fusion of EAVM and LGE-MRI data in VT ablation with registration errors less than 3.5  mm.

Diagnostic accuracy of stress perfusion CMR in comparison with quantitative coronary angiography: fully quantitative, semiquantitative, and qualitative assessment.

PubMed

Mordini, Federico E; Haddad, Tariq; Hsu, Li-Yueh; Kellman, Peter; Lowrey, Tracy B; Aletras, Anthony H; Bandettini, W Patricia; Arai, Andrew E

2014-01-01

This study's primary objective was to determine the sensitivity, specificity, and accuracy of fully quantitative stress perfusion cardiac magnetic resonance (CMR) versus a reference standard of quantitative coronary angiography. We hypothesized that fully quantitative analysis of stress perfusion CMR would have high diagnostic accuracy for identifying significant coronary artery stenosis and exceed the accuracy of semiquantitative measures of perfusion and qualitative interpretation. Relatively few studies apply fully quantitative CMR perfusion measures to patients with coronary disease and comparisons to semiquantitative and qualitative methods are limited. Dual bolus dipyridamole stress perfusion CMR exams were performed in 67 patients with clinical indications for assessment of myocardial ischemia. Stress perfusion images alone were analyzed with a fully quantitative perfusion (QP) method and 3 semiquantitative methods including contrast enhancement ratio, upslope index, and upslope integral. Comprehensive exams (cine imaging, stress/rest perfusion, late gadolinium enhancement) were analyzed qualitatively with 2 methods including the Duke algorithm and standard clinical interpretation. A 70% or greater stenosis by quantitative coronary angiography was considered abnormal. The optimum diagnostic threshold for QP determined by receiver-operating characteristic curve occurred when endocardial flow decreased to <50% of mean epicardial flow, which yielded a sensitivity of 87% and specificity of 93%. The area under the curve for QP was 92%, which was superior to semiquantitative methods: contrast enhancement ratio: 78%; upslope index: 82%; and upslope integral: 75% (p = 0.011, p = 0.019, p = 0.004 vs. QP, respectively). Area under the curve for QP was also superior to qualitative methods: Duke algorithm: 70%; and clinical interpretation: 78% (p < 0.001 and p < 0.001 vs. QP, respectively). Fully quantitative stress perfusion CMR has high diagnostic accuracy for detecting obstructive coronary artery disease. QP outperforms semiquantitative measures of perfusion and qualitative methods that incorporate a combination of cine, perfusion, and late gadolinium enhancement imaging. These findings suggest a potential clinical role for quantitative stress perfusion CMR. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Myocardial infarct sizing by late gadolinium-enhanced MRI: Comparison of manual, full-width at half-maximum, and n-standard deviation methods.

PubMed

Zhang, Lin; Huttin, Olivier; Marie, Pierre-Yves; Felblinger, Jacques; Beaumont, Marine; Chillou, Christian DE; Girerd, Nicolas; Mandry, Damien

2016-11-01

To compare three widely used methods for myocardial infarct (MI) sizing on late gadolinium-enhanced (LGE) magnetic resonance (MR) images: manual delineation and two semiautomated techniques (full-width at half-maximum [FWHM] and n-standard deviation [SD]). 3T phase-sensitive inversion-recovery (PSIR) LGE images of 114 patients after an acute MI (2-4 days and 6 months) were analyzed by two independent observers to determine both total and core infarct sizes (TIS/CIS). Manual delineation served as the reference for determination of optimal thresholds for semiautomated methods after thresholding at multiple values. Reproducibility and accuracy were expressed as overall bias ± 95% limits of agreement. Mean infarct sizes by manual methods were 39.0%/24.4% for the acute MI group (TIS/CIS) and 29.7%/17.3% for the chronic MI group. The optimal thresholds (ie, providing the closest mean value to the manual method) were FWHM30% and 3SD for the TIS measurement and FWHM45% and 6SD for the CIS measurement (paired t-test; all P > 0.05). The best reproducibility was obtained using FWHM. For TIS measurement in the acute MI group, intra-/interobserver agreements, from Bland-Altman analysis, with FWHM30%, 3SD, and manual were -0.02 ± 7.74%/-0.74 ± 5.52%, 0.31 ± 9.78%/2.96 ± 16.62% and -2.12 ± 8.86%/0.18 ± 16.12, respectively; in the chronic MI group, the corresponding values were 0.23 ± 3.5%/-2.28 ± 15.06, -0.29 ± 10.46%/3.12 ± 13.06% and 1.68 ± 6.52%/-2.88 ± 9.62%, respectively. A similar trend for reproducibility was obtained for CIS measurement. However, semiautomated methods produced inconsistent results (variabilities of 24-46%) compared to manual delineation. The FWHM technique was the most reproducible method for infarct sizing both in acute and chronic MI. However, both FWHM and n-SD methods showed limited accuracy compared to manual delineation. J. Magn. Reson. Imaging 2016;44:1206-1217. © 2016 International Society for Magnetic Resonance in Medicine.

Prognostic Value of Late Gadolinium Enhancement CMR in Systemic Amyloidosis.

PubMed

Raina, Sameer; Lensing, Shelly Y; Nairooz, Ramez S; Pothineni, Naga Venkata K; Hakeem, Abdul; Bhatti, Sabha; Pandey, Tarun

2016-11-01

The aim of this study was to access the prognostic implication of late gadolinium enhancement (LGE) in patients with systemic amyloidosis undergoing cardiac magnetic resonance (CMR). Cardiac amyloidosis confers significantly worse prognosis in patients with systemic amyloidosis. CMR imaging has emerged as an attractive noninvasive modality to diagnose cardiac involvement in patients with systemic amyloidosis. We performed a systemic review and meta-analysis to evaluate the prognostic role of LGE-CMR imaging in patients with systemic amyloidosis. Electronic databases MEDLINE, PubMed, Embase, and Cochrane were systematically searched to identify studies evaluating the association between LGE-CMR and prognosis in systemic amyloidosis with cardiac involvement. The present study was designed to systematically review and assess the association between LGE and the primary endpoint of all-cause mortality. A random effects model was used to calculate a pooled odds ratio using inverse-variance weighting. Data were included from 7 studies with a total of 425 patients and a mean follow-up of 25 months. Patients had a weighted average age of 64 years and left ventricular ejection fraction of 59.2%; 67% were male. Endomyocardial biopsy was positive for amyloidosis in 20%, whereas LGE was present in 73% of patients. LGE-positive patients had increased overall mortality compared with those without LGE (pooled odds ratio: 4.96; 95% confidence interval [CI]: 1.90 to 12.93; p = 0.001). For the LGE group, the pooled death rate was 0.07 (95% CI: 0.03 to 0.19) events per year and for the LGE+ group, the rate was 0.25 (95% CI: 0.16 to 0.39 per year; p = 0.001). The proportion of patients with cardiac biopsy within each study ranged from 3% to 68%, and the relationship between LGE status and death did not vary according to cardiac biopsy proportion across studies. LGE on CMR in patients with systemic amyloidosis with known or suspected cardiac amyloidosis is associated with increased risk of all-cause mortality. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Association of left ventricular late gadolinium enhancement with left atrial low voltage areas in patients with atrial fibrillation.

PubMed

Stegmann, Clara; Jahnke, Cosima; Paetsch, Ingo; Hilbert, Sebastian; Arya, Arash; Bollmann, Andreas; Hindricks, Gerhard; Sommer, Philipp

2018-02-06

Presence of late gadolinium enhancement (LGE) is related to adverse cardiovascular outcome. Many patients suffering from atrial fibrillation (AF) undergo cardiovascular magnetic resonance (CMR) imaging prior to ablation. Since quantification of atrial fibrosis still lacks reproducibility, we sought to investigate risk factors for the presence of left ventricular (LV)-LGE and a possible correlation between ventricular fibrosis as defined by positive LGE and pathological atrial voltage maps evaluated by 3D mapping systems. Between May 2015 and January 2017, 241 patients with AF (73% persistent AF, 71% male, mean age 62.8 ± 10.1 years, Redo procedure in 24%, AF history 4.5 ± 5.2 years) underwent CMR including LV LGE prior to pulmonary vein (PV) isolation at Heart Center Leipzig. Depending on CMR results, two groups were separated: 'LV-LGE negative' (Group A, n = 197, 82%) and 'LV-LGE positive' (Group B, n = 44, 18%). To identify low voltage areas (LVA), a 3D electro-anatomic map was created during PV isolation. Multivariate analysis revealed male gender [odds ratio (OR) 7.6, 95% confidence interval (95% CI) 2.4-23.9, P = 0.001] and an increased CHA2DS2VASc Score (OR 1.6, 95% CI 1.2-2.2, P = 0.004) as significantly associated with LV-LGE. Impaired left ventricular ejection fraction, LV dilatation, larger LA size and, enlarged septum diameter occurred significantly more often in the 'LGE positive' group. Low voltage areas were detected in 83 patients overall (34%): Group A: n = 64/197 (33%), Group B: n = 19/44 (43%) (P = 0.177). Male gender and high CHA2DS2VASc Score are significantly associated with presence of LV-LGE, but LV-LGE is not associated with left atrial LVA. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

Myocardial Infarct Size by CMR in Clinical Cardioprotection Studies: Insights From Randomized Controlled Trials.

PubMed

Bulluck, Heerajnarain; Hammond-Haley, Matthew; Weinmann, Shane; Martinez-Macias, Roberto; Hausenloy, Derek J

2017-03-01

The aim of this study was to review randomized controlled trials (RCTs) using cardiac magnetic resonance (CMR) to assess myocardial infarct (MI) size in reperfused patients with ST-segment elevation myocardial infarction (STEMI). There is limited guidance on the use of CMR in clinical cardioprotection RCTs in patients with STEMI treated by primary percutaneous coronary intervention. All RCTs in which CMR was used to quantify MI size in patients with STEMI treated with primary percutaneous coronary intervention were identified and reviewed. Sixty-two RCTs (10,570 patients, January 2006 to November 2016) were included. One-third did not report CMR vendor or scanner strength, the contrast agent and dose used, and the MI size quantification technique. Gadopentetate dimeglumine was most commonly used, followed by gadoterate meglumine and gadobutrol at 0.20 mmol/kg each, with late gadolinium enhancement acquired at 10 min; in most RCTs, MI size was quantified manually, followed by the 5 standard deviation threshold; dropout rates were 9% for acute CMR only and 16% for paired acute and follow-up scans. Weighted mean acute and chronic MI sizes (≤12 h, initial TIMI [Thrombolysis in Myocardial Infarction] flow grade 0 to 3) from the control arms were 21 ± 14% and 15 ± 11% of the left ventricle, respectively, and could be used for future sample-size calculations. Pre-selecting patients most likely to benefit from the cardioprotective therapy (≤6 h, initial TIMI flow grade 0 or 1) reduced sample size by one-third. Other suggested recommendations for standardizing CMR in future RCTs included gadobutrol at 0.15 mmol/kg with late gadolinium enhancement at 15 min, manual or 6-SD threshold for MI quantification, performing acute CMR at 3 to 5 days and follow-up CMR at 6 months, and adequate reporting of the acquisition and analysis of CMR. There is significant heterogeneity in RCT design using CMR in patients with STEMI. The authors provide recommendations for standardizing the assessment of MI size using CMR in future clinical cardioprotection RCTs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Gadolinium photoionization process

DOEpatents

Paisner, J.A.; Comaskey, B.J.; Haynam, C.A.; Eggert, J.H.

1993-04-13

A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.

Gadolinium photoionization process

DOEpatents

Paisner, Jeffrey A.; Comaskey, Brian J.; Haynam, Christopher A.; Eggert, Jon H.

1993-01-01

A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.

Kinetic characteristics of the luminescence decay for industrial yttrium-gadolinium-aluminium garnet based phosphors

NASA Astrophysics Data System (ADS)

Lisitsyn, V. M.; Stepanov, S. A.; Valiev, D. T.; Vishnyakova, E. A.; Abdullin, H. A.; Marhabaeva, A. A.; Tulegenova, A. T.

2016-02-01

The spectral and decay kinetic characteristics of pulse cathodoluminescence and photoluminescence of phosphors based on yttrium-gadolinium-aluminum garnet were investigated using pulsed optical time resolved spectroscopy.

Transient arterial phase respiratory motion-related artifact in MR imaging of the liver: an analysis of four different gadolinium-based contrast agents.

PubMed

Shah, Mansi R; Flusberg, Milana; Paroder, Viktoriya; Rozenblit, Alla M; Chernyak, Victoria

The purpose was to compare hepatic arterial phase (HAP) respiratory motion artifact (RMA) between gadoxetate, gadobutrol, gadopentetate, and gadobenate. Two hundred cases of each gadolinium agent were included. RMA was assigned using 5-point Likert scale (1=no motion, 5=extreme motion) on precontrast and HAP. RMA increase (increase ≥1 on HAP from precontrast) was the outcome in logistic regression. Odds of RMA increase for gadoxetate were 5.5 (P<.001), 3.6 (P=.034), and 9.5 (P<.001) times higher than gadobutrol, gadopentetate, and gadobenate, respectively. Gadolinium volume and dose were not independent predictors of RMA increase. Gadoxetate has increased odds of RMA compared with other gadolinium agents; tight contrast bolus is not a contributor. Copyright © 2016 Elsevier Inc. All rights reserved.

The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

NASA Astrophysics Data System (ADS)

Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

2016-07-01

We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps.

Characterization of the reaction products and precipitates at the interface of carbon fiber reinforced magnesium–gadolinium composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yaping; Jiang, Longtao, E-mail: longtaojiang@163.com; Chen, Guoqin

2016-03-15

In the present work, carbon fiber reinforced magnesium-gadolinium composite was fabricated by pressure infiltration method. The phase composition, micro-morphology, and crystal structure of reaction products and precipitates at the interface of the composite were investigated. Scanning electron microscopy and energy dispersive spectroscopy analysis revealed the segregation of gadolinium element at the interface between carbon fiber and matrix alloy. It was shown that block-shaped Gd4C5, GdC2 and nano-sized Gd2O3 were formed at the interface during the fabrication process due to the interfacial reaction. Furthermore, magnesium-gadolinium precipitates including needle-like Mg5Gd (or Mg24Gd5) and thin plate-shaped long period stacking-ordered phase, were also observedmore » at the interface and in the matrix near the interface. The interfacial microstructure and bonding mode were influenced by these interfacial products, which were beneficial for the improvement of the interfacial bonding strength. - Highlights: • Gadolinium element segregated on the surface of carbon fibers. • Block-shaped Gd{sub 4}C{sub 5} and GdC{sub 2} were formed at the interface via chemical reaction. • Gadolinium and oxygen reacted at the interface and formed nano-scaled Gd{sub 2}O{sub 3}. • The precipitates formed in the interface were identified to be Mg{sub 5}Gd (or Mg{sub 24}Gd{sub 5}) and plate-shaped long period stacking-ordered phase.« less

Contributions of late-type dwarf stars to the soft X-ray diffuse background

NASA Technical Reports Server (NTRS)

Schmitt, J. H. M. M.; Snowden, S. L.

1990-01-01

Comprehensive calculations of the contribution of late-type dwarf stars to the soft X-ray diffuse background are presented. The mean X-ray luminosity as derived from optically and X-ray selected samples is examined, using the Bahcall-Soneira Galaxy model to describe the spatial distribution of stars and recent results on the X-ray spectra. The model calculations are compared with the Wisconsin sky maps in the C, M1, M2, I and J bands to assess the uncertainties of the calculations. Contributions of up to 10 percent to the M2 and I band background at high Galactic latitudes are found, while at low Galactic latitudes late-type stars contribute up to 40 percent of the background. However, a Galactic ridge as well as a relatively isotropic component still remains unexplained, even with the added contribution of the extrapolated high-energy power law.

Experimental tests of truncated diffusion in fault damage zones

NASA Astrophysics Data System (ADS)

Suzuki, Anna; Hashida, Toshiyuki; Li, Kewen; Horne, Roland N.

2016-11-01

Fault zones affect the flow paths of fluids in groundwater aquifers and geological reservoirs. Fault-related fracture damage decreases to background levels with increasing distance from the fault core according to a power law. This study investigated mass transport in such a fault-related structure using nonlocal models. A column flow experiment is conducted to create a permeability distribution that varies with distance from a main conduit. The experimental tracer response curve is preasymptotic and implies subdiffusive transport, which is slower than the normal Fickian diffusion. If the surrounding area is a finite domain, an upper truncated behavior in tracer response (i.e., exponential decline at late times) is observed. The tempered anomalous diffusion (TAD) model captures the transition from subdiffusive to Fickian transport, which is characterized by a smooth transition from power-law to an exponential decline in the late-time breakthrough curves.

Automated segmentation of myocardial scar in late enhancement MRI using combined intensity and spatial information.

PubMed

Tao, Qian; Milles, Julien; Zeppenfeld, Katja; Lamb, Hildo J; Bax, Jeroen J; Reiber, Johan H C; van der Geest, Rob J

2010-08-01

Accurate assessment of the size and distribution of a myocardial infarction (MI) from late gadolinium enhancement (LGE) MRI is of significant prognostic value for postinfarction patients. In this paper, an automatic MI identification method combining both intensity and spatial information is presented in a clear framework of (i) initialization, (ii) false acceptance removal, and (iii) false rejection removal. The method was validated on LGE MR images of 20 chronic postinfarction patients, using manually traced MI contours from two independent observers as reference. Good agreement was observed between automatic and manual MI identification. Validation results showed that the average Dice indices, which describe the percentage of overlap between two regions, were 0.83 +/- 0.07 and 0.79 +/- 0.08 between the automatic identification and the manual tracing from observer 1 and observer 2, and the errors in estimated infarct percentage were 0.0 +/- 1.9% and 3.8 +/- 4.7% compared with observer 1 and observer 2. The difference between the automatic method and manual tracing is in the order of interobserver variation. In conclusion, the developed automatic method is accurate and robust in MI delineation, providing an objective tool for quantitative assessment of MI in LGE MR imaging.

Porphyrin-containing polyaspartamide gadolinium complexes as potential magnetic resonance imaging contrast agents.

PubMed

Yan, Guo-Ping; Li, Zhen; Xu, Wei; Zhou, Cheng-Kai; Yang, Lian; Zhang, Qiao; Li, Liang; Liu, Fan; Han, Lin; Ge, Yuan-Xing; Guo, Jun-Fang

2011-04-04

Porphyrin-containing polyaspartamide ligands (APTSPP-PHEA-DTPA) were synthesized by the incorporation of diethylenetriaminepentaacetic acid (DTPA) and 5-(4'-aminophenyl)-10,15,20-tris(4'-sulfonatophenyl) porphyrin, trisodium salt (APTSPP) into poly-α,β-[N-(2-hydroxyethyl)-l-aspartamide] (PHEA). These ligands were further reacted with gadolinium chloride to produce macromolecule-gadolinium complexes (APTSPP-PHEA-DTPA-Gd). Experimental data of (1)H NMR, IR, UV and elemental analysis evidenced the formation of the polyaspartamide ligands and gadolinium complexes. In vitro and in vivo property tests indicated that APTSPP-PHEA-DTPA-Gd possessed noticeably higher relaxation effectiveness, less toxicity to HeLa cells, and significantly higher enhanced signal intensities (SI) of the VX2 carcinoma in rabbits with lower injection dose requirement than that of Gd-DTPA. Moreover, APTSPP-PHEA-DTPA-Gd was found to greatly enhance the contrast of MR images of the VX2 carcinoma, providing prolonged intravascular duration, and distinguished the VX2 carcinoma and normal tissues in rabbits according to MR image signal enhancements. These porphyrin-containing polyaspartamide gadolinium complexes can be used as the candidates of contrast agents for targeted MRI to tumors. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Solid solutions of gadolinium doped zinc oxide nanorods by combined microwave-ultrasonic irradiation assisted crystallization

NASA Astrophysics Data System (ADS)

Kiani, Armin; Dastafkan, Kamran; Obeydavi, Ali; Rahimi, Mohammad

2017-12-01

Nanocrystalline solid solutions consisting of un-doped and gadolinium doped zinc oxide nanorods were fabricated by a modified sol-gel process utilizing combined ultrasonic-microwave irradiations. Polyvinylpyrrolidone, diethylene glycol, and triethylenetetramine respectively as capping, structure directing, and complexing agents were used under ultrasound dynamic aging and microwave heating to obtain crystalline nanorods. Crystalline phase monitoring, lattice parameters and variation, morphology and shape, elemental analysis, functional groups, reducibility, and the oxidation state of emerged species were examined by PXRD, FESEM, TEM, EDX, FTIR, micro Raman, H2-TPR, and EPR techniques. Results have verified that irradiation mechanism of gelation and crystallization reduces the reaction time, augments the crystal quality, and formation of hexagonal close pack structure of Wurtzite morphology. Besides, dissolution of gadolinium within host lattice involves lattice deformation, unit cell distortion, and angular position variation. Structure related shape and growth along with compositional purity were observed through microscopic and spectroscopic surveys. Furthermore, TPR and EPR studies elucidated more detailed behavior upon exposure to the exerted irradiations and subsequent air-annealing including the formed oxidation states and electron trapping centers, presence of gadolinium, zinc, and oxygen disarrays and defects, as well as alteration in the host unit cell via gadolinium addition.

Intravascular lymphoma: magnetic resonance imaging correlates of disease dynamics within the central nervous system

PubMed Central

Baehring, J; Henchcliffe, C; Ledezma, C; Fulbright, R; Hochberg, F

2005-01-01

Background: Intravascular lymphoma (IVL) is a rare non-Hodgkin's lymphoma with relative predilection for the central nervous system. In the absence of extraneural manifestations, the disease is not recognised until autopsy in the majority of cases underlining the need for new clinical markers. Methods: This is a retrospective series of five patients with IVL seen at a single institution over three years. An advanced magnetic resonance imaging (MRI) protocol was performed at various time points prior to diagnosis and during treatment. Results: MRI revealed multiple lesions scattered throughout the cerebral hemispheres; the brainstem, cerebellum, and spinal cord were less frequently involved. On initial presentation, hyperintense lesions were seen on diffusion weighted images suggestive of ischaemia in three of four patients in whom the images were obtained at that time point. In four patients lesions were also identifiable as hyperintense areas on fluid attenuated inversion recovery (FLAIR) sequences. Initial contrast enhancement was encountered in three cases. Diffusion weighted imaging lesions either vanished or followed the typical pattern of an ischaemic small vessel stroke with evolution of abnormal FLAIR signal followed by enhancement with gadolinium in the subacute stage and tissue loss in the chronic stage. Diffusion weighted imaging and FLAIR abnormalities proved to be partially reversible, correlating with the response to chemotherapy. Conclusion: We provide the first detailed description of the dynamic pattern of diffusion weighted MRI in IVL. These patterns in combination with systemic findings may facilitate early diagnosis and serve as a new tool to monitor treatment response. PMID:15774442

Intratympanic Iodine Contrast Injection Diffuses Across the Round Window Membrane Allowing for Perilymphatic CT Volume Acquisition Imaging.

PubMed

Abt, Nicholas B; Lehar, Mohamed; Guajardo, Carolina Trevino; Penninger, Richard T; Ward, Bryan K; Pearl, Monica S; Carey, John P

2016-04-01

Whether the round window membrane (RWM) is permeable to iodine-based contrast agents (IBCA) is unknown; therefore, our goal was to determine if IBCAs could diffuse through the RWM using CT volume acquisition imaging. Imaging of hydrops in the living human ear has attracted recent interest. Intratympanic (IT) injection has shown gadolinium's ability to diffuse through the RWM, enhancing the perilymphatic space. Four unfixed human cadaver temporal bones underwent intratympanic IBCA injection using three sequentially studied methods. The first method was direct IT injection. The second method used direct RWM visualization via tympanomeatal flap for IBCA-soaked absorbable gelatin pledget placement. In the third method, the middle ear was filled with contrast after flap elevation. Volume acquisition CT images were obtained immediately postexposure, and at 1-, 6-, and 24-hour intervals. Postprocessing was accomplished using color ramping and subtraction imaging. After the third method, positive RWM and perilymphatic enhancement were observed with endolymph sparing. Gray scale and color ramp multiplanar reconstructions displayed increased signal within the cochlea compared with precontrast imaging. The cochlea was measured for attenuation differences compared with pure water, revealing a preinjection average of -1,103 HU and a postinjection average of 338 HU. Subtraction imaging shows enhancement remaining within the cochlear space, Eustachian tube, middle ear epithelial lining, and mastoid. Iohexol iodine contrast is able to diffuse across the RWM. Volume acquisition CT imaging was able to detect perilymphatic enhancement at 0.5-mm slice thickness. The clinical application of IBCA IT injection seems promising but requires further safety studies.

Magnetization reversal and inverted magnetoresistance of exchange-biased spin valves with a gadolinium layer

NASA Astrophysics Data System (ADS)

Milyaev, M.; Naumova, L.; Chernyshova, T.; Proglyado, V.; Kamensky, I.; Krinitsina, T.; Ryabukhina, M.; Ustinov, V.

2017-03-01

FeMn-based spin valves with a gadolinium layer have been fabricated by magnetron sputtering. The magnetoresistive properties of the spin valves have been investigated at temperatures of 80-293 K. Temperature-induced switching between low- and high-resistance magnetic states has been revealed. Realization of the low- or high-resistance states depends on which magnetic moment dominates in the exchange-coupled Gd/CoFe, of Gd or CoFe. It has been shown that the switching temperature depends on the thickness of the gadolinium layer.

Introduction to Shaped Charges

DTIC Science & Technology

2007-03-01

Figure 144. Late time collapse of a hemispherical depleted uranium liner. COPPER 430MM(17") LEAD-TIN EUTECTIC Figure 145. Comparison between...46 Figure 91. Setup for diffusion bonding of copper- nickel assemblies, temperature is 982 °C, time is 1–3 hr, argon atmosphere...46 Figure 92. Diffusion-bonded alternately layered copper- nickel

MRI of normal and abnormal duodenum using Half-Fourier Single-Shot RARE and gadolinium-enhanced spoiled gradient echo sequences.

PubMed

Marcos, H B; Semelka, R C; Noone, T C; Woosley, J T; Lee, J K

1999-07-01

The objective of this research was two-fold: First, to describe the normal and abnormal MR appearances of the duodenum using combined Half-Fourier Acquisition Single Shot RARE (HASTE) and gadolinium-enhanced standard and fat suppressed spoiled gradient echo (SGE) sequences. The second objective was to assess the ability of these combined sequences to detect and characterize duodenal diseases. MR examinations were performed on fifty consecutive patients with no clinical history of duodenal diseases, who were 1) imaged with HASTE and gadolinium-enhanced standard and fat suppressed SGE sequences and 2) referred to MR examination for reasons other than duodenal diseases, and were reviewed retrospectively to determine the normal MR appearances of the duodenum. A second population of patients with abnormal duodenum who were imaged with the same MR sequences were included in the second part of this study. This population was composed of 20 consecutive patients with subsequently proven duodenal abnormalities, including: malrotation (2), diverticula (4), intussusception (1), sprue (1), polyps (2), neurofibroma (1), lymphoma (1), Zollinger Ellison syndrome (1), metastatic disease (1), Crohn's disease (1), and wall thickening and duodenitis (5). Normal measurements of the duodenum are described. Abnormalities of wall thickness and duodenal masses required combined HASTE and gadolinium-enhanced SGE images to evaluate well. Abnormalities of the bowel lumen (e.g., diverticula and intussusception), and developmental variants (e.g., malrotation), were sufficiently visualized on HASTE images alone. Bowel inflammation was best shown on gadolinium-enhanced fat suppressed SGE images. HASTE and gadolinium-enhanced fat suppressed SGE sequences are complementary techniques for the demonstration of normal and abnormal duodenum. The combined use of both sequences allows evaluation of different aspects of bowel diseases; abnormalities of position, lumen, and contents are well shown on HASTE, while inflammation is best shown on gadolinium enhanced fat suppressed SGE, and wall thickening and masses are best evaluated with the combined use of both techniques.

Effect of gadolinium injection on diffusion-weighted imaging with background body signal suppression (DWIBS) imaging of breast lesions.

PubMed

Moschetta, Marco; Telegrafo, Michele; Rella, Leonarda; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe

2014-12-01

Diffusion-weighted imaging with background body signal suppression (DWIBS) provides both qualitative and quantitative imaging of breast lesions and are usually performed before contrast material injection (CMI). This study aims to assess whether the administration of gadolinium significantly affects DWIBS imaging. 200 patients were prospectively evaluated by MRI with STIR, TSE-T2, pre-CMI DWIBS, contrast enhanced THRIVE-T1 and post-CMI DWIBS sequences. Pre and post-CMI DWIBS were analyzed searching for the presence of breast lesions and calculating the ADC value. ADC values of ≤1.44×10(-3) mm(2)/s were considered suspicious for malignancy. This analysis was then compared with the histological findings. Sensitivity, specificity, diagnostic accuracy (DA), positive predictive value (PPV) and negative (NPV) were calculated for both sequences and represented by ROC analysis. Pre and post-CMI ADC values were compared by using the paired t test. In 150/200 (59%) patients, pre and post-CMI DWIBS indicated the presence of breast lesions, 53 (35%) with ADC values of >1.44×10(-3) mm(2)/s and 97 (65%) with ADC≤1.44×10(-3) mm(2)/s. Pre-CMI and post-DWIBS sequences obtained the same sensitivity, specificity, DA, PPV and NPV values of 97%, 83%, 89%, 79% and 98%. The mean ADC value of benign lesions was 1.831±0.18×10(-3) mm(2)/s before and 1.828±0.18×10(-3) mm(2)/s after CMI. The mean ADC value of the malignant lesions was 1.146±0.16×10(-3) mm(2)/s before and 1.144±0.16×10(-3) mm(2)/s after CMI. No significant difference was found between pre and post CMI ADC values (p>0.05). DWIBS imaging is not influenced by CMI. Breast MR protocol could be modified by placing DWIBS after dynamic contrast enhanced sequences in order to maximize patient cooperation. Copyright © 2014 Elsevier Inc. All rights reserved.

Measurement of gamma-ray production from thermal neutron capture on gadolinium for neutrino experiments

NASA Astrophysics Data System (ADS)

Yano, Takatomi; 2012B0025 Collaboration; 2014B0126 Collaboration

2017-02-01

Recently, several scientific applications of gadolinium are found in neutrino physics experiments. Gadolinium-157 is the nucleus, which has the largest thermal neutron capture cross-section among all stable nuclei. Gadolinium-155 also has the large cross-section. These neutron capture reactions provide the gamma-ray cascade with the total energy of about 8 MeV. This reaction is applied for several neutrino experiments, e.g. reactor neutrino experiments and Gd doped large water Cherenkov detector experiments, to recognize inverse-beta-decay reaction. A good Gd(n,γ) simulation model is needed to evaluate the detection efficiency of the neutron capture reaction, i.e. the efficiency of IBD detection. In this presentation, we will report the development and study status of a Gd(n,γ) calculation model and comparison with our experimental data taken at ANNRI/MLF beam line, J-PARC.

A comparison of the COG and MCNP codes in computational neutron capture therapy modeling, Part II: gadolinium neutron capture therapy models and therapeutic effects.

PubMed

Wangerin, K; Culbertson, C N; Jevremovic, T

2005-08-01

The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for gadolinium neutron capture therapy (GdNCT) related modeling. The validity of COG NCT model has been established for this model, and here the calculation was extended to analyze the effect of various gadolinium concentrations on dose distribution and cell-kill effect of the GdNCT modality and to determine the optimum therapeutic conditions for treating brain cancers. The computational results were compared with the widely used MCNP code. The differences between the COG and MCNP predictions were generally small and suggest that the COG code can be applied to similar research problems in NCT. Results for this study also showed that a concentration of 100 ppm gadolinium in the tumor was most beneficial when using an epithermal neutron beam.

Gadolinium-enhanced computed tomographic angiography: current status.

PubMed

Rosioreanu, Alex; Alberico, Ronald A; Litwin, Alan; Hon, Man; Grossman, Zachary D; Katz, Douglas S

2005-01-01

This article reviews the research to date, as well as our clinical experience from two institutions, on gadolinium-enhanced computed tomographic angiography (gCTA) for imaging the body. gCTA may be an appropriate examination for the small percentage of patients who would benefit from noninvasive vascular imaging, but who have contraindications to both iodinated contrast and magnetic resonance imaging. gCTA is more expensive than CTA with iodinated contrast, due to the dose of gadolinium administered, and gCTA has limitations compared with CTA with iodinated contrast, in that parenchymal organs are not optimally enhanced at doses of 0.5 mmol/kg or lower. However, in our experience, gCTA has been a very useful problem-solving examination in carefully selected patients. With the advent of 16-64 detector CT, in combination with bolus tracking, we believe that the overall dose of gadolinium needed for diagnostic CTA examinations, while relatively high, can be safely administered.

Room temperature ferromagnetic gadolinium silicide nanoparticles

DOEpatents

Hadimani, Magundappa Ravi L.; Gupta, Shalabh; Harstad, Shane; Pecharsky, Vitalij; Jiles, David C.

2018-03-06

A particle usable as T₁ and T₂ contrast agents is provided. The particle is a gadolinium silicide (Gd₅Si₄) particle that is ferromagnetic at temperatures up to 290 K and is less than 2 .mu.m in diameter. An MRI contrast agent that includes a plurality of gadolinium silicide (Gd.sub.5Si.sub.4) particles that are less than 1 .mu.m in diameter is also provided. A method for creating gadolinium silicide (Gd₅Si₄) particles is also provided. The method includes the steps of providing a Gd₅Si₄ bulk alloy; grinding the Gd₅Si₄ bulk alloy into a powder; and milling the Gd₅Si₄ bulk alloy powder for a time of approximately 20 minutes or less.

Biocompatible blood pool MRI contrast agents based on hyaluronan

PubMed Central

Zhu, Wenlian; Artemov, Dmitri

2010-01-01

Biocompatible gadolinium blood pool contrast agents based on a biopolymer, hyaluronan, were investigated for magnetic resonance angiography application. Hyaluronan, a non-sulfated linear glucosaminoglycan composed of 2000–25,000 repeating disaccharide subunits of D-glucuronic acid and N-acetylglucosamine with molecular weight up to 20 MDa, is a major component of the extracellular matrix. Two gadolinium contrast agents based on 16 and 74 kDa hyaluronan were synthesized, both with R1 relaxivity around 5 mM−1 s−1 per gadolinium at 9.4 T at 25°C. These two hyaluronan based agents show significant enhancement of the vasculature for an extended period of time. Initial excretion was primarily through the renal system. Later uptake was observed in the stomach and lower gastrointestinal tract. Macromolecular hyaluronan-based gadolinium agents have a high clinical translation potential as hyaluronan is already approved by FDA for a variety of medical applications. PMID:21504061

The network formers role of gadolinium(III) ions in some zinc-borate glass ceramics

NASA Astrophysics Data System (ADS)

Bosca, Maria; Pop, Lidia; Pascuta, Petru

2017-12-01

EPR and magnetic susceptibility measurements were performed on glass ceramics from the (Gd2O3)x.(B2O3)(60-x).(ZnO)40 system, with 0 ≤ x ≤ 15 mol%, in order to determine the role of gadolinium ions on structural and magnetic properties. At low Gd2O3 contents (x ≤ 1 mol%) the EPR spectra show four resonance lines with effective g-values of ˜ 6, 4.8, 2.8 and 2, typical for Gd3+ ions uniformly distributed in the glass and glass ceramic samples. For higher contents of gadolinium ions (x ≥ 3 mol%) the EPR spectra are dominated by a single broad line centered at g ˜ 2, which can be due to the magnetic clusters containing Gd3+ ions. The magnetic susceptibility data show that the gadolinium ions are involved in superexchange interactions in all the investigated glass ceramics, being antiferromagnetically coupled.

Long-term white matter tract reorganization following prolonged febrile seizures.

PubMed

Pujar, Suresh S; Seunarine, Kiran K; Martinos, Marina M; Neville, Brian G R; Scott, Rod C; Chin, Richard F M; Clark, Chris A

2017-05-01

Diffusion magnetic resonance imaging (MRI) studies have demonstrated acute white matter changes following prolonged febrile seizures (PFS), but their longer-term evolution is unknown. We investigated a population-based cohort to determine white matter diffusion properties 8 years after PFS. We used diffusion tensor imaging (DTI) and applied Tract-Based Spatial Statistics for voxel-wise comparison of white matter microstructure between 26 children with PFS and 27 age-matched healthy controls. Age, gender, handedness, and hippocampal volumes were entered as covariates for voxel-wise analysis. Mean duration between the episode of PFS and follow-up was 8.2 years (range 6.7-9.6). All children were neurologically normal, and had normal conventional neuroimaging. On voxel-wise analysis, compared to controls, the PFS group had (1) increased fractional anisotropy in early maturing central white matter tracts, (2) increased mean and axial diffusivity in several peripheral white matter tracts and late-maturing central white matter tracts, and (3) increased radial diffusivity in peripheral white matter tracts. None of the tracts had reduced fractional anisotropy or diffusivity indices in the PFS group. In this homogeneous, population-based sample, we found increased fractional anisotropy in early maturing central white matter tracts and increased mean and axial diffusivity with/without increased radial diffusivity in several late-maturing peripheral white matter tracts 8 years post-PFS. We propose disruption in white matter maturation secondary to seizure-induced axonal injury, with subsequent neuroplasticity and microstructural reorganization as a plausible explanation. © 2017 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.

Cardiovascular Magnetic Resonance Imaging of Myocardial Infarction, Viability, and Cardiomyopathies

PubMed Central

West, Amy M.; Kramer, Christopher M.

2010-01-01

Cardiovascular magnetic resonance provides the opportunity for a truly comprehensive evaluation of patients with a history of MI, with regards to characterizing the extent of disease, impact on LV function and degree of viable myocardium. The use of contrast-enhanced CMR for first-pass perfusion and late gadolinium enhancement is a powerful technique for delineating areas of myocardial ischemia and infarction. Using a combination of T2-weighted and contrast-enhanced CMR images, information about the acuity of an infarct can be obtained. There is an extensive amount of literature using contrast-enhanced CMR to predict myocardial functional recovery with revascularization in patients with ischemic cardiomyopathies. In addition, CMR imaging in patients with cardiomyopathies can distinguish between ischemic and non-ischemic etiologies, with the ability to further characterize the underlying pathology for non-ischemic cardiomyopathies. PMID:20197150

Myocardial Tissue Characterization by Magnetic Resonance Imaging

PubMed Central

Ferreira, Vanessa M.; Piechnik, Stefan K.; Robson, Matthew D.; Neubauer, Stefan

2014-01-01

Cardiac magnetic resonance (CMR) imaging is a well-established noninvasive imaging modality in clinical cardiology. Its unsurpassed accuracy in defining cardiac morphology and function and its ability to provide tissue characterization make it well suited for the study of patients with cardiac diseases. Late gadolinium enhancement was a major advancement in the development of tissue characterization techniques, allowing the unique ability of CMR to differentiate ischemic heart disease from nonischemic cardiomyopathies. Using T2-weighted techniques, areas of edema and inflammation can be identified in the myocardium. A new generation of myocardial mapping techniques are emerging, enabling direct quantitative assessment of myocardial tissue properties in absolute terms. This review will summarize recent developments involving T1-mapping and T2-mapping techniques and focus on the clinical applications and future potential of these evolving CMR methodologies. PMID:24576837

The Role of CMR in Cardiomyopathies

PubMed Central

Kramer, Christopher M.

2015-01-01

Cardiac magnetic resonance imaging (CMR) has made major inroads in the new millenium in the diagnosis and assessment of prognosis for patients with cardiomyopathies. Imaging of left and right ventricular structure and function and tissue characterization with late gadolinium enhancement (LGE) as well as T1 and T2 mapping enable accurate diagnosis of the underlying etiology. In the setting of coronary artery disease, either transmurality of LGE or contractile reserve in response to dobutamine can assess the likelihood of recovery of function after revascularization. The presence of scar reduces the likelihood of response to medical therapy and to cardiac resynchronization therapy in heart failure. The presence and extent of LGE relate to overall cardiovascular outcome in cardiomyopathies. An emerging major role for CMR in cardiomyopathies is to identify myocardial scar for diagnostic and prognostic purposes. PMID:26033902

Effect of intravascular contrast agent on diffusion and perfusion fraction coefficients in the peripheral zone and prostate cancer.

PubMed

Mazaheri, Yousef; Hötker, Andreas M; Shukla-Dave, Amita; Akin, Oguz; Hricak, Hedvig

2018-09-01

To determine whether water diffusion and the perfusion fraction coefficients in prostate peripheral zone (PZ) and prostate cancer (PCa) are affected by intravenous contrast injection and explore the potential mechanism behind previously reported differences between pre- and post-contrast ADC values. Our institutional review board waived informed consent for this HIPAA-compliant, retrospective study, which included 32 patients (median age, 63 years; range, 47-77 years) with biopsy-proven, untreated PCa who underwent 3-Tesla MRI, including DW-MRI at b-values 0, 400, 700, 1000 s/mm 2 before and after gadolinium injection. For regions of interest (ROIs) in presumed benign PZ and PZ PCa, apparent diffusion coefficient (ADC), perfusion fraction f, and diffusion coefficient D were estimated voxel-wise, and signal-to-noise ratio (SNR) and contrast-to-noise (CNR) were estimated. Pre- and post-contrast measurements were compared by Wilcoxon signed-rank test; P < 0.05 was considered significant. In PZ, f (P = 0.002) was significantly higher on post-contrast imaging than on pre-contrast imaging, but ADC and D values did not change significantly (P = 0.562 and 0.295 respectively). In PCa, all parameters differed significantly between post-contrast and pre-contrast imaging (P < 0.0001 for ADC, P = 0.0084 for D, and P = 0.029 for f). On post-contrast imaging, SNR was not significantly different in PZ (P = 0.260) but was significantly lower in PCa (P < 0.0001); CNR did not change significantly (P = 0.059). After contrast injection, ADC and D declined significantly in PCa only, while f increased significantly in both PCa and PZ. Pre- and post-contrast diffusion parameters cannot be used interchangeably for diagnostic purposes that require quantitative diffusion estimates. Copyright © 2018. Published by Elsevier Inc.

MR-guided conformal heating of canine prostate using interstitial applicators

NASA Astrophysics Data System (ADS)

Nau, William H.; Diederich, Chris J.; Ross, Anthony; Butts, R. K.; Rieke, Viola; Bouley, Donna; Gill, Harchi; Daniel, Bruce; Sommer, Graham

2003-06-01

MRI compatible, multi-element ultrasound applicators were fabricated using cylindrical piezoceramic transducers sectored to 180 degrees to provide angular directional heating. The applicators were designed to be inserted into standard 13 or 14 gage brachytherapy catheters integrated with water-cooling. Two applicators were inserted transperinealy into the posterior region of a canine prostate. Power output ranged from 5-15 W per element during the 15 minute heating period. Phase-sensitive gradient-recalled MR imaging was used to monitor the treatment in real-time on a 0.5 Tesla MRT system. Gadolinium-enhanced T1 weighted images and diffusion-weighted images were obtained to view the regions which had been ablated during the heating procedure. Upon euthanasia, the prostate was removed, axially sectioned, and stained with TTC to reveal any regions of remaining viable tissue. Results from this study indicated a large volume of ablated tissue within the prostate which was highly correlated to the regions in the T1-weighted and diffusion-weighted images which had decreased intensity, and to the 52C contour displayed in the images obtained during the treatment. This study demonstrates the ability to control thermal coagulation within a targeted tissue volume while protecting surrounding tissue from thermal damage.

Social-Psychological Profiles of Identity Styles: Attitudinal and Social-Cognitive Correlates in Late Adolescence

ERIC Educational Resources Information Center

Soenens, Bart; Duriez, Bart; Goossens, Luc

2005-01-01

This study examined the relationships between three identity styles (i.e. the information style, the normative style, and the diffuse/avoidant style) and a number of social-cognitive and attitudinal variables (including empathy, prejudice, and conservatism). Discriminant analysis on a sample of late adolescents (N=393) led to the conclusion that…

Increased Prognostic Value of Query Amyloid Late Enhancement Score in Light-Chain Cardiac Amyloidosis.

PubMed

Wan, Ke; Sun, Jiayu; Han, Yuchi; Liu, Hong; Yang, Dan; Li, Weihao; Wang, Jie; Cheng, Wei; Zhang, Qing; Zeng, Zhi; Chen, Yucheng

2018-02-23

Late gadolinium enhancement (LGE) pattern is a powerful imaging biomarker for prognosis of cardiac amyloidosis. It is unknown if the query amyloid late enhancement (QALE) score in light-chain (AL) amyloidosis could provide increased prognostic value compared with LGE pattern.Methods and Results:Seventy-eight consecutive patients with AL amyloidosis underwent contrast-enhanced cardiovascular magnetic resonance imaging. Patients with cardiac involvement were grouped by LGE pattern and analyzed using QALE score. Receiver operating characteristic curve was used to identify the optimal cut-off for QALE score in predicting all-cause mortality. Survival of these patients was analyzed with the Kaplan-Meier method and multivariate Cox regression. During a median follow-up of 34 months, 53 of 78 patients died. The optimal cut-off for QALE score to predict mortality at 12-month follow-up was 9.0. On multivariate Cox analysis, QALE score ≥9 (HR, 5.997; 95% CI: 2.665-13.497; P<0.001) and log N-terminal pro-brain natriuretic peptide (HR, 1.525; 95% CI: 1.112-2.092; P=0.009) were the only 2 independent predictors of all-cause mortality. On Kaplan-Meier analysis, patients with subendocardial LGE can be further risk stratified using QALE score ≥9. The QALE scoring system provides powerful independent prognostic value in AL cardiac amyloidosis. QALE score ≥9 has added value to differentiate prognosis in AL amyloidosis patients with a subendocardial LGE pattern.

Improved paramagnetic chelate for molecular imaging with MRI

NASA Astrophysics Data System (ADS)

Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

2005-05-01

The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

Do we need gadolinium-based contrast medium for brain magnetic resonance imaging in children?

PubMed

Dünger, Dennis; Krause, Matthias; Gräfe, Daniel; Merkenschlager, Andreas; Roth, Christian; Sorge, Ina

2018-06-01

Brain imaging is the most common examination in pediatric magnetic resonance imaging (MRI), often combined with the use of a gadolinium-based contrast medium. The application of gadolinium-based contrast medium poses some risk. There is limited evidence of the benefits of contrast medium in pediatric brain imaging. To assess the diagnostic gain of contrast-enhanced sequences in brain MRI when the unenhanced sequences are normal. We retrospectively assessed 6,683 brain MR examinations using contrast medium in children younger than 16 years in the pediatric radiology department of the University Hospital Leipzig to determine whether contrast-enhanced sequences delivered additional, clinically relevant information to pre-contrast sequences. All examinations were executed using a 1.5-T or a 3-T system. In 8 of 3,003 (95% confidence interval 0.12-0.52%) unenhanced normal brain examinations, a relevant additional finding was detected when contrast medium was administered. Contrast enhancement led to a change in diagnosis in only one of these cases. Children with a normal pre-contrast brain MRI rarely benefit from contrast medium application. Comparing these results to the risks and disadvantages of a routine gadolinium application, there is substantiated numerical evidence for avoiding routine administration of gadolinium in a pre-contrast normal MRI examination.

Accumulation of MRI contrast agents in malignant fibrous histiocytoma for gadolinium neutron capture therapy.

PubMed

Fujimoto, T; Ichikawa, H; Akisue, T; Fujita, I; Kishimoto, K; Hara, H; Imabori, M; Kawamitsu, H; Sharma, P; Brown, S C; Moudgil, B M; Fujii, M; Yamamoto, T; Kurosaka, M; Fukumori, Y

2009-07-01

Neutron-capture therapy with gadolinium (Gd-NCT) has therapeutic potential, especially that gadolinium is generally used as a contrast medium in magnetic resonance imaging (MRI). The accumulation of gadolinium in a human sarcoma cell line, malignant fibrosis histiocytoma (MFH) Nara-H, was visualized by the MRI system. The commercially available MRI contrast medium Gd-DTPA (Magnevist, dimeglumine gadopentetate aqueous solution) and the biodegradable and highly gadopentetic acid (Gd-DTPA)-loaded chitosan nanoparticles (Gd-nanoCPs) were prepared as MRI contrast agents. The MFH cells were cultured and collected into three falcon tubes that were set into the 3-tesra MRI system to acquire signal intensities from each pellet by the spin echo method, and the longitudinal relaxation time (T1) was calculated. The amount of Gd in the sample was measured by inductively coupled plasma atomic emission spectrography (ICP-AES). The accumulation of gadolinium in cells treated with Gd-nanoCPs was larger than that in cells treated with Gd-DTPA. In contrast, and compared with the control, Gd-DTPA was more effective than Gd-nanoCPs in reducing T1, suggesting that the larger accumulation exerted the adverse effect of lowering the enhancement of MRI. Further studies are warranted to gain insight into the therapeutic potential of Gd-NCT.

In vitro radiosensitizing effects of ultrasmall gadolinium based particles on tumour cells.

PubMed

Mowat, P; Mignot, A; Rima, W; Lux, F; Tillement, O; Roulin, C; Dutreix, M; Bechet, D; Huger, S; Humbert, L; Barberi-Heyob, M; Aloy, M T; Armandy, E; Rodriguez-Lafrasse, C; Le Duc, G; Roux, S; Perriat, P

2011-09-01

Since radiotherapy is widely used in cancer treatment, it is essential to develop strategies which lower the irradiation burden while increasing efficacy and become efficient even in radio resistant tumors. Our new strategy is relying on the development of solid hybrid nanoparticles based on rare-earth such as gadolinium. In this paper, we then evidenced that gadolinium-based particles can be designed to enter efficiently into the human glioblastoma cell line U87 in quantities that can be tuned by modifying the incubation conditions. These sub-5 nm particles consist in a core of gadolinium oxide, a shell of polysiloxane and are functionalized by diethylenetriaminepentaacetic acid (DTPA). Although photoelectric effect is maximal in the [10-100 keV] range, such particles were found to possess efficient in-vitro radiosensitizing properties at an energy of 660 keV by using the "single-cell gel electrophoresis comet assay," an assay that measures the number of DNA damage that occurs during irradiation. Even more interesting, the particles have been evidenced by MTT assays to be also efficient radiosensitizers at an energy of 6 MeV for doses comprised between 2 and 8 Gy. The properties of the gadolinium-based particles give promising opening to a particle-assisted radio-therapy by using irradiation systems already installed in the majority of hospitals.

Application of classification trees for the qualitative differentiation of focal liver lesions suspicious for metastasis in gadolinium-EOB-DTPA-enhanced liver MR imaging.

PubMed

Schelhorn, J; Benndorf, M; Dietzel, M; Burmeister, H P; Kaiser, W A; Baltzer, P A T

2012-09-01

To evaluate the diagnostic accuracy of qualitative descriptors alone and in combination for the classification of focal liver lesions (FLLs) suspicious for metastasis in gadolinium-EOB-DTPA-enhanced liver MR imaging. Consecutive patients with clinically suspected liver metastases were eligible for this retrospective investigation. 50 patients met the inclusion criteria. All underwent Gd-EOB-DTPA-enhanced liver MRI (T2w, chemical shift T1w, dynamic T1w). Primary liver malignancies or treated lesions were excluded. All investigations were read by two blinded observers (O1, O2). Both independently identified the presence of lesions and evaluated predefined qualitative lesion descriptors (signal intensities, enhancement pattern and morphology). A reference standard was determined under consideration of all clinical and follow-up information. Statistical analysis besides contingency tables (chi square, kappa statistics) included descriptor combinations using classification trees (CHAID methodology) as well as ROC analysis. In 38 patients, 120 FLLs (52 benign, 68 malignant) were present. 115 (48 benign, 67 malignant) were identified by the observers. The enhancement pattern, relative SI upon T2w and late enhanced T1w images contributed significantly to the differentiation of FLLs. The overall classification accuracy was 91.3 % (O1) and 88.7 % (O2), kappa = 0.902. The combination of qualitative lesion descriptors proposed in this work revealed high diagnostic accuracy and interobserver agreement in the differentiation of focal liver lesions suspicious for metastases using Gd-EOB-DTPA-enhanced liver MRI. © Georg Thieme Verlag KG Stuttgart · New York.

Delayed contrast-enhanced MRI of the coronary artery wall in takayasu arteritis.

PubMed

Schneeweis, Christopher; Schnackenburg, Bernhard; Stuber, Matthias; Berger, Alexander; Schneider, Udo; Yu, Jing; Gebker, Rolf; Weiss, Robert G; Fleck, Eckart; Kelle, Sebastian

2012-01-01

Takayasu arteritis (TA) is a rare form of chronic inflammatory granulomatous arteritis of the aorta and its major branches. Late gadolinium enhancement (LGE) with magnetic resonance imaging (MRI) has demonstrated its value for the detection of vessel wall alterations in TA. The aim of this study was to assess LGE of the coronary artery wall in patients with TA compared to patients with stable CAD. We enrolled 9 patients (8 female, average age 46±13 years) with proven TA. In the CAD group 9 patients participated (8 male, average age 65±10 years). Studies were performed on a commercial 3T whole-body MR imaging system (Achieva; Philips, Best, The Netherlands) using a 3D inversion prepared navigator gated spoiled gradient-echo sequence, which was repeated 34-45 minutes after low-dose gadolinium administration. No coronary vessel wall enhancement was observed prior to contrast in either group. Post contrast, coronary LGE on IR scans was detected in 28 of 50 segments (56%) seen on T2-Prep scans in TA and in 25 of 57 segments (44%) in CAD patients. LGE quantitative assessment of coronary artery vessel wall CNR post contrast revealed no significant differences between the two groups (CNR in TA: 6.0±2.4 and 7.3±2.5 in CAD; p = 0.474). Our findings suggest that LGE of the coronary artery wall seems to be common in patients with TA and similarly pronounced as in CAD patients. The observed coronary LGE seems to be rather unspecific, and differentiation between coronary vessel wall fibrosis and inflammation still remains unclear.

Usefulness of the advanced neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state images for gamma knife radiosurgery and planning microsurgical procedures for skull base tumors.

PubMed

Hayashi, Motohiro; Chernov, Mikhail F; Tamura, Noriko; Yomo, Shoji; Tamura, Manabu; Horiba, Ayako; Izawa, Masahiro; Muragaki, Yoshihiro; Iseki, Hiroshi; Okada, Yoshikazu; Ivanov, Pavel; Régis, Jean; Takakura, Kintomo

2013-01-01

Gamma Knife radiosurgery (GKS) is currently performed with 0.1 mm preciseness, which can be designated microradiosurgery. It requires advanced methods for visualizing the target, which can be effectively attained by a neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state (CISS) images. Since 2003, the following thin-sliced images are routinely obtained before GKS of skull base lesions in our practice: axial CISS, gadolinium-enhanced axial CISS, gadolinium-enhanced axial modified time-of-flight (TOF), and axial computed tomography (CT). Fusion of "bone window" CT and magnetic resonance imaging (MRI), and detailed three-dimensional (3D) delineation of the anatomical structures are performed with the Leksell GammaPlan (Elekta Instruments AB). Recently, a similar technique has been also applied to evaluate neuroanatomy before open microsurgical procedures. Plain CISS images permit clear visualization of the cranial nerves in the subarachnoid space. Gadolinium-enhanced CISS images make the tumor "lucid" but do not affect the signal intensity of the cranial nerves, so they can be clearly delineated in the vicinity to the lesion. Gadolinium-enhanced TOF images are useful for 3D evaluation of the interrelations between the neoplasm and adjacent vessels. Fusion of "bone window" CT and MRI scans permits simultaneous assessment of both soft tissue and bone structures and allows 3D estimation and correction of MRI distortion artifacts. Detailed understanding of the neuroanatomy based on application of the advanced neuroimaging protocol permits performance of highly conformal and selective radiosurgical treatment. It also allows precise planning of the microsurgical procedures for skull base tumors.

Population continuity, demic diffusion and Neolithic origins in central-southern Germany: the evidence from body proportions.

PubMed

Gallagher, A; Gunther, M M; Bruchhaus, H

2009-01-01

The transition to agro-pastoralism in central Europe has been framed within a dichotomy of "regional continuity" versus exogenous "demic diffusion". While substantial genetic support exists for a model of demographic diffusion from an ancestral source in the Near East, archaeological data furnish weak support for the "wave of advance" model. Nevertheless, archaeological evidence attests the widespread introduction of an exogenous "package" comprising ceramics, cereals, pulses and domesticated animals to central Europe at 5600calBCE. Body proportions are under strong climatic selection and evince remarkable stability within regional lineages. As such, they offer a viable and robust alternative to cranio-facial data in assessing hypothesised continuity and replacement with the transition to agro-pastoralism in central Europe. Humero-clavicular, brachial and crural indices in a large sample (n=75) of Linienbandkeramik (LBK), Late Neolithic and Early Bronze Age specimens from the middle Elbe-Saale-Werra valley (MESV) were compared with Eurasian and African terminal Pleistocene, European Mesolithic and geographically disparate recent human specimens. Mesolithic Europeans display considerable variation in humero-clavicular and brachial indices yet none approach the extreme "hyper-polar" morphology of LBK humans from the MESV. In contrast, Late Neolithic and Early Bronze Age peoples display elongated brachial and crural indices reminiscent of terminal Pleistocene and "tropically adapted" recent humans. These marked morphological changes likely reflect exogenous immigration during the terminal Fourth millennium cal BC. Population expansion and diffusion is a function of increased mobility and settlement dispersal concomitant with significant technological and subsistence changes in later Neolithic societies during the late fourth millennium cal BCE.

Type-II domains in ferroelectric gadolinium molybdate (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohm, J.; Kuersten, H.D.

Etching (001)-faces of gadolinium molybdate (GMO) reveals new kinds of domains. They are created by a translation, that leaves the spontaneous polarization and the transition parameter invariant. The translation vector is a part of a lattice vector, similar to stacking faults. (auth)

[Rapid imaging in orbito-ocular pathology. Contribution of gadolinium].

PubMed

Pigeau, I; Legeais, J M; D'Hermies, F; Fayet, B; Leport, M; Abenhaim, A; Guinet, C; Levy, C; Renard, G; Vadrot, D

1990-01-01

To evaluate Gradient-Echo Imaging (GEI) in orbito-ocular pathology, 15 volunteers and 34 patients (40 lesions) were examined with GEA T1 and GEA T2 (0.5 T). Results were compared with SE T1 in all cases, with SE T2 in 20 cases and with other imaging modalities (CT). 30 patients were examined before and after injection of gadolinium. Final diagnosis was obtained by surgery or biopsy in 24 cases or by combined results of imaging and clinical findings in 16 cases. Compared with SE, GEA demonstrated a better visualisation of optic nerve, orbital muscles, choroidal-retinal layer, lens capsule and episclera and a better detection of small lesions. It is very helpful for characterisation of lesions containing hemorrhages or paramagnetic components (melanine, gadolinium) or of vascular nature (angioma). Gadolinium was useful for detection of small lesions or characterisation of a few lesions. Thus GEA seems to be an efficient method for the evaluation of orbito-ocular pathology.

Stellar models with microscopic diffusion and rotational mixing. 2: Application to open clusters

NASA Technical Reports Server (NTRS)

Chaboyer, B.; Demarque, P.; Pinsonneault, M. H.

1995-01-01

Stellar models with masses ranging from 05.5 to 1.3 solar mass were constructed for comparison with young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of overshoot at the base of the surface convection zone, and the exact metallicity of the models. Even when this is taken into account, the Li observations are a severe constraint for the models and rule out standard models and pure diffusion models. Stellar models which include diffusion and rotational mixing in the radiative regions of stars are able to simultaneously match the Li abundances observed in the Pleiades, the UMa Group, The Hyades, Praesepe, NGC 752, and M67. They also match the observed rotation periods in the Hyades. However, these models are unable to simultaneously explain the presence of the rapidly rotating late G and K stars in the Pleiades and the absence of rapidly rotating late F and early G stars.

Myocardial oxygen delivery after experimental hemorrhagic shock.

PubMed Central

Archie, J P; Mertz, W R

1978-01-01

The two components of myocardial oxygen delivery, coronary blood flow to capillaries and diffusion from capillaries to mitochondria, were studied in six dogs, (1) prior to shock, (2) after three hours of hemorrhage shock at a mean systemic arterial pressure of 40 torr, (3) after reinfusion of shed blood, and (4) during the irreversible late posttransfusion stage. There was a maldistribution of left ventricular coronary flow during late shock consistent with subendocardial ischemia. Cardiac performance was significantly impaired after resuscitation and all dogs became irreversible. Total and regional left ventricular coronary blood flow and myocardial oxygen delivery to capillaries were significantly greater than preshock values in (3) but not different from preshock values in (4). However, the myocardial oxygen diffusion area to distance ratio was significantly lower than preshock values in (3), and slightly lower in (4). These data suggest that myocardial oxygen diffusion may be impaired in the early post transfusion period, (3). Accordingly, the probable etiology of left ventricular dysfunction and possibly irreversibility after resuscitation from hemorrhagic shock is subendocardial ischemia during shock with either post-resuscitation impairment of myocardial oxygen diffusion, or in cellular oxygen utilization, or both. PMID:629622

Gadolinium chelate coated gold nanoparticles as contrast agents for both X-ray computed tomography and magnetic resonance imaging.

PubMed

Alric, Christophe; Taleb, Jacqueline; Le Duc, Géraldine; Mandon, Céline; Billotey, Claire; Le Meur-Herland, Alice; Brochard, Thierry; Vocanson, Francis; Janier, Marc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

2008-05-07

Functionalized gold nanoparticles were applied as contrast agents for both in vivo X-ray and magnetic resonance imaging. These particles were obtained by encapsulating gold cores within a multilayered organic shell which is composed of gadolinium chelates bound to each other through disulfide bonds. The contrast enhancement in MRI stems from the presence of gadolinium ions which are entrapped in the organic shell, whereas the gold core provides a strong X-ray absorption. This study revealed that these particles suited for dual modality imaging freely circulate in the blood vessels without undesirable accumulation in the lungs, spleen, and liver.

Diffuse intrinsic pontine gliomas in children: Interest of robotic frameless assisted biopsy. A technical note.

PubMed

Coca, H A; Cebula, H; Benmekhbi, M; Chenard, M P; Entz-Werle, N; Proust, F

2016-12-01

Diffuse intrinsic pontine gliomas (DIPG) constitute 10-15% of all brain tumors in the pediatric population; currently prognosis remains poor, with an overall survival of 7-14 months. Recently the indication of DIPG biopsy has been enlarged due to the development of molecular biology and various ongoing clinical and therapeutic trials. Classically a biopsy is performed using a stereotactic frame assisted procedure but the workflow may sometimes be heavy and more complex especially in children. In this study the authors present their experience with frameless robotic-guided biopsy of DIPG in a pediatric population. Retrospective study on a series of five consecutive pediatric patients harboring DIPG treated over a 4-year period. All patients underwent frameless robotic-guided biopsy via a transcerebellar approach. Among the 5 patients studied 3 were male and 2 female with a median age of 8.6 years [range 5 to 13 years]. Clinical presentation included ataxia, hemiparesis and cranial nerve palsy in all patients. MRI imaging of the lesion showed typical DIPG features (3 of them located in the pons) with hypo-intensity on T1 and hyper-intensity signal on T2 sequences and diffuse gadolinium enhancement. The mean procedure time was 56minutes (range 45 to 67minutes). No new postoperative neurological deficits were recorded. Histological diagnosis was achieved in all cases as follows: two anaplastic astrocytomas (grade III), two glioblastomas, and one diffuse astrocytoma (grade III). Frameless robotic assisted biopsy of DIPG in pediatric population is an easier, effective, safe and highly accurate method to achieve diagnosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Intratympanic Iodine Contrast Injection Diffuses Across the Round Window Membrane Allowing for Perilymphatic CT Volume Acquisition Imaging

PubMed Central

Abt, Nicholas B.; Lehar, Mohamed; Guajardo, Carolina Trevino; Penninger, Richard T.; Ward, Bryan K.; Pearl, Monica S.; Carey, John P.

2016-01-01

Hypothesis Whether the RWM is permeable to iodine-based contrast agents (IBCA) is unknown; therefore, our goal was to determine if IBCAs could diffuse through the RWM using CT volume acquisition imaging. Introduction Imaging of hydrops in the living human ear has attracted recent interest. Intratympanic (IT) injection has shown gadolinium's ability to diffuse through the round window membrane (RWM), enhancing the perilymphatic space. Methods Four unfixed human cadaver temporal bones underwent intratympanic IBCA injection using three sequentially studied methods. The first method was direct IT injection. The second method used direct RWM visualization via tympanomeatal flap for IBCA-soaked absorbable gelatin pledget placement. In the third method, the middle ear was filled with contrast after flap elevation. Volume acquisition CT images were obtained immediately post-exposure, and at 1, 6, and 24 hour intervals. Post-processing was accomplished using color ramping and subtraction imaging. Results Following the third method, positive RWM and perilymphatic enhancement were seen with endolymph sparing. Gray scale and color ramp multiplanar reconstructions displayed increased signal within the cochlea compared to pre-contrast imaging. The cochlea was measured for attenuation differences compared to pure water, revealing a pre-injection average of −1,103 HU and a post-injection average of 338 HU. Subtraction imaging shows enhancement remaining within the cochlear space, Eustachian tube, middle ear epithelial lining, and mastoid. Conclusions Iohexol iodine contrast is able to diffuse across the RWM. Volume acquisition CT imaging was able to detect perilymphatic enhancement at 0.5mm slice thickness. The clinical application of IBCA IT injection appears promising but requires further safety studies. PMID:26859543

Technical Basis for Peak Reactivity Burnup Credit for BWR Spent Nuclear Fuel in Storage and Transportation Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, William BJ J; Ade, Brian J; Bowman, Stephen M

2015-01-01

Oak Ridge National Laboratory and the United States Nuclear Regulatory Commission have initiated a multiyear project to investigate application of burnup credit for boiling-water reactor (BWR) fuel in storage and transportation casks. This project includes two phases. The first phase (1) investigates applicability of peak reactivity methods currently used in spent fuel pools (SFPs) to storage and transportation systems and (2) evaluates validation of both reactivity (k eff) calculations and burnup credit nuclide concentrations within these methods. The second phase will focus on extending burnup credit beyond peak reactivity. This paper documents the first phase, including an analysis of latticemore » design parameters and depletion effects, as well as both validation components. Initial efforts related to extended burnup credit are discussed in a companion paper. Peak reactivity analyses have been used in criticality analyses for licensing of BWR fuel in SFPs over the last 20 years. These analyses typically combine credit for the gadolinium burnable absorber present in the fuel with a modest amount of burnup credit. Gadolinium burnable absorbers are used in BWR assemblies to control core reactivity. The burnable absorber significantly reduces assembly reactivity at beginning of life, potentially leading to significant increases in assembly reactivity for burnups less than 15–20 GWd/MTU. The reactivity of each fuel lattice is dependent on gadolinium loading. The number of gadolinium-bearing fuel pins lowers initial lattice reactivity, but it has a small impact on the burnup and reactivity of the peak. The gadolinium concentration in each pin has a small impact on initial lattice reactivity but a significant effect on the reactivity of the peak and the burnup at which the peak occurs. The importance of the lattice parameters and depletion conditions are primarily determined by their impact on the gadolinium depletion. Criticality code validation for BWR burnup credit at peak reactivity requires a different set of experiments than for pressurized-water reactor burnup credit analysis because of differences in actinide compositions, presence of residual gadolinium absorber, and lower fission product concentrations. A survey of available critical experiments is presented along with a sample criticality code validation and determination of undercoverage penalties for some nuclides. The validation of depleted fuel compositions at peak reactivity presents many challenges which largely result from a lack of radiochemical assay data applicable to BWR fuel in this burnup range. In addition, none of the existing low burnup measurement data include residual gadolinium measurements. An example bias and uncertainty associated with validation of actinide-only fuel compositions is presented.« less

Corrosion resistance of 0Kh18N10T steel in gadolinium nitrate solutions in the liquid regulation of the reactivity of nuclear reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganzha, V.D.; Konoplev, K.A.; Mashchetov, V.P.

1986-03-01

This study was carried out in connection with the preparation of the design for the PIK research reactor. The corrosion resistance of 0Kh18N10T steel in gadolinium nitrate solutions was tested in laboratory, ampule, and loop corrosion tests. At all stages of the tests, the authors investigated the effect produced on the corrosion processes by factors related to the technology of preparation of the equipment (mechanical working of the surfaces, welding, sensitizing, annealing, stressed state of the material, cracks, etc.). Ampule tests were conducted in order to determine the effect produced by reactor radiation and shutdown regimes on the corrosion resistancemore » of the steel. Special ampules made of 0Kh18N10T steel were filled with gadolinium nitrate solutions of various concentrations, sealed, and irradiated for a long period in the core of the VVR-M reactor at a temperature of 20-50 degrees C. The results of the tests are shown. The investigations showed that the corrosion of 0Kh18N10T steel in solutions of gadolinium nitrate is uniform, regardless of the state of the surface, the concentration of gadolinium nitrate, the duration of the tests, the action of the reactor radiation under static and dynamic conditions, and the presence of mechanical stresses.« less

Diagnostic and prognostic value of cardiovascular magnetic resonance in non-ischaemic cardiomyopathies

PubMed Central

2012-01-01

Cardiovascular Magnetic Resonance (CMR) is recognised as a valuable clinical tool which in a single scan setting can assess ventricular volumes and function, myocardial fibrosis, iron loading, flow quantification, tissue characterisation and myocardial perfusion imaging. The advent of CMR using extrinsic and intrinsic contrast-enhanced protocols for tissue characterisation have dramatically changed the non-invasive work-up of patients with suspected or known cardiomyopathy. Although the technique initially focused on the in vivo identification of myocardial necrosis through the late gadolinium enhancement (LGE) technique, recent work highlighted the ability of CMR to provide more detailed in vivo tissue characterisation to help establish a differential diagnosis of the underlying aetiology, to exclude an ischaemic substrate and to provide important prognostic markers. The potential application of CMR in the clinical approach of a patient with suspected non-ischaemic cardiomyopathy is discussed in this review. PMID:22857649

Gadolinium: Central Metal of the Lanthanoids

ERIC Educational Resources Information Center

Laing, Michael

2009-01-01

The physical and chemical properties of gadolinium are compared with those of the other lanthanoids. Some properties are intermediate between those of lanthanum and lutetium; some between those of barium and hafnium; and others (unexpectedly) between those of ytterbium and lutetium. Both the remarkably high molar heat capacity of the metal and the…

Revisiting the Pharmacokinetic Profiles of Gadolinium-Based Contrast Agents: Differences in Long-Term Biodistribution and Excretion.

PubMed

Lancelot, Eric

2016-11-01

Gadolinium-based contrast agents (GBCAs) have been used for years for magnetic resonance imaging examinations. Because of their rapid blood clearance, they were considered as very safe products until some of them were shown to induce nephrogenic systemic fibrosis in patients with renal failure and hypersignals on T1-weighted unenhanced brain scans of patients with normal renal function. To date, these adverse effects have been related almost exclusively to the use of low-stability linear agents, which are more prone to release free gadolinium. The aim of the present meta-analysis was to ascertain the existence of a deep compartment for gadolinium storage in the body and to assess whether all the GBCAs present the same toxicokinetic profile. Applying a systematic literature search methodology, all clinical and preclinical studies reporting time-dependent plasma concentrations and renal excretion data of gadolinium were identified and analyzed. Since the individual data were not available, the analysis focused on the average values per groups of subjects or animals, which had received a given GBCA at a given dose. The rate constants of the distribution phase (α), rapid elimination phase (β), and residual excretion phase (γ) of gadolinium were determined in each group from the plasma concentration (Cp) time curves and the relative urinary excretion rate (rER) time curves, taking the 2-hour time point as a reference. Moreover, as bone may represent a reservoir for long-term gadolinium accumulation and slow release into the blood stream, the time curves of the relative concentration in the bone (rCB) of Gd-labeled GBCAs in mice or rats were analyzed taking day 1 concentrations as a reference. The ratio of gadolinium concentrations in the bone marrow (CBM) as compared with the bone (CB) was also calculated. The relative urinary excretion rate (rER) plots revealed a prolonged residual excretion phase of gadolinium in healthy volunteers, consistent with the existence of a deep compartment of distribution for the GBCAs. The rate constant γ of gadoterate meglumine (0.107 hour) is 5 times higher than that of the linear agents (0.020 ± 0.008 hour), indicating a much faster blood clearance for the macrocyclic GBCA. Similar results were obtained in the preclinical studies. A strong correlation was shown between the γ values of the different products and their respective thermodynamic stability constants (Ktherm). Greater clearance rates of Gd from murine bone were also found after gadoterate meglumine or gadoteridol injection (0.131-0.184 day) than after administration of the linear agents (0.004-0.067 day). The concentrations of Gd in the bone marrow (CBM) from animals exposed to either gadoterate meglumine or gadodiamide are higher than those in the bone (CB) for at least 24 hours. Moreover, the ratio of concentrations (CBM/CB) at 4 hours is significantly lower with the former agent than the latter (1.9 vs 6.5, respectively). Using a nonconventional pharmacokinetic approach, we showed that gadoterate meglumine undergoes a much faster residual excretion from the body than the linear GBCAs, a process that seems related to the thermodynamic stability of the different chelates. Gadolinium dissociation occurs in vivo for some linear chelates, a mechanism that may explain their long-term retention and slow release from bone. Potential consequences in terms of bone toxicity warrant further investigations.

Orogenic inheritance in Death Valley region, western US Basin and Range: implications for Neogene crustal extension.

NASA Astrophysics Data System (ADS)

Lima, R. D.; Hayman, N. W.; Prior, M. G.; Stockli, D. F.; Kelly, E. D.

2016-12-01

Deformation and temperature evolution during orogenic stages may influence later fabric development, thus controlling large-scale extensional processes that can occur millions of years later. Here, we describe pressure-temperature and fabric evolution from the Death Valley (DV) region and show how inherited fabrics, formed in late orogenic stages during Late Cretaceous time, influenced later Neogene age Basin and Range (BR) extension. The DV region is one of the most extended and thinned regions in the western US BR province, and the two of the ranges that bound the eastern valley expose basement rocks exhumed during the Neogene extension. In the Funeral range, it has been established that older (Precambrian) basement underwent Mesozoic age syn-deformational metamorphism during the Sevier-Laramide orogeny. In contrast, the Black Mountains record widespread tectonic stretching and magmatism of Miocene age on Precambrian basement, and have, overall, been lacking previous evidence of Mesozoic metamorphism and fabric development. In the Funeral Range Late Cretaceous migmatitic fabrics were overprinted by zones of high-strain fabrics formed due to melt-consuming reaction that define an overall P-T cooling path likely during late- to post-orogenesis. These fabrics form interconnected layers of quartz + biotite aggregates, in which individual quartz grains lack evidence of intracrystalline plastic deformation and show consistently random [c]-axis microfabrics. This suggests coupled reaction-diffusion processes that favored diffusion-assisted creep. New geochronometric results of melt products in the Black Mountains show evidence of partial melting of Late Cretaceous age. Contrasting with the neighboring Funeral Range, overprinting by extensional fabrics of Miocene age is widespread, and consists of high-strain, anastomosing foliation composed of retrograde products from preexisting, higher-temperature fabrics. These include interconnected fine-grained chlorite + quartz and sericite aggregates showing [c]-axis quartz microfabrics consistent with diffusion-assisted creep. In both ranges, the formation of new-over-old fabric due to the extensional deformation is favored by local heterogeneities in bulk composition due previous melt segregation during late- to post-orogenic stages.

Toxicological and pharmacological effects of gadolinium and samarium chlorides

PubMed Central

Haley, T. J.; Raymond, K.; Komesu, N.; Upham, H. C.

1961-01-01

A study has been made of the toxicology and pharmacology of gadolinium and samarium chlorides. The symptoms of acute toxicity following intraperitoneal injection are described. The chronic oral ingestion of both chemicals for 12 weeks produced no effects on growth or the blood picture, and only the male rats receiving gadolinium chloride showed liver damage. The pharmacological responses to both chemicals were mainly depressant on all systems studied, and death was associated with cardiovascular collapse coupled with respiratory paralysis. The greatest damage seen was on abraded skin, where non-healing ulcers were produced by both chemicals, whereas irritation of intact skin and ocular tissues was only transient in nature. PMID:13903826

Primary Central Nervous System Lymphoma of Optic Chiasma: Endoscopic Endonasal Treatment.

PubMed

Ozdemir, Evin Singar; Yildirim, Ali Erdem; Can, Aslihan Yavas

2018-01-01

Isolated primary central nervous system lymphoma arising from anterior visual pathway is very rare. A 76-year-old immunocompetent previously healthy man presented bilateral decreased visual acuity in 1 month. Pituitary magnetic resonans imaging (MRI) showed a lobulated mass with homogeneous enhancement after gadolinium administration that arising from optic chiasm suggested that inflammatory disease or an optic glioma. The patient underwent an extended endoscopic endonasal transsphenoidal surgery. Postoperative course and outcomes were wonderful. Histopathological diagnosis was diffuse large B-cell lymphoma. The patient underwent investigations for systemic lymphomatous involvement, did not detect any evidence of systemic disease. In this case, we claimed that differential diagnoses of anterior visual pathway lesions are difficult because of similarity of lesions on clinical and radiological examinations. Biopsy is essential for these lesions. As a biopsy technique, endoscopic endonasal transsphenoidal approach is safer and more effective than open procedures.

[Primary central nervous system lymphoma mimicking ventriculitis].

PubMed

Yamamoto, Shiro; Nagano, Seiji; Shibata, Sumiya; Kunieda, Takeharu; Imai, Yukihiro; Kohara, Nobuo

2013-01-01

A 66-year-old man presented with deteriorated bradykinesia, gait disturbance, disorientation, and urinary incontinence for three weeks. Magnetic resonance imaging (MRI) showed dilatation of the ventricles. Cerebrospinal fluid (CSF) examination demonstrated lymphocytic pleocytosis, elevation of protein levels, and decreased of glucose levels. A gadolinium-enhanced MRI revealed lesions in the ventricular wall and choroid plexus, mimicking ventriculitis. No evidence of bacterial, fungal, mycobacterial, or viral infections were observed in the CSF. Flow cytometry of CSF showed predominance of CD20+, λ+ cells. PCR examination of CSF revealed positive IgH gene rearrangement, suggesting B cell lymphoma. Endoscopic brain biopsy showed diffuse large B cell lymphoma. As the patient had no evidence of lymphoma in the other organs, we made a diagnosed of primary central nervous system lymphoma (PCNSL). A limited intraventricular spread of PCNSL is rare but important as one of differential diagnosis of ventriculitis.

Cerebral white matter maturation patterns in preterm infants: an MRI T2 relaxation anisotropy and diffusion tensor imaging study

PubMed Central

Knight, Michael J.; Smith-Collins, Adam; Newell, Sarah; Denbow, Mark; Kauppinen, Risto A.

2017-01-01

Background and Purpose Preterm birth is associated with worse neurodevelopmental outcome, but brain maturation in preterm infants is poorly characterised with standard methods. We evaluated white matter (WM) of infant brains at term-equivalent age, as a function of gestational age at birth, using multi-modal MRI. Methods Infants born very pre-term (< 32 weeks gestation) and late pre-term (33-36 weeks gestation) were scanned at 3T at term-equivalent age using diffusion tensor imaging (DTI) and T2 relaxometry. MRI data were analysed using tract-based spatial statistics, and anisotropy of T2 relaxation was also determined. Principal component analysis and linear discriminant analysis were applied to seek the variables best distinguishing very pre-term and late pre-term groups. Results Across widespread regions of WM, T2 is longer in very pre-term infants than in late pre-term ones. These effects are more prevalent in regions of WM which myelinate earlier and faster. Similar effects are obtained from DTI, showing that fractional anisotropy (FA) is lower and radial diffusivity higher in the very pre-term group, with a bias towards earlier myelinating regions. Discriminant analysis shows high sensitivity and specificity of combined T2 relaxometry and DTI for the detection of a distinct WM development pathway in very preterm infants. T2 relaxation is anisotropic, depending on the angle between WM fibre and magnetic field, and this effect is modulated by FA. Conclusions Combined T2 relaxometry and DTI characterises specific patterns of retarded WM maturation, at term equivalent age, in infants born very pre-term relative to late pre-term. PMID:29205635

Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction: The CAMERA-MRI Study.

PubMed

Prabhu, Sandeep; Taylor, Andrew J; Costello, Ben T; Kaye, David M; McLellan, Alex J A; Voskoboinik, Aleksandr; Sugumar, Hariharan; Lockwood, Siobhan M; Stokes, Michael B; Pathik, Bhupesh; Nalliah, Chrishan J; Wong, Geoff R; Azzopardi, Sonia M; Gutman, Sarah J; Lee, Geoffrey; Layland, Jamie; Mariani, Justin A; Ling, Liang-Han; Kalman, Jonathan M; Kistler, Peter M

2017-10-17

Atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate control. Existing randomized studies of AF and LVSD of varying etiologies have reported modest benefits with a rhythm control strategy. The goal of this study was to determine whether catheter ablation (CA) for AF could improve LVSD compared with medical rate control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF. This multicenter, randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included pulmonary vein isolation and posterior wall isolation. AF burden post-CA was assessed by using an implanted loop recorder, and adequacy of MRC was assessed by using serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months. A total of 301 patients were screened; 68 patients were enrolled between November 2013 and October 2016 and randomized with 33 in each arm (accounting for 2 dropouts). The average AF burden post-CA was 1.6 ± 5.0% at 6 months. In the intention-to-treat analysis, absolute LVEF improved by 18 ± 13% in the CA group compared with 4.4 ± 13% in the MRC group (p < 0.0001) and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing CA, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (10.7%; p = 0.0069) and normalization at 6 months (73% vs. 29%; p = 0.0093). AF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of ventricular fibrosis on CMR. This outcome challenges the current treatment paradigm that rate control is the appropriate strategy in patients with AF and LVSD. (Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction [CAMERA-MRI]; ACTRN12613000880741). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

3D image fusion of whole-heart dynamic cardiac MR perfusion and late gadolinium enhancement: Intuitive delineation of myocardial hypoperfusion and scar.

PubMed

von Spiczak, Jochen; Mannil, Manoj; Kozerke, Sebastian; Alkadhi, Hatem; Manka, Robert

2018-03-30

Since patients with myocardial hypoperfusion due to coronary artery disease (CAD) with preserved viability are known to benefit from revascularization, accurate differentiation of hypoperfusion from scar is desirable. To develop a framework for 3D fusion of whole-heart dynamic cardiac MR perfusion and late gadolinium enhancement (LGE) to delineate stress-induced myocardial hypoperfusion and scar. Prospective feasibility study. Sixteen patients (61 ± 14 years, two females) with known/suspected CAD. 1.5T (nine patients); 3.0T (seven patients); whole-heart dynamic 3D cardiac MR perfusion (3D-PERF, under adenosine stress); 3D LGE inversion recovery sequences (3D-SCAR). A software framework was developed for 3D fusion of 3D-PERF and 3D-SCAR. Computation steps included: 1) segmentation of the left ventricle in 3D-PERF and 3D-SCAR; 2) semiautomatic thresholding of perfusion/scar data; 3) automatic calculation of ischemic/scar burden (ie, pathologic relative to total myocardium); 4) projection of perfusion/scar values onto artificial template of the left ventricle; 5) semiautomatic coregistration to an exemplary heart contour easing 3D orientation; and 6) 3D rendering of the combined datasets using automatically defined color tables. All tasks were performed by two independent, blinded readers (J.S. and R.M.). Intraclass correlation coefficients (ICC) for determining interreader agreement. Image acquisition, postprocessing, and 3D fusion were feasible in all cases. In all, 10/16 patients showed stress-induced hypoperfusion in 3D-PERF; 8/16 patients showed LGE in 3D-SCAR. For 3D-PERF, semiautomatic thresholding was possible in all patients. For 3D-SCAR, automatic thresholding was feasible where applicable. Average ischemic burden was 11 ± 7% (J.S.) and 12 ± 7% (R.M.). Average scar burden was 8 ± 5% (J.S.) and 7 ± 4% (R.M.). Interreader agreement was excellent (ICC for 3D-PERF = 0.993, for 3D-SCAR = 0.99). 3D fusion of 3D-PERF and 3D-SCAR facilitates intuitive delineation of stress-induced myocardial hypoperfusion and scar. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Prospective Evaluation of 18F-Fluorodeoxyglucose Uptake in Postischemic Myocardium by Simultaneous Positron Emission Tomography/Magnetic Resonance Imaging as a Prognostic Marker of Functional Outcome.

PubMed

Rischpler, Christoph; Dirschinger, Ralf J; Nekolla, Stephan G; Kossmann, Hans; Nicolosi, Stefania; Hanus, Franziska; van Marwick, Sandra; Kunze, Karl P; Meinicke, Alexander; Götze, Katharina; Kastrati, Adnan; Langwieser, Nicolas; Ibrahim, Tareq; Nahrendorf, Matthias; Schwaiger, Markus; Laugwitz, Karl-Ludwig

2016-04-01

The immune system orchestrates the repair of infarcted myocardium. Imaging of the cellular inflammatory response by (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/magnetic resonance imaging in the heart has been demonstrated in preclinical and clinical studies. However, the clinical relevance of post-MI (18)F-FDG uptake in the heart has not been elucidated. The objective of this study was to explore the value of (18)F-FDG positron emission tomography/magnetic resonance imaging in patients after acute myocardial infarction as a biosignal for left ventricular functional outcome. We prospectively enrolled 49 patients with ST-segment-elevation myocardial infarction and performed (18)F-FDG positron emission tomography/magnetic resonance imaging 5 days after percutaneous coronary intervention and follow-up cardiac magnetic resonance imaging after 6 to 9 months. In a subset of patients, (99m)Tc-sestamibi single-photon emission computed tomography was performed with tracer injection before revascularization. Cellular innate immune response was analyzed at multiple time points. Segmental comparison of (18)F-FDG-uptake and late gadolinium enhancement showed substantial overlap (κ=0.66), whereas quantitative analysis demonstrated that (18)F-FDG extent exceeded late gadolinium enhancement extent (33.2±16.2% left ventricular myocardium versus 20.4±10.6% left ventricular myocardium, P<0.0001) and corresponded to the area at risk (r=0.87, P<0.0001). The peripheral blood count of CD14(high)/CD16(+) monocytes correlated with the infarction size and (18)F-FDG signal extent (r=0.53, P<0.002 and r=0.42, P<0.02, respectively). (18)F-FDG uptake in the infarcted myocardium was highest in areas with transmural scar, and the standardized uptake valuemean was associated with left ventricular functional outcome independent of infarct size (Δ ejection fraction: P<0.04, Δ end-diastolic volume: P<0.02, Δ end-systolic volume: P<0.005). In this study, the intensity of (18)F-FDG uptake in the myocardium after acute myocardial infarction correlated inversely with functional outcome at 6 months. Thus, (18)F-FDG uptake in infarcted myocardium may represent a novel biosignal of myocardial injury. © 2016 American Heart Association, Inc.

Prevalence of Subclinical Coronary Artery Disease in Masters Endurance Athletes With a Low Atherosclerotic Risk Profile.

PubMed

Merghani, Ahmed; Maestrini, Viviana; Rosmini, Stefania; Cox, Andrew T; Dhutia, Harshil; Bastiaenan, Rachel; David, Sarojini; Yeo, Tee Joo; Narain, Rajay; Malhotra, Aneil; Papadakis, Michael; Wilson, Mathew G; Tome, Maite; AlFakih, Khaled; Moon, James C; Sharma, Sanjay

2017-07-11

Studies in middle-age and older (masters) athletes with atherosclerotic risk factors for coronary artery disease report higher coronary artery calcium (CAC) scores compared with sedentary individuals. Few studies have assessed the prevalence of coronary artery disease in masters athletes with a low atherosclerotic risk profile. We assessed 152 masters athletes 54.4±8.5 years of age (70% male) and 92 controls of similar age, sex, and low Framingham 10-year coronary artery disease risk scores with an echocardiogram, exercise stress test, computerized tomographic coronary angiogram, and cardiovascular magnetic resonance imaging with late gadolinium enhancement and a 24-hour Holter. Athletes had participated in endurance exercise for an average of 31±12.6 years. The majority (77%) were runners, with a median of 13 marathon runs per athlete. Most athletes (60%) and controls (63%) had a normal CAC score. Male athletes had a higher prevalence of atherosclerotic plaques of any luminal irregularity (44.3% versus 22.2%; P =0.009) compared with sedentary males, and only male athletes showed a CAC ≥300 Agatston units (11.3%) and a luminal stenosis ≥50% (7.5%). Male athletes demonstrated predominantly calcific plaques (72.7%), whereas sedentary males showed predominantly mixed morphology plaques (61.5%). The number of years of training was the only independent variable associated with increased risk of CAC >70th percentile for age or luminal stenosis ≥50% in male athletes (odds ratio, 1.08; 95% confidence interval, 1.01-1.15; P =0.016); 15 (14%) male athletes but none of the controls revealed late gadolinium enhancement on cardiovascular magnetic resonance imaging. Of these athletes, 7 had a pattern consistent with previous myocardial infarction, including 3(42%) with a luminal stenosis ≥50% in the corresponding artery. Most lifelong masters endurance athletes with a low atherosclerotic risk profile have normal CAC scores. Male athletes are more likely to have a CAC score >300 Agatston units or coronary plaques compared with sedentary males with a similar risk profile. The significance of these observations is uncertain, but the predominantly calcific morphology of the plaques in athletes indicates potentially different pathophysiological mechanisms for plaque formation in athletic versus sedentary men. Coronary plaques are more abundant in athletes, whereas their stable nature could mitigate the risk of plaque rupture and acute myocardial infarction. © 2017 American Heart Association, Inc.

Preparation of 152Gd targets from a small quantity of gadolinium oxide in a pyrochemical reaction

NASA Astrophysics Data System (ADS)

Lipski, A. R.

1995-02-01

A simple method utilizing small amounts (< 5 mg) of isotopically enriched material for the production of gadolinium targets is discussed. An electrostatically focused e-gun is used in the procedure in which 152Gd 2O 3 powder undergoes reduction-distillation and deposition onto an Fe foil.

Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy (abstract)

NASA Astrophysics Data System (ADS)

Lee, Dongkyu; Maeng, Inhee; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol; Son, Joo-Hiuk

2009-04-01

The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd2O3) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

Measurement of gadolinium retention: current status and review from an applied radiation physics perspective.

PubMed

Gräfe, James L; McNeill, Fiona E

2018-06-28

This article briefly reviews the main measurement techniques for the non-invasive detection of residual gadolinium (Gd) in those exposed to gadolinium-based contrast agents (GBCAs). Approach and Main results: The current status of in vivo Gd measurement is discussed and is put into the context of concerns within the radiology community. The main techniques are based on applied atomic/nuclear medicine utilizing the characteristic atomic and nuclear spectroscopic signature of Gd. The main emission energies are in the 40-200 keV region and require spectroscopic detectors with good energy resolution. The two main techniques, prompt gamma neutron activation analysis and x-ray fluorescence, provide adequate detection limits for in vivo measurement, whilst delivering a low effective radiation dose on the order of a few µSv. Gadolinium is being detected in measureable quantities in people with healthy renal function who have received FDA approved GBCAs. The applied atomic/nuclear medicine techniques discussed in this review will be useful in determining the significance of this retention, and will help on advising future administration protocols.

K3 Li3 Gd7 (BO3 )9 : A New Gadolinium-Rich Orthoborate for Cryogenic Magnetic Cooling.

PubMed

Xia, Mingjun; Shen, Shipeng; Lu, Jun; Sun, Young; Li, Rukang

2018-03-02

Magnetic cooling technology based on magnetocaloric effect (MCE) has attracted great interest in obtaining extremely low temperatures, for example, for space exploration. Here, we grew a new gadolinium-rich orthoborate K 3 Li 3 Gd 7 (BO 3 ) 9 (1) as a promising cryogenic magnetic coolant. It exhibits a complicated three dimensional framework constructed from BO 3 groups and gadolinium-oxygen chains. The Gd-O chain consists of two types of clusters of Gd 3 O 20 and Gd 3 O 19 interconnection by Gd(4)O 8 polyhydron. Due to its high gadolinium concentration, a large -ΔS m of 56.6 J kg -1  K -1 for 1 was obtained at 2 K and ΔH=7 T, much larger than that of the commercial benchmark Gd 3 Ga 5 O 12 (GGG) crystal (38.4 J kg -1  K -1 ), suggesting it to be an excellent MCE material. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Boosting Classification Accuracy of Diffusion MRI Derived Brain Networks for the Subtypes of Mild Cognitive Impairment Using Higher Order Singular Value Decomposition

PubMed Central

Zhan, L.; Liu, Y.; Zhou, J.; Ye, J.; Thompson, P.M.

2015-01-01

Mild cognitive impairment (MCI) is an intermediate stage between normal aging and Alzheimer's disease (AD), and around 10-15% of people with MCI develop AD each year. More recently, MCI has been further subdivided into early and late stages, and there is interest in identifying sensitive brain imaging biomarkers that help to differentiate stages of MCI. Here, we focused on anatomical brain networks computed from diffusion MRI and proposed a new feature extraction and classification framework based on higher order singular value decomposition and sparse logistic regression. In tests on publicly available data from the Alzheimer's Disease Neuroimaging Initiative, our proposed framework showed promise in detecting brain network differences that help in classifying early versus late MCI. PMID:26413202

Imaging of cauda equina edema in lumbar canal stenosis by using gadolinium-enhanced MR imaging: experimental constriction injury.

PubMed

Kobayashi, S; Uchida, K; Takeno, K; Baba, H; Suzuki, Y; Hayakawa, K; Yoshizawa, H

2006-02-01

It has been reported that disturbance of blood flow arising from circumferential compression of the cauda equina by surrounding tissue plays a major role in the appearance of neurogenic intermittent claudication (NIC) associated with lumbar spinal canal stenosis (LSCS). We created a model of LSCS to clarify the mechanism of enhancement within the cauda equina on gadolinium-enhanced MR images from patients with LSCS. In 20 dogs, a lumbar laminectomy was performed by applying circumferential constriction to the cauda equina by using a silicon tube, to produce 30% stenosis of the circumferential diameter of the dural tube. After 1 and 3 weeks, gadolinium and Evans blue albumin were injected intravenously at the same time. The sections were used to investigate the status of the blood-nerve barrier function under a fluorescence microscope and we compared gadolinium-enhanced MR images with Evans blue albumin distribution in the nerve. The other sections were used for light and transmission electron microscopic study. In this model, histologic examination showed congestion and dilation in many of the intraradicular veins, as well as inflammatory cell infiltration. The intraradicular edema caused by venous congestion and Wallerian degeneration can also occur at sites that are not subject to mechanical compression. Enhanced MR imaging showed enhancement of the cauda equina at the stenosed region, demonstrating the presence of edema. Gadolinium-enhanced MR imaging may be a useful tool for the diagnosis of microcirculatory disorders of the cauda equina associated with LSCS.

Stress Perfusion Cardiac Magnetic Resonance Imaging Effectively Risk Stratifies Diabetic Patients With Suspected Myocardial Ischemia.

PubMed

Heydari, Bobak; Juan, Yu-Hsiang; Liu, Hui; Abbasi, Siddique; Shah, Ravi; Blankstein, Ron; Steigner, Michael; Jerosch-Herold, Michael; Kwong, Raymond Y

2016-04-01

Diabetics remain at high risk of cardiovascular disease and mortality despite advancements in medical therapy. Noninvasive cardiac risk profiling is often more difficult in diabetics owing to the prevalence of silent ischemia with unrecognized myocardial infarction, reduced exercise capacity, nondiagnostic electrocardiographic changes, and balanced ischemia from diffuse epicardial coronary atherosclerosis and microvascular dysfunction. A consecutive cohort of 173 patients with diabetes mellitus (mean age, 61.7±11.9 years; 37% women) with suspected myocardial ischemia underwent stress perfusion cardiac magnetic resonance imaging. Patients were evaluated for adverse cardiac events after cardiac magnetic resonance imaging with mean follow-up time of 2.9±2.5 years. Mean hemoglobin A1c for the population was 7.9±1.8%. Primary end point was a composite of cardiac death and nonfatal myocardial infarction. Diabetics with no inducible ischemia (n=94) experienced an annualized event rate of 1.4% compared with 8.2% (P=0.0003) in those with inducible ischemia (n=79). Diabetics without late gadolinium enhancement or inducible ischemia had a low annual cardiac event rate (0.5% per year). The presence of inducible ischemia was the strongest unadjusted predictor (hazard ratio, 4.86; P<0.01) for cardiac death and nonfatal myocardial infarction. This association remained robust in adjusted stepwise multivariable Cox regression analysis (hazard ratio, 4.28; P=0.02). In addition, categorical net reclassification index using 5-year risk cutoffs of 5% and 10% resulted in reclassification of 43.4% of the diabetic cohort with net reclassification index of 0.38 (95% confidence interval, 0.20-0.56; P<0.0001). Stress perfusion cardiac magnetic resonance imaging provided independent prognostic utility and effectively reclassified risk in patients with diabetes mellitus referred for ischemic assessment. Further evaluation is required to determine whether a noninvasive imaging strategy with cardiac magnetic resonance imaging can favorably affect downstream outcomes and improve cost-effectiveness of care in diabetics. © 2016 American Heart Association, Inc.

Delayed Contrast-Enhanced MRI of the Coronary Artery Wall in Takayasu Arteritis

PubMed Central

Schneeweis, Christopher; Schnackenburg, Bernhard; Stuber, Matthias; Berger, Alexander; Schneider, Udo; Yu, Jing; Gebker, Rolf; Weiss, Robert G.; Fleck, Eckart; Kelle, Sebastian

2012-01-01

Background Takayasu arteritis (TA) is a rare form of chronic inflammatory granulomatous arteritis of the aorta and its major branches. Late gadolinium enhancement (LGE) with magnetic resonance imaging (MRI) has demonstrated its value for the detection of vessel wall alterations in TA. The aim of this study was to assess LGE of the coronary artery wall in patients with TA compared to patients with stable CAD. Methods We enrolled 9 patients (8 female, average age 46±13 years) with proven TA. In the CAD group 9 patients participated (8 male, average age 65±10 years). Studies were performed on a commercial 3T whole-body MR imaging system (Achieva; Philips, Best, The Netherlands) using a 3D inversion prepared navigator gated spoiled gradient-echo sequence, which was repeated 34–45 minutes after low-dose gadolinium administration. Results No coronary vessel wall enhancement was observed prior to contrast in either group. Post contrast, coronary LGE on IR scans was detected in 28 of 50 segments (56%) seen on T2-Prep scans in TA and in 25 of 57 segments (44%) in CAD patients. LGE quantitative assessment of coronary artery vessel wall CNR post contrast revealed no significant differences between the two groups (CNR in TA: 6.0±2.4 and 7.3±2.5 in CAD; p = 0.474). Conclusion Our findings suggest that LGE of the coronary artery wall seems to be common in patients with TA and similarly pronounced as in CAD patients. The observed coronary LGE seems to be rather unspecific, and differentiation between coronary vessel wall fibrosis and inflammation still remains unclear. PMID:23236382

T1 Measurements Identify Extracellular Volume Expansion in Hypertrophic Cardiomyopathy Sarcomere Mutation Carriers With and Without Left Ventricular Hypertrophy

PubMed Central

Ho, Carolyn Y.; Abbasi, Siddique A.; Neilan, Tomas G.; Shah, Ravi V.; Chen, Yucheng; Heydari, Bobak; Cirino, Allison L.; Lakdawala, Neal K.; Orav, E. John; González, Arantxa; López, Begoña; Díez, Javier; Jerosch-Herold, Michael; Kwong, Raymond Y.

2013-01-01

Background Myocardial fibrosis is a hallmark of hypertrophic cardiomyopathy (HCM) and a potential substrate for arrhythmias and heart failure. Sarcomere mutations appear to induce profibrotic changes before left ventricular hypertrophy (LVH) develops. To further evaluate these processes, we used cardiac magnetic resonance (CMR) with T1 measurements on a genotyped HCM population to quantify myocardial extracellular volume (ECV). Methods and Results Sarcomere mutation carriers with LVH (G+/LVH+, n = 37) and without LVH (G+/LVH−, n = 29); HCM patients without mutations (sarcomere-negative HCM, n = 11); and healthy controls (n = 11) underwent contrast CMR, measuring T1 times pre- and post-gadolinium infusion. Concurrent echocardiography and serum biomarkers of collagen synthesis, hemodynamic stress, and myocardial injury were also available in a subset. Compared to controls, ECV was increased in patients with overt HCM, as well as G+/LVH− mutation carriers (ECV= 0.36±0.01, 0.33±0.01, 0.27±0.01 in G+/LVH+, G+/LVH−, controls, respectively, P≤0.001 for all comparisons). ECV correlated with NT-proBNP levels (r = 0.58, P<0.001) and global E’ velocity (r = −0.48, P<0.001). Late gadolinium enhancement (LGE) was present in >60% of overt HCM patients but absent from G+/LVH− subjects. Both ECV and LGE were more extensive in sarcomeric HCM than sarcomere-negative HCM. Conclusions Myocardial ECV is increased in HCM sarcomere mutation carriers even in the absence of LVH. These data provide additional support that fibrotic remodeling is triggered early in disease pathogenesis. Quantifying ECV may help characterize the development myocardial fibrosis in HCM and ultimately assist in developing novel disease-modifying therapy, targeting interstitial fibrosis. PMID:23549607

Simple method for quantification of gadolinium magnetic resonance imaging contrast agents using ESR spectroscopy.

PubMed

Takeshita, Keizo; Kinoshita, Shota; Okazaki, Shoko

2012-01-01

To develop an estimation method of gadolinium magnetic resonance imaging (MRI) contrast agents, the effect of concentration of Gd compounds on the ESR spectrum of nitroxyl radical was examined. A solution of either 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPONE) or 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) was mixed with a solution of Gd compound and the ESR spectrum was recorded. Increased concentration of gadolinium-diethylenetriamine pentaacetic acid chelate (Gd-DTPA), an MRI contrast agent, increased the peak-to-peak line widths of ESR spectra of the nitroxyl radicals, in accordance with a decrease of their signal heights. A linear relationship was observed between concentration of Gd-DTPA and line width of ESR signal, up to approximately 50 mmol/L Gd-DTPA, with a high correlation coefficient. Response of TEMPONE was 1.4-times higher than that of TEMPOL as evaluated from the slopes of the lines. The response was slightly different among Gd compounds; the slopes of calibration curves for acua[N,N-bis[2-[(carboxymethyl)[(methylcarbamoyl)methyl]amino]ethyl]glycinato(3-)]gadolinium hydrate (Gd-DTPA-BMA) (6.22 μT·L/mmol) and gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelate (Gd-DOTA) (6.62 μT·L/mmol) were steeper than the slope for Gd-DTPA (5.45 μT·L/mmol), whereas the slope for gadolinium chloride (4.94 μT·L/mmol) was less steep than that for Gd-DTPA. This method is simple to apply. The results indicate that this method is useful for rough estimation of the concentration of Gd contrast agents if calibration is carried out with each standard compound. It was also found that the plot of the reciprocal square root of signal height against concentrations of contrast agents could be useful for the estimation if a constant volume of sample solution is taken and measured at the same position in the ESR cavity every time.

Acute side effects of three commonly used gadolinium contrast agents in the paediatric population.

PubMed

Neeley, Chris; Moritz, Michael; Brown, Jeffrey J; Zhou, Yihua

2016-07-01

To determine the incidence of acute side effects of three commonly used gadolinium contrast agents in the paediatric population. A retrospective review of medical records was performed to determine the incidence of acute adverse side effects of i.v. gadolinium contrast agents [MultiHance(®) (Bracco Diagnostics Inc., Princeton, NJ), Magnevist(®) (Bayer Healthcare Pharmaceuticals, Wayne, NJ) or Gadavist(®) (Bayer HealthCare Pharmaceuticals)] in paediatric patients. 40 of the 2393 patients who received gadolinium contrast agents experienced acute side effects, representing an incidence of 1.7%. The majority of the acute side effects (in 30 patients) were nausea and vomiting. The incidence was significantly higher in non-sedated patients (2.37% vs 0.7%; p = 0.0018). Furthermore, without sedation, the incidence of both nausea and vomiting was significantly higher in children receiving MultiHance, with a 4.48% incidence of nausea when compared with Magnevist (0.33%, p < 0.0001) and Gadavist (0.28%, p < 0.0001) and a 2.36% incidence of vomiting compared with those for Magnevist (0.50%, p = 0.0054) and Gadavist (0.28%, p = 0.014), whereas no difference was observed between Magnevist and Gadavist within the power of the study. In addition, there was no apparent difference between any of the three contrast agents for the incidence of allergy or other acute side effects detected, given the sample size. The gadolinium contrast agents MultiHance, Magnevist and Gadavist have a low incidence of acute side effects in the paediatric population, a rate that is further reduced in moderately sedated patients. MultiHance demonstrated significantly increased incidence of gastrointestinal symptoms compared with Magnevist and Gadavist. The incidence of acute side effects of three commonly used gadolinium contrast agents was determined in the paediatric population, which can have clinical implications.

Monte Carlo simulation of energy absorbed in phenolic ESR dosimeters added with gadolinium exposed to thermal, epithermal and fast neutrons

NASA Astrophysics Data System (ADS)

Longo, A.; Collura, G.; Gallo, S.; Bartolotta, A.; Marrale, M.

2017-11-01

In this work analyses of the energy released per unit mass in phenolic compound exposed to neutron beams were performed with the aim of predicting the increase in dose achievable by addition of gadolinium (Gd) inside the pellets. In particular, Monte Carlo (MC) simulations were carried out for IRGANOX® 1076 phenolic compound irradiated with neutron beams with different energy spectra at various depths inside a water phantom. The addition of gadolinium increases sensitivity of phenolic ESR (electron spin resonance) dosimeters to neutrons thanks to the high gadolinium cross section for neutron capture and to the large number of secondary particles (mainly Auger and internal conversion electrons) which are able to release energy inside the sensitive material layers. For small depths in water phantom and low energy neutron spectra the increase in dose due to gadolinium is large (more than a factor 50). The enhancement is smaller in case of epithermal neutron beam, whereas the increase in dose for fast neutrons is less than 50%. In order to have a comparison with other ESR dosimeters the energy released per unit mass in phenolic compound was compared with that calculated in alanine pellets. For thermal neutron beams the energy released in phenolic compound with gadolinium is comparable to that released in alanine for small depths in phantom, whereas it is larger than in alanine for large depths. In case of epithermal and fast neutron beams the energy released in phenolic compound is larger than in alanine samples because the elastic scattering with hydrogen nuclei is more probable for high neutron energies and this phenolic compound is characterized by an higher number of 1H nuclei than alanine. All results here found suggest that these phenolic pellets could be fruitfully used for dosimetric applications in Neutron Capture Therapy.

On the Progression and Stability of Adolescent Identity Formation: A Five-Wave Longitudinal Study in Early-to-Middle and Middle-to-Late Adolescence

ERIC Educational Resources Information Center

Meeus, Wim; Van De Schoot, Rens; Keijsers, Loes; Schwartz, Seth J.; Branje, Susan

2010-01-01

This study examined identity development in a 5-wave study of 923 early-to-middle and 390 middle-to-late adolescents thereby covering the ages of 12-20. Systematic evidence for identity progression was found: The number of diffusions, moratoriums, and searching moratoriums (a newly obtained status) decreased, whereas the representation of the…

Synthesis of internally functionalized silica nanoparticles for theranostic applications

NASA Astrophysics Data System (ADS)

Walton, Nathan Isaac

This thesis addresses the synthesis and characterization of novel inorganic silica nanoparticle hybrids. It focuses in large part on their potential applications in the medical field. Silica acts as a useful carrier for a variety of compounds and this thesis silica will demonstrate its use as a carrier for boron or gadolinium. Boron-10 and gadolinium-157 have been suggested for the radiological treatment of tumor cells through the process called neutron capture therapy (NCT). Gadolinium is also commonly used as a Magnetic Resonance Imaging (MRI) contrast agent. Particles that carry it have potential theranostic applications of both imaging and treating tumors. Chapter 1 presents a background on synthetic strategies and usages of silica nanoparticles, and NCT theory. Chapter 2 describes a procedure to create mesoporous metal chelating silica nanoparticles, mDTTA. This is achieved via a co-condensation of tetraethoxysilane (TEOS) and 3-trimethoxysilyl-propyl diethylenetriamine (SiDETA) followed by a post-synthesis modification step with bromoacetic acid (BrAA). These particles have a large surface area and well-defined pores of ~2 nm. The mDTTA nanoparticles were used to chelate the copper(II), cobalt(II) and gadolinium(III). The chelating of gadolinium is the most interesting since it can be used as a MRI contrast agent and a neutron capture therapeutic. The synthetic procedure developed also allows for the attachment of a fluorophore that gives the gadolinium chelating mDTTA nanoparticles a dual imaging modality. Chapter 3 presents the synthetic method used to produce two classes of large surface area organically modified silica (ORMOSIL) nanoparticles. Condensating the organosilane vinyltrimethoxysilane in a micellar solution results in nanoparticles that are either surface rough (raspberry-like) or mesoporous nanoparticles, which prior to this thesis has not been demonstrated in ORMOSIL chemistry. Furthermore, the vinyl functionalities are modified, using hydroboration, to make the nanoparticles into water-dispersible boron carriers that also have potential boron neutron capture therapy (BNCT) applications. Lastly, Chapter 4 provides a general description of NCT, specifically that involving boron-10 and gadolinium-157. It further describes the synthetic methodology used in producing fatty acid coated boron nanoparticles (BNPs). The BNPs are encapsulated with silica to add a hydrophilic shell so that they can potentially be used in biological systems as BNCT agents. The silica shell is also modified with a fluorophore, dansyl chloride, so that the particle hybrid could be imaged during cell studies.

Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

NASA Technical Reports Server (NTRS)

Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

1997-01-01

In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P < 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.

Fossil woods of Detarioideae subfamily (Fabaceae) from El Palmar Formation (Late Pleistocene) in South America

NASA Astrophysics Data System (ADS)

Ramos, R. Soledad; Brea, Mariana; Kröhling, Daniela M.

2017-11-01

The main aim of the present paper is to describe the first Detarioideae fossil woods from El Palmar Formation (Late Pleistocene) in the Uruguay River Basin (Entre Ríos, Argentina). This study is based on five silicified wood specimens preserved in fluvial deposits, which were transported from their growth site. Two new genera and species are described: Paraoxystigma concordiensis gen. nov and sp. nov. has medium-sized vessels, paratracheal axial parenchyma, heterocellular and multiseriate rays, and diffuse axial canals similar in size and shape to vessels, and Gossweilerodendroxylon palmariensis gen. nov and sp. nov. has medium-sized vessels, alternate intervessel pits, paratracheal and apotracheal axial parenchyma, homocellular and uni to-multiseriate rays, and small diffuse axial canals. These Detarioideae fossil records in south-eastern South America support the existence of a very old relationship with the extant West African forests. Eco-anatomical features observed in these fossil woods, along with the climatic information available from the Nearest Living Relatives (NLRs) comparison, suggest warm and humid climatic conditions for the upper-middle basin of the Uruguay River during some periods of the Late Pleistocene.

Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex.

PubMed

Degnan, Andrew J; Wisnowski, Jessica L; Choi, SoYoung; Ceschin, Rafael; Bhushan, Chitresh; Leahy, Richard M; Corby, Patricia; Schmithorst, Vincent J; Panigrahy, Ashok

2015-01-01

Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. Thirty-eight preadolescents (ages 9-13; 19 born in the late preterm period (≥32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant executive neurocognitive differences. Selective increased structural connectivity was observed in the setting of decreased posterior interhemispheric connections. Future work is needed to determine if these findings represent a compensatory adaptation employing alternate neural circuitry or could reflect subtle pathology resulting in emotional processing deficits not seen with neurocognitive testing.

Use of gadolinium chloride as a contrast agent for imaging spruce knots by magnetic resonance

Treesearch

Thomas L. Eberhardt; Chi-Leung So; Amy H. Herlihy; Po-Wah So

2006-01-01

Treatments of knot-containing spruce wood blocks with a paramagnetic salt, gadolinium (III) chloride, in combination with solvent pretreatments, were evaluated as strategies to enhance the visualization of wood features by magnetic resonance imaging (MRI). Initial experiments with clear wood and excised knot samples showed differences in moisture uptake after...

CONTROL ROD FOR A NUCLEAR REACTOR AND METHOD OF PREPARATION

DOEpatents

Hausner, H.H.

1958-12-30

BS>An improved control rod is presented for a nuclear reactor. This control rod is comprised of a rare earth metal oxide or rare earth metal carbide such as gadolinium oxide or gadolinium carbide, uniformly distributed in a metal matrix having a low cross sectional area of absorption for thermal neutrons, such as aluminum, beryllium, and zirconium.

Layered gadolinium hydroxides for low-temperature magnetic cooling.

PubMed

Abellán, Gonzalo; Espallargas, Guillermo Mínguez; Lorusso, Giulia; Evangelisti, Marco; Coronado, Eugenio

2015-09-28

Layered gadolinium hydroxides have revealed to be excellent candidates for cryogenic magnetic refrigeration. These materials behave as pure 2D magnetic systems with a Heisenberg-Ising critical crossover, induced by dipolar interactions. This 2D character and the possibility offered by these materials to be delaminated open the possibility of rapid heat dissipation upon substrate deposition.

Rapid colorimetric sensing of gadolinium by EGCG-derived AgNPs: the development of a nanohybrid bioimaging probe.

PubMed

Singh, Rohit Kumar; Mishra, Sourav; Jena, Satyapriya; Panigrahi, Bijayananda; Das, Bhaskar; Jayabalan, Rasu; Parhi, Pankaj Kumar; Mandal, Dindyal

2018-04-17

Polyphenol functionalized silver nanoparticles (AgNPs) have been developed and demonstrated as colorimetric sensors for the selective detection of gadolinium. The newly obtained AgNP-Gd3+ conjugates exhibit high aqueous dispersibility and excitation dependent fluorescence emission. The conjugates offer multicolor bioimaging potential owing to their excellent luminescence properties.

Neutron Absorbing Alloys

DOEpatents

Mizia, Ronald E.; Shaber, Eric L.; DuPont, John N.; Robino, Charles V.; Williams, David B.

2004-05-04

The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

[Gadolinium-based contrast agents for magnetic resonance imaging].

PubMed

Carrasco Muñoz, S; Calles Blanco, C; Marcin, Javier; Fernández Álvarez, C; Lafuente Martínez, J

2014-06-01

Gadolinium-based contrast agents are increasingly being used in magnetic resonance imaging. These agents can improve the contrast in images and provide information about function and metabolism, increasing both sensitivity and specificity. We describe the gadolinium-based contrast agents that have been approved for clinical use, detailing their main characteristics based on their chemical structure, stability, and safety. In general terms, these compounds are safe. Nevertheless, adverse reactions, the possibility of nephrotoxicity from these compounds, and the possibility of developing nephrogenic systemic fibrosis will be covered in this article. Lastly, the article will discuss the current guidelines, recommendations, and contraindications for their clinical use, including the management of pregnant and breast-feeding patients. Copyright © 2014 SERAM. Published by Elsevier Espana. All rights reserved.

Gadolinium-based nanoparticles for highly efficient T1-weighted magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Jang, Eunji; Han, Seungmin; Lee, Kwangyeol; Suh, Jin-Suck; Haam, Seungjoo; Huh, Yong-Min

2014-06-01

We developed Pyrene-Gadolinium (Py-Gd) nanoparticles as pH-sensitive magnetic resonance imaging (MRI) contrast agents capable of showing a high-Mr signal in cancer-specific environments, such as acidic conditions. Py-Gd nanoparticles were prepared by coating Py-Gd, which is a complex of gadolinium with pyrenyl molecules, with pyrenyl polyethyleneglycol PEG using a nano-emulsion method. These particles show better longitudinal relaxation time (T1) MR signals in acidic conditions than they do in neutral conditions. Furthermore, the particles exhibit biocompatibility and MR contrast effects in both in vitro and in vivo studies. From these results, we confirm that Py-Gd nanoparticles have the potential to be applied for accurate cancer diagnosis and therapy.

The evolution of gadolinium based contrast agents: from single-modality to multi-modality

NASA Astrophysics Data System (ADS)

Zhang, Li; Liu, Ruiqing; Peng, Hui; Li, Penghui; Xu, Zushun; Whittaker, Andrew K.

2016-05-01

Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications.

Regional convection-enhanced delivery of gadolinium-labeled albumin in the rat hippocampus in vivo.

PubMed

Astary, Garrett W; Kantorovich, Svetlana; Carney, Paul R; Mareci, Thomas H; Sarntinoranont, Malisa

2010-03-15

Convection-enhanced delivery (CED) has emerged as a promising method of targeted drug delivery for treating central nervous system (CNS) disorders, but the influence of brain structure on infusate distribution is unclear. We have utilized this approach to study extracellular transport and distribution of a contrast agent in the hippocampus, a complex structure susceptible to CNS disorders. The magnetic resonance (MR) contrast agent diethylene triamene penta-acetic acid chelated gadolinium-labeled albumin (Gd-albumin), tagged with Evans blue dye, was directly infused (V(i)=5 microl) into the dorsal and ventral hippocampus of seven male Sprague-Dawley rats. The final distribution profile of the contrast agent, a product of CED and limited diffusion, was observed in vivo using high-resolution T1-weighted MR imaging at 11.1T. Dense cell layers, such as the granule cell layer of the dentate gyrus and the pyramidal cell layer of CA1, appeared to be barriers to transport of the tracer. Three-dimensional distribution shape and volume (V(d)) differences, between the dorsal and ventral hippocampus infusions, were determined from the MR images using a semi-automatic segmentation routine (dorsal V(d)=23.4+/-1.8 microl, ventral V(d)=36.4+/-5.1 microl). Finer structural detail of the hippocampus was obtained using a combination of histological analysis and fluorescence imaging. This study demonstrates that CED has the potential to target all regions of the hippocampus and that tracer distribution is influenced by infusion site, underlying structure and circuitry, and extent of backflow. Therefore, CED, combined with high-resolution MR imaging, may be a useful strategy for delivering therapeutics for the treatment of CNS disorders affecting the hippocampus. Published by Elsevier B.V.

Long-term effects of neonatal hypoxia-ischemia on structural and physiological integrity of the eye and visual pathway by multimodal MRI.

PubMed

Chan, Kevin C; Kancherla, Swarupa; Fan, Shu-Juan; Wu, Ed X

2014-12-09

Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways. Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner. Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres. High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Long-Term Effects of Neonatal Hypoxia-Ischemia on Structural and Physiological Integrity of the Eye and Visual Pathway by Multimodal MRI

PubMed Central

Chan, Kevin C.; Kancherla, Swarupa; Fan, Shu-Juan; Wu, Ed X.

2015-01-01

Purpose. Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways. Methods. Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner. Results. Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres. Conclusions. High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury. PMID:25491295

Multivariate modelling of prostate cancer combining magnetic resonance derived T2, diffusion, dynamic contrast-enhanced and spectroscopic parameters.

PubMed

Riches, S F; Payne, G S; Morgan, V A; Dearnaley, D; Morgan, S; Partridge, M; Livni, N; Ogden, C; deSouza, N M

2015-05-01

The objectives are determine the optimal combination of MR parameters for discriminating tumour within the prostate using linear discriminant analysis (LDA) and to compare model accuracy with that of an experienced radiologist. Multiparameter MRIs in 24 patients before prostatectomy were acquired. Tumour outlines from whole-mount histology, T2-defined peripheral zone (PZ), and central gland (CG) were superimposed onto slice-matched parametric maps. T2, Apparent Diffusion Coefficient, initial area under the gadolinium curve, vascular parameters (K(trans),Kep,Ve), and (choline+polyamines+creatine)/citrate were compared between tumour and non-tumour tissues. Receiver operating characteristic (ROC) curves determined sensitivity and specificity at spectroscopic voxel resolution and per lesion, and LDA determined the optimal multiparametric model for identifying tumours. Accuracy was compared with an expert observer. Tumours were significantly different from PZ and CG for all parameters (all p < 0.001). Area under the ROC curve for discriminating tumour from non-tumour was significantly greater (p < 0.001) for the multiparametric model than for individual parameters; at 90 % specificity, sensitivity was 41 % (MRSI voxel resolution) and 59 % per lesion. At this specificity, an expert observer achieved 28 % and 49 % sensitivity, respectively. The model was more accurate when parameters from all techniques were included and performed better than an expert observer evaluating these data. • The combined model increases diagnostic accuracy in prostate cancer compared with individual parameters • The optimal combined model includes parameters from diffusion, spectroscopy, perfusion, and anatominal MRI • The computed model improves tumour detection compared to an expert viewing parametric maps.

Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

NASA Astrophysics Data System (ADS)

Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

2016-08-01

Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

Liver acquisition with acceleration volume acquisition gadolinium-enhanced magnetic resonance combined with T2 sequences in the diagnosis of local recurrence of rectal cancer.

PubMed

Cao, Wuteng; Li, Fangqian; Gong, Jiaying; Liu, Dechao; Deng, Yanhong; Kang, Liang; Zhou, Zhiyang

2016-11-22

To investigate the efficacy of liver acquisition with acceleration volume acquisition (LAVA) gadolinium-enhanced magnetic resonance (MR) sequences and to assess its added accuracy in diagnosing local recurrence (LR) of rectal cancer with conventional T2-weighted fast spin echo (FSE) sequences. Pelvic MRI, including T2-weighted FSE sequences, gadolinium-enhanced sequences of LAVA and T1-weighted FSE with fat suppression, was performed on 225 patients with postoperative rectal cancer. Two readers evaluated the presence of LR according to "T2" (T2 sequences only), "T2 + LAVA-Gad" (LAVA and T2 imaging), and "T2 + T1-fs-Gad" (T1 fat suppression-enhanced sequence with T2 images). To evaluate diagnostic efficiency, imaging quality with LAVA and T1-fs-Gad by subjective scores and the signal intensity (SI) ratio. In the result, the SI ratio of LAVA was significantly higher than that of T1-fs-Gad (p = 0.0001). The diagnostic efficiency of "T2 + LAVA-Gad" was better than that of "T2 + T1-fs-Gad" (p = 0.0016 for Reader 1, p = 0.0001 for Reader 2) and T2 imaging only (p = 0.0001 for Reader 1; p = 0.0001 for Reader 2). Therefore, LAVA gadolinium-enhanced MR increases the accuracy of diagnosis of LR from rectal cancer and could replace conventional T1 gadolinium-enhanced sequences in the postoperative pelvic follow-up of rectal cancer.

Investigation of Magnetostatic Surface Waves for Anisotropic Effects.

DTIC Science & Technology

1986-06-01

inves- tigate the effect of launching magnetostatic surface waves at different angles on a yttrium-iron- garnet (YIG) single crystal film . Many...propagation indeed could be achieved on a YIG thin film ring grown on a gadolinium-gallium- garnet (GGG) substrate (Sethares, 1975) (see Figure 1.1). The use of...thin films grown on a gadolinium-gallium- garnet substrate. The films were 27

Gadolinium chloride as a contrast agent for imaging wood composite components by magnetic resonance

Treesearch

Thomas L. Eberhardt; Chi-Leung So; Andrea Protti; Po-Wah So

2009-01-01

Although paramagnetic contrast agents have an established track record in medical uses of magnetic resonance imaging (MRI), only recently has a contrast agent been used for enhancing MRI images of solid wood specimens. Expanding on this concept, wood veneers were treated with a gadolinium-based contrast agent and used in a model system comprising three-ply plywood...

An Integrated Rare Earth Elements Supply Chain Strategy

DTIC Science & Technology

2011-02-24

iron boron magnets in Joint Direct Attack Munitions (JDAM) smart bombs; neodymium-yttrium- aluminum - garnet lasers and range finders in multiple weapon...components Europium 63 computer screens, fluorescent lights Gadolinium 64 magnetic applications, phosphors Terbium 65 phosphors, projection TV’s...Defense Stockpile report advised several production delays of weapons systems were caused by lanthanum, cerium, europium and gadolinium supply

Type of MRI contrast, tissue gadolinium, and fibrosis.

PubMed

Do, Catherine; Barnes, Jeffrey L; Tan, Chunyan; Wagner, Brent

2014-10-01

It has been presupposed that the thermodynamic stability constant (K(therm)) of gadolinium-based MRI chelates relate to the risk of precipitating nephrogenic systemic fibrosis. The present study compared low-K(therm) gadodiamide with high-K(therm) gadoteridol in cultured fibroblasts and rats with uninephrectomies. Gadolinium content was assessed using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy in paraffin-embedded tissues. In vitro, fibroblasts demonstrated dose-dependent fibronectin generation, transforming growth factor-β production, and expression of activated myofibroblast stress fiber protein α-smooth muscle actin. There were negligible differences with respect to toxicity or proliferation between the two contrast agents. In the rodent model, gadodiamide treatment led to greater skin fibrosis and dermal cellularity than gadoteridol. In the kidney, both contrast agents led to proximal tubule vacuolization and increased fibronectin accumulation. Despite large detectable gadolinium signals in the spleen, skin, muscle, and liver from the gadodiamide-treated group, contrast-induced fibrosis appeared to be limited to the skin and kidney. These findings support the hypothesis that low-K(therm) chelates have a greater propensity to elicit nephrogenic systemic fibrosis and demonstrate that certain tissues are resistant to these effects.

Diagnostic value of three-dimensional magnetic resonance imaging of inner ear after intratympanic gadolinium injection, and clinical application of magnetic resonance imaging scoring system in patients with delayed endolymphatic hydrops.

PubMed

Gu, X; Fang, Z-M; Liu, Y; Lin, S-L; Han, B; Zhang, R; Chen, X

2014-01-01

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging of the inner ear after intratympanic injection of gadolinium, together with magnetic resonance imaging scoring of the perilymphatic space, were used to investigate the positive identification rate of hydrops and determine the technique's diagnostic value for delayed endolymphatic hydrops. Twenty-five patients with delayed endolymphatic hydrops underwent pure tone audiometry, bithermal caloric testing, vestibular-evoked myogenic potential testing and three-dimensional magnetic resonance imaging of the inner ear after bilateral intratympanic injection of gadolinium. The perilymphatic space of the scanned images was analysed to investigate the positive identification rate of endolymphatic hydrops. According to the magnetic resonance imaging scoring of the perilymphatic space and the diagnostic standard, 84 per cent of the patients examined had endolymphatic hydrops. In comparison, the positive identification rates for vestibular-evoked myogenic potential and bithermal caloric testing were 52 per cent and 72 per cent respectively. Three-dimensional magnetic resonance imaging after intratympanic injection of gadolinium is valuable in the diagnosis of delayed endolymphatic hydrops and its classification. The perilymphatic space scoring system improved the diagnostic accuracy of magnetic resonance imaging.

Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case.

PubMed

Fukushima, Munehisa; Oya, Ryohei; Akazawa, Hitoshi; Tsuruta, Yukinori; Inohara, Hidenori

2016-01-01

The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Seven patients (age range = 21-77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5-4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH.

Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Dongkyu; Maeng, Inhee; Son, Joo-Hiuk

2009-04-19

The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRImore » technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.« less

Gadolinium based contrast agents in current practice: Risks of accumulation and toxicity in patients with normal renal function

PubMed Central

Ranga, Anju; Agarwal, Yatish; Garg, Kanika J

2017-01-01

Despite being decked as the most prized compounds in the nugget box of contrast agents for clinical radiologists, and carrying an indisputable tag of safety of the US Food and Drug Administration for close to three decades, all may not be seemingly well with the family of gadolinium compounds. If the first signs of violations of primum non nocere in relation to gadolinium-based contrast agents (GBCAs) appeared in the millennium year with the first published report of skin fibrosis in patients with compromised renal function, the causal relationship between the development of nephrogenic systemic fibrosis (NSF) and GBCAs, first proposed by two European groups in 2006, further precluded their use in renocompromised patients. The toxicity, pharmacokinetics, and pharmacodynamics of GBCAs, however, has come under hawk-eyed scrutiny with recent reports that gadolinium tends to deposit cumulatively in the brain of patients with normal hepatobiliary function and intact blood–brain barrier. While the jury on the long-term hazard significance of this critical scientific finding is still out, the use of GBCAs must be guided by due clinical diligence, avoidance of repeated doses, and preferring GBCAs with the best safety profiles. PMID:28744073

Application of an oscillation-type linear cadmium telluride detector to enhanced gadolinium K-edge computed tomography

NASA Astrophysics Data System (ADS)

Matsukiyo, Hiroshi; Sato, Eiichi; Hagiwara, Osahiko; Abudurexiti, Abulajiang; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-03-01

A linear cadmium telluride (CdTe) detector is useful for carrying out energy-discrimination X-ray imaging, including computed tomography (CT). To perform enhanced gadolinium K-edge CT, we used an oscillation-type linear CdTe detector with an energy resolution of 1.2 keV. CT is performed by repeating the linear scan and the rotation of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. Both the photon energy and the energy width are selected using a multichannel analyzer, and the number of photons is counted by a counter card. In energy-discrimination CT, tube voltage and current were 80 kV and 20 μA, respectively, and X-ray intensity was 1.55 μGy/s at 1.0 m from the source at a tube voltage of 80 kV. Demonstration of enhanced gadolinium K-edge X-ray CT was carried out by selecting photons with energies just beyond gadolinium K-edge energy of 50.3 keV.

Investigation of suspected Guillain-Barre syndrome in childhood: what is the role for gadolinium enhanced magnetic resonance imaging of the spine?

PubMed

Smith, Nicholas; Pereira, John; Grattan-Smith, Padraic

2014-10-01

To review the role of gadolinium-enhanced magnetic resonance imaging of the spine in the diagnosis of paediatric Guillain-Barre syndrome and compare it with nerve conduction studies and cerebrospinal fluid analysis. A retrospective review of investigations undertaken in children admitted to our institution with acute Guillain-Barre syndrome over a 10-year period was performed. Seven of eight children (88%) displayed post-gadolinium nerve root enhancement consistent with Guillain-Barre syndrome. This compared with supportive nerve conduction studies in 21/24 children (88%) and cerebrospinal fluid protein analysis consistent with the diagnosis in 16/20 children (80%). Nerve conduction studies are the recognised 'gold standard' technique for confirming a clinical diagnosis of Guillain-Barre syndrome. In this study, a high positive rate was demonstrated. While more experience is necessary, this study and the literature support gadolinium enhanced magnetic resonance imaging of the spine as a valuable, although not necessarily superior, investigation in the diagnosis of Guillain-Barre syndrome. It may be of particular benefit when specialist neurophysiology expertise is unavailable. © 2010 The Authors. Journal compilation © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Jeong, Sang Young; Kim, Hyo Jeong; Kwak, Byung-Kook; Lee, Ha-Young; Seong, Hasoo; Shin, Byung Cheol; Yuk, Soon Hong; Hwang, Sung-Joo; Cho, Sun Hang

2010-12-01

Biocompatible poly-[ N-(2-hydroxyethyl)- d, l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd.

Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media.

PubMed

Canga, Ana; Kislikova, Maria; Martínez-Gálvez, María; Arias, Mercedes; Fraga-Rivas, Patricia; Poyatos, Cecilio; de Francisco, Angel L M

2014-01-01

Nephrogenic systemic fibrosis is a fibrosing disorder that affects patients with impaired renal function and is associated with the administration of gadolinium-based contrast media used in MRI. Despite being in a group of drugs that were considered safe, report about this potentially serious adverse reaction was a turning point in the administration guidelines of these contrast media. There has been an attempt to establish safety parameters to identify patients with risk factors of renal failure. The close pharmacovigilance and strict observation of current regulations, with special attention being paid to the value of glomerular filtration, have reduced the published cases involving the use of gadolinium-based contrast media. In a meeting between radiologists and nephrologists we reviewed the most relevant aspects currently and recommendations for its prevention.

The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor

NASA Astrophysics Data System (ADS)

Imel, G. R.; Hart, P. R.

1996-05-01

The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by using uranium wires that were analyzed by radiochemistry techniques to determine total fissions during the transient. This was correlated to the time-integrated current of the detectors during the transient. A temperature correction factor was derived to account for self-shielding effects in the hafnium and gadolinium detectors. The dynamic response of the detectors under transient conditions was studied, and found to be excellent.

Current status of SK-Gd project and EGADS

NASA Astrophysics Data System (ADS)

Xu, Chenyuan; Super-Kamiokande Collaboration

2016-05-01

Supernova Relic Neutrino (SRN) has not been observed yet because of its low event rate and high background. By adding gadolinium into water Cherenkov detector, inverse beta decay will have two signals, the prompt one is positron signal and the delayed one is a ~8 MeV gamma cascade from neutron capture on gadolinium. By this way, background for SRN can be largely reduced by detecting prompt and delayed signals coincidently, and Super-K will also have the ability to distinguish neutrino and anti-neutrino. SK-Gd is a R&D project proposed to dissolve gadolinium into Super-K. As a part of it, EGADS, a 200 ton water Cherenkov detector was built in Kamioka mine. Current status of SK-Gd project and the physics work being performed in EGADS will be presented here.

Graphene oxide-gadolinium (III) oxide nanoparticle composite: a novel MR contrast agent with high longitudinal and transverse relaxivity

NASA Astrophysics Data System (ADS)

Venkatesha, N.; Poojar, Pavan; Geethanath, Sairam; Srivastava, Chandan

2014-12-01

Production of bio-compatible contrast agent materials to enhance the sensitivity of the magnetic resonance imaging (MRI) technique is a highly active area in MRI related research. This work illustrates the potential of a new material: graphene oxide-gadolinium (III) oxide nanoparticle (GO-Gd2O3) composite in yielding both transverse (16.3 mM-1 s-1) and longitudinal relaxivity (40 mM-1 s-1) values which are significantly higher than the proton relaxivity values achieved using the gadolinium based contrast agents currently used in MRI. Such high proton relaxivity values can facilitate low dosage of GO-Gd2O3 composite for obtaining both T1 and T2 weighted high signal-to-noise ratio images in MRI.

Suppression of Rabbit VX‐2 Subcutaneous Tumor Growth by Gadolinium Neutron Capture Therapy

PubMed Central

Tokita, Nobuhiko; Tokuuye, Koichi; Satoh, Michinao; Churei, Hisahiko; Pechoux, Cécile Le; Kobayashi, Tooru; Kanda, Keiji

1993-01-01

VX‐2 tumors growing in hind legs of New Zealand White rabbits (n=4) were exposed to thermal neutrons for 40 min (2.1 × 1012 neutrons cm−2) while one of two hind leg tumors of each rabbit was infused continuously with meglumine gadopentetate through a branch of the left femoral artery. The contralateral (uninfused) tumors served as controls. Although no differential distribution of gadolinium was achieved between the tumor and its adjacent normal tissue, the gadolinium concentration in the infused tumor was approximately 5–6 fold higher than that in the contralateral tumor. Growth of gadolinium‐infused tumors was significantly inhibited compared to that of control tumors (P<0.05) between the 16th and 23rd days after treatment. PMID:8407547

Gadolinium concentration analysis in brain phantom by X-ray fluorescence.

PubMed

Almalki, Musaed; Majid, Samir Abdul; Butler, Philip H; Reinisch, Lou

2010-06-01

We have measured the X-ray fluorescence from gadolinium as a function of concentration and position in tumors of different sizes and shapes in a head phantom. The gadolinium fluorescence was excited with a 36 GBq Am-241 source. The fluorescence signal was detected with a CdTe detector and a multi-channel analyzer. The fluorescence peak was clearly separated from the scattered X-rays. Concentrations of 5.62-78.63 mg/ml of Gd ion were used in 1, 2, and 3 cm diameter spherical tumors and a 2x4 cm oblate spheroid tumor. The data show trends approaching saturation for the highest concentrations, probably due to reabsorption in the tumor. A comparison of X-ray photographic imaging and densitometer measurements to determine concentration is also presented.

Dramatic impact of the giant local magnetic fields on spin-dependent recombination processes in gadolinium based garnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romanov, N. G., E-mail: nikolai.romanov@mail.ioffe.ru; Tolmachev, D. O.; Gurin, A. S.

2015-06-29

A giant magnetic field effect on spin-dependent recombination of the radiation-induced defects has been found in cerium doped gadolinium based garnet crystals and ceramics, promising materials for scintillator applications. A sharp and strong increase in the afterglow intensity stimulated by external magnetic field and an evidence of the magnetic field memory have been discovered. The effect was ascribed to huge Gd-induced internal magnetic fields, which suppress the recombination, and cross-relaxation with Gd{sup 3+} ions leading to reorientation of the spins of the electron and hole centers. Thus, the spin system of radiation-induced defects in gadolinium garnet based scintillator materials wasmore » shown to accumulate significant energy which can be released in external magnetic fields.« less

Chorea in Late-Infantile Neuronal Ceroid Lipofuscinosis: An Atypical Presentation.

PubMed

Saini, Arushi Gahlot; Sankhyan, Naveen; Singhi, Pratibha

2016-07-01

Classic late-infantile neuronal ceroid lipofuscinosis is characterized by progressive intellectual and motor deterioration, seizures, vision loss, and early death. Prominent chorea is an atypical feature and is rarely described in children. A four-year-old girl with seizures followed by a year-long progressive cognitive decline and a three month history of intermittent chorea leading to rapid motor deterioration. The onset of illness was marked by seizures occurring as generalized tonic-clonic seizures and myoclonic jerks. There was gradual regression of cognitive milestones with increasing forgetfulness and impaired quality and content of speech. Nine months later, she developed chorea. These movements were associated with clumsiness, incoordination, and progressive loss of motor milestones. She was unable to perform manual tasks or maintain antigravity posture resulting in unsteadiness and frequent falls. The movements were aggravated by action or excitement and were absent in sleep. Magnetic resonance imaging depicted diffuse cerebral and cerebellar atrophy. Sequencing analysis of TPP1 gene showed a novel, homozygous, splice site mutation c.89+1G>A which resulted in nil enzyme activity and a severe phenotype with onset of disease symptoms at an early age of three years. The presence of chorea in late-infantile neuronal ceroid lipofuscinoses is atypical but does not exclude the diagnosis of late-infantile neuronal ceroid lipofuscinoses, especially in children with psychomotor regression, seizures and diffuse brain atrophy. Copyright © 2016 Elsevier Inc. All rights reserved.

Myocardial Fibrosis in Hypertrophic Cardiomyopathy: Volumetric Assessment of Late Enhancement Provided by Cardiac Computed Tomography.

PubMed

Langer, Christoph; Schaefer, Philipp; Lutz, Matthias; Eden, Matthias; Hohnhorst, Mirko; Harders, Hauke; Faber, Lothar; Jansen, Olav; Both, Marcus; Frey, Norbert

2015-01-01

With subgroups of patients with hypertrophic cardiomyopathy (HCM) confers a 4% to 5% risk for adverse prognosis. Besides left-ventricular muscle mass (LV-MM) myocardial fibrosis (MF) assessable by late gadolinium enhancement in cardiovascular magnetic resonance (LGE-CMR) has been related to that. Myocardial fibrosis can also be demonstrated by late enhancement (LE) in late-enhanced multislice computed tomography (leMDCT). This analysis investigates leMDCT whether to enable quantification of LE load in terms of LE mass by percent LV-MM in HCM. In a prospective validation study, we included 30 consecutive patients with HCM who underwent leMDCT (64 slice) and LGE-CMR (1.5 T). The leMDCT scan was performed 7 minutes after injection of iodine contrast (Iopromid). Endocardial and epicardial planimetry served for the assessment of LV-MM. Visually detectable LE was quantified using the manual quantification method resulting in LE by percent LV-MM (%LE). The LGE-CMR data served for validation. Mean (SD) age was 64.1 (13.9) years. Myocardial fibrosis prevalence was 63.3% (19/30 patients indentified by both leMDCT and LGE-CMR). In leMDCT, tissue density in LE areas compared with normal myocardium was higher (138.2 [23.9] HU vs 98.4 [16.5] HU, P < 0.001) but lower than in the LV cavity (138.2 [23.9] HU vs 169.2 [35.9] HU, P < 0.001). Late enhancement mass in leMDCT seemed to be 7.9 (8.5) g LE versus 8.6 [11] g LGE in CMR (P = 0.497, r = 0.95) resulting in a leMDCT/LGE-CMR relation of 1.2. Referring LE mass to LV-MM gave an LE proportion measured by leMDCT of 4 (3.9) %LE versus 3.9 (4.1) %LGE in LGE-CMR (r = 0.88, P = 0.75). Intraobserver/interobserver reliability of LE mass assessment showed an intraclass correlation coefficient of 0.99 and 0.97. In patients with HCM, leMDCT provides volumetric assessment of LE mass-absolutely and by percent LV-MM.

Switching of the polarization of ferroelectric-ferroelastic gadolinium molybdate in a magnetic field

NASA Astrophysics Data System (ADS)

Yakushkin, E. D.

2017-10-01

A change in the character of the electric switching of polydomain ferroelectric-ferroelastic gadolinium molybdate in an external magnetic field has been detected. This change has been attributed to a magnetically stimulated increase in the pinning of domain walls. Under certain conditions, the loop of switchable polarization is degenerated into an ellipse characteristic of a linear insulator with leakage current.

Fuel bundle design for enhanced usage of plutonium fuel

DOEpatents

Reese, Anthony P.; Stachowski, Russell E.

1995-01-01

A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced.

Fuel bundle design for enhanced usage of plutonium fuel

DOEpatents

Reese, A.P.; Stachowski, R.E.

1995-08-08

A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced. 10 figs.

Thermal energy harvesting and solar energy conversion utilizing carbon-based nanomaterials

NASA Astrophysics Data System (ADS)

McCarthy, Patrick T.

This dissertation provides details of carbon-based nanomaterial fabrication for applications in energy harvesting and generation. As energy demands increase, and concerns about mankind's environmental impact increase, alternative methods of generating energy will be widely researched. Carbon-based nanomaterials may be effective in such applications as their fabrication is often inexpensive and they have highly desirable electrical, mechanical, and thermal properties. Synthesis and characterization of carbon nanotube thermal interfaces on gadolinium foils is described herein. Total thermal interface resistances of carbon nanotube coated gadolinium were measured using a one-dimensional reference calorimeter technique, and the effect of hydrogen embrittlement on the magnetic properties of gadolinium foils is discussed. The samples generated in this study were consistently measured with reduced total thermal interface resistances of 55-70% compared to bare gadolinium. Characterization of gadolinium foils in a cooling device called a magneto thermoelectric generator was also performed. A gadolinium shuttle drives the device as it transitions between ferromagnetic and paramagnetic states. Reduced interface resistances from the carbon nanotube arrays led to increased shuttle frequency and effective heat transfer coefficients. Detailed theoretical derivations for electron emission during thermal and photo-excitation are provided for both three-dimensional and two-dimensional materials. The derived theories were fitted to experimental data from variable temperature photoemission studies of potassium-intercalated graphitic nanopetals. A work function reduction from approximately 4.5 eV to 2 -- 3 eV resulted from potassium intercalation and adsorption. While changes in the electron energy distribution shape and intensity were significant within 310 -- 680 K, potassium-intercalated graphitic petals demonstrate very high thermal stability after heating to nearly 1000 K. Boron nitride modification of the nanopetals was performed in an effort to minimize deintercalation of potassium from the nanopetal lattice and while multiple work functions were present within the electron energy distribution, massive reductions in emission intensity took place above 580 K. Finally, a device for measuring the current density during photoemission was also developed and photoemission induced by a solar simulator at room temperature produced currents on the order of 1 nA/cm 2 resulting in a quantum efficiency of approximately 8.0x10 --8 electrons emitted per photon of illumination.

Gadolinium-148 and other spallation production cross section measurements for accelerator target facilities

NASA Astrophysics Data System (ADS)

Kelley, Karen Corzine

At the Los Alamos Neutron Science Center accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research facility and the 1L target at the Lujan Center. The Department of Energy requires hazard classification analyses to be performed on these targets and places limits on certain radionuclide inventories in the targets to avoid characterizing the facilities as "nuclear facilities." Gadolinium-148 is a radionuclide created from the spallation of tungsten. Allowed isotopic inventories are particularly low for this isotope because it is an alpha-particle emitter with a 75-year half-life. The activity level of Gadolinium-148 is low, but it encompasses almost two-thirds of the total dose burden for the two tungsten targets based on present yield estimates. From a hazard classification standpoint, this severely limits the lifetime of these tungsten targets. The cross section is not well-established experimentally and this is the motivation for measuring the Gadolinium-148 production cross section from tungsten. In a series of experiments at the Weapons Neutron Research facility, Gadolinium-148 production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 mum thin tungsten, tantalum, and gold foils and 10 mum thin aluminum activation foils. In addition, spallation yields were determined for many short-lived and long-lived spallation products with these foils using gamma and alpha spectroscopy and compared with predictions of the Los Alamos National Laboratory codes CEM2k+GEM2 and MCNPX. The cumulative Gadolinium-148 production cross section measured from tantalum, tungsten, and gold for incident 600-MeV protons were 15.2 +/- 4.0, 8.31 +/- 0.92, and 0.591 +/- 0.155, respectively. The average production cross sections measured at 800 MeV were 28.6 +/- 3.5, 19.4 +/- 1.8, and 3.69 +/- 0.50 for tantalum, tungsten, and gold, respectively. These cumulative measurements compared best with Bertini and were within a factor of two to three of CEM2k+GEM2.

Flow regimes for fluid injection into a confined porous medium

DOE PAGES

Zheng, Zhong; Guo, Bo; Christov, Ivan C.; ...

2015-02-24

We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governingmore » equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.« less

Characterizing the audibility of sound field with diffusion in architectural spaces

NASA Astrophysics Data System (ADS)

Utami, Sentagi Sesotya

The significance of diffusion control in room acoustics is that it attempts to avoid echoes by dispersing reflections while removing less valuable sound energy. Some applications place emphasis on the enhancement of late reflections to promote a sense of envelopment, and on methods required to measure the performance of diffusers. What still remains unclear is the impact of diffusion on the audibility quality due to the geometric arrangement of architectural elements. The objective of this research is to characterize the audibility of the sound field with diffusion in architectural space. In order to address this objective, an approach utilizing various methods and new techniques relevant to room acoustics standards was applied. An array of microphones based on beam forming (i.e., an acoustic camera) was utilized for field measurements in a recording studio, classrooms, auditoriums, concert halls and sport arenas. Given the ability to combine a visual image with acoustical data, the impulse responses measured were analyzed to identify the impact of diffusive surfaces on the early, late, and reverberant sound fields. The effects of the room geometry and the proportions of the diffusive and absorptive surfaces were observed by utilizing geometrical room acoustics simulations. The degree of diffuseness in each space was measured by coherences from different measurement positions along with the acoustical conditions predicted by well-known objective parameters such as T30, EDT, C80, and C50. Noticeable differences of the auditory experience were investigated by utilizing computer-based survey techniques, including the use of an immersive virtual environment system, given the current software auralization capabilities. The results based on statistical analysis demonstrate the users' ability to localize the sound and to distinguish the intensity, clarity, and reverberation created within the virtual environment. Impact of architectural elements in diffusion control is evaluated by the design variable interaction, objectively and subjectively. Effectiveness of the diffusive surfaces is determined by the echo reduction and the sense of complete immersion in a given room acoustics volume. Application of such methodology at various stages of design provides the ability to create a better auditory experience by the users. The results based on the cases studied have contributed to the development of new acoustical treatment based on the diffusion characteristics.

Impact of knowledge-based iterative model reconstruction on myocardial late iodine enhancement in computed tomography and comparison with cardiac magnetic resonance.

PubMed

Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Fukuyama, Naoki; Yokoi, Takahiro; Kido, Tomoyuki; Uetani, Teruyoshi; Vembar, Mani; Dhanantwari, Amar; Tokuyasu, Shinichi; Yamashita, Natsumi; Mochizuki, Teruhito

2017-10-01

We evaluated the image quality and diagnostic performance of late iodine enhancement computed tomography (LIE-CT) with knowledge-based iterative model reconstruction (IMR) for the detection of myocardial infarction (MI) in comparison with late gadolinium enhancement magnetic resonance imaging (LGE-MRI). The study investigated 35 patients who underwent a comprehensive cardiac CT protocol and LGE-MRI for the assessment of coronary artery disease. The CT protocol consisted of stress dynamic myocardial CT perfusion, coronary CT angiography (CTA) and LIE-CT using 256-slice CT. LIE-CT scans were acquired 5 min after CTA without additional contrast medium and reconstructed with filtered back projection (FBP), a hybrid iterative reconstruction (HIR), and IMR. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed. Sensitivity and specificity of LIE-CT for detecting MI were assessed according to the 16-segment model. Image quality scores, and diagnostic performance were compared among LIE-CT with FBP, HIR and IMR. Among the 35 patients, 139 of 560 segments showed MI in LGE-MRI. On LIE-CT with FBP, HIR, and IMR, the median SNRs were 2.1, 2.9, and 6.1; and the median CNRs were 1.7, 2.2, and 4.7, respectively. Sensitivity and specificity were 56 and 93% for FBP, 62 and 91% for HIR, and 80 and 91% for IMR. LIE-CT with IMR showed the highest image quality and sensitivity (p < 0.05). The use of IMR enables significant improvement of image quality and diagnostic performance of LIE-CT for detecting MI in comparison with FBP and HIR.

Gadolinium-based Contrast Media, Cerebrospinal Fluid and the Glymphatic System: Possible Mechanisms for the Deposition of Gadolinium in the Brain.

PubMed

Taoka, Toshiaki; Naganawa, Shinji

2018-04-10

After Kanda's first report in 2014 on gadolinium (Gd) deposition in brain tissue, a considerable number of studies have investigated the explanation for the observation. Gd deposition in brain tissue after repeated administration of gadolinium-based contrast medium (GBCM) has been histologically proven, and chelate stability has been shown to affect the deposition. However, the mechanism for this deposition has not been fully elucidated. Recently, a hypothesis was introduced that involves the 'glymphatic system', which is a coined word that combines 'gl' for glia cell and 'lymphatic' system. According to this hypothesis, the perivascular space functions as a conduit for cerebrospinal fluid to flow into the brain parenchyma. The perivascular space around the arteries allows cerebrospinal fluid to enter the interstitial space of the brain tissue through water channels controlled by aquaporin 4. The cerebrospinal fluid entering the interstitial space clears waste proteins from the tissue. It then flows into the perivascular space around the vein and is discharged outside the brain. In addition to the hypothesis regarding the glymphatic system, some reports have described that after GBCM administration, some of the GBCM distributes through systemic blood circulation and remains in other compartments including the cerebrospinal fluid. It is thought that the GBCM distributed into the cerebrospinal fluid cavity via the glymphatic system may remain in brain tissue for a longer duration compared to the GBCM in systemic circulation. Glymphatic system may of course act as a clearance system for GBCM from brain tissue. Based on these findings, the mechanism for Gd deposition in the brain will be discussed in this review. The authors speculate that the glymphatic system may be the major contributory factor to the deposition and clearance of gadolinium in brain tissue.

Penetration and distribution of gadolinium-based contrast agents into the cerebrospinal fluid in healthy rats: a potential pathway of entry into the brain tissue.

PubMed

Jost, Gregor; Frenzel, Thomas; Lohrke, Jessica; Lenhard, Diana Constanze; Naganawa, Shinji; Pietsch, Hubertus

2017-07-01

Signal hyperintensity on unenhanced MRI in certain brain regions has been reported after multiple administrations of some, but not all, gadolinium-based contrast agents (GBCAs). One potential initial pathway of GBCA entry into the brain, infiltration from blood into the cerebrospinal fluid (CSF), was systematically evaluated in this preclinical study. GBCA infiltration and distribution in the CSF were investigated in healthy rats using repeated fluid-attenuated MRI up to 4 h after high-dose (1.8 mmol/kg) administration of six marketed and one experimental GBCA. Additionally, gadolinium measurements in CSF, blood and brain tissue samples (after 24 h) were performed using inductively coupled plasma mass spectrometry. Enhanced MRI signals in the CSF spaces with similar distribution kinetics were observed for all GBCAs. No substantial differences in the gadolinium concentrations among the marketed GBCAs were found in the CSF, blood or brain tissue. After 4.5 h, the concentration in the CSF was clearly higher than in blood but was almost completely cleared and lower than the brain tissue concentration after 24 h. In contrast to the brain signal hyperintensities, no differences in penetration and distribution into the CSF of healthy rats exist among the marketed GBCAs. • Gadolinium-based contrast agents can cross the blood-CSF barrier. • Fluid-attenuated MRI shows GBCA distribution with CSF flow. • GBCA structure and physicochemical properties do not impact CSF penetration and distribution. • GBCA clearance from CSF was almost complete within 24 h in rats. • CSF is a potential pathway of GBCA entry into the brain.

Gadolinium-based Contrast Media, Cerebrospinal Fluid and the Glymphatic System: Possible Mechanisms for the Deposition of Gadolinium in the Brain

PubMed Central

Taoka, Toshiaki; Naganawa, Shinji

2018-01-01

After Kanda’s first report in 2014 on gadolinium (Gd) deposition in brain tissue, a considerable number of studies have investigated the explanation for the observation. Gd deposition in brain tissue after repeated administration of gadolinium-based contrast medium (GBCM) has been histologically proven, and chelate stability has been shown to affect the deposition. However, the mechanism for this deposition has not been fully elucidated. Recently, a hypothesis was introduced that involves the ‘glymphatic system’, which is a coined word that combines ‘gl’ for glia cell and ‘lymphatic’ system. According to this hypothesis, the perivascular space functions as a conduit for cerebrospinal fluid to flow into the brain parenchyma. The perivascular space around the arteries allows cerebrospinal fluid to enter the interstitial space of the brain tissue through water channels controlled by aquaporin 4. The cerebrospinal fluid entering the interstitial space clears waste proteins from the tissue. It then flows into the perivascular space around the vein and is discharged outside the brain. In addition to the hypothesis regarding the glymphatic system, some reports have described that after GBCM administration, some of the GBCM distributes through systemic blood circulation and remains in other compartments including the cerebrospinal fluid. It is thought that the GBCM distributed into the cerebrospinal fluid cavity via the glymphatic system may remain in brain tissue for a longer duration compared to the GBCM in systemic circulation. Glymphatic system may of course act as a clearance system for GBCM from brain tissue. Based on these findings, the mechanism for Gd deposition in the brain will be discussed in this review. The authors speculate that the glymphatic system may be the major contributory factor to the deposition and clearance of gadolinium in brain tissue. PMID:29367513

Hyperintense Dentate Nuclei on T1-Weighted MRI: Relation to Repeat Gadolinium Administration

PubMed Central

Adin, M.E.; Kleinberg, L.; Vaidya, D.; Zan, E.; Mirbagheri, S.; Yousem, D.M.

2016-01-01

BACKGROUND AND PURPOSE A hyperintense appearance of the dentate nucleus on T1-weighted MR images has been related to various clinical conditions, but the etiology remains indeterminate. We aimed to investigate the possible associations between a hyperintense appearance of the dentate nucleus on T1-weighted MR images in patients exposed to radiation and factors including, but not limited to, the cumulative number of contrast-enhanced MR images, amount of gadolinium administration, dosage of ionizing radiation, and patient demographics. MATERIALS AND METHODS The medical records of 706 consecutive patients who were treated with brain irradiation at The Johns Hopkins Medical Institutions between 1995 and 2010 were blindly reviewed by 2 readers. RESULTS One hundred eighty-four subjects were included for dentate nuclei analysis. Among the 184 subjects who cumulatively underwent 2677 MR imaging studies following intravenous gadolinium administration, 103 patients had hyperintense dentate nuclei on precontrast T1-weighted MR images. The average number of gadolinium-enhanced MR imaging studies performed in the group with normal dentate nuclei was significantly lower than that of the group with hyperintense dentate nuclei. The average follow-up time was 62.5 months. No significant difference was observed between hyperintense and normal dentate nuclei groups in terms of exposed radiation dose, serum creatinine and calcium/phosphate levels, patient demographics, history of chemotherapy, and strength of the scanner. No dentate nuclei abnormalities were found on the corresponding CT scans of patients with hyperintense dentate nuclei (n = 44). No dentate nuclei abnormalities were found in 53 healthy volunteers. CONCLUSIONS Repeat performance of gadolinium-enhanced studies likely contributes to a long-standing hyperintense appearance of dentate nuclei on precontrast T1-weighted-MR images. PMID:26294649

Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

2013-03-01

We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential. Electronic supplementary information (ESI) available: Protocols for the characterization, immunotoxicity and pharmacokinetics analyses. Additional supporting figures. See DOI: 10.1039/c3nr00170a

Serial nonenhancing magnetic resonance imaging scans of high grade glioblastoma multiforme.

PubMed Central

Moore-Stovall, J.; Venkatesh, R.

1993-01-01

Magnetic resonance imaging (MRI) from clinical experience has proven to be superior to all other diagnostic imaging modalities, including computed tomography (CT) in the detection of intracranial neoplasms. Although glioblastoma multiforme presents a challenge for all diagnostic imaging modalities including MRI, MRI is paramount to CT in detecting subtle abnormal water accumulation in brain tissue caused by tumor even before there is disruption of the blood brain barrier. Currently, clinical research and investigational trials on nonionic gadolinium contrast agents have proven that nonionic gadolinium HP-DO3A (ProHance) contrast agents have lower osmolality and greater stability, which make them superior compounds to gadolinium diethylenetriamine-pentacetic acid (Gd-DTPA). Therefore, the nonionic gadolinium contrasts have been safely administered more rapidly, in higher or multiple doses for contrast enhanced MRI without adverse side effects or changes in serum iron or total bilirubin, and the intensity of the area of enhancement and number of lesions detected were superior to that of Gd-DTPA (Magnevist) at the standard dose (0.1 mmol/Kg). Perhaps if the nonionic gadolinium contrast agent, ProHance, had been approved by the Food and Drug Administration (FDA) when this MRI was performed in 1990 it would have aided in providing contrast enhancement and visualization of the tumor lesion to assist in patient diagnosis and management. Magnetic resonance imaging also provides unique multiplanar capabilities that allow for optimal visualization of the temporal and occipital lobes of the brain without bone interference.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9A Figure 9B Figure 10 Figure 11 Figure 12 Figure 13 PMID:8382751

Activity in Very Cool Stars: Magnetic Dissipation in Late M and L Dwarf Atmospheres

NASA Astrophysics Data System (ADS)

Mohanty, Subhanjoy; Basri, Gibor; Shu, Frank; Allard, France; Chabrier, Gilles

2002-05-01

Recent observations show that chromospheric Hα activity in late M and L dwarfs is much lower than in the earlier M types. This is particularly surprising given that the late M and L dwarfs are comparatively very rapid rotators: in the early M dwarfs, rapid rotation is associated with high activity levels. One possibility is that the drop-off in activity in the late M and L dwarfs is a result of very high electrical resistivities in their dense, cool, and predominantly neutral atmospheres.We calculate the magnetic field diffusivity in the atmospheres of objects with Teff in the range 3000-1500 K (mid M to late L) using the atmospheric structure models of Allard and Hauschildt. We find that the combination of very low ionization fraction and high density in these atmospheres results in very large resistivities and thus efficient field diffusion. While both ambipolar diffusion and Ohmic decay of currents due to ion-electron collisions occur, the primary diffusion effects are due to current decay through collisions of charged particles with neutrals. Moreover, the latter resistivity is a strong function of both effective temperature and optical depth, increasing rapidly as either Teff or optical depth decreases. This has two implications: (1) Any magnetic field present is increasingly decoupled from atmospheric fluid motions as one moves from mid M to L. In the late M and L dwarfs, atmospheric motions cannot lead to equilibrium field configurations very different from potential ones. That is, the magnitude of magnetic stresses generated by atmospheric motions is very small in these objects. We quantify this effect by a simple Reynolds number calculation. (2) Even if magnetic stresses are easily produced by fluid motions in the hot interior (where the coupling between field and matter is good), their propagation up through the atmosphere will be increasingly hampered by the growing atmospheric resistivity as one moves from mid M to late L. Thus both the generation and propagation of magnetic stresses are increasingly damped with decreasing Teff in these cool dwarfs. As a result, the magnetic free energy available for the support of a chromosphere, and activity becomes smaller and smaller with later type. This can account for the observed drop in Hα activity from mid M to L, assuming that activity in these dwarfs is magnetically driven. To check the latter assumption, we estimate the emergent acoustic fluxes in these objects through a Lighthill-Proudman calculation. While the acoustic fluxes also decrease with decreasing Teff, they appear inadequate to explain the observed Hα fluxes in mid M to L dwarfs. In the absence of acoustic heating, magnetic heating indeed seems the most viable way of generating activity. We emphasize that our calculations are equilibrium ones and do not address time-dependent phenomena. We also do not examine the highest atmospheric layers, where correction is not expected, but which we show are rarefied enough to permit charged particles to remain coupled to the field. Finally, while our calculations do not address flares in late M and L dwarfs, we speculate that the latter could be created by buoyant flux tubes that are generated in the interior and rise rapidly through the atmosphere, dissipating their associated currents in the upper atmospheric layers.

Social-psychological profiles of identity styles: attitudinal and social-cognitive correlates in late adolescence.

PubMed

Soenens, Bart; Duriez, Bart; Goossens, Luc

2005-02-01

This study examined the relationships between three identity styles (i.e. the information style, the normative style, and the diffuse/avoidant style) and a number of social-cognitive and attitudinal variables (including empathy, prejudice, and conservatism). Discriminant analysis on a sample of late adolescents (N=393) led to the conclusion that two classes of variables differentiate between the three identity styles. Maladaptive coping strategies and, to a lesser extent, low empathy distinguished mainly between the information style and the normative style on the one hand and the diffuse/avoidant style on the other hand. Need for closure and measures of prejudice and conservatism differentiated primarily between the normative style and the two other styles. These two classes of variables can be related to two basic dimensions in current theory on adolescents' identity styles, that is, active vs. superficial processing of information and adherence to traditional opinions vs. openmindedness.

Gadolinium-Induced Fibrosis.

PubMed

Todd, Derrick J; Kay, Jonathan

2016-01-01

Gadolinium-based contrast agents (GBCAs), once believed to be safe for patients with renal disease, have been strongly associated with nephrogenic systemic fibrosis (NSF), a severe systemic fibrosing disorder that predominantly afflicts individuals with advanced renal dysfunction. We provide a historical perspective on the appearance and disappearance of NSF, including its initial recognition as a discrete clinical entity, its association with GBCA exposure, and the data supporting a causative relationship between GBCA exposure and NSF. On the basis of this body of evidence, we propose that the name gadolinium-induced fibrosis (GIF) more accurately reflects the totality of knowledge regarding this disease. Use of high-risk GBCAs, such as formulated gadodiamide, should be avoided in patients with renal disease. Restriction of GBCA use in this population has almost completely eradicated new cases of this debilitating condition. Emerging antifibrotic therapies may be useful for patients who suffer from GIF.

Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

PubMed Central

2010-01-01

Biocompatible poly-[N-(2-hydroxyethyl)-d,l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd. PMID:21170410

Method of separating and purifying gadolinium-153

DOEpatents

Bray, Lane A [Richland, WA; Corneillie, Todd M [Davis, CA

2001-01-01

The present invention is an improvement to the method of separating and purifying gadolinium from a mixture of gadolinium and europium having the steps of (a) dissolving the mixture in an acid; (b) reducing europium+3 to europium+2; and (c) precipitating the europium+2 with a sulfate ion in a superstoichiometric amount; wherein the improvement is achieved by using one or more of the following: (i) the acid is an anoic acid; (ii) the reducing is with zinc metal in the absence of a second metal or with an amount of the second metal that is ineffective in the reducing; (iii) adding a group IIA element after step (c) for precipitating the excess sulfate prior to repeating step (c); (iv) the sulfate is a sulfate salt with a monovalent cation; (v) adding cold europium+3 prior to repeating step (c).

The effect of boron and gadolinium burnable poisons on the hot-to-cold reactivity swing of a pressurized water reactor assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galperin, A.; Segev, M.; Radkowsky, A.

1986-11-01

Control requirements for advanced pressurized water reactor designs must be met with heavy loadings of burnable poison rods, the required reactivity hold-down typically amounting to 30% or more in a poisoned subassembly. Two apparent choices for poisons are natural boron rods and natural gadolinium rods. Studied and analyzed is the effect of these two poisons on the hot-to-cold reactivity upswing. Compared with an upswing of 2.9% in a nonpoisoned assembly, the upswing in the gadolinium-poisoned assembly is 3.0%, and the upswing in the boron-poisoned assembly is 8.8%. Thus the hot-to-cold control penalty is almost nil for the choice of gadoliniummore » and is considerable for the choice of boron.« less

Insights into the use of gadolinium and gadolinium/boron-based agents in imaging-guided neutron capture therapy applications.

PubMed

Deagostino, Annamaria; Protti, Nicoletta; Alberti, Diego; Boggio, Paolo; Bortolussi, Silva; Altieri, Saverio; Crich, Simonetta Geninatti

2016-05-01

Gadolinium neutron capture therapy (Gd-NCT) is currently under development as an alternative approach for cancer therapy. All of the clinical experience to date with NCT is done with (10)B, known as boron neutron capture therapy (BNCT), a binary treatment combining neutron irradiation with the delivery of boron-containing compounds to tumors. Currently, the use of Gd for NCT has been getting more attention because of its highest neutron cross-section. Although Gd-NCT was first proposed many years ago, its development has suffered due to lack of appropriate tumor-selective Gd agents. This review aims to highlight the recent advances for the design, synthesis and biological testing of new Gd- and B-Gd-containing compounds with the task of finding the best systems able to improve the NCT clinical outcome.

Emerging MRI Methods in Translational Cardiovascular Research

PubMed Central

Vandsburger, Moriel H; Epstein, Frederick H

2011-01-01

Cardiac magnetic resonance imaging (CMR) has become a reference standard modality for imaging of left ventricular (LV) structure and function, and, using late gadolinium enhancement, for imaging myocardial infarction. Emerging CMR techniques enable a more comprehensive examination of the heart, making CMR an excellent tool for use in translational cardiovascular research. Specifically, emerging CMR methods have been developed to measure the extent of myocardial edema, changes in ventricular mechanics, changes in tissue composition as a result of fibrosis, and changes in myocardial perfusion as a function of both disease and infarct healing. New CMR techniques also enable the tracking of labeled cells, molecular imaging of biomarkers of disease, and changes in calcium flux in cardiomyocytes. In addition, MRI can quantify blood flow velocity and wall shear stress in large blood vessels. Almost all of these techniques can be applied in both pre-clinical and clinical settings, enabling both the techniques themselves and the knowledge gained using such techniques in pre-clinical research to be translated from the lab bench to the patient bedside. PMID:21452060

Tunable Microwave Transversal Filters.

DTIC Science & Technology

1984-05-01

magnetostatic waves MSW propagating at microwave frequency in magnetically biased, liquid phase epitaxial films of yttrium iron garnet (YIG) grown on...25 uM-thick 3 mm-wide and 15 mm-long YIG film grown by liquid phase epitaxy On a 500 uM-thick ( ) gadolinium gallium garnet (GGG) substrate was used...obtained. The delay line material was prepared by growing YIG films on one inch diameter gallium gadolinium garnet (GGG) wafers using the liquid

Optical Properties of Nd Doped Rare Earth Vanadates (Preprint)

DTIC Science & Technology

2010-07-01

Rare earth orthovanadates are being used as substitute for traditional solid state laser hosts such as yttrium aluminium garnet (YAG). While the most...common of these is yttrium orthovanadate, other rare earth vanadates such as lutetium vanadate and gadolinium vanadate are being used for their... gadolinium vanadate are being used for their special properties in certain applications. We report new measurements of the refractive indices and thermo

Spectral Properties of Limit-Periodic Schrödinger Operators (PhD Thesis)

NASA Astrophysics Data System (ADS)

Gideonse, Hendrik David, XIX

The Acoustic Ramp is a wedge-shaped, number-theoretical quadratic-residue-type acoustic diffuser. Since the late 1970's, several methodologies for the testing and analysis of diffusers have been developed including, the ISO Scattering Coefficient and the AES Diffusion Coefficient. These coefficients are the source of some controversy today and this paper makes the attempt to investigate the benefits and weaknesses of these tools by using them to research and test the Acoustic Ramp. Several issues are exposed in using the coefficients, the most important of which being the validity of the comparison of the diffuser's behavior to that of a like sized flat panel. Further issues comprise of an intuitive disconnect between the perceived merits of polar plots and the numerical value of coefficients derived from the plots.

The effects of diffuse and distinct affect.

PubMed

Stapel, Diederik A; Koomen, Willem; Ruys, Kirsten I

2002-07-01

In a series of suboptimal priming studies, it was shown that both affective and nonaffective reactions to a stimulus may occur without awareness. Moreover, it was demonstrated that affective information is detected earlier than nonaffective information. Therefore, early reactions to an affect-laden stimulus (e.g., a smiling man) are cognitively unappraised and thus diffuse (e.g., "positive"), whereas later affective reactions can be more specific and distinct (e.g., "a smiling man"). Through variations of prime exposure (extremely short, moderately short) the impact of early diffuse and late distinct affect on judgment was investigated. Findings show that distinctness (and prime-target similarity) is an essential determinant of whether the effect of affect is null, assimilation, or contrast. Furthermore, whether affect priming activates diffuse or distinct reactions is a matter of a fraction of seconds.

Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury.

PubMed

Gulati, Puja; Muthuraman, Arunachalam; Jaggi, Amteshwar S; Singh, Nirmal

2013-03-01

The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.

Safe Use of Contrast Media: What the Radiologist Needs to Know.

PubMed

Beckett, Katrina R; Moriarity, Andrew K; Langer, Jessica M

2015-10-01

Iodinated and gadolinium-based contrast media are used on a daily basis in most radiology practices. These agents often are essential to providing accurate diagnoses, and are nearly always safe and effective when administered correctly. However, reactions to contrast media do occur and can be life threatening. Therefore, it is critical for faculty and staff to know how reactions to contrast agents manifest and how to treat them promptly. The decline in renal function seen occasionally after intravenous administration of iodinated contrast agents is poorly understood and likely multifactorial, and its association with the contrast medium may be overemphasized. However, it is important that radiologists be aware of current understanding and strategies to decrease the incidence of renal dysfunction. Nephrogenic systemic fibrosis, a skin disease, is an adverse reaction related to use of some gadolinium-based contrast agents in patients with chronic renal failure. The types of gadolinium most often associated with this condition and the indications for withholding gadolinium are important and are discussed in this article. The use of enteric contrast agents and contrast agents during pregnancy and nursing are reviewed briefly. Current knowledge for safe use of contrast media and key concepts that all radiologists should know are summarized in this review. © RSNA, 2015.

Study of the Photon Strength Functions for Gadolinium Isotopes with the DANCE Array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dashdorj, D.; Mitchell, G. E.; Baramsai, B.

2009-03-10

The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight pathmore » 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.« less

Gadolinium-loaded Plastic Scintillators for Thermal Neutron Detection using Compensation

NASA Astrophysics Data System (ADS)

Dumazert, Jonathan; Coulon, Romain; Hamel, Matthieu; Carrel, Frédérick; Sguerra, Fabien; Normand, Stéphane; Méchin, Laurence; Bertrand, Guillaume H. V.

2016-06-01

Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by Gd-155 and Gd-157, alternative treatment to pulse-shape discrimination has to be proposed in order to display a count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon and fast neutron radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a not-gadolinium loaded compensation scintillator solely interacts with the fast neutron and photon part of incident radiation. After the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate post-background response compensation falls into statistical fluctuations or provides a robust indication of neutron activity. Laboratory samples are tested under both photon and neutron irradiations, allowing the authors to investigate the performance of the overall detection system in terms of sensitivity and detection limits, especially with regards to a similar-active volume He-3 based commercial counter. The study reveals satisfactory figures of merit in terms of sensitivity and directs future investigation toward promising paths.

Ferromagnetic coupling in the three-dimensional malonato-bridged gadoliniumIII complex [Gd2(mal)3(H2O)6] (H2mal = malonic acid).

PubMed

Hernández-Molina, María; Ruiz-Pérez, Catalina; López, Trinidad; Lloret, Francesc; Julve, Miguel

2003-09-08

The novel gadolinium(III) complex of formula [Gd(2)(mal)(3)(H(2)O)(6)] (1) (H(2)mal = 1,3-propanedioic acid) has been prepared and characterized by X-ray diffraction analysis. Crystal data for 1: monoclinic, space group I2/a, a = 11.1064(10) A, b = 12.2524(10) A, c =13.6098(2) A, beta = 92.925(10) degrees, U = 1849.5(3) A(3), Z = 4. Compound 1 is a three-dimensional network made up of malonate-bridged gadolinium(III) ions where the malonate exhibits two bridging modes, eta(5)-bidentate + unidentate and eta(3):eta(3) + bis(unidentate). The gadolinium atom is nine-coordinate with three water molecules and six malonate oxygen atoms from three malonate ligands forming a distorted monocapped square antiprism. The shortest metal-metal separations are 4.2763(3) A [through the oxo-carboxylate bridge] and 6.541(3) A [through the carboxylate in the anti-syn coordination mode]. The value of the angle at the oxo-carboxylate atom is 116.8(2) degrees. Variable-temperature magnetic susceptibility measurements reveal the occurrence of a significant ferromagnetic interaction through the oxo-carboxylate pathway (J = +0.048(1) cm(-1), H = -JS(Gd(1)) x S(Gd(1a))).

High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

NASA Astrophysics Data System (ADS)

Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

2016-04-01

A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0-10 GPa and 300-650 K.

Core-shell monodisperse spherical mSiO2/Gd2O3:Eu3+@mSiO2 particles as potential multifunctional theranostic agents

NASA Astrophysics Data System (ADS)

Eurov, Daniil A.; Kurdyukov, Dmitry A.; Kirilenko, Demid A.; Kukushkina, Julia A.; Nashchekin, Alexei V.; Smirnov, Alexander N.; Golubev, Valery G.

2015-02-01

Core-shell nanoparticles with diameters in the range 100-500 nm have been synthesized as monodisperse spherical mesoporous (pore diameter 3 nm) silica particles with size deviation of less than 4 %, filled with gadolinium and europium oxides and coated with a mesoporous silica shell. It is shown that the melt technique developed for filling with gadolinium and europium oxides provides a nearly maximum filling of mesopores in a single-run impregnation, with gadolinium and europium uniformly distributed within the particles and forming no bulk oxides on their surface. The coating with a shell does not impair the monodispersity and causes no coagulation. The coating technique enables controlled variation of the shell thickness within the range 5-100 % relative to the core diameter. The thus produced nanoparticles are easily dispersed in water, have large specific surface area (300 m2 g-1) and pore volume (0.3 cm3 g-1), and are bright solid phosphor with superior stability in aqueous media. The core-shell structured particles can be potentially used for cancer treatment as a therapeutic agent (gadolinium neutron-capture therapy and drug delivery system) and, simultaneously, as a multimodal diagnostic tool (fluorescence and magnetic resonance imaging), thereby serving as a multifunctional theranostic agent.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis.

PubMed

Toslak, Iclal Erdem; Cekic, Bulent; Turk, Aysen; Eraslan, Ali; Parlak, A Eda

2017-10-10

Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP). 42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm 2 . Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured. 36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions. DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play.

Demonstration of the reproducibility of free-breathing diffusion-weighted MRI and dynamic contrast enhanced MRI in children with solid tumours: a pilot study.

PubMed

Miyazaki, Keiko; Jerome, Neil P; Collins, David J; Orton, Matthew R; d'Arcy, James A; Wallace, Toni; Moreno, Lucas; Pearson, Andrew D J; Marshall, Lynley V; Carceller, Fernando; Leach, Martin O; Zacharoulis, Stergios; Koh, Dow-Mu

2015-09-01

The objectives are to examine the reproducibility of functional MR imaging in children with solid tumours using quantitative parameters derived from diffusion-weighted (DW-) and dynamic contrast enhanced (DCE-) MRI. Patients under 16-years-of age with confirmed diagnosis of solid tumours (n = 17) underwent free-breathing DW-MRI and DCE-MRI on a 1.5 T system, repeated 24 hours later. DW-MRI (6 b-values, 0-1000 sec/mm(2)) enabled monoexponential apparent diffusion coefficient estimation using all (ADC0-1000) and only ≥100 sec/mm(2) (ADC100-1000) b-values. DCE-MRI was used to derive the transfer constant (K(trans)), the efflux constant (kep), the extracellular extravascular volume (ve), and the plasma fraction (vp), using a study cohort arterial input function (AIF) and the extended Tofts model. Initial area under the gadolinium enhancement curve and pre-contrast T1 were also calculated. Percentage coefficients of variation (CV) of all parameters were calculated. The most reproducible cohort parameters were ADC100-1000 (CV = 3.26%), pre-contrast T1 (CV = 6.21%), and K(trans) (CV = 15.23%). The ADC100-1000 was more reproducible than ADC0-1000, especially extracranially (CV = 2.40% vs. 2.78%). The AIF (n = 9) derived from this paediatric population exhibited sharper and earlier first-pass and recirculation peaks compared with the literature's adult population average. Free-breathing functional imaging protocols including DW-MRI and DCE-MRI are well-tolerated in children aged 6 - 15 with good to moderate measurement reproducibility. • Diffusion MRI protocol is feasible and well-tolerated in a paediatric oncology population. • DCE-MRI for pharmacokinetic evaluation is feasible and well tolerated in a paediatric oncology population. • Paediatric arterial input function (AIF) shows systematic differences from the adult population-average AIF. • Variation of quantitative parameters from paired functional MRI measurements were within 20%.

Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex

PubMed Central

Degnan, Andrew J.; Wisnowski, Jessica L.; Choi, SoYoung; Ceschin, Rafael; Bhushan, Chitresh; Leahy, Richard M.; Corby, Patricia; Schmithorst, Vincent J.; Panigrahy, Ashok

2015-01-01

Objective Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. Methods Thirty-eight preadolescents (ages 9–13; 19 born in the late preterm period (≥32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). Results Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. Conclusion Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant executive neurocognitive differences. Selective increased structural connectivity was observed in the setting of decreased posterior interhemispheric connections. Future work is needed to determine if these findings represent a compensatory adaptation employing alternate neural circuitry or could reflect subtle pathology resulting in emotional processing deficits not seen with neurocognitive testing. PMID:26098888

Forging Fast Ion Conducting Nanochannels with Swift Heavy Ions: The Correlated Role of Local Electronic and Atomic Structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sachan, Ritesh; Cooper, Valentino R.; Liu, Bin

2016-12-19

Atomically disordered oxides have attracted significant attention in recent years due to the possibility of enhanced ionic conductivity. However, the correlation between atomic disorder, corresponding electronic structure, and the resulting oxygen diffusivity is not well understood. The disordered variants of the ordered pyrochlore structure in gadolinium titanate (Gd 2Ti 2O 7) are seen as a particularly interesting prospect due to intrinsic presence of a vacant oxygen site in the unit atomic structure, which could provide a channel for fast oxygen conduction. In this paper, we provide insights into the subangstrom scale on the disordering-induced variations in the local atomic environmentmore » and its effect on the electronic structure in high-energy ion irradiation-induced disordered nanochannels, which can be utilized as pathways for fast oxygen ion transport. With the help of an atomic plane-by-plane-resolved analyses, the work shows how the presence of various types of TiO x polyhedral that exist in the amorphous and disordered crystalline phase modify the electronic structures relative to the ordered pyrochlore phase in Gd 2Ti 2O 7. Finally, the correlated molecular dynamics simulations on the disordered structures show a remarkable enhancement in oxygen diffusivity as compared with ordered pyrochlore lattice and make that a suitable candidate for applications requiring fast oxygen conduction.« less

Susceptibility Tensor Imaging (STI) of the Brain

PubMed Central

Li, Wei; Liu, Chunlei; Duong, Timothy Q.; van Zijl, Peter C.M.; Li, Xu

2016-01-01

Susceptibility tensor imaging (STI) is a recently developed MRI technique that allows quantitative determination of orientation-independent magnetic susceptibility parameters from the dependence of gradient echo signal phase on the orientation of biological tissues with respect to the main magnetic field. By modeling the magnetic susceptibility of each voxel as a symmetric rank-2 tensor, individual magnetic susceptibility tensor elements as well as the mean magnetic susceptibility (MMS) and magnetic susceptibility anisotropy (MSA) can be determined for brain tissues that would still show orientation dependence after conventional scalar-based quantitative susceptibility mapping (QSM) to remove such dependence. Similar to diffusion tensor imaging (DTI), STI allows mapping of brain white matter fiber orientations and reconstruction of 3D white matter pathways using the principal eigenvectors of the susceptibility tensor. In contrast to diffusion anisotropy, the main determinant factor of susceptibility anisotropy in brain white matter is myelin. Another unique feature of susceptibility anisotropy of white matter is its sensitivity to gadolinium-based contrast agents. Mechanistically, MRI-observed susceptibility anisotropy is mainly attributed to the highly ordered lipid molecules in myelin sheath. STI provides a consistent interpretation of the dependence of phase and susceptibility on orientation at multiple scales. This article reviews the key experimental findings and physical theories that led to the development of STI, its practical implementations, and its applications for brain research. PMID:27120169

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases.

PubMed

Koh, D-M; Collins, D J; Wallace, T; Chau, I; Riddell, A M

2012-07-01

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases. 72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T(1) and T(2) weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics. 417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az)=0.96, 0.97] than Gd-EOB-DTPA image set (Az=0.86, 0.89) or DW-MRI image set (Az=0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ=0.81-0.88). Combining DW-MRI with Gd-EOB-DTPA-enhanced T(1) weighted MRI significantly improved the detection of colorectal liver metastases.

Detection of liver metastasis: is diffusion-weighted imaging needed in Gd-EOB-DTPA-enhanced MR imaging for evaluation of colorectal liver metastases?

PubMed

Tajima, Taku; Akahane, Masaaki; Takao, Hidemasa; Akai, Hiroyuki; Kiryu, Shigeru; Imamura, Hiroshi; Watanabe, Yasushi; Kokudo, Norihiro; Ohtomo, Kuni

2012-10-01

We compared diagnostic ability for detecting hepatic metastases between gadolinium ethoxy benzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) on a 1.5-T system, and determined whether DWI is necessary in Gd-EOB-DTPA-enhanced MRI for diagnosing colorectal liver metastases. We assessed 29 consecutive prospectively enrolled patients with suspected metachronous colorectal liver metastases; all patients underwent surgery and had preoperative Gd-EOB-DTPA-enhanced MRI. Overall detection rate, sensitivity for detecting metastases and benign lesions, positive predictive value, and diagnostic accuracy (Az value) were compared among three image sets [unenhanced MRI (DWI set), Gd-EOB-DTPA-enhanced MRI excluding DWI (EOB set), and combined set]. Gd-EOB-DTPA-enhanced MRI yielded better overall detection rate (77.8-79.0 %) and sensitivity (87.1-89.4 %) for detecting metastases than the DWI set (55.9 % and 64.7 %, respectively) for one observer (P < 0.001). No statistically significant difference was seen between the EOB and combined sets, although several metastases were newly detected on additional DWI. Gd-EOB-DTPA-enhanced MRI yielded a better overall detection rate and higher sensitivity for detecting metastases compared with unenhanced MRI. Additional DWI may be able to reduce oversight of lesions in Gd-EOB-DTPA-enhanced 1.5-T MRI for detecting colorectal liver metastases.

Diffuse Winter Lighting of the Chasma Boreale Scarp

NASA Image and Video Library

2013-08-08

Sunlight was just starting to reach the high Northern latitudes in late winter when NASA Mars Reconnaissance Orbiter HiRISE camera captured this image of part of the steep scarps around portions of the North Polar layered deposits.

Spread spectrum time-resolved diffuse optical measurement system for enhanced sensitivity in detecting human brain activity

NASA Astrophysics Data System (ADS)

Mehta, Kalpesh; Hasnain, Ali; Zhou, Xiaowei; Luo, Jianwen; Penney, Trevor B.; Chen, Nanguang

2017-04-01

Diffuse optical spectroscopy (DOS) and imaging methods have been widely applied to noninvasive detection of brain activity. We have designed and implemented a low cost, portable, real-time one-channel time-resolved DOS system for neuroscience studies. Phantom experiments were carried out to test the performance of the system. We further conducted preliminary human experiments and demonstrated that enhanced sensitivity in detecting neural activity in the cortex could be achieved by the use of late arriving photons.

A Stable Finite-Difference Scheme for Population Growth and Diffusion on a Map

PubMed Central

Callegari, S.; Lake, G. R.; Tkachenko, N.; Weissmann, J. D.; Zollikofer, Ch. P. E.

2017-01-01

We describe a general Godunov-type splitting for numerical simulations of the Fisher–Kolmogorov–Petrovski–Piskunov growth and diffusion equation on a world map with Neumann boundary conditions. The procedure is semi-implicit, hence quite stable. Our principal application for this solver is modeling human population dispersal over geographical maps with changing paleovegetation and paleoclimate in the late Pleistocene. As a proxy for carrying capacity we use Net Primary Productivity (NPP) to predict times for human arrival in the Americas. PMID:28085882

Trojan War displayed as a full annihilation-diffusion-reaction model

NASA Astrophysics Data System (ADS)

Flores, J. C.

2017-02-01

The diffusive pair annihilation model with embedded topological domains and archaeological data is applied in an analysis of the hypothetical Trojan-Greek war during the late Bronze Age. Estimations of parameter are explicitly made for critical dynamics of the model. In particular, the 8-metre walls of Troy could be viewed as the effective shield that provided the technological difference between the two armies. Suggestively, the numbers in The Iliad are quite sound, being in accord with Lanchester's laws of warfare.

A Stable Finite-Difference Scheme for Population Growth and Diffusion on a Map.

PubMed

Petersen, W P; Callegari, S; Lake, G R; Tkachenko, N; Weissmann, J D; Zollikofer, Ch P E

2017-01-01

We describe a general Godunov-type splitting for numerical simulations of the Fisher-Kolmogorov-Petrovski-Piskunov growth and diffusion equation on a world map with Neumann boundary conditions. The procedure is semi-implicit, hence quite stable. Our principal application for this solver is modeling human population dispersal over geographical maps with changing paleovegetation and paleoclimate in the late Pleistocene. As a proxy for carrying capacity we use Net Primary Productivity (NPP) to predict times for human arrival in the Americas.

Diffusivity in the core of chronic multiple sclerosis lesions.

PubMed

Klistorner, Alexander; Wang, Chenyu; Yiannikas, Con; Parratt, John; Barton, Joshua; You, Yuyi; Graham, Stuart L; Barnett, Michael H

2018-01-01

Diffusion tensor imaging (DTI) has been suggested as a potential biomarker of disease progression, neurodegeneration and de/remyelination in MS. However, the pathological substrates that underpin alterations in brain diffusivity are not yet fully delineated. We propose that in highly cohesive fiber tracts: 1) a relative increase in parallel (axial) diffusivity (AD) may serve as a measure of increased extra-cellular space (ESC) within the core of chronic MS lesions and, as a result, may provide an estimate of the degree of tissue destruction, and 2) the contribution of the increased extra-cellular water to perpendicular (radial) diffusivity (RD) can be eliminated to provide a more accurate assessment of membranal (myelin) loss. The purpose of this study was to isolate the contribution of extra-cellular water and demyelination to observed DTI indices in the core of chronic MS lesions, using the OR as an anatomically cohesive tract. Pre- and post-gadolinium (Gd) enhanced T1, T2 and DTI images were acquired from 75 consecutive RRMS patients. In addition, 25 age and gender matched normal controls were imaged using an identical MRI protocol (excluding Gd). The optic radiation (OR) was identified in individual patients using probabilistic tractography. The T2 lesions were segmented and intersected with the OR. Average eigenvalues were calculated within the core of OR lesions mask. The proportion of extra-cellular space (ECS) within the lesional core was calculated based on relative increase of AD, which was then used to normalise the perpendicular eigenvalues to eliminate the effect of the expanded ECS. In addition, modelling was implemented to simulate potential effect of various factors on lesional anisotropy. Of 75 patients, 41 (55%) demonstrated sizable T2 lesion volume within the ORs. All lesional eigenvalues were significantly higher compared to NAWM and controls. There was a strong correlation between AD and RD within the core of OR lesions, which was, however, not seen in OR NAWM of MS patients or normal controls. In addition, lesional anisotropy (FA) was predominantly driven by the perpendicular diffusivity, while in NAWM and in OR of normal controls all eigenvectors contributed to variation in FA. Estimated volume of ECS component constituted significant proportion of OR lesional volume and correlated significantly with lesional T1 hypointensity. While perpendicular diffusivity dropped significantly following normalisation, it still remained higher compared with diffusivity in OR NAWM. The "residual" perpendicular diffusivity also showed a substantial reduction of inter-subject variability. Both observed and modelled diffusion data suggested anisotropic nature of water diffusion in ESC. In addition, the simulation procedure offered a possible explanation for the discrepancy in relationship between eigenvalues and anisotropy in lesional tissue and NAWM. This paper presents a potential technique for more reliably quantifying the effects of neurodegeneration (tissue loss) versus demyelination in OR MS lesions. This may provide a simple and effective way for applying single tract diffusion analysis in MS clinical trials, with particular relevance to pro-remyelinating and neuroprotective therapeutics.

In vivo characterization of a smart MRI agent that displays an inverse response to calcium concentration.

PubMed

Mamedov, Ilgar; Canals, Santiago; Henig, Jörg; Beyerlein, Michael; Murayama, Yusuke; Mayer, Hermann A; Logothetis, Nikos K; Angelovski, Goran

2010-12-15

Contrast agents for magnetic resonance imaging (MRI) that exhibit sensitivity toward specific ions or molecules represent a challenging but attractive direction of research. Here a Gd(3+) complex linked to an aminobis(methylenephosphonate) group for chelating Ca(2+) was synthesized and investigated. The longitudinal relaxivity (r(1)) of this complex decreases during the relaxometric titration with Ca(2+) from 5.76 to 3.57 mM(-1) s(-1) upon saturation. The r(1) is modulated by changes in the hydration number, which was confirmed by determination of the luminescence emission lifetimes of the analogous Eu(3+) complex. The initial in vivo characterization of this responsive contrast agent was performed by means of electrophysiology and MRI experiments. The investigated complex is fully biocompatible, having no observable effect on neuronal function after administration into the brain ventricles or parenchyma. Distribution studies demonstrated that the diffusivity of this agent is significantly lower compared with that of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA).

[Transformation from chronic subdural hematoma into subdural empyema following cat bites: a case report].

PubMed

Konno, Takuya; Yamada, Kei; Kasahara, Sou; Umeda, Yoshitaka; Oyake, Mutsuo; Fujita, Nobuya

2015-01-01

A 69-year-old man developed motor aphasia and right hemiparesis with severe headache, during the treatment of cellulitis and sepsis due to cat bites. Brain CT showed a low density, crescent-shaped lesion in the left subdural space, which was hypointense on brain diffusion-weighted imaging (DWI). One week later, when his neurological symptoms had worsened, the signal of the subdural lesion had changed to hyperintense on DWI. The lesion was capsule-shaped when enhanced by Gadolinium. The signal changes on DWI of the lesion indicated the existing hematoma had changed to an empyema, or so-called infected subdural hematoma, due to a hematogenous bacterial infection. Pasteurella multocida, a resident microbe in the oral cavity of cats, could be the responsible pathogen in this case. The patient recovered completely after treatment with intravenous high dose antibiotics. This is an important case report describing the transformation from a chronic subdural hematoma into a subdural empyema by DWI.

The use of innovative gadolinium-based contrast agent for MR-diagnosis of cancer in the experiment

NASA Astrophysics Data System (ADS)

Chernov, V.; Medvedeva, A.; Sinilkin, I.; Zelchan, R.; Grigorev, E.; Frolova, I.; Nam, I.

2016-02-01

The present study of the functional suitability and specific activity of the contrast agent gadolinium-based for magnetic resonance imaging demonstrated that the investigated contrast agent intensively accumulates in organs and anatomical structures of the experimental animals. In the model of tumor lesions in animals, study have shown that investigational contrast agent accumulates in the tumor tissue and retained there in for a long enough time.

How to Evaluate and Synthesize Literature Data on Physical Properties.

DTIC Science & Technology

1980-09-01

experimental set-up, refined technique for fabri - cating and installing the specimen heater so as to minimize heat leakage, technique for installing...Conductivity of Gadolinium Figure 3 shows another type of disagreement in experimental data from the literature. Here the two sets of thermal conductivity data...for gadolinium are for the same one piece of specimen measured in the same laboratory which S-" is one of the best known internationally, and published

Gadolinium Endohedral Metallofullerene-Based MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Bolskar, Robert D.

With the ability to encapsulate and carry the highly paramagnetic Gd3+ ion, gadolinium endohedral metallofullerenes or "gadofullerenes" are being explored as alternatives to the chelate complexes that are currently used for contrast-enhanced magnetic resonance imaging (MRI). Reviewed here are the various water-soluble derivatives of the gadofullerenes Gd@C82, Gd@C60, and Gd3N@C80 that have been investigated as MRI contrast agents. The water proton r1 relaxivities of gadofullerenes can be more than an order of magnitude higher than those of clinically used chelate agents. Gadofullerene relaxivity mechanisms have been studied, and multiple factors are found to contribute to their high relaxivities. In vitro and in vivoT1-weighted MRI tests of gadofullerene derivatives have shown their utility as bright image-enhancing agents. The gadofullerene MRI contrast agents are a promising new and unique style of gadolinium carrier for advanced imaging applications, including cellular and molecular imaging.

Multimodal targeted high relaxivity thermosensitive liposome for in vivo imaging

NASA Astrophysics Data System (ADS)

Kuijten, Maayke M. P.; Hannah Degeling, M.; Chen, John W.; Wojtkiewicz, Gregory; Waterman, Peter; Weissleder, Ralph; Azzi, Jamil; Nicolay, Klaas; Tannous, Bakhos A.

2015-11-01

Liposomes are spherical, self-closed structures formed by lipid bilayers that can encapsulate drugs and/or imaging agents in their hydrophilic core or within their membrane moiety, making them suitable delivery vehicles. We have synthesized a new liposome containing gadolinium-DOTA lipid bilayer, as a targeting multimodal molecular imaging agent for magnetic resonance and optical imaging. We showed that this liposome has a much higher molar relaxivities r1 and r2 compared to a more conventional liposome containing gadolinium-DTPA-BSA lipid. By incorporating both gadolinium and rhodamine in the lipid bilayer as well as biotin on its surface, we used this agent for multimodal imaging and targeting of tumors through the strong biotin-streptavidin interaction. Since this new liposome is thermosensitive, it can be used for ultrasound-mediated drug delivery at specific sites, such as tumors, and can be guided by magnetic resonance imaging.

Kondo effect and enhanced magnetic properties in gadolinium functionalized carbon nanotube supramolecular complex.

PubMed

Ncube, S; Coleman, C; Strydom, A; Flahaut, E; de Sousa, A; Bhattacharyya, S

2018-05-23

We report on the enhancement of magnetic properties of multiwalled carbon nanotubes (MWNTs) functionalized with a gadolinium based supramolecular complex. By employing a newly developed synthesis technique we find that the functionalization method of the nanocomposite enhances the strength of magnetic interaction leading to a large effective moment of 15.79 µ B and non-superparamagnetic behaviour unlike what has been previously reported. Saturating resistance at low temperatures is fitted with the numerical renormalization group formula verifying the Kondo effect for magnetic impurities on a metallic electron system. Magnetoresistance shows devices fabricated from aligned gadolinium functionalized MWNTs (Gd-Fctn-MWNTs) exhibit spin-valve switching behaviour of up to 8%. This study highlights the possibility of enhancing magnetic interactions in carbon systems through chemical modification, moreover we demonstrate the rich physics that might be useful for developing spin based quantum computing elements based on one-dimensional (1D) channels.

CMR imaging of edema in myocardial infarction using cine balanced steady-state free precession.

PubMed

Kumar, Andreas; Beohar, Nirat; Arumana, Jain Mangalathu; Larose, Eric; Li, Debiao; Friedrich, Matthias G; Dharmakumar, Rohan

2011-12-01

The aim of this study was to investigate the capabilities of balanced steady-state free precession (bSSFP) cardiac magnetic resonance imaging as a novel cine imaging approach for characterizing myocardial edema in animals and patients after reperfused myocardial infarction. Current cardiac magnetic resonance methods require 2 separate scans for assessment of myocardial edema and cardiac function. Mini-pigs (n = 13) with experimentally induced reperfused myocardial infarction and patients with reperfused ST-segment elevation myocardial infarction (n = 26) underwent cardiac magnetic resonance scans on days 2 to 4 post-reperfusion. Cine bSSFP, T2-weighted short TI inversion recovery (T2-STIR), and late gadolinium enhancement were performed at 1.5-T. Cine bSSFP and T2-STIR images were acquired with a body coil to mitigate surface coil bias. Signal, contrast, and the area of edema were compared. Additional patients (n = 10) were analyzed for the effect of microvascular obstruction on bSSFP. A receiver-operator characteristic analysis was performed to assess the accuracy of edema detection. An area of hyperintense bSSFP signal consistent with edema was observed in the infarction zone (contrast-to-noise ratio: 37 ± 13) in all animals and correlated well with the area of late gadolinium enhancement (R = 0.83, p < 0.01). In all patients, T2-STIR and bSSFP images showed regional hyperintensity in the infarction zone. Normalized contrast-to-noise ratios were not different between T2-STIR and bSSFP. On a slice basis, the volumes of hyperintensity on T2-STIR and bSSFP images correlated well (R = 0.86, p < 0.001), and their means were not different. When compared with T2-STIR, bSSFP was positive for edema in 25 of 26 patients (96% sensitivity) and was negative in all controls (100% specificity). All patients with microvascular obstruction showed a significant reduction of signal in the subendocardial infarction zone compared with infarcted epicardial tissue without microvascular obstruction (p < 0.05). Myocardial edema from ST-segment elevation myocardial infarction can be detected using cine bSSFP imaging with image contrast similar to T2-STIR. This new imaging approach allows evaluation of cardiac function and edema simultaneously, thereby reducing patient scan time and increasing efficiency. Further work is necessary to optimize edema contrast in bSSFP images. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Ancient DNA from South-East Europe Reveals Different Events during Early and Middle Neolithic Influencing the European Genetic Heritage

PubMed Central

Hervella, Montserrat; Rotea, Mihai; Izagirre, Neskuts; Constantinescu, Mihai; Alonso, Santos; Ioana, Mihai; Lazăr, Cătălin; Ridiche, Florin; Soficaru, Andrei Dorian; Netea, Mihai G.; de-la-Rua, Concepcion

2015-01-01

The importance of the process of Neolithization for the genetic make-up of European populations has been hotly debated, with shifting hypotheses from a demic diffusion (DD) to a cultural diffusion (CD) model. In this regard, ancient DNA data from the Balkan Peninsula, which is an important source of information to assess the process of Neolithization in Europe, is however missing. In the present study we show genetic information on ancient populations of the South-East of Europe. We assessed mtDNA from ten sites from the current territory of Romania, spanning a time-period from the Early Neolithic to the Late Bronze Age. mtDNA data from Early Neolithic farmers of the Starčevo Criş culture in Romania (Cârcea, Gura Baciului and Negrileşti sites), confirm their genetic relationship with those of the LBK culture (Linienbandkeramik Kultur) in Central Europe, and they show little genetic continuity with modern European populations. On the other hand, populations of the Middle-Late Neolithic (Boian, Zau and Gumelniţa cultures), supposedly a second wave of Neolithic migration from Anatolia, had a much stronger effect on the genetic heritage of the European populations. In contrast, we find a smaller contribution of Late Bronze Age migrations to the genetic composition of Europeans. Based on these findings, we propose that permeation of mtDNA lineages from a second wave of Middle-Late Neolithic migration from North-West Anatolia into the Balkan Peninsula and Central Europe represent an important contribution to the genetic shift between Early and Late Neolithic populations in Europe, and consequently to the genetic make-up of modern European populations. PMID:26053041

Ancient DNA from South-East Europe Reveals Different Events during Early and Middle Neolithic Influencing the European Genetic Heritage.

PubMed

Hervella, Montserrat; Rotea, Mihai; Izagirre, Neskuts; Constantinescu, Mihai; Alonso, Santos; Ioana, Mihai; Lazăr, Cătălin; Ridiche, Florin; Soficaru, Andrei Dorian; Netea, Mihai G; de-la-Rua, Concepcion

2015-01-01

The importance of the process of Neolithization for the genetic make-up of European populations has been hotly debated, with shifting hypotheses from a demic diffusion (DD) to a cultural diffusion (CD) model. In this regard, ancient DNA data from the Balkan Peninsula, which is an important source of information to assess the process of Neolithization in Europe, is however missing. In the present study we show genetic information on ancient populations of the South-East of Europe. We assessed mtDNA from ten sites from the current territory of Romania, spanning a time-period from the Early Neolithic to the Late Bronze Age. mtDNA data from Early Neolithic farmers of the Starčevo Criş culture in Romania (Cârcea, Gura Baciului and Negrileşti sites), confirm their genetic relationship with those of the LBK culture (Linienbandkeramik Kultur) in Central Europe, and they show little genetic continuity with modern European populations. On the other hand, populations of the Middle-Late Neolithic (Boian, Zau and Gumelniţa cultures), supposedly a second wave of Neolithic migration from Anatolia, had a much stronger effect on the genetic heritage of the European populations. In contrast, we find a smaller contribution of Late Bronze Age migrations to the genetic composition of Europeans. Based on these findings, we propose that permeation of mtDNA lineages from a second wave of Middle-Late Neolithic migration from North-West Anatolia into the Balkan Peninsula and Central Europe represent an important contribution to the genetic shift between Early and Late Neolithic populations in Europe, and consequently to the genetic make-up of modern European populations.

Evidence of Hierarchy in the Complex Fractured System of Geropotamos (Crete, Greece), as Extracted from Transient Electromagnetic Responses

NASA Astrophysics Data System (ADS)

Vallianatos, Filippos; Kouli, Maria; Kalisperi, Despina

2018-03-01

The essential goals of this paper are to test the transient electromagnetic (TEM) response in a fractured geological complex medium and to better understand the physics introduced by associating a roughness parameter β to the geological formation. An anomalous fractional diffusion approach is incorporated to describe the electromagnetic induction in rough multi-scaled geological structures. The multi-scaling characteristics of Geropotamos basin in Crete are revealed through the analysis of transient step-off response of an EM loop antenna. The semi-empirical parameters derived from late-time TEM measurements are correlated with the multi-scale heterogeneities of the medium. Certain interesting properties of the late-time slope γ(β) and the power law of near surface resistivity distribution, as extracted from TEM inversion for different depth, are presented. The analysis of the parameter γ(β) which scales the induced voltage in the loop in the late stage of the electromagnetic response leads to a different view of the EM geophysical data interpretation. We show that it is strongly correlated with areas of high fracture density within the geological formations of the Geropotamos area. For that reason, it is proposed as a local multi-scaling empirical index. The results of this paper suggest that anomalous diffusion could be a viable physical mechanism for the fractal transport of charge carriers, explaining observed late-time TEM responses across a variety of natural geological settings.

Long-term outcomes among 2-year survivors of autologous hematopoietic cell transplantation for Hodgkin and diffuse large b-cell lymphoma.

PubMed

Myers, Regina M; Hill, Brian T; Shaw, Bronwen E; Kim, Soyoung; Millard, Heather R; Battiwalla, Minoo; Majhail, Navneet S; Buchbinder, David; Lazarus, Hillard M; Savani, Bipin N; Flowers, Mary E D; D'Souza, Anita; Ehrhardt, Matthew J; Langston, Amelia; Yared, Jean A; Hayashi, Robert J; Daly, Andrew; Olsson, Richard F; Inamoto, Yoshihiro; Malone, Adriana K; DeFilipp, Zachariah; Margossian, Steven P; Warwick, Anne B; Jaglowski, Samantha; Beitinjaneh, Amer; Fung, Henry; Kasow, Kimberly A; Marks, David I; Reynolds, Jana; Stockerl-Goldstein, Keith; Wirk, Baldeep; Wood, William A; Hamadani, Mehdi; Satwani, Prakash

2018-02-15

Autologous hematopoietic cell transplantation (auto-HCT) is a standard therapy for relapsed classic Hodgkin lymphoma (cHL) and diffuse large B-cell lymphoma (DLBCL); however, long-term outcomes are not well described. This study analyzed survival, nonrelapse mortality, late effects, and subsequent malignant neoplasms (SMNs) in 1617 patients who survived progression-free for ≥2 years after auto-HCT for cHL or DLBCL between 1990 and 2008. The median age at auto-HCT was 40 years; the median follow-up was 10.6 years. The 5-year overall survival rate was 90% (95% confidence interval [CI], 87%-92%) for patients with cHL and 89% (95% CI, 87%-91%) for patients with DLBCL. The risk of late mortality in comparison with the general population was 9.6-fold higher for patients with cHL (standardized mortality ratio [SMR], 9.6) and 3.4-fold higher for patients with DLBCL (SMR, 3.4). Relapse accounted for 44% of late deaths. At least 1 late effect was reported for 9% of the patients. A total of 105 SMNs were confirmed: 44 in the cHL group and 61 in the DLBCL group. According to a multivariate analysis, older age, male sex, a Karnofsky score < 90, total body irradiation (TBI) exposure, and a higher number of lines of chemotherapy before auto-HCT were risk factors for overall mortality in cHL. Risk factors in DLBCL were older age and TBI exposure. A subanalysis of 798 adolescent and young adult patients mirrored the outcomes of the overall study population. Despite generally favorable outcomes, 2-year survivors of auto-HCT for cHL or DLBCL have an excess late-mortality risk in comparison with the general population and experience an assortment of late complications. Cancer 2018;124:816-25. © 2017 American Cancer Society. © 2017 American Cancer Society.

Current German Laser and Quantum Optics Research Reviewed at the 50th Annual Meeting of the Physikalische Gesellschaft.

DTIC Science & Technology

1986-04-23

Physics, Munster In the area of generating useable University) studied an interesting de- coherent high-frequency radiation, I vice, a silicon Fabry ...has a substantial crys- tingen) described studies with Cr- plus tal growing capability. One paper from Nd-doped gadolinium -scandium-gallium the Hamburg...institute, read by J. Drube, garnets (GSGG), and also with Cr-doped reported on Xe-flashlamp-pumped Cr:CSA(; % gadolinium -scandium-aluminum garnets

Crystallography, Spectroscopic Analysis, and Lasing Properties of Nd(3+) :Y3Sc2Al3O12

DTIC Science & Technology

1989-12-01

aluminum garnet (GSAG), are formed from more stable constitu- ent oxides than gallium-containing materials, 2. Experimental Results and such as gadolinium ...the which an assessment can be made regarding aluminum -based systems, such as YAG, YSAG, Nd:YSAG as a laser material. or gadolinium scandium...Structure oxidation state variation or oxygen vacancies, and this problem is greatly reduced in alumi- Yttrium scandium aluminum garnet be- nate systems

High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery, J. M.; Samudrala, G. K.; Vohra, Y. K.

A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phasemore » diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10 GPa and 300–650 K.« less

Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deli, Martin, E-mail: martin.deli@web.de; Fritz, Jan, E-mail: jfritz9@jhmi.edu; Mateiescu, Serban, E-mail: mateiescu@microtherapy.de

Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 withmore » gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.« less

[Combined use of contrast media containing iodine and gadolinium for imaging and intervention : A hitherto widely ignored topic in radiological practice].

PubMed

Golder, W

2012-02-01

The synchronous use of chemically different contrast media in the same body compartment is a challenge for the radiologist, whether it is scheduled or unexpected. However, to inject contrast media containing iodine and gadolinium at the same time can be a prerequisite for the examination of several organs or organ systems. Unlike other topics of contrast-enhanced imaging procedures, the difficulties encountered with double contrast injections have been widely ignored in the literature. In the absence of reliable data from experimental and clinical studies the radiologist is dependent on case reports, information provided by the contrast media manufacturers, personal communications, mostly scanty personal experiences and a skilful time management, in order to overcome the situation. Only the combination of X-ray, computed tomography and magnetic resonance arthrography can be performed without another thought. However, the more or less synchronous vascular application of contrast media containing iodine and gadolinium requires vigilance. The more seriously ill the patient is, the more caution is advised even if the decision on the combined administration has to be reached urgently. The following overview gives a description of the properties of contrast media containing iodine and gadolinium as far as interactions following simultaneous administration are concerned. Subsequently, the clinically relevant situations and constellations are outlined and analyzed.

Convection-enhanced delivery of MANF--volume of distribution analysis in porcine putamen and substantia nigra.

PubMed

Barua, N U; Bienemann, A S; Woolley, M; Wyatt, M J; Johnson, D; Lewis, O; Irving, C; Pritchard, G; Gill, S

2015-10-15

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a 20kDa human protein which has both neuroprotective and neurorestorative activity on dopaminergic neurons and therefore may have application for the treatment of Parkinson's Disease. The aims of this study were to determine the translational potential of convection-enhanced delivery (CED) of MANF for the treatment of PD by studying its distribution in porcine putamen and substantia nigra and to correlate histological distribution with co-infused gadolinium-DTPA using real-time magnetic resonance imaging. We describe the distribution of MANF in porcine putamen and substantia nigra using an implantable CED catheter system using co-infused gadolinium-DTPA to allow real-time MRI tracking of infusate distribution. The distribution of gadolinium-DTPA on MRI correlated well with immunohistochemical analysis of MANF distribution. Volumetric analysis of MANF IHC staining indicated a volume of infusion (Vi) to volume of distribution (Vd) ratio of 3 in putamen and 2 in substantia nigra. This study confirms the translational potential of CED of MANF as a novel treatment strategy in PD and also supports the co-infusion of gadolinium as a proxy measure of MANF distribution in future clinical studies. Further study is required to determine the optimum infusion regime, flow rate and frequency of infusions in human trials. Copyright © 2015 Elsevier B.V. All rights reserved.

T1 relaxivity of core-encapsulated gadolinium liposomal contrast agents--effect of liposome size and internal gadolinium concentration.

PubMed

Ghaghada, Ketan; Hawley, Catherine; Kawaji, Keigo; Annapragada, Ananth; Mukundan, Srinivasan

2008-10-01

Long circulating core-encapsulated gadolinium (CE-Gd) liposomal nanoparticles that have surface conjugated polyethylene glycol are a promising platform technology for use as blood pool T1-based magnetic resonance (MR) contrast agents. The objective of this study was to investigate the effect of liposome size and internal (core) Gd concentration on the T1 relaxivity of CE-Gd liposomes. Twelve different liposomal formulations were synthesized and characterized, resulting in a size (50, 100, 200, and 400 nm) and core Gd-concentration (200, 350, and 500 mM) "matrix" of test samples. Subsequently, CE-Gd liposomes were diluted in deionized water (four diluted samples) and molar T1 relaxivity (r1) measurements were performed at 2- and 7-T MR field strengths. The r1 of CE-Gd liposomes was inversely related to the liposome size. The largest change in r1 was observed between liposomes that were extruded through 50- and 100-nm filter membranes. At both field strengths, the variation in internal gadolinium concentration did not show any significant correlation (alpha < or = 0.05) with r1. The size of CE-Gd liposomal nanoparticles significantly affects the T1 relaxivity. An inverse relation was observed between liposome size and T1 relaxivity. The T1 relaxivity did not change significantly with core Gd concentration over the measured concentration range.

Gadolinium prevents high airway pressure-induced permeability increases in isolated rat lungs.

PubMed

Parker, J C; Ivey, C L; Tucker, J A

1998-04-01

To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 microM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient (Kfc), a measure of capillary hydraulic conductivity. Kfc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, Kfc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, Kfc was unchanged from baseline (0.060 +/- 0.010 ml . min-1 . cmH2O-1 . 100 g-1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last Kfc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

In vivo evaluation of neutron capture therapy effectivity using calcium phosphate-based nanoparticles as Gd-DTPA delivery agent.

PubMed

Dewi, Novriana; Mi, Peng; Yanagie, Hironobu; Sakurai, Yuriko; Morishita, Yasuyuki; Yanagawa, Masashi; Nakagawa, Takayuki; Shinohara, Atsuko; Matsukawa, Takehisa; Yokoyama, Kazuhito; Cabral, Horacio; Suzuki, Minoru; Sakurai, Yoshinori; Tanaka, Hiroki; Ono, Koji; Nishiyama, Nobuhiro; Kataoka, Kazunori; Takahashi, Hiroyuki

2016-04-01

A more immediate impact for therapeutic approaches of current clinical research efforts is of major interest, which might be obtained by developing a noninvasive radiation dose-escalation strategy, and neutron capture therapy represents one such novel approach. Furthermore, some recent researches on neutron capture therapy have focused on using gadolinium as an alternative or complementary for currently used boron, taking into account several advantages that gadolinium offers. Therefore, in this study, we carried out feasibility evaluation for both single and multiple injections of gadolinium-based MRI contrast agent incorporated in calcium phosphate nanoparticles as neutron capture therapy agent. In vivo evaluation was performed on colon carcinoma Col-26 tumor-bearing mice irradiated at nuclear reactor facility of Kyoto University Research Reactor Institute with average neutron fluence of 1.8 × 10(12) n/cm(2). Antitumor effectivity was evaluated based on tumor growth suppression assessed until 27 days after neutron irradiation, followed by histopathological analysis on tumor slice. The experimental results showed that the tumor growth of irradiated mice injected beforehand with Gd-DTPA-incorporating calcium phosphate-based nanoparticles was suppressed up to four times higher compared to the non-treated group, supported by the results of histopathological analysis. The results of antitumor effectivity observed on tumor-bearing mice after neutron irradiation indicated possible effectivity of gadolinium-based neutron capture therapy treatment.

Investigation of the radiological safety concerns and medical history of the late Joseph T. Harding, former employee of the Paducah Gaseous Diffusion Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vallario, E.J.; Wolfe, H.R.

1981-03-01

An ex-employee's claims that inadequate enforcement of radiation safety regulations allowed excess radiation exposure thereby causing his deteriorating health was not substantiated by a thorough investigation.

Structural, kinetic, and thermodynamic characterization of the interconverting isomers of MS-325, a gadolinium(III)-based magnetic resonance angiography contrast agent.

PubMed

Tyeklar, Zoltan; Dunham, Stephen U; Midelfort, Katarina; Scott, Daniel M; Sajiki, Hirano; Ong, Karen; Lauffer, Randall B; Caravan, Peter; McMurry, Thomas J

2007-08-06

The amphiphilic gadolinium complex MS-325 ((trisodium-{(2-(R)-[(4,4-diphenylcyclohexyl) phosphonooxymethyl] diethylenetriaminepentaacetato) (aquo)gadolinium(III)}) is a contrast agent for magnetic resonance angiography (MRA). MS-325 comprises a GdDTPA core with an appended phosphodiester moiety linked to a diphenylcyclohexyl group to facilitate noncovalent binding to serum albumin and extension of the plasma half-life in vivo. The chiral DTPA ligand (R) was derived from L-serine, and upon complexation with gadolinium, forms two interconvertible diastereomers, denoted herein as isomers A and B. X-ray crystallography of the tris(ethylenediamine)cobalt(III) salt derivative of isomer A revealed a structure in the polar acentric space group P32. The structure consisted of three independent molecules of the gadolinium complex in the asymmetric unit along with three Delta-[Co(en)3]3+ cations, and it represents an unusual example of spontaneous Pasteur resolution of the cobalt cation. The geometry of the coordination core was best described as a distorted trigonal prism, and the final R factor was 5.6%. The configuration of the chiral central nitrogen of the DTPA core was S. The Gd-water (2.47-2.48 A), the Gd-acetate oxygens (2.34-2.42 A), and the Gd-N bond distances (central N, 2.59-2.63 A; terminal N, 2.74-2.80 A) were similar to other reported GdDTPA structures. The structurally characterized single crystal was one of two interconvertable diastereomers (isomers A and B) that equilibrated to a ratio of 1.81 to 1 at pH 7.4 and were separable at elevated pH by ion-exchange chromatography. The rate of isomerization was highly pH dependent: k1 = (1.45 +/- 0.08) x 102[H+] + (4.16 +/- 0.30) x 105[H+]2; k-1 = (2.57 +/- 0.17) x 102[H+] + (7.54 +/- 0.60) x 105[H+]2.

Image-guided convection-enhanced delivery of muscimol to the primate brain

PubMed Central

Heiss, John D.; Walbridge, Stuart; Asthagiri, Ashok R.; Lonser, Russell R.

2009-01-01

Object Muscimol is a potent γ-aminobutyric acid-A receptor agonist (GABAA) that temporarily and selectively suppresses neurons. Targeted muscimol-suppression of neuronal structures could provide insight into the pathophysiology and treatment of a variety of neurologic disorders. To determine if muscimol delivered to the brain by convection-enhanced delivery (CED) could be monitored using a co-infused surrogate magnetic resonance (MR)-imaging tracer, we perfused the striata of primates with tritiated muscimol and gadolinium-DTPA. Methods Three primates underwent convective co-infusion of 3H-muscimol (0.8 μM) and gadolinium-DTPA (−5 mM) into the bilateral striata. Primates underwent serial MR-imaging during infusion and animals were sacrificed immediately after infusion. Post-mortem quantitative autoradiography and histological analysis was performed. Results MR-imaging revealed that infusate (tritiated muscimol and gadolinium-DTPA) distribution was clearly discernible from the non-infused parenchyma. Real-time MR-imaging of the infusion revealed the precise region of anatomic perfusion in each animal. Imaging analysis during infusion revealed that the distribution volume of infusate linearly increased (R=0.92) with volume of infusion. Overall, the mean (±S.D.) volume of distribution to volume of infusion ratio was 8.2±1.3. Autoradiographic analysis revealed that MR-imaging of gadolinium-DTPA closely correlated with the distribution of 3H-muscimol and precisely estimated its volume of distribution (mean difference in volume of distribution, 7.4%). Quantitative autoradiograms revealed that muscimol was homogeneously distributed over the perfused region in a square-shaped concentration profile. Conclusions Muscimol can be effectively delivered to clinically relevant volumes of the primate brain. Moreover, the distribution of muscimol can be tracked by co-infusion of gadolinium-DTPA using MR-imaging. The ability to accurately monitor and control the anatomic extent of muscimol distribution during its convection-enhanced delivery will enhance safety, permit correlations of muscimol distribution with clinical effect, and should lead to an improved understanding of the pathophysiologic processes underlying a variety of neurologic disorders. PMID:19715424

Effect of Cu2+ substitution on the structural, magnetic and electrical properties of gadolinium orthoferrite

NASA Astrophysics Data System (ADS)

Sai Vandana, C.; Hemalatha Rudramadevi, B.

2018-04-01

The pure and copper (Cu) substituted Gadolinium orthoferrites, GdFeO3, GdCu0.1Fe0.9O3, GdCu0.2Fe0.8O3 and GdCu0.3Fe0.7O3 were synthesized by conventional solid state method. The structural, morphological, dielectric, magnetic and impedance properties of Cu substituted Gadolinium orthoferrites have been investigated. The crystallographic phase as well as the substitution of Cu2+ ions in the lattice of GdFeO3 is confirmed from the x-ray diffraction patterns. The Fourier transform infrared spectra exhibit two prominent fundamental absorption peaks at ∼417 cm‑1 and 545 cm‑1. These bands are related to inherent stretching vibrations of metals at octahedral and tetrahedral sites respectively. The coercivity (Hc) and saturation magnetization (Ms) of the synthesized samples at different temperatures were determined from the hysteresis plots. Higher coercive values, 598 Oe and 600 Oe were achieved in GdCu0.1Fe0.9O3 ferrites compared to 527 Oe and 360 Oe in pure GdFeO3 at room temperature (300 K) and low temperature (20 k) respectively. Dielectric dispersion has been observed for gadolinium ferrite samples with Maxwell–Wagner type interfacial polarization. The decrease of dielectric constant and dielectric loss tangent with an increase in frequency was observed. The conduction due to charge hopping between localized states was confirmed from AC conductivity measurements. The composition dependent cationic distributions estimated from XRD, magnetic and electrical studies are in good agreement with each other. The achieved results indicate that the substitution of Cu in gadolinium orthoferrite strongly influences the crystal structure, magnetic and electrical properties thereby making them suitable as multiple state memory devices, transducers, electronic field controlled ferromagnetic resonance devices and spintronic devices.

Gadolinium embedded iron oxide nanoclusters as T1-T2 dual-modal MRI-visible vectors for safe and efficient siRNA delivery

NASA Astrophysics Data System (ADS)

Wang, Xiaoyong; Zhou, Zijian; Wang, Zhiyong; Xue, Yunxin; Zeng, Yun; Gao, Jinhao; Zhu, Lei; Zhang, Xianzhong; Liu, Gang; Chen, Xiaoyuan

2013-08-01

This report illustrates a new strategy of designing a T1-T2 dual-modal magnetic resonance imaging (MRI)-visible vector for siRNA delivery and MRI. Hydrophobic gadolinium embedded iron oxide (GdIO) nanocrystals are self-assembled into nanoclusters in the water phase with the help of stearic acid modified low molecular weight polyethylenimine (stPEI). The resulting water-dispersible GdIO-stPEI nanoclusters possess good stability, monodispersity with narrow size distribution and competitive T1-T2 dual-modal MR imaging properties. The nanocomposite system is capable of binding and delivering siRNA for knockdown of a gene of interest while maintaining its magnetic properties and biocompatibility. This new gadolinium embedded iron oxide nanocluster provides an important platform for safe and efficient gene delivery with non-invasive T1-T2 dual-modal MRI monitoring capability.This report illustrates a new strategy of designing a T1-T2 dual-modal magnetic resonance imaging (MRI)-visible vector for siRNA delivery and MRI. Hydrophobic gadolinium embedded iron oxide (GdIO) nanocrystals are self-assembled into nanoclusters in the water phase with the help of stearic acid modified low molecular weight polyethylenimine (stPEI). The resulting water-dispersible GdIO-stPEI nanoclusters possess good stability, monodispersity with narrow size distribution and competitive T1-T2 dual-modal MR imaging properties. The nanocomposite system is capable of binding and delivering siRNA for knockdown of a gene of interest while maintaining its magnetic properties and biocompatibility. This new gadolinium embedded iron oxide nanocluster provides an important platform for safe and efficient gene delivery with non-invasive T1-T2 dual-modal MRI monitoring capability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr02797j

Role of myocardial collagen degradation and fibrosis in right ventricle dysfunction in transposition of the great arteries after atrial switch.

PubMed

Ladouceur, Magalie; Baron, Stephanie; Nivet-Antoine, Valérie; Maruani, Gérard; Soulat, Gilles; Pereira, Helena; Blanchard, Anne; Boutouyrie, Pierre; Paul, Jean Louis; Mousseaux, Elie

2018-05-01

Heart failure is a serious event in patients with transposition of the great arteries (D-TGA) after atrial redirection surgery. We aimed to determine the association between myocardial fibrosis and systolic and diastolic systemic right ventricle (sRV) dysfunction. Diastolic and systolic function of sRV was prospectively assessed using echocardiography and cardiac magnetic resonance imaging (CMR) in 48 patients with atrially switched D-TGA and 26 healthy subjects. Diastolic function of the subaortic ventricle was assessed by echocardiography Doppler and DTI. In CMR, ejection fraction of sRV and wall stress defined as the product of the systolic blood pressure and volume/mass ratio were assessed. Fibrosis extent within sRV myocardium was evaluated using gadolinium-enhanced magnetic resonance and serum collagen turnover biomarkers. Late gadolinium enhancement (LGE) was found in 35% of D-TGA patients, and the collagen degradation biomarker pro-MMP1:TIMP1 ratio was significantly increased in D-TGA patients compared to healthy subjects (1.0 × 10 -2 vs. 2.5 × 10 -2 , p = 0.04). Increase in sRV wall stress was significantly associated with LGE (p = 0.01) and pro-MMP1:TIMP1 ratio (r = 0.77, p < 0.01). After adjustment for age, sex, BMI, blood pressure and cardiac treatment, pro-MMP1:TIMP1 ratio was the strongest determinant of sRVEF (R 2  = 0.85, p < 0.01). Pro-MMP1:TIMP1 ratio was also significantly correlated with the early diastolic filling parameter E/E' (r = 0.53, p = 0.02), but this was not anymore the case after adjustment. Diastolic and systolic sRV dysfunction is related to myocardial collagen degradation and fibrosis. Research in medical therapies that reduce systemic sRV afterload and limit collagen degradation is warranted in this setting. Copyright © 2018 Elsevier B.V. All rights reserved.

Cardiac magnetic resonance findings predict increased resource utilization in elective coronary artery bypass grafting.

PubMed

Berry, Colin; Zimmerli, Lukas U; Steedman, Tracey; Foster, John E; Dargie, Henry J; Berg, Geoffrey A; Dominiczak, Anna F; Delles, Christian

2008-03-01

Morbidity following CABG (coronary artery bypass grafting) is difficult to predict and leads to increased healthcare costs. We hypothesized that pre-operative CMR (cardiac magnetic resonance) findings would predict resource utilization in elective CABG. Over a 12-month period, patients requiring elective CABG were invited to undergo CMR 1 day prior to CABG. Gadolinium-enhanced CMR was performed using a trueFISP inversion recovery sequence on a 1.5 tesla scanner (Sonata; Siemens). Clinical data were collected prospectively. Admission costs were quantified based on standardized actual cost/day. Admission cost greater than the median was defined as 'increased'. Of 458 elective CABG cases, 45 (10%) underwent pre-operative CMR. Pre-operative characteristics [mean (S.D.) age, 64 (9) years, mortality (1%) and median (interquartile range) admission duration, 7 (6-8) days] were similar in patients who did or did not undergo CMR. In the patients undergoing CMR, eight (18%) and 11 (24%) patients had reduced LV (left ventricular) systolic function by CMR [LVEF (LV ejection fraction) <55%] and echocardiography respectively. LE (late enhancement) with gadolinium was detected in 17 (38%) patients. The average cost/day was $2723. The median (interquartile range) admission cost was $19059 ($10891-157917). CMR LVEF {OR (odds ratio), 0.93 [95% CI (confidence interval), 0.87-0.99]; P=0.03} and SV (stroke volume) index [OR 1.07 (95% CI, 1.00-1.14); P=0.02] predicted increased admission cost. CMR LVEF (P=0.08) and EuroScore tended to predict actual admission cost (P=0.09), but SV by CMR (P=0.16) and LV function by echocardiography (P=0.95) did not. In conclusion, in this exploratory investigation, pre-operative CMR findings predicted admission duration and increased admission cost in elective CABG surgery. The cost-effectiveness of CMR in risk stratification in elective CABG surgery merits prospective assessment.

Fibrin-Targeted Magnetic Resonance Imaging Allows In Vivo Quantification of Thrombus Fibrin Content and Identifies Thrombi Amenable for Thrombolysis

PubMed Central

Jenkins, Julia; Modarai, Bijan; Wiethoff, Andrea J.; Phinikaridou, Alkystis; Grover, Steven P.; Patel, Ashish S.; Schaeffter, Tobias; Smith, Alberto; Botnar, Rene M.

2014-01-01

Objective Deep venous thrombosis is a major health problem. Thrombolytic therapies are effective in recanalizing the veins and preventing post-thrombotic complications, but there is no consensus on selection criteria. The aim of this study was to investigate a fibrin-specific MRI contrast agent (EP-2104R) for the accurate quantification of thrombus’ fibrin content in vivo and for the identification of thrombus suitable for thrombolysis. Approach and Results Venous thrombosis was induced in the inferior vena cava of 8- to 10-week-old male BALB/C mice and MRI performed 2, 4, 7, 10, 14, and 21 days later. Eighteen mice were scanned at each time point pre and 2 hours post injection of EP-2104R (8.0 μmol/kg) with 12 mice at each time point used to correlate fibrin contrast uptake with thrombus’ histological stage and fibrin content. Six mice at each time point were immediately subjected to intravascular thrombolytic therapy (10 mg/kg of tissue-type plasminogen activator). Mice were imaged to assess response to lytic therapy 24 hours after thrombolytic treatment. Two mice at each time point were scanned post injection of 0.2 mmol/kg of Gd-DTPA (gadolinium with diethylenetriaminepentacetate, Magnevist, Schering AG, Berlin, Germany) for control purpose. Contrast uptake was correlated positively with the fibrin content of the thrombus measured by Western blotting (R2=0.889; P<0.001). Thrombus relaxation rate (R1) post contrast and the change in visualized thrombus size on late gadolinium enhancement inversion recovery MRI pre–EP-2104R and post–EP-2104R injection were the best predictors for successful thrombolysis (area under the curve, 0.989 [95% confidence interval, 0.97–1.00] and 0.994 [95% confidence interval, 0.98–1.00] respectively). Conclusions MRI with a fibrin-specific contrast agent accurately estimates thrombus fibrin content in vivo and identifies thrombi that are amenable for thrombolysis. PMID:24723557

Identification and assessment of Anderson-Fabry disease by cardiovascular magnetic resonance noncontrast myocardial T1 mapping.

PubMed

Sado, Daniel M; White, Steven K; Piechnik, Stefan K; Banypersad, Sanjay M; Treibel, Thomas; Captur, Gabriella; Fontana, Marianna; Maestrini, Viviana; Flett, Andrew S; Robson, Matthew D; Lachmann, Robin H; Murphy, Elaine; Mehta, Atul; Hughes, Derralynn; Neubauer, Stefan; Elliott, Perry M; Moon, James C

2013-05-01

Anderson-Fabry disease (AFD) is a rare but underdiagnosed intracellular lipid disorder that can cause left ventricular hypertrophy (LVH). Lipid is known to shorten the magnetic resonance imaging parameter T1. We hypothesized that noncontrast T1 mapping by cardiovascular magnetic resonance would provide a novel and useful measure in this disease with potential to detect early cardiac involvement and distinguish AFD LVH from other causes. Two hundred twenty-seven subjects were studied: patients with AFD (n=44; 55% with LVH), healthy volunteers (n=67; 0% with LVH), patients with hypertension (n=41; 24% with LVH), patients with hypertrophic cardiomyopathy (n=34; 100% with LVH), those with severe aortic stenosis (n=21; 81% with LVH), and patients with definite amyloid light-chain (AL) cardiac amyloidosis (n=20; 100% with LVH). T1 mapping was performed using the shortened modified Look-Locker inversion sequence on a 1.5-T magnet before gadolinium administration with primary results derived from the basal and midseptum. Compared with health volunteers, septal T1 was lower in AFD and higher in other diseases (AFD versus healthy volunteers versus other patients, 882±47, 968±32, 1018±74 milliseconds; P<0.0001). In patients with LVH (n=105), T1 discriminated completely between AFD and other diseases with no overlap. In AFD, T1 correlated inversely with wall thickness (r=-0.51; P=0.0004) and was abnormal in 40% of subjects who did not have LVH. Segmentally, AFD showed pseudonormalization or elevation of T1 in the left ventricular inferolateral wall, correlating with the presence or absence of late gadolinium enhancement (1001±82 versus 891±38 milliseconds; P<0.0001). Noncontrast T1 mapping shows potential as a unique and powerful measurement in the imaging assessment of LVH and AFD.

Determination of Location, Size and Transmurality of Chronic Myocardial Infarction Without Exogenous Contrast Media Using Cardiac Magnetic Resonance Imaging at 3T

PubMed Central

Kali, Avinash; Cokic, Ivan; Tang, Richard L Q; Yang, Hsin-Jung; Sharif, Behzad; Marbán, Eduardo; Li, Debiao; Berman, Daniel; Dharmakumar, Rohan

2014-01-01

Background LGE CMR is a powerful method for characterizing MI, but the requisite gadolinium infusion is estimated to be contraindicated in nearly 20% of MI patients due to end-stage chronic kidney disease. The purpose of this study is to investigate whether T1 Cardiovascular-Magnetic-Resonance Imaging (CMR) obtained without contrast agents at 3T could be an alternative to Late-Gadolinium-Enhanced (LGE) CMR for characterizing chronic myocardial infarctions (MIs) using a canine model of MI. Methods and Results Canines (n=29) underwent CMR at 7 days (acute, AMI) and 4 months (chronic, CMI) post-MI. Infarct location, size and transmurality measured using native T1 maps and LGE images at 1.5T and 3T were compared. Resolution of edema between AMI and CMI was examined with T2 maps. T1 maps overestimated infarct size and transmurality relative to LGE images in AMI (p=0.016 and p=0.007, respectively), which was not observed in CMI (p=0.49 and p=0.81, respectively), at 3T. T1 maps underestimated infarct size and transmurality relative to LGE images in AMI and CMI (p<0.001), at 1.5T. Relative to the remote territories, T1 of the infarcted myocardium was increased in CMI and AMI (p<0.05); and T2 of the infarcted myocardium was increased in AMI (p<0.001), but not in CMI (p >0.20) at both field strengths. Histology showed extensive replacement fibrosis within the CMI territories. CMI detection sensitivity and specificity of T1 CMR at 3T were 95% and 97%, respectively. Conclusions Native T1 maps at 3T can determine the location, size and transmurality of CMI with high diagnostic accuracy. Patient studies are necessary for clinical translation. PMID:24682268

Cardiac profile of asymptomatic children with Becker and Duchenne muscular dystrophy under treatment with steroids and with/without perindopril.

PubMed

Mavrogeni, Sophie; Giannakopoulou, Aikaterini; Papavasiliou, Antigoni; Markousis-Mavrogenis, George; Pons, Roser; Karanasios, Evangelos; Noutsias, Michel; Kolovou, Genovefa; Papadopoulos, George

2017-07-24

To evaluate cardiovascular function in boys with Duchenne (DMD) and Becker (BMD) muscular dystrophy, using cardiac magnetic resonance (CMR). This is a single point cross sectional study of twenty-four boys with genetically ascertained DMD, and 10 with BMD, aged 10.5 ± 1.5 years (range 9-13), were prospectively evaluated by a 1.5 T system and compared with those of age-sex matched controls. The DMD patients were divided in 2 groups. Group A (N = 12) were under treatment with both deflazacort and perindopril, while Group B (n = 12) were under treatment with deflazacort, only. BMD patients did not take any medication. Biventricular function was assessed using a standard SSFP sequence. Late gadolinium enhancement (LGE) was assessed from T1 images taken 15 min after injection of 0.2 mg/Kg gadolinium DTPA using a 3D-T1-TFE sequence. Group A and BMDs were asymptomatic with normal ECG, 24 h ECG recording and echocardiogram. Group B were asymptomatic but 6/12 had abnormal ECG and mildly impaired LVEF. Their 24 h ECG recording revealed supraventricular and ventricular extrasystoles (all at 12-13 yrs). LV indices in Group A and BMD did not differ from those of controls. However, LV indices in Group B were significantly impaired compared with controls, Group A and BMDs (p < 0.001). An epicardial LGE area = 3 ± 0.5% of LV mass was identified in the posterolateral wall of LV only in 6/12 patients of Group B, but in not in any BMD or Group A. Children with either BMD or DMD under treatment with both deflazacort and perindopril present preserved LV function and lack of LGE. However, further large scale multicenter studies are warranted to confirm these data, including further CMR mapping approaches.

Serum and cerebrospinal fluid levels of visinin-like protein-1 in acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Hasegawa, Shunji; Matsushige, Takeshi; Inoue, Hirofumi; Takahara, Midori; Kajimoto, Madoka; Momonaka, Hiroshi; Oka, Momoko; Isumi, Hiroshi; Emi, Sakie; Hayashi, Megumi; Ichiyama, Takashi

2014-08-01

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) has recently been recognized as an encephalopathy subtype. Typical clinical symptoms of AESD are biphasic seizures, and MRI findings show reduced subcortical diffusion during clustering seizures with unconsciousness after the acute phase. Visinin-like protein-1 (VILIP-1) is a recently discovered protein that is abundant in the central nervous system, and some reports have shown that VILIP-1 may be a prognostic biomarker of conditions such as Alzheimer's disease, stroke, and brain injury. However, there have been no reports regarding serum and cerebrospinal fluid (CSF) levels of VILIP-1 in patients with AESD. We measured the serum and CSF levels of VILIP-1 in patients with AESD, and compared the levels to those in patients with prolonged febrile seizures (FS). Both serum and CSF levels of VILIP-1 were significantly higher in patients with AESD than in patients with prolonged FS. Serum and CSF VILIP-1 levels were normal on day 1 of AESD. Our results suggest that both serum and CSF levels of VILIP-1 may be one of predictive markers of AESD. Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

[The medical world of Juan Gil de Zamora's Historia Naturalis (ca. 1275-1296)].

PubMed

García Ballester, L; Domínguez, A

1994-01-01

The article describes the authors and works which were quoted by the Franciscan Juan Gil de Zamora in his Historia naturalis, a scientific encyclopaedia written between c. 1275 and before 1296, probably in the Franciscan monastery of Zamora (Kingdom of Castille). Juan Gil made wide use of the Avicenna's Canon, Gilbertus de Aquila (Anglicus)'s Compendium medicine, and Salernitan medical literature. His work contributed to the diffusion of these medical authors and works throughout the Christian intellectual milieu of late medieval Castille. This diffusion was not without problems.

The number of unrecognized myocardial infarction scars detected at DE-MRI increases during a 5-year follow-up.

PubMed

Themudo, Raquel; Johansson, Lars; Ebeling-Barbier, Charlotte; Lind, Lars; Ahlström, Håkan; Bjerner, Tomas

2017-02-01

In an elderly population, the prevalence of unrecognized myocardial infarction (UMI) scars found via late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging was more frequent than expected. This study investigated whether UMI scars detected with LGE-CMR at age 70 would be detectable at age 75 and whether the scar size changed over time. From 248 participants that underwent LGE-CMR at age 70, 185 subjects underwent a follow-up scan at age 75. A myocardial infarction (MI) scar was defined as late enhancement involving the subendocardium. In the 185 subjects that underwent follow-up, 42 subjects had a UMI scar at age 70 and 61 subjects had a UMI scar at age 75. Thirty-seven (88 %) of the 42 UMI scars seen at age 70 were seen in the same myocardial segment at age 75. The size of UMI scars did not differ between age 70 and 75. The prevalence of UMI scars detected at LGE-CMR increases with age. During a 5-year follow-up, 88 % (37/42) of the UMI scars were visible in the same myocardial segment, reassuring that UMI scars are a consistent finding. The size of UMI scars detected during LGE-CMR did not change over time. • UMI scars detected by LGE-CMR are frequent in elderly. • The prevalence of UMI scars detected with LGE-CMR increases with age. • UMI scar size does not change over time.

Neurosarcoidosis--demonstration of meningeal disease by gadolinium enhanced magnetic resonance imaging.

PubMed Central

Khaw, K T; Manji, H; Britton, J; Schon, F

1991-01-01

Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of presentation of neurosarcoidosis is with cranial nerve palsies. Two cases of presumed neurosarcoidosis with cranial nerve palsies showed clear evidence of focal meningeal disease on gadolinium-DTPA enhanced MRI brain scans. Although not specific for sarcoidosis, this technique may be very useful in aiding the diagnosis in suspected cases. Images PMID:1880510

Tunable Microwave Transversal Filters and Dispersive Delay Lines Based on Oblique Incidence Reflection of Magnetostatic Wave Propagating in Epitaxial Garnets.

DTIC Science & Technology

1986-09-30

surface. Ferromagnetic resonance measurements on Ion implanted garnet films (2.18, 2.19) have confirmed that the principal effects of ion implantation...Yttrium Iro Garnet (Y 3FesO1 2 ) films used in the experiments were grown or one Inch polished [111] oriented Gadolinium Gallium Garnet (GGG) wafers, by...Yttrium Iron Garnet ) films grown on 0.5mm thick substrate of GGG (Gadolinium Gallium Garnet ). Samples were angle lapped to optimize coupling into and

Feasibility analysis of reciprocating magnetic heat pumps

NASA Technical Reports Server (NTRS)

Larson, A. V.; Hartley, J. G.; Shelton, S. V.; Smith, M. M.

1986-01-01

The conceptual design selected for detailed system analysis and optimization is the reciprocating gadolinium core in a regenerative fluid column within the bore of a superconducting magnet. The thermodynamic properties of gadolinium are given. A computerized literature search for relevant papers was conducted and is being analyzed. Contact was made with suppliers of superconducting magnets and accessories, magnetic materials, and various types of hardware. A description of the model for the thermal analysis of the core and regenerator fluids is included.

Quality Control and Nondestructive Evaluation Techniques for Composites. Part 4. Radiography - A State-of-the-Art Review

DTIC Science & Technology

1982-06-01

attenuation caused by planar delaminations and voids are indistin- guishable on a radiograph. In this investigation, center-slit specimens were fabri - cated...vendor and as modified by the addition of a gadolinium oxide neutron radiog- raphy image enhancer. A number of specimen assemblies were prepared to...film, types SR-54 and AA were used. A 0.001-inch-thick vapor-deposited gadolinium metal film was used as a converter, see Figure 41 (given as

Synthesis of samarium doped gadolinium oxide nanorods, its spectroscopic and physical properties

NASA Astrophysics Data System (ADS)

Boopathi, G.; Gokul Raj, S.; Ramesh Kumar, G.; Mohan, R.; Mohan, S.

2018-06-01

One-dimensional samarium doped gadolinium oxide [Sm:Gd2O3] nanorods have been synthesized successfully through co-precipitation technique in aqueous solution. The as-synthesized and calcined products were characterized by using powder X-ray diffraction pattern, Fourier transform Raman spectroscopy, thermogravimetric/differential thermal analysis, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, Ultraviolet-Visible spectrometry, photoluminescence spectrophotometer and X-ray photoelectron spectroscopy techniques. The obtained results are discussed in detailed manner.

Rare-Earth Doping and Co-Doping of GaN for Magnetic and Luminescent Applications

DTIC Science & Technology

2010-08-16

The main focus of this project is the study of Gadolinium doped Gallium Nitride. Calculations were carried out to elucidate the origin of the reported...Ga vacancies in the triple negative charge state, which is the most likely charge state in semi-insulating samples, 1. REPORT DATE (DD-MM-YYYY) 4...applications Report Title ABSTRACT The main focus of this project is the study of Gadolinium doped Gallium Nitride. Calculations were carried out to

Diffusivities of Ag, Cs, Sr, and Kr in TRISO fuel particles and graphite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collin, Blaise Paul

Tri-structural isotropic (TRISO) coated particles have been developed and studied since the late 1950s when the concept of coated particles was invented by Roy Huddle of the United Kingdom Atomic Energy Authority. Several decades of work by half a dozen countries on fission product transport in TRISO fuel through numerous irradiation and heating experiments have led to several recommendations of transport data and to the adoption of various sets of diffusion coefficients. In 1997, the International Atomic Energy Agency (IAEA) gathered all these historical results and issued a technical document (TECDOC-978 [IAEA]) that summarizes these sets of recommended diffusion coefficients.more » Table 1 shows the reference literature articles for the diffusivities that have historically been recommended by the American and German TRISO fuel development programs and that are summarized in the IAEA report (see section 7 for full references of these articles).« less

Independent measurement of the neutrino mixing angle θ 13 via neutron capture on hydrogen at Daya Bay

DOE PAGES

Jaffe, D. E.

2014-10-03

A new measurement of the θ 13 mixing angle has been obtained at the Daya Bay Reactor Neutrino Experiment via the detection of inverse beta decays tagged by neutron capture on hydrogen. The antineutrino events for hydrogen capture are distinct from those for gadolinium capture with largely different systematic uncertainties, allowing a determination independent of the gadolinium-capture result and an improvement on the precision of the θ 13 measurement. With a 217-day antineutrino data set obtained with six antineutrino detectors and from six 2.9 GW th reactors, the rate deficit observed at the far hall is interpreted as sin 22θmore » 13=0.083±0.018 in the three-flavor oscillation model. When combined with the gadolinium-capture result from Daya Bay, we obtain sin 22θ 13=0.089±0.008 as the final result for the six-antineutrino-detector configuration of the Daya Bay experiment.« less

Gadolinium-modulated 19F signals from Perfluorocarbon Nanoparticles as a New Strategy for Molecular Imaging

PubMed Central

Neubauer, Anne M.; Myerson, Jacob; Caruthers, Shelton D.; Hockett, Franklin D.; Winter, Patrick M.; Chen, Junjie; Gaffney, Patrick J.; Robertson, J. David; Lanza, Gregory M.; Wickline, Samuel A.

2008-01-01

Recent advances in the design of fluorinated nanoparticles for magnetic resonance molecular imaging have enabled specific detection of 19F nuclei, providing unique and quantifiable spectral signatures. However, a pressing need for signal enhancement exists because the total 19F in imaging voxels is often limited. By directly incorporating a relaxation agent (gadolinium) into the lipid monolayer that surrounds the perfluorocarbon, a marked augmentation of the 19F signal from 200nm nanoparticles was achieved. This design increases the magnetic relaxation rate of the 19F nuclei 4-fold at 1.5 T and effects a 125% increase in signal, an effect which is maintained when they are targeted to human plasma clots. By varying the surface concentration of gadolinium, the relaxation effect can be quantitatively modulated to tailor particle properties. This novel strategy dramatically improves the sensitivity and range of 19F MRI/MRS and forms the basis for designing contrast agents capable of sensing their surface chemistry. PMID:18956457

Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal

PubMed Central

Frietsch, B.; Bowlan, J.; Carley, R.; Teichmann, M.; Wienholdt, S.; Hinzke, D.; Nowak, U.; Carva, K.; Oppeneer, P. M.; Weinelt, M.

2015-01-01

The Heisenberg–Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale. PMID:26355196

Hybrid Calcium Phosphate-Polymeric Micelles Incorporating Gadolinium Chelates for Imaging-Guided Gadolinium Neutron Capture Tumor Therapy.

PubMed

Mi, Peng; Dewi, Novriana; Yanagie, Hironobu; Kokuryo, Daisuke; Suzuki, Minoru; Sakurai, Yoshinori; Li, Yanmin; Aoki, Ichio; Ono, Koji; Takahashi, Hiroyuki; Cabral, Horacio; Nishiyama, Nobuhiro; Kataoka, Kazunori

2015-06-23

Gadolinium (Gd) chelates-loaded nanocarriers have high potential for achieving magnetic resonance imaging (MRI)-guided Gd neutron capture therapy (GdNCT) of tumors. Herein, we developed calcium phosphate micelles hybridized with PEG-polyanion block copolymers, and incorporated with the clinical MRI contrast agent Gd-diethylenetriaminepentaacetic acid (Gd-DTPA/CaP). The Gd-DTPA/CaP were nontoxic to cancer cells at the concentration of 100 μM based on Gd-DTPA, while over 50% of the cancer cells were killed by thermal neutron irradiation at this concentration. Moreover, the Gd-DTPA/CaP showed a dramatically increased accumulation of Gd-DTPA in tumors, leading to the selective contrast enhancement of tumor tissues for precise tumor location by MRI. The enhanced tumor-to-blood distribution ratio of Gd-DTPA/CaP resulted in the effective suppression of tumor growth without loss of body weight, indicating the potential of Gd-DTPA/CaP for safe cancer treatment.

Gadolinium-based nanoparticles to improve the hadrontherapy performances.

PubMed

Porcel, Erika; Tillement, Olivier; Lux, François; Mowat, Pierre; Usami, Noriko; Kobayashi, Katsumi; Furusawa, Yoshiya; Le Sech, Claude; Li, Sha; Lacombe, Sandrine

2014-11-01

Nanomedicine is proposed as a novel strategy to improve the performance of radiotherapy. High-Z nanoparticles are known to enhance the effects of ionizing radiation. Recently, multimodal nanoparticles such as gadolinium-based nanoagents were proposed to amplify the effects of x-rays and g-rays and to improve MRI diagnosis. For tumors sited in sensitive tissues, childhood cases and radioresistant cancers, hadrontherapy is considered superior to x-rays and g-rays. Hadrontherapy, based on fast ion radiation, has the advantage of avoiding damage to the tissues behind the tumor; however, the damage caused in front of the tumor is its major limitation. Here, we demonstrate that multimodal gadolinium-based nanoparticles amplify cell death with fast ions used as radiation. Molecular scale experiments give insights into the mechanisms underlying the amplification of radiation effects. This proof-of-concept opens up novel perspectives for multimodal nanomedicine in hadrontherapy, ultimately reducing negative radiation effects in healthy tissues in front of the tumor. Gadolinium-chelating polysiloxane nanoparticles were previously reported to amplify the anti-tumor effects of x-rays and g-rays and to serve as MRI contrast agents. Fast ion radiation-based hadrontherapy avoids damage to the tissues behind the tumor, with a major limitation of tissue damage in front of the tumor. This study demonstrates a potential role for the above nanoagents in optimizing hadrontherapy with preventive effects in healthy tissue and amplified cell death in the tumor. Copyright © 2014 Elsevier Inc. All rights reserved.

Evaluation of Novel 64Cu-Labeled Theranostic Gadolinium-Based Nanoprobes in HepG2 Tumor-Bearing Nude Mice.

PubMed

Hu, Pengcheng; Cheng, Dengfeng; Huang, Tao; Banizs, Anna B; Xiao, Jie; Liu, Guobing; Chen, Quan; Wang, Yuenan; He, Jiang; Shi, Hongcheng

2017-09-06

Radiation therapy of liver cancer is limited by low tolerance of the liver to radiation. Radiosensitizers can effectively reduce the required radiation dose. AGuIX nanoparticles are small, multifunctional gadolinium-based nanoparticles that can carry radioisotopes or fluorescent markers for single-photon emission computed tomography (SPECT), positron emission tomography (PET), fluorescence imaging, and even multimodality imaging. In addition, due to the high atomic number of gadolinium, it can also serve as a tumor radiation sensitizer. It is critical to define the biodistribution and pharmacokinetics of these gadolinium-based nanoparticles to quantitate the magnitude and duration of their retention within the tumor microenvironment during radiotherapy. Therefore, in this study, we successfully labeled AGuIX with 64 Cu through the convenient built-in chelator. The biodistribution studies indicated that the radiotracer 64 Cu-AGuIX accumulates to high levels in the HepG2 xenograft of nude mice, suggesting that it would be a potential theranostic nanoprobe for image-guided radiotherapy in HCC. We also used a transmission electron microscope to confirm AGuIX uptake in the HepG2 cells. In radiation therapy studies, a decrease in 18 F-FDG uptake was observed in the xenografts of the nude mice irradiated with AGuIX, which was injected 1 h before. These results provide proof-of-concept that AGuIX can be used as a theranostic radiosensitizer for PET imaging to guide radiotherapy for liver cancer.

High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.

A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially-grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high pressure area on the order of a few tens of seconds. This device is then used to scanmore » the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in the experiment the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp→αSm transition proceeds in discontinuous steps at points along the expected phase boundary. Additionally, the unit cell volumes of each phase deviate from the expected thermal expansion behavior just before each transition is observed from the diffraction data. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0 - 10 GPa and 300 - 650 K.« less

Quantitative assessment of the rheumatoid synovial microvascular bed by gadolinium-DTPA enhanced magnetic resonance imaging

PubMed Central

Gaffney, K.; Cookson, J.; Blades, S.; Coumbe, A.; Blake, D.

1998-01-01

OBJECTIVE—To examine the relation between rate of synovial membrane enhancement, intra-articular pressure (IAP), and histologically determined synovial vascularity in rheumatoid arthritis, using gadolinium-DTPA enhanced magnetic resonance imaging (MRI).
METHODS—Dynamic gadolinium-DTPA enhanced MRI was performed in 31 patients with knee synovitis (10 patients IAP study, 21 patients vascular morphometry study). Rate of synovial membrane enhancement was quantified by line profile analysis using the image processing package ANALYZE. IAP was measured using an intra-compartmental pressure monitor system. Multiple synovial biopsy specimens were obtained by a blind biopsy technique. Blood vessels were identified immunohistochemically using the endothelial cell marker QBend30 and quantified (blood vessel numerical density and fractional area).
RESULTS—Median blood vessel numerical density and fractional area were 77.5/mm2 (IQR; 69.3-110.7) and 5.6% (IQR; 3.4-8.5) respectively. The rate of synovial membrane enhancement (median 2.74 signal intensity units/s, IQR 2.0-3.8) correlated with both blood vessel numerical density (r = 0.46, p < 0.05) and blood vessel fractional area (r = 0.55, p < 0.02). IAP did not influence the rate of enhancement.
CONCLUSIONS—Gadolinium-DTPA enhanced MRI may prove to be a valuable technique for evaluating drugs that influence angiogenesis.

 Keywords: magnetic resonance imaging; rheumatoid arthritis; synovitis; vascularity PMID:9640130

Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol.

PubMed

Jingu, Akiko; Fukuda, Junya; Taketomi-Takahashi, Ayako; Tsushima, Yoshito

2014-10-06

Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR).The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. The protocol was applied to a total of 252 examinations (153 patients, ages 15-87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma.

Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol

PubMed Central

2014-01-01

Background Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR). The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. Methods All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. Results The protocol was applied to a total of 252 examinations (153 patients, ages 15–87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. Conclusion Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma. PMID:25287952

Evaluation of Novel 64Cu-Labeled Theranostic Gadolinium-Based Nanoprobes in HepG2 Tumor-Bearing Nude Mice

NASA Astrophysics Data System (ADS)

Hu, Pengcheng; Cheng, Dengfeng; Huang, Tao; Banizs, Anna B.; Xiao, Jie; Liu, Guobing; Chen, Quan; Wang, Yuenan; He, Jiang; Shi, Hongcheng

2017-09-01

Radiation therapy of liver cancer is limited by low tolerance of the liver to radiation. Radiosensitizers can effectively reduce the required radiation dose. AGuIX nanoparticles are small, multifunctional gadolinium-based nanoparticles that can carry radioisotopes or fluorescent markers for single-photon emission computed tomography (SPECT), positron emission tomography (PET), fluorescence imaging, and even multimodality imaging. In addition, due to the high atomic number of gadolinium, it can also serve as a tumor radiation sensitizer. It is critical to define the biodistribution and pharmacokinetics of these gadolinium-based nanoparticles to quantitate the magnitude and duration of their retention within the tumor microenvironment during radiotherapy. Therefore, in this study, we successfully labeled AGuIX with 64Cu through the convenient built-in chelator. The biodistribution studies indicated that the radiotracer 64Cu-AGuIX accumulates to high levels in the HepG2 xenograft of nude mice, suggesting that it would be a potential theranostic nanoprobe for image-guided radiotherapy in HCC. We also used a transmission electron microscope to confirm AGuIX uptake in the HepG2 cells. In radiation therapy studies, a decrease in 18F-FDG uptake was observed in the xenografts of the nude mice irradiated with AGuIX, which was injected 1 h before. These results provide proof-of-concept that AGuIX can be used as a theranostic radiosensitizer for PET imaging to guide radiotherapy for liver cancer.

First demonstration of 10 keV-width energy-discrimination K-edge radiography using a cadmium-telluride X-ray camera with a tungsten-target tube

NASA Astrophysics Data System (ADS)

Watanabe, Manabu; Sato, Eiichi; Abderyim, Purkhet; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-05-01

Energy-discrimination X-ray camera is useful to perform monochromatic radiography using polychromatic X-rays. This X-ray camera was developed to carry out K-edge radiography using cerium and gadolinium-based contrast media. In this camera, objects are irradiated by a cone beam from a tungsten-target X-ray generator, and penetrating X-ray photons are detected by a cadmium-telluride detector with amplifiers. Both optimal photon-energy level and energy width are selected using a multichannel analyzer, and the photon number is counted by a counter card. Radiography was performed by the detector scanning using an x- y stage driven by a two-stage controller, and radiograms were shown on a personal computer monitor. In radiography, tube voltage and current were 90 kV and 5.8 μA, respectively, and the X-ray intensity was 0.61 μGy/s at 1.0 m from the X-ray source. The K-edge energies of cerium and gadolinium are 40.3 and 50.3 keV, respectively, and 10 keV-width enhanced K-edge radiography was performed using X-ray photons with energies just beyond K-edge energies of cerium and gadolinium. Thus, cerium K-edge radiography was carried out using X-ray photons with an energy range from 40.3 to 50. 3 keV, and gadolinium K-edge radiography was accomplished utilizing photon energies ranging from 50.3 to 60.3 keV.

High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

DOE PAGES

Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; ...

2016-04-07

A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially-grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high pressure area on the order of a few tens of seconds. This device is then used to scanmore » the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in the experiment the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp→αSm transition proceeds in discontinuous steps at points along the expected phase boundary. Additionally, the unit cell volumes of each phase deviate from the expected thermal expansion behavior just before each transition is observed from the diffraction data. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0 - 10 GPa and 300 - 650 K.« less

Relaxivity enhancement of aquated Tris(β-diketonate)gadolinium(III) chelates by confinement within ultrashort single-walled carbon nanotubes.

PubMed

Law, Justin J; Guven, Adem; Wilson, Lon J

2014-01-01

Ultrashort single-walled carbon nanotubes loaded with gadolinium ions (gadonanotubes) have been previously shown to exhibit extremely high T1 -weighted relaxivities (>100 mm(-1) s(-1) ). To further examine the effect of nanoconfinement on the relaxivity of gadolinium-based contrast agents for magnetic resonance imaging, a series of ultrashort single-walled carbon nanotube (US-tube) materials internally loaded with gadolinium chelates have been prepared and studied. US-tubes were loaded with Gd(acac)3  · 2H2 O, Gd(hfac)3  · 2H2 O, and Gd(thd)3 (acac = acetylacetone, hfac = hexafluoroacetylacetone, thd = tetramethylheptanedione). The longitudinal relaxivities of the prepared materials determined at 25°C in a 1.5 T field were 103 mm(-1) s(-1) for Gd(acac)3  · 2H2 O@US-tubes, 105 mm(-1) s(-1) for Gd(hfac)3  · 2H2 O@US-tubes and 26 mm(-1) s(-1) for Gd(thd)3 @US-tubes. Compared with the relaxivities obtained for the unloaded chelates (<10 mm(-1) s(-1) ) as well as accounting for the T1 reduction observed for the empty US-tubes, the boost in relaxivity for chelate-loaded US-tubes is attributed to confinement within the nanotube and depends on the number of coordinated water molecules. Copyright © 2014 John Wiley & Sons, Ltd.

Diffusive Imaging of Hydraulically Induced and Natural Fracture Systems

NASA Astrophysics Data System (ADS)

Eftekhari, B.; Marder, M. P.; Patzek, T. W.

2017-12-01

Hydraulic fracturing of tight shales continues to provide the US with a major source of energy. Efficiency of gas recovery in shales depends upon the geometry of the resulting network of fractures, the details of which are not yet fully understood. The present research explores how much of the underlying geometry can be deduced from the time dependence of the flow of gas out of the reservoir. We consider both ideal and real gas. In the case of real gas, we calculate production rate for parallel planar hydrofractures embedded in an infinite reservoir. Transport is governed by a nonlinear diffusion equation, which we solve exactly with a scaling curve. The scaling curve production rate declines initially as 1 over square root time, then as an exponential, and finally as 1 over square root of time again at late time. We show that for a given hydraulically fractured well, the onsets of transition between different decline regimes provides a direct estimate of a characteristic spacing of the underlying fracture network. We show that the scaling solution accurately fits the production history of more than 15,000 wells in the Barnett Shale. Almost all of the wells either have not yet transitioned into the late time decline or have been refractured while in exponential decline. However, there are 36 wells which show the late time transition. These allow us to calculate the characteristic spacing, which turns out to have a mode at about 10 m, a minimum at 1.6 m and a maximum at 13.3 m. We estimate that over 30 years these wells will produce on average about 45% more gas because of diffusion from the infinite external reservoir than they would if this contribution is neglected. Finally, we compute the rate at which ideal gas diffuses within an infinite region of rock into a specific absorbing fractal fracture network, which we model using geological constraints and percolation theory. Our solution employs a Brownian walk and the first passage kinetic Monte Carlo algorithm that is robust and efficient. A striking feature of this solution is the presence of a power law decline.

Quantitative Susceptibility Mapping and R2* Measured Changes during White Matter Lesion Development in Multiple Sclerosis: Myelin Breakdown, Myelin Debris Degradation and Removal, and Iron Accumulation.

PubMed

Zhang, Y; Gauthier, S A; Gupta, A; Chen, W; Comunale, J; Chiang, G C-Y; Zhou, D; Askin, G; Zhu, W; Pitt, D; Wang, Y

2016-09-01

Quantitative susceptibility mapping and R2* are sensitive to myelin and iron changes in multiple sclerosis lesions. This study was designed to characterize lesion changes on quantitative susceptibility mapping and R2* at various gadolinium-enhancement stages. This study included 64 patients with MS with different enhancing patterns in white matter lesions: nodular, shell-like, nonenhancing < 1 year old, and nonenhancing 1-3 years old. These represent acute, late acute, early chronic, and late chronic lesions, respectively. Susceptibility values measured on quantitative susceptibility mapping and R2* values were compared among the 4 lesion types. Their differences were assessed with a generalized estimating equation, controlling for Expanded Disability Status Scale score, age, and disease duration. We analyzed 203 lesions: 80 were nodular-enhancing, of which 77 (96.2%) were isointense on quantitative susceptibility mapping; 33 were shell-enhancing, of which 30 (90.9%) were hyperintense on quantitative susceptibility mapping; and 49 were nonenhancing lesions < 1 year old and 41 were nonenhancing lesions 1-3 years old, all of which were hyperintense on quantitative susceptibility mapping. Their relative susceptibility/R2* values were 0.5 ± 4.4 parts per billion/-5.6 ± 2.9 Hz, 10.2 ± 5.4 parts per billion/-8.0 ± 2.6 Hz, 20.2 ± 7.8 parts per billion/-3.1 ± 2.3 Hz, and 33.2 ± 8.2 parts per billion/-2.0 ± 2.6 Hz, respectively, and were significantly different (P < .005). Early active MS lesions with nodular enhancement show R2* decrease but no quantitative susceptibility mapping change, reflecting myelin breakdown; late active lesions with peripheral enhancement show R2* decrease and quantitative susceptibility mapping increase in the lesion center, reflecting further degradation and removal of myelin debris; and early or late chronic nonenhancing lesions show both quantitative susceptibility mapping and R2* increase, reflecting iron accumulation. © 2016 by American Journal of Neuroradiology.

Major Superficial White Matter Abnormalities in Huntington's Disease

PubMed Central

Phillips, Owen R.; Joshi, Shantanu H.; Squitieri, Ferdinando; Sanchez-Castaneda, Cristina; Narr, Katherine; Shattuck, David W.; Caltagirone, Carlo; Sabatini, Umberto; Di Paola, Margherita

2016-01-01

Background: The late myelinating superficial white matter at the juncture of the cortical gray and white matter comprising the intracortical myelin and short-range association fibers has not received attention in Huntington's disease. It is an area of the brain that is late myelinating and is sensitive to both normal aging and neurodegenerative disease effects. Therefore, it may be sensitive to Huntington's disease processes. Methods: Structural MRI data from 25 Pre-symptomatic subjects, 24 Huntington's disease patients and 49 healthy controls was run through a cortical pattern-matching program. The surface corresponding to the white matter directly below the cortical gray matter was then extracted. Individual subject's Diffusion Tensor Imaging (DTI) data was aligned to their structural MRI data. Diffusivity values along the white matter surface were then sampled at each vertex point. DTI measures with high spatial resolution across the superficial white matter surface were then analyzed with the General Linear Model to test for the effects of disease. Results: There was an overall increase in the axial and radial diffusivity across much of the superficial white matter (p < 0.001) in Pre-symptomatic subjects compared to controls. In Huntington's disease patients increased diffusivity covered essentially the whole brain (p < 0.001). Changes are correlated with genotype (CAG repeat number) and disease burden (p < 0.001). Conclusions: This study showed broad abnormalities in superficial white matter even before symptoms are present in Huntington's disease. Since, the superficial white matter has a unique microstructure and function these abnormalities suggest it plays an important role in the disease. PMID:27242403

Water permeability of acinar cell membranes in the isolated perfused rabbit mandibular salivary gland.

PubMed Central

Steward, M C; Seo, Y; Rawlings, J M; Case, R M

1990-01-01

1. The diffusive water permeability of epithelial cell membranes in the perfused rabbit mandibular salivary gland was measured at 37 degrees C by a 1H nuclear magnetic resonance relaxation method using an extracellular relaxation reagent, gadolinium diethylenetriaminepentaacetic acid (Gd(DTPA)). 2. In glands perfused with a HEPES-buffered solution containing 10 mmol l-1 Gd(DTPA), the spin-lattice (T1) relaxation of the water protons showed two exponential components. The water compartment responsible for the slower component corresponded in magnitude to 71 +/- 5% of the wet weight of the gland, and was attributed to the exchangeable intracellular water of the acinar cells. 3. The rate constant for water efflux from the cells was estimated to be 4.1 +/- 0.1 s-1 which would be consistent with a diffusive membrane permeability (Pd) of approximately 3 x 10(-3) cm s-1. Stimulation with acetylcholine (10(-6) mol l-1) did not cause any detectable change in membrane water permeability. 4. Since the basolateral membrane probably provides the main pathway for water efflux, the osmotic water permeability of this barrier (expressed per gland) was estimated to be less than 6.2 cm3 s-1. This would be insufficient to account for the generation of a near-isosmotic fluid at the flow rates observed during secretion, and suggests that a substantial fraction of the flow of water occurs via a paracellular route. PMID:1966053

PET/MRI assessment of the infarcted mouse heart

NASA Astrophysics Data System (ADS)

Buonincontri, Guido; Methner, Carmen; Krieg, Thomas; Hawkes, Robert C.; Adrian Carpenter, T.; Sawiak, Stephen J.

2014-01-01

Heart failure originating from myocardial infarction (MI) is a leading cause of death worldwide. Mouse models of ischaemia and reperfusion injury (I/R) are used to study the effects of novel treatment strategies targeting MI, however staging disease and treatment efficacy is a challenge. Damage and recovery can be assessed on the cellular, tissue or whole-organ scale but these are rarely measured in concert. Here, for the first time, we present data showing measures of injury in infarcted mice using complementary techniques for multi-modal characterisation of the heart. We use in vivo magnetic resonance imaging (MRI) to assess heart function with cine-MRI, hindered perfusion with late gadolinium enhancement imaging and muscular function with displacement encoded with stimulated echoes (DENSE) MRI. These measures are followed by positron emission tomography (PET) with 18-F-fluorodeoxyglucose to assess cellular metabolism. We demonstrate a protocol combining each of these measures for the same animal in the same imaging session and compare how the different markers can be used to quantify cardiac recovery on different scales following injury.

[Diagnostic performance of surface electrocardiogram in early detection of chagasic cardiomyopathy].

PubMed

Bochard-Villanueva, Bruno; Estornell-Erill, Jordi; Fabregat-Andrés, Óscar; García-González, Pilar; Morell-Cabedo, Salvador; Ridocci-Soriano, Francisco

2015-03-15

Contrast-enhanced cardiac magnetic resonance imaging (CMR) allows early detection of myocardial involvement by Trypanosoma cruzi infection. The aim of our study was to assess the diagnostic performance of the surface electrocardiogram (ECG) in the early detection of Chagas' cardiomyopathy (CCM) compared with CMR. We included 43 asymptomatic patients (30 women, 42 ± 9.8 years), diagnosed of Chagas disease. The sample was divided into 2 groups according to the presence (n=17) or absence (n=26) of electrocardiographic abnormalities. All patients underwent CMR and late gadolinium enhancement (LGE) was used as a marker of early myocardial involvement. Six (14%) patients had a LGE significantly higher in the group who had electrocardiographic abnormalities (29 vs. 4%, P<.05). With CMR as the method of reference, the ECG had a sensitivity of 83% and a negative predictive value of 96% to detect CCM. ECG is a useful, inexpensive and globally available tool for the screening of CCM in asymptomatic patients but with proven myocardial involvement in CMR. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Myocardial fibrosis as the first sign of cardiac involvement in a male patient with Fabry disease: report of a clinical case and discussion on the utility of the magnetic resonance in Fabry pathology.

PubMed

Sechi, Annalisa; Nucifora, Gaetano; Piccoli, Gianluca; Dardis, Andrea; Bembi, Bruno

2014-07-16

Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) imaging is increasingly used to assess myocardial involvement in patients with Fabry disease, an X linked lipid storage disorder. However, it is often proposed as an optional tool. A different cardiomyopathic disease progression between male and female patients was hypothesised in previous studies, as in female myocardial fibrosis was found without left ventricular (LV) hypertrophy, while myocardial fibrosis was always detected in association to LV hypertrophy in men. A male Caucasian patient, 19 years old, diagnosed through a family-based molecular screening, presented with LGE of the LV inferolateral wall evidenced at the CMR, without LV hypertrophy, or other clinical signs of the disease. This is the first report of cardiac fibrosis as the first sign of organ involvement in a male patient with Fabry disease. This finding stresses the importance of performing CMR with LGE imaging for the initial staging and monitoring of Fabry patients of both genders.

Myocardial fibrosis as the first sign of cardiac involvement in a male patient with Fabry disease: report of a clinical case and discussion on the utility of the magnetic resonance in Fabry pathology

PubMed Central

2014-01-01

Background Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) imaging is increasingly used to assess myocardial involvement in patients with Fabry disease, an X linked lipid storage disorder. However, it is often proposed as an optional tool. A different cardiomyopathic disease progression between male and female patients was hypothesised in previous studies, as in female myocardial fibrosis was found without left ventricular (LV) hypertrophy, while myocardial fibrosis was always detected in association to LV hypertrophy in men. Case presentation A male Caucasian patient, 19 years old, diagnosed through a family-based molecular screening, presented with LGE of the LV inferolateral wall evidenced at the CMR, without LV hypertrophy, or other clinical signs of the disease. Conclusion This is the first report of cardiac fibrosis as the first sign of organ involvement in a male patient with Fabry disease. This finding stresses the importance of performing CMR with LGE imaging for the initial staging and monitoring of Fabry patients of both genders. PMID:25026990

Electric Field Tunable Microwave and MM-wave Ferrite Devices

DTIC Science & Technology

2010-04-30

xm thick YIG film grown by liquid-phase epitaxy on a (111) gadolinium gallium garnet was used. A PZT plate with the dimensions 4x1x0.5 mm3 was...of width ~ 150 micron and length 20 mm. An YIG film , 6 u.m thick, 0.5 mm in width and 2.5 mm long, grown on a 0.5 mm thick gadolinium gallium garnet ...yttrium iron garnet film and a ceramic barium strontium titanate slab. The electrical tunability of the differential phase shift Acp is achieved through

Light deflection in gadolinium molybdate ferroelastic crystals

NASA Astrophysics Data System (ADS)

Staniorowski, Piotr; Bornarel, Jean

2000-02-01

The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i on the sample at room temperature. The A and B deflected beams do not cross each other during the icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i variation, in contrast to results and calculations previously published. The model using the Fresnel equation confirms this result. The model presented is more accurate for numerical calculation than that using the Huygens construction.

Dielectric properties and activation behavior of gadolinium doped nanocrystalline yttrium chromite

NASA Astrophysics Data System (ADS)

Sinha, R.; Basu, S.; Meikap, A. K.

2018-04-01

Gadolinium doped Yttrium Chromite nanoparticles are synthesized following sol-gel method. The formation of the nanoparticles are confirmed by XRD and TEM measurements. Dielectric permittivity and dielectric loss are estimated within the temperature range 298K to 523K and in the frequency range 20 Hz to 1 MHz. Dielectric permittivity follows the power law ɛ'(f) ∝ Tm. It is observed that the temperature exponent m increases with the decreasing frequency. The temperature variation of resistivity shows that the samples have semiconducting behavior. The activation energy is also measured.

Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostafiychuk, B. K.; Yaremiy, I. P., E-mail: yaremiy@rambler.ru; Yaremiy, S. I.

2013-12-15

The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

Fibromyalgia syndrome and chronotype: late chronotypes are more affected.

PubMed

Kantermann, Thomas; Theadom, Alice; Roenneberg, Till; Cropley, Mark

2012-04-01

Sleep has strong links to the symptomology of fibromyalgia syndrome (FMS), a diffuse musculoskeletal pain disorder. Information about the involvement of the circadian clock is, however, sparse. In this study, 1548 individuals with FMS completed an online survey containing questions on demographics, stimulant consumption, sleep quality, well-being and subjective pain, chronotype (assessed by the Munich ChronoType Questionnaire, MCTQ), and FMS impact. Chronotype (expressed as the mid-sleep-point on free days, corrected for sleep deficit on workdays, MSF(sc)) significantly correlated with stress-ratings, so-called "memory failures in everyday life," fatigue, FMS impact, and depression but not with anxiety. When chronotypes were categorized into 3 groups (early, intermediate, late), significant group differences were found for sum scores of perceived stress, memory failures in everyday life, fatigue, FMS impact, and depression but not anxiety, with late chronotypes being more affected than early chronotypes. Sleepiness ratings were highest in early chronotypes. Challenges of sleep quality and subjective pain were significantly increased in both early and late chronotypes. The results show that according to their reports, late chronotypes are more affected by fibromyalgia.

Multi-Ethnic Study of Atherosclerosis: Association between Left Atrial Function Using Tissue Tracking from Cine MR Imaging and Myocardial Fibrosis

PubMed Central

Imai, Masamichi; Ambale Venkatesh, Bharath; Samiei, Sanaz; Donekal, Sirisha; Habibi, Mohammadali; Armstrong, Anderson C.; Heckbert, Susan R.; Wu, Colin O.; Bluemke, David A.

2014-01-01

Purpose To investigate the association between left atrial (LAleft atrium) function and left ventricular myocardial fibrosis using cardiac magnetic resonance (MR) imaging in a multi-ethnic population. Materials and Methods For this HIPAA-compliant study, the institutional review board at each participating center approved the study protocol, and all participants provided informed consent. Of 2839 participants who had undergone cardiac MR in 2010–2012, 143 participants with myocardial scar determined with late gadolinium enhancement and 286 age-, sex-, and ethnicity-matched control participants were identified. LAleft atrium volume, strain, and strain rate were analyzed by using multimodality tissue tracking from cine MR imaging. T1 mapping was applied to assess diffuse myocardial fibrosis. The association between LAleft atrium parameters and myocardial fibrosis was evaluated with the Student t test and multivariable regression analysis. Results The scar group had significantly higher minimum LAleft atrium volume than the control group (mean, 22.0 ± 10.5 [standard deviation] vs 19.0 ± 7.8, P = .002) and lower LAleft atrium ejection fraction (45.9 ± 10.7 vs 51.3 ± 8.7, P < .001), maximal LAleft atrium strain (Smaxmaximum LA strain) (25.4 ± 10.7 vs 30.6 ± 10.6, P < .001) and maximum LAleft atrium strain rate (SRmaxmaximum LA strain rate) (1.08 ± 0.45 vs 1.29 ± 0.51, P < .001), and lower absolute LAleft atrium strain rate at early diastolic peak (SRELA strain rate at early diastolic peak) (−0.77 ± 0.42 vs −1.01 ± 0.48, P < .001) and LAleft atrium strain rate at atrial contraction peak (SRALA strain rate at atrial contraction peak) (−1.50 ± 0.62 vs −1.78 ± 0.69, P < .001) than the control group. T1 time 12 minutes after contrast material injection was significantly associated with Smaxmaximum LA strain (β coefficient = 0.043, P = .013), SRmaxmaximum LA strain rate (β coefficient = 0.0025, P = .001), SRELA strain rate at early diastolic peak (β coefficient = −0.0016, P = .027), and SRALA strain rate at atrial contraction peakLA strain rate at atrial contraction peak (β coefficient −0.0028, P = .01) in the regression model. T1 time 25 minutes after contrast material injection was significantly associated with SRmaxmaximum LA strain rate (β coefficient = 0.0019, P = .016) and SRALA strain rate at atrial contraction peak (β coefficient = −0.0022, P = .034). Conclusion Reduced LAleft atrium regional and global function are related to both replacement and diffuse myocardial fibrosis processes. Clinical trial registration no. NCT00005487 © RSNA, 2014 Online supplemental material is available for this article. PMID:25019562

[Diffusion of fluorescent and magnetic molecular probes in brain interstitial space].

PubMed

Li, Huai-ye; Zhao, Yue; Zuo, Long; Fu, Yu; Li, Nan; Yuan, Lan; Zhang, Shu-jia; Han, Hong-bin

2015-08-18

To compare the diffusion properties of fluorescent probes dextran-tetramethylrhodamine (DT) and lucifer yellow CH (LY) and magnetic probe gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) in porous media and to screen out a suitable fluorescent probe for optical imaging of brain interstitial space (ISS). Agarose gels sample were divided into DT group, LY group and Gd-DTPA group, and the corresponding molecular probes were imported in each group. The dynamic diffusions of DT and LY in agarose gels at different time points (15, 30, 45, 60, 90, and 120 min) were scanned with laser scanning confocal microscope, the dynamic diffusion of Gd-DTPA was imaged with magnetic resonance imaging. The average diffusion speed of LY were demonstrated to be consistent with those of Gd-DTPA. The LY was introduced into caudate putamen of 18 rats, respectively, the diffusion of LY in the sequential slices of rat brain at different time points (0.5, 1, 2, 3, 7, 11 h) were scanned, and the results were compared with those of rats' brain with Gd-DTPA imported and imaged in vivo with magnetic resonance imaging. The diffusions of the three probes were isotropic in the agarose gels, and the average diffusion speeds of DT, LY and Gd-DTPA were: (0.07±0.02)×10(-2) mm2/s, (1.54±0.47)×10(-2) mm2/s, (1.45±0.50)×10(-2) mm2/s, respectively. The speed of DT was more slower than both LY and Gd-DTPA (ANOVA, F=367.15, P<0.001; Post-Hoc LSD, P<0.001), and there was no significant difference between the speeds of LY and Gd-DTPA (Post-Hoc LSD, P=0.091). The variation tendency of diffusion area of DT was different with both that of LY and that of Gd-DTPA (Bonferroni correction, α=0.0125, P<0.001), and there was no significant difference between LY and Gd-DTPA (Bonferroni correction, α=0.0125, P=0.203), in analysis by repeated measures data of ANOVA. The diffusions of LY and Gd-DTPA were anisotropy in rat caudate putamen,and the average diffusion speeds of LY and Gd-DTPA were: (1.03±0.29)×10(-3) mm2/s, (0.81±0.27)×10(-3) mm2/s, respectively, no significant difference was demonstrated (t=0.759, P=0.490); half-time of single intensity of LY and Gd-DTPA was (2.58±0.04) h, (2.46±0.10) h, respectively, no significant difference was found (t=2.025, P=0.113). The diffusion area ratios between LY and Gd-DTPA in rat caudate putamen was not statistically different at hours 0.5, 1, 2, 3 and 7 (t=2.249, P=0.088; t=2.582, P=0.061; t=1.966, P=0.121; t=0.132, P=0.674; t=0.032, P=0.976), while, a slightly difference was found at 11 h (t=2.917, P=0.043,in analysis by t test). LY present the same diffusion property with Gd-DTPA in porous media witch including agarose gels and live rat brain tissue, indicates that LY is a suitable fluorescent probe for optical imaging of brain ISS, and it can be used for microscopic, macro and in vitro measure of brain ISS.

Magnetic resonance imaging indicators of blood-brain barrier and brain water changes in young rats with kaolin-induced hydrocephalus.

PubMed

Del Bigio, Marc R; Slobodian, Ili; Schellenberg, Angela E; Buist, Richard J; Kemp-Buors, Tanya L

2011-08-11

Hydrocephalus is associated with enlargement of cerebral ventricles. We hypothesized that magnetic resonance (MR) imaging parameters known to be influenced by tissue water content would change in parallel with ventricle size in young rats and that changes in blood-brain barrier (BBB) permeability would be detected. Hydrocephalus was induced by injection of kaolin into the cisterna magna of 4-week-old rats, which were studied 1 or 3 weeks later. MR was used to measure longitudinal and transverse relaxation times (T1 and T2) and apparent diffusion coefficients in several regions. Brain tissue water content was measured by the wet-dry weight method, and tissue density was measured in Percoll gradient columns. BBB permeability was measured by quantitative imaging of changes on T1-weighted images following injection of gadolinium diethylenetriamine penta-acetate (Gd-DTPA) tracer and microscopically by detection of fluorescent dextran conjugates. In nonhydrocephalic rats, water content decreased progressively from age 3 to 7 weeks. T1 and T2 and apparent diffusion coefficients did not exhibit parallel changes and there was no evidence of BBB permeability to tracers. The cerebral ventricles enlarged progressively in the weeks following kaolin injection. In hydrocephalic rats, the dorsal cortex was more dense and the white matter less so, indicating that the increased water content was largely confined to white matter. Hydrocephalus was associated with transient elevation of T1 in gray and white matter and persistent elevation of T2 in white matter. Changes in the apparent diffusion coefficients were significant only in white matter. Ventricle size correlated significantly with dorsal water content, T1, T2, and apparent diffusion coefficients. MR imaging showed evidence of Gd-DTPA leakage in periventricular tissue foci but not diffusely. These correlated with microscopic leak of larger dextran tracers. MR characteristics cannot be used as direct surrogates for water content in the immature rat model of hydrocephalus, probably because they are also influenced by other changes in tissue composition that occur during brain maturation. There is no evidence for widespread persistent opening of BBB as a consequence of hydrocephalus in young rats. However, increase in focal BBB permeability suggests that periventricular blood vessels may be disrupted.

White Matter Microstructure in Transsexuals and Controls Investigated by Diffusion Tensor Imaging

PubMed Central

Kranz, Georg S.; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F.; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

2015-01-01

Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects’ sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. PMID:25392513

Involuntary movements and coma as the prognostic marker for acute encephalopathy with biphasic seizures and late reduced diffusion.

PubMed

Lee, Sooyoung; Sanefuji, Masafumi; Torio, Michiko; Kaku, Noriyuki; Ichimiya, Yuko; Mizuguchi, Soichi; Baba, Haruhisa; Sakai, Yasunari; Ishizaki, Yoshito; Torisu, Hiroyuki; Kira, Ryutaro; Hara, Toshiro; Ohga, Shouichi

2016-11-15

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) occurs in children associated with infection. It is characterized by a prolonged febrile seizure in the first phase, and a cluster of seizures, deterioration of consciousness and the white matter lesions with reduced diffusion in the second phase. The patients often have severe neurological sequelae, but the prognostic indicators remain unknown. The present study aimed to clarify the characteristics of AESD patients who subsequently exhibited severe neurological sequelae. We retrospectively analyzed the clinical and laboratory findings along with the brain imaging in patients who had severe (n=8) and non-severe neurodevelopmental outcomes (n=12). Severe group more frequently showed coma (p=0.014) or involuntary movements including dystonia and oral dyskinesia (p=0.018) before the second phase than non-severe group. Severe group exhibited higher levels of serum alanine aminotransferase than non-severe group (p=0.001). Quantitatively assessed MRI in the second phase revealed that severe group had more extensive lesions than non-severe group, in the anterior (p=0.015) and posterior parts (p=0.011) of the cerebrum and basal ganglia (p=0.020). Early appearing involuntary movements or coma might account for the extension of acute brain lesions and the poor neurological outcomes in AESD patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis

PubMed Central

Toslak, Iclal Erdem; Cekic, Bulent; Turk, Aysen; Eraslan, Ali; Parlak, A. Eda

2017-01-01

Purpose: Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP). Materials and Methods: 42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm2. Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured. Results: 36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions. Conclusion: DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play. PMID:28190854

Readout-segmented multi-shot diffusion-weighted MRI of the knee joint in patients with juvenile idiopathic arthritis.

PubMed

Sauer, Alexander; Li, Mengxia; Holl-Wieden, Annette; Pabst, Thomas; Neubauer, Henning

2017-10-12

Diffusion-weighted MRI has been proposed as a new technique for imaging synovitis without intravenous contrast application. We investigated diagnostic utility of multi-shot readout-segmented diffusion-weighted MRI (multi-shot DWI) for synovial imaging of the knee joint in patients with juvenile idiopathic arthritis (JIA). Thirty-two consecutive patients with confirmed or suspected JIA (21 girls, median age 13 years) underwent routine 1.5 T MRI with contrast-enhanced T1w imaging (contrast-enhanced MRI) and with multi-shot DWI (RESOLVE, b-values 0-50 and 800 s/mm 2 ). Contrast-enhanced MRI, representing the diagnostic standard, and diffusion-weighted images at b = 800 s/mm 2 were separately rated by three independent blinded readers at different levels of expertise for the presence and the degree of synovitis on a modified 5-item Likert scale along with the level of subjective diagnostic confidence. Fourteen (44%) patients had active synovitis and joint effusion, nine (28%) patients showed mild synovial enhancement not qualifying for arthritis and another nine (28%) patients had no synovial signal alterations on contrast-enhanced imaging. Ratings by the 1st reader on contrast-enhanced MRI and on DWI showed substantial agreement (κ = 0.74). Inter-observer-agreement was high for diagnosing, or ruling out, active arthritis of the knee joint on contrast-enhanced MRI and on DWI, showing full agreement between 1st and 2nd reader and disagreement in one case (3%) between 1st and 3rd reader. In contrast, ratings in cases of absent vs. little synovial inflammation were markedly inconsistent on DWI. Diagnostic confidence was lower on DWI, compared to contrast-enhanced imaging. Multi-shot DWI of the knee joint is feasible in routine imaging and reliably diagnoses, or rules out, active arthritis of the knee joint in paediatric patients without the need of gadolinium-based i.v. contrast injection. Possibly due to "T2w shine-through" artifacts, DWI does not reliably differentiate non-inflamed joints from knee joints with mild synovial irritation.

The Long and Viscous Road: Uncovering Nuclear Diffusion Barriers in Closed Mitosis

PubMed Central

Zavala, Eder; Marquez-Lago, Tatiana T.

2014-01-01

Diffusion barriers are effective means for constraining protein lateral exchange in cellular membranes. In Saccharomyces cerevisiae, they have been shown to sustain parental identity through asymmetric segregation of ageing factors during closed mitosis. Even though barriers have been extensively studied in the plasma membrane, their identity and organization within the nucleus remains poorly understood. Based on different lines of experimental evidence, we present a model of the composition and structural organization of a nuclear diffusion barrier during anaphase. By means of spatial stochastic simulations, we propose how specialised lipid domains, protein rings, and morphological changes of the nucleus may coordinate to restrict protein exchange between mother and daughter nuclear lobes. We explore distinct, plausible configurations of these diffusion barriers and offer testable predictions regarding their protein exclusion properties and the diffusion regimes they generate. Our model predicts that, while a specialised lipid domain and an immobile protein ring at the bud neck can compartmentalize the nucleus during early anaphase; a specialised lipid domain spanning the elongated bridge between lobes would be entirely sufficient during late anaphase. Our work shows how complex nuclear diffusion barriers in closed mitosis may arise from simple nanoscale biophysical interactions. PMID:25032937

Temporal deformation pattern in acute and late phases of ST-elevation myocardial infarction: incremental value of longitudinal post-systolic strain to assess myocardial viability.

PubMed

Huttin, Olivier; Marie, Pierre-Yves; Benichou, Maxime; Bozec, Erwan; Lemoine, Simon; Mandry, Damien; Juillière, Yves; Sadoul, Nicolas; Micard, Emilien; Duarte, Kevin; Beaumont, Marine; Rossignol, Patrick; Girerd, Nicolas; Selton-Suty, Christine

2016-10-01

Identification of transmural extent and degree of non-viability after ST-segment elevation myocardial infarction (STEMI) is clinically important. The objective of the present study was to assess the regional mechanics and temporal deformation patterns using speckle tracking echocardiography (STE) in acute and later phases of STEMI to predict myocardial damage in these patients. Ninety-eight patients with first STEMI underwent both echocardiography and cardiac magnetic resonance imaging in acute phase and at 6 months follow-up with 2D STE-derived measurements of peak longitudinal strain (PLS), Pre-STretch index (PST) and post-systolic deformation index (PSI). For each segment, late gadolinium enhancement (LGE) was defined as transmural (LGE >66 %) or non-transmural (<66 %). Global deformation values were significantly correlated with LVEFCMR and infarct size at both visits. A significantly lower value of segmental PLS and higher PSI and PST in necrotic segments were observed comparatively to control, adjacent and remote segments. The best parameters to predict transmural extent in acute phase were PSI with a cutoff value of 8 % (AUC: 0.84) and PLS with a cutoff value of -13 % (AUC: 0.86). PST showed high specificity, but poor sensitivity in predicting transmural extent. More importantly, the addition of PSI and PST to PLS in acute phase was associated with improved prediction of viability at 6 months (integrated discrimination improvement 2.5 % p < 0.01; net reclassification improvement 27 %; p < 0.01). All systolic deformation values separated transmural from non-transmural scarring. PLS combined with additional information relative to post-systolic deformation appears to be the most informative parameters to predict the transmural extent of MI in the early and late phases of MI. http://clinicaltrials.gov/show/NCT01109225 ; NCT01109225.

Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogunlade, Olumide, E-mail: o.ogunlade@ucl.ac.uk; Beard, Paul

2015-01-15

Purpose: Thermoacoustic imaging at microwave excitation frequencies is limited by the low differential contrast exhibited by high water content tissues. To overcome this, exogenous thermoacoustic contrast agents based on gadolinium compounds, iron oxide, and single wall carbon nanotubes have previously been suggested and investigated. However, these previous studies did not fully characterize the electric, magnetic, and thermodynamic properties of these agents thus precluding identification of the underlying sources of contrast. To address this, measurements of the complex permittivity, complex permeability, DC conductivity, and Grüneisen parameter have been made. These measurements allowed the origins of the contrast provided by each substancemore » to be identified. Methods: The electric and magnetic properties of the contrast agents were characterized at 3 GHz using two rectangular waveguide cavities. The DC conductivity was measured separately using a conductivity meter. Thermoacoustic signals were then acquired and compared to those generated in water. Finally, 3D electromagnetic simulations were used to decouple the different contributions to the absorbed power density. Results: It was found that the gadolinium compounds provided appreciable electric contrast but not originating from the gadolinium itself. The contrast was either due to dissociation of the gadolinium salt which increased ionic conductivity or its nondissociated polar fraction which increased dielectric polarization loss or a combination of both. In addition, very high concentrations were required to achieve appreciable contrast, to the extent that the Grüneisen parameter increased significantly and became a source of contrast. Iron oxide particles were found to produce low but measurable dielectric contrast due to dielectric polarization loss, but this is attributed to the coating of the particles not the iron oxide. Single wall carbon nanotubes did not provide measurable contrast of any type. Conclusions: It is concluded that gadolinium based contrast agents, iron oxide particles, and single walled carbon nanotubes have little intrinsic merit as thermoacoustic contrast agents. Simple electrolytes such as saline which yield high contrast based on ionic conductivity provide much higher dielectric contrast per unit solute concentration and are likely to be significantly more effective as contrast agents.« less

Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

NASA Astrophysics Data System (ADS)

Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

2016-02-01

High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis. Electronic supplementary information (ESI) available: Supplementary Fig. S1-S6. See DOI: 10.1039/c5nr08402d

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aldridge, James D.; Womick, Jordan M.; Rosmus, Kimberly A.

Novel quaternary lanthanide-substituted oxides of stoichiometry LnxY2-xTi2O7 (where Ln is lanthanum, neodymium, samarium, gadolinium, or ytterbium) were prepared by traditional high-temperature, solid-state techniques and characterized by X-ray powder diffraction. Samples with nominal values of x up to 1.0 were attempted. The well-studied ternary cubic pyrochlore compound yttrium titanium oxide (Y2Ti2O7, space group Fd-3m, Z = 8), served as a parent structural framework in which Ln3+ cations were substituted on the Y3+ site. Laboratory-grade X-ray powder diffraction data revealed pure quaternary pyrochlore phases for LnxY2-xTi2O7 with x ≤ 0.2. Pyrochlore phase purity was verified by Rietveld analysis using high-resolution synchrotron X-raymore » powder diffraction data when x ≤ 0.2, however, for La3+ substitution specifically, pure quaternary pyrochlore formed at x<0.1. Band gap energies on selected samples were determined using optical diffuse reflectance spectroscopy and showed that these materials can be classified as electrical insulators with indirect band gap energies around 3.7 eV.« less

Clinical application of a gadolinium-based capsule as an MRI contrast agent in slow transit constipation diagnostics.

PubMed

Zhi, M; Zhou, Z; Chen, H; Xiong, F; Huang, J; He, H; Zhang, M; Su, M; Gao, X; Hu, P

2017-06-01

As a traditional method for the assessment of colon dynamics, radio-opaque markers (ROMs) are limited in clinical use because of their ionizing radiation. We compared the accuracy and applicability of gadolinium-based capsules with ROMs in the measurement of colon dynamics in healthy controls and slow transit constipation (STC) patients. Seven patients with STC and nine healthy controls under a normal diet orally consumed ROMs and gadolinium-based capsules simultaneously. All subjects underwent X-ray and magnetic resonance imaging (MRI). Healthy control images were acquired at 12, 24, and 48 h, and STC patient images were acquired at 24, 48, and 72 h. The scores based on the position of the labeling capsules and ROMs in the colon and the colon transit times (CTTs) in the two groups were compared. The CTTs obtained via the ROMs were 34.7±17.4 and 67.3±6.5 h in the healthy controls and STC patients, respectively (P<.05). The CTTs obtained via MRI were 30.9±15.9 and 74.1±7.2 h in the healthy controls and STC patients, respectively (P<.05). The CTTs of the STC patients were significantly longer than the healthy controls. The correlation (r s ) between the scores based on the position of the labeling capsule and ROMs in the healthy group and the STC patients was .880 (P<.05) and .889 (P<.05), respectively. As a MRI contrast label, gadolinium-based capsules exhibit results comparable to ROMs in colon motility measurements. © 2017 John Wiley & Sons Ltd.

A new automatic algorithm for quantification of myocardial infarction imaged by late gadolinium enhancement cardiovascular magnetic resonance: experimental validation and comparison to expert delineations in multi-center, multi-vendor patient data.

PubMed

Engblom, Henrik; Tufvesson, Jane; Jablonowski, Robert; Carlsson, Marcus; Aletras, Anthony H; Hoffmann, Pavel; Jacquier, Alexis; Kober, Frank; Metzler, Bernhard; Erlinge, David; Atar, Dan; Arheden, Håkan; Heiberg, Einar

2016-05-04

Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) using magnitude inversion recovery (IR) or phase sensitive inversion recovery (PSIR) has become clinical standard for assessment of myocardial infarction (MI). However, there is no clinical standard for quantification of MI even though multiple methods have been proposed. Simple thresholds have yielded varying results and advanced algorithms have only been validated in single center studies. Therefore, the aim of this study was to develop an automatic algorithm for MI quantification in IR and PSIR LGE images and to validate the new algorithm experimentally and compare it to expert delineations in multi-center, multi-vendor patient data. The new automatic algorithm, EWA (Expectation Maximization, weighted intensity, a priori information), was implemented using an intensity threshold by Expectation Maximization (EM) and a weighted summation to account for partial volume effects. The EWA algorithm was validated in-vivo against triphenyltetrazolium-chloride (TTC) staining (n = 7 pigs with paired IR and PSIR images) and against ex-vivo high resolution T1-weighted images (n = 23 IR and n = 13 PSIR images). The EWA algorithm was also compared to expert delineation in 124 patients from multi-center, multi-vendor clinical trials 2-6 days following first time ST-elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) (n = 124 IR and n = 49 PSIR images). Infarct size by the EWA algorithm in vivo in pigs showed a bias to ex-vivo TTC of -1 ± 4%LVM (R = 0.84) in IR and -2 ± 3%LVM (R = 0.92) in PSIR images and a bias to ex-vivo T1-weighted images of 0 ± 4%LVM (R = 0.94) in IR and 0 ± 5%LVM (R = 0.79) in PSIR images. In multi-center patient studies, infarct size by the EWA algorithm showed a bias to expert delineation of -2 ± 6 %LVM (R = 0.81) in IR images (n = 124) and 0 ± 5%LVM (R = 0.89) in PSIR images (n = 49). The EWA algorithm was validated experimentally and in patient data with a low bias in both IR and PSIR LGE images. Thus, the use of EM and a weighted intensity as in the EWA algorithm, may serve as a clinical standard for the quantification of myocardial infarction in LGE CMR images. CHILL-MI: NCT01379261 . NCT01374321 .

Apparent diffusion coefficient histogram analysis can evaluate radiation-induced parotid damage and predict late xerostomia degree in nasopharyngeal carcinoma

PubMed Central

Zhou, Nan; Guo, Tingting; Zheng, Huanhuan; Pan, Xia; Chu, Chen; Dou, Xin; Li, Ming; Liu, Song; Zhu, Lijing; Liu, Baorui; Chen, Weibo; He, Jian; Yan, Jing; Zhou, Zhengyang; Yang, Xiaofeng

2017-01-01

We investigated apparent diffusion coefficient (ADC) histogram analysis to evaluate radiation-induced parotid damage and predict xerostomia degrees in nasopharyngeal carcinoma (NPC) patients receiving radiotherapy. The imaging of bilateral parotid glands in NPC patients was conducted 2 weeks before radiotherapy (time point 1), one month after radiotherapy (time point 2), and four months after radiotherapy (time point 3). From time point 1 to 2, parotid volume, skewness, and kurtosis decreased (P < 0.001, = 0.001, and < 0.001, respectively), but all other ADC histogram parameters increased (all P < 0.001, except P = 0.006 for standard deviation [SD]). From time point 2 to 3, parotid volume continued to decrease (P = 0.022), and SD, 75th and 90th percentiles continued to increase (P = 0.024, 0.010, and 0.006, respectively). Early change rates of parotid ADCmean, ADCmin, kurtosis, and 25th, 50th, 75th, 90th percentiles (from time point 1 to 2) correlated with late parotid atrophy rate (from time point 1 to 3) (all P < 0.05). Multiple linear regression analysis revealed correlations among parotid volume, time point, and ADC histogram parameters. Early mean change rates for bilateral parotid SD and ADCmax could predict late xerostomia degrees at seven months after radiotherapy (three months after time point 3) with AUC of 0.781 and 0.818 (P = 0.014, 0.005, respectively). ADC histogram parameters were reproducible (intraclass correlation coefficient, 0.830 - 0.999). ADC histogram analysis could be used to evaluate radiation-induced parotid damage noninvasively, and predict late xerostomia degrees of NPC patients treated with radiotherapy. PMID:29050274

Apparent diffusion coefficient histogram analysis can evaluate radiation-induced parotid damage and predict late xerostomia degree in nasopharyngeal carcinoma.

PubMed

Zhou, Nan; Guo, Tingting; Zheng, Huanhuan; Pan, Xia; Chu, Chen; Dou, Xin; Li, Ming; Liu, Song; Zhu, Lijing; Liu, Baorui; Chen, Weibo; He, Jian; Yan, Jing; Zhou, Zhengyang; Yang, Xiaofeng

2017-09-19

We investigated apparent diffusion coefficient (ADC) histogram analysis to evaluate radiation-induced parotid damage and predict xerostomia degrees in nasopharyngeal carcinoma (NPC) patients receiving radiotherapy. The imaging of bilateral parotid glands in NPC patients was conducted 2 weeks before radiotherapy (time point 1), one month after radiotherapy (time point 2), and four months after radiotherapy (time point 3). From time point 1 to 2, parotid volume, skewness, and kurtosis decreased ( P < 0.001, = 0.001, and < 0.001, respectively), but all other ADC histogram parameters increased (all P < 0.001, except P = 0.006 for standard deviation [SD]). From time point 2 to 3, parotid volume continued to decrease ( P = 0.022), and SD, 75 th and 90 th percentiles continued to increase ( P = 0.024, 0.010, and 0.006, respectively). Early change rates of parotid ADC mean , ADC min , kurtosis, and 25 th , 50 th , 75 th , 90 th percentiles (from time point 1 to 2) correlated with late parotid atrophy rate (from time point 1 to 3) (all P < 0.05). Multiple linear regression analysis revealed correlations among parotid volume, time point, and ADC histogram parameters. Early mean change rates for bilateral parotid SD and ADC max could predict late xerostomia degrees at seven months after radiotherapy (three months after time point 3) with AUC of 0.781 and 0.818 ( P = 0.014, 0.005, respectively). ADC histogram parameters were reproducible (intraclass correlation coefficient, 0.830 - 0.999). ADC histogram analysis could be used to evaluate radiation-induced parotid damage noninvasively, and predict late xerostomia degrees of NPC patients treated with radiotherapy.

Diffusion of subsidized ACTs in accredited drug shops in Tanzania: determinants of stocking and characteristics of early and late adopters

PubMed Central

2013-01-01

Background Many households in sub-Saharan Africa utilize the private sector as a primary source of treatment for malaria episodes. Expanding access to effective treatment in private drug shops may help reduce incidence of severe disease and mortality. This research leveraged a longitudinal survey of stocking of subsidized artemisinin combination therapies (ACTs), an effective anti-malarial, in Accredited Drug Dispensing Outlets (ADDOs) in two regions of Tanzania. This provided a unique opportunity to explore shop and market level determinants of product diffusion in a developing country retail market. Methods 356 ADDOs in the Rukwa and Mtwara regions of Tanzania were surveyed at seven points between Feb 2011 and May 2012. Shop level audits were used to measure the availability of subsidized ACTs at each shop. Data on market and shop level factors were collected during the survey and also extracted from GIS layers. Regression and network based methodologies were used. Shops classified as early and late adopters, following Rogers’ model of product diffusion, were compared. The Bass model of product diffusion was applied to determine whether shops stocked ACTs out of a need to imitate market competitors or a desire to satisfy customer needs. Results Following the introduction of a subsidy for ACTs, stocking increased from 12% to nearly 80% over the seven survey rounds. Stocking was influenced by higher numbers of proximal shops and clinics, larger customer traffic and the presence of a licensed pharmacist. Early adopters were characterized by a larger percentage of customers seeking care for malaria, a larger catchment and sourcing from specific wholesalers/suppliers. The Bass model of product diffusion indicated that shops were adopting products in response to competitor behavior, rather than customer demand. Conclusions Decisions to stock new pharmaceutical products in Tanzanian ADDOs are influenced by a combination of factors related to both market competition and customer demand, but are particularly influenced by the behavior of competing shops. Efforts to expand access to new pharmaceutical products in developing country markets could benefit from initial targeting of high profile shops in competitive markets and wholesale suppliers to encourage faster product diffusion across all drug retailers. PMID:24350611

Diffusion of subsidized ACTs in accredited drug shops in Tanzania: determinants of stocking and characteristics of early and late adopters.

PubMed

Larson, Peter S; Yadav, Prashant; Alphs, Sarah; Arkedis, Jean; Massaga, Julius; Sabot, Oliver; Cohen, Jessica L

2013-12-18

Many households in sub-Saharan Africa utilize the private sector as a primary source of treatment for malaria episodes. Expanding access to effective treatment in private drug shops may help reduce incidence of severe disease and mortality. This research leveraged a longitudinal survey of stocking of subsidized artemisinin combination therapies (ACTs), an effective anti-malarial, in Accredited Drug Dispensing Outlets (ADDOs) in two regions of Tanzania. This provided a unique opportunity to explore shop and market level determinants of product diffusion in a developing country retail market. 356 ADDOs in the Rukwa and Mtwara regions of Tanzania were surveyed at seven points between Feb 2011 and May 2012. Shop level audits were used to measure the availability of subsidized ACTs at each shop. Data on market and shop level factors were collected during the survey and also extracted from GIS layers. Regression and network based methodologies were used. Shops classified as early and late adopters, following Rogers' model of product diffusion, were compared. The Bass model of product diffusion was applied to determine whether shops stocked ACTs out of a need to imitate market competitors or a desire to satisfy customer needs. Following the introduction of a subsidy for ACTs, stocking increased from 12% to nearly 80% over the seven survey rounds. Stocking was influenced by higher numbers of proximal shops and clinics, larger customer traffic and the presence of a licensed pharmacist. Early adopters were characterized by a larger percentage of customers seeking care for malaria, a larger catchment and sourcing from specific wholesalers/suppliers. The Bass model of product diffusion indicated that shops were adopting products in response to competitor behavior, rather than customer demand. Decisions to stock new pharmaceutical products in Tanzanian ADDOs are influenced by a combination of factors related to both market competition and customer demand, but are particularly influenced by the behavior of competing shops. Efforts to expand access to new pharmaceutical products in developing country markets could benefit from initial targeting of high profile shops in competitive markets and wholesale suppliers to encourage faster product diffusion across all drug retailers.

Evaluating the potential of chelation therapy to prevent and treat gadolinium deposition from MRI contrast agents

DOE PAGES

Rees, Julian A.; Deblonde, Gauthier J. -P.; An, Dahlia D.; ...

2018-03-13

Several MRI contrast agent clinical formulations are now known to leave deposits of the heavy metal gadolinium in the brain, bones, and other organs of patients. This persistent biological accumulation of gadolinium has been recently recognized as a deleterious outcome in patients administered Gd-based contrast agents (GBCAs) for MRI, prompting the European Medicines Agency to recommend discontinuing the use of over half of the GBCAs currently approved for clinical applications. Here, to address this problem, we find that the orally-available metal decorporation agent 3,4,3-LI(1,2-HOPO) demonstrates superior efficacy at chelating and removing Gd from the body compared to diethylenetriaminepentaacetic acid, amore » ligand commonly used in the United States in the GBCA Gadopentetate (Magnevist). Using the radiotracer 153Gd to obtain precise biodistribution data, the results herein, supported by speciation simulations, suggest that the prophylactic or post-hoc therapeutic use of 3,4,3-LI(1,2-HOPO) may provide a means to mitigate Gd retention in patients requiring contrast-enhanced MRI.« less

Evaluating the potential of chelation therapy to prevent and treat gadolinium deposition from MRI contrast agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rees, Julian A.; Deblonde, Gauthier J. -P.; An, Dahlia D.

Several MRI contrast agent clinical formulations are now known to leave deposits of the heavy metal gadolinium in the brain, bones, and other organs of patients. This persistent biological accumulation of gadolinium has been recently recognized as a deleterious outcome in patients administered Gd-based contrast agents (GBCAs) for MRI, prompting the European Medicines Agency to recommend discontinuing the use of over half of the GBCAs currently approved for clinical applications. Here, to address this problem, we find that the orally-available metal decorporation agent 3,4,3-LI(1,2-HOPO) demonstrates superior efficacy at chelating and removing Gd from the body compared to diethylenetriaminepentaacetic acid, amore » ligand commonly used in the United States in the GBCA Gadopentetate (Magnevist). Using the radiotracer 153Gd to obtain precise biodistribution data, the results herein, supported by speciation simulations, suggest that the prophylactic or post-hoc therapeutic use of 3,4,3-LI(1,2-HOPO) may provide a means to mitigate Gd retention in patients requiring contrast-enhanced MRI.« less

Gadolinium-hydrogen ion exchange of zirconium phosphate

NASA Technical Reports Server (NTRS)

Liu, D. C.; Power, J. L.

1972-01-01

The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

Comparative theoretical study of the structures and stabilities of four typical gadolinium carboxylates in different scintillator solvents.

PubMed

Huang, Pin-Wen

2016-03-01

The structural properties and stabilities of four typical gadolinium carboxylates (Gd-CBX) in toluene, linear alkyl benzene (LAB), and phenyl xylyl ethane (PXE) solvents were theoretically studied using density functional theory (DFT/B3LYP with the basis sets 6-311G(d) and MWB54) and the polarizable continuum model (PCM). The average Gd-ligand interaction energies (E int, corrected for dispersion) and the values of the energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital (ΔHL) for the gadolinium complexes were calculated to compare the relative stabilities of the four Gd-CBX molecules in the three liquid scintillator solvents. According to the calculations, the values of E int and ΔHL for Gd-CBX in LAB are larger than the corresponding values in PXE and toluene. Gd-CBX may therefore be more compatible with LAB than with PXE and toluene. It was also found that, in the three scintillator solvents, the stabilities of the four Gd-CBX molecules increase in the order Gd-2EHA < Gd-2MVA < Gd-pivalate < Gd-TMHA.

Rare-earth doped gadolinia based phosphors for potential multicolor and white light emitting deep UV LEDs.

PubMed

Bedekar, Vinila; Dutta, Dimple P; Mohapatra, M; Godbole, S V; Ghildiyal, R; Tyagi, A K

2009-03-25

Gadolinium oxide host and europium/dysprosium/terbium doped gadolinium oxide nanoparticles were synthesized using the sonochemical technique. Gadolinium oxide nanocrystals were also co-doped with total 2 mol% of Eu(3+)/Dy(3+),Eu(3+)/Tb(3+),Dy(3+)/Tb(3+), and also Eu(3+)/Dy(3+)/Tb(3+) ions, by the same method. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) techniques. The size of the particles ranged from 15 to 30 nm. The triple doped samples showed multicolor emission on single wavelength excitation. The photoluminescence results were correlated with the lifetime data to get an insight into the luminescence and energy transfer processes taking place in the system. On excitation at 247 nm, the novel nanocrystalline Gd(2)O(3):RE (RE = Dy, Tb) phosphor resulted in having very impressive CIE chromaticity coordinates of x = 0.315 and y = 0.316, and a correlated color temperature of 6508 K, which is very close to standard daylight.

Effect of solid-phase amorphization on the spectral characteristics of europium-doped gadolinium molybdate

NASA Astrophysics Data System (ADS)

Shmurak, S. Z.; Kiselev, A. P.; Kurmasheva, D. M.; Red'Kin, B. S.; Sinitsyn, V. V.

2010-05-01

A method is proposed for detecting spectral characteristics of optically inactive molybdates of rare-earth elements by their doping with rare-earth ions whose luminescence lies in the transparency region of all structural modifications of the sample. Gadolinium molybdate is chosen as the object of investigations, while europium ions are used as an optically active and structurally sensitive admixture. It is shown that after the action of a high pressure under which gadolinium molybdate passes to the amorphous state, the spectral characteristics of Gd1.99Eu0.01(MoO4)3 (GMO:Eu) change radically; namely, considerable line broadening is observed in the luminescence spectra and the luminescence excitation spectra, while the long-wave threshold of optical absorption is shifted considerably (by approximately 1.1 eV) towards lower energies. It is found that by changing the structural state of GMO:Eu by solid-state amorphization followed by annealing, the spectral characteristics of the sample can be purposefully changed. This is extremely important for solving the urgent problem of designing high-efficiency light-emitting diodes producing “white” light.

An investigation of multi-rate sound decay under strongly non-diffuse conditions: The crypt of the Cathedral of Cadiz

NASA Astrophysics Data System (ADS)

Martellotta, Francesco; Álvarez-Morales, Lidia; Girón, Sara; Zamarreño, Teófilo

2018-05-01

Multi-rate sound decays are often found and studied in complex systems of coupled volumes where diffuse field conditions generally apply, although the openings connecting different sub-spaces are by themselves potential causes of non-diffuse behaviour. However, in presence of spaces in which curved surfaces clearly prevent diffuse field behaviour from being established, things become more complex and require more sophisticated tools (or, better, combinations of them) to be fully understood. As an example of such complexity, the crypt of the Cathedral of Cadiz is a relatively small space characterised by a central vaulted rotunda, with five radial galleries with flat and low ceiling. In addition, the crypt is connected to the main cathedral volume by means of several small openings. Acoustic measurements carried out in the crypt pointed out the existence of at least two decay processes combined, in some points, with flutter echoes. Application of conventional methods of analysis pointed out the existence of significant differences between early decay time and reverberation time, but was inconclusive in explaining the origin of the observed phenomena. The use of more robust Bayesian analysis permitted the conclusion that the late decay appearing in the crypt had a different rate than that observed in the cathedral, thus excluding the explanation based on acoustic coupling of different volumes. Finally, processing impulse responses collected by means of a B-format microphone to obtain directional intensity maps demonstrated that the late decay was originated from the rotunda where a repetitive reflection pattern appeared between the floor and the dome causing both flutter echoes and a longer reverberation time.

Occidental diffusion of cucumber (Cucumis sativus) 500–1300 CE: two routes to Europe

PubMed Central

Paris, Harry S.; Daunay, Marie-Christine; Janick, Jules

2012-01-01

Background The cucumber, Cucumis sativus, is one of the most widely consumed fruit vegetables the world over. The history of its dispersal to the Occident from its centre of origin, the Indian subcontinent, has been incorrectly understood for some time, due to the confusion of cucumbers with vegetable melons. Iconographic and literary evidence has shown that cucumber was absent in Roman times, up to 500 CE, but present in Europe by late medieval times, 1300. The objective of the present investigation was to determine more accurately when the cucumber arrived in Europe and by what route. Findings and Conclusions The evidence for the movement of C. sativus westward is entirely lexicographical until the 10th century. Syriac, Persian and Byzantine Greek sources suggest the presence of cucumbers, to the east and north-east of the Mediterranean Sea (modern Iran, Iraq and Turkey), by the 6th or 7th century. Arabic medical writings suggest the presence of cucumbers in Spain as early as the mid-9th century and in Tunisia by the early 10th century. Descriptive evidence in Arabic establishes the presence of cucumbers in Andalusia by the second half of the 10th century. Latin translations from Arabic sources indicate the presence of cucumbers in southern Italy by the second half of the 11th century. These writings, together with lexicographical discrepancies in names of cucurbits in late medieval Latin writings, suggest that cucumber was introduced to Europe by two independent diffusions. One diffusion appears to have been overland from Persia into eastern and northern Europe and preceded the Islamic conquests. The other, subsequent diffusion into western and southern Europe, was probably by a mostly maritime route from Persia or the Indian subcontinent into Andalusia. PMID:22104164

Occidental diffusion of cucumber (Cucumis sativus) 500-1300 CE: two routes to Europe.

PubMed

Paris, Harry S; Daunay, Marie-Christine; Janick, Jules

2012-01-01

The cucumber, Cucumis sativus, is one of the most widely consumed fruit vegetables the world over. The history of its dispersal to the Occident from its centre of origin, the Indian subcontinent, has been incorrectly understood for some time, due to the confusion of cucumbers with vegetable melons. Iconographic and literary evidence has shown that cucumber was absent in Roman times, up to 500 CE, but present in Europe by late medieval times, 1300. The objective of the present investigation was to determine more accurately when the cucumber arrived in Europe and by what route. The evidence for the movement of C. sativus westward is entirely lexicographical until the 10th century. Syriac, Persian and Byzantine Greek sources suggest the presence of cucumbers, to the east and north-east of the Mediterranean Sea (modern Iran, Iraq and Turkey), by the 6th or 7th century. Arabic medical writings suggest the presence of cucumbers in Spain as early as the mid-9th century and in Tunisia by the early 10th century. Descriptive evidence in Arabic establishes the presence of cucumbers in Andalusia by the second half of the 10th century. Latin translations from Arabic sources indicate the presence of cucumbers in southern Italy by the second half of the 11th century. These writings, together with lexicographical discrepancies in names of cucurbits in late medieval Latin writings, suggest that cucumber was introduced to Europe by two independent diffusions. One diffusion appears to have been overland from Persia into eastern and northern Europe and preceded the Islamic conquests. The other, subsequent diffusion into western and southern Europe, was probably by a mostly maritime route from Persia or the Indian subcontinent into Andalusia.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging With Gadolinium Ethoxybenzyl Diethylenetriamine Pentaacetic Acid for Quantitative Assessment of Vascular Effects on Hepatocellular-Carcinoma Lesions Treated by Transarterial Chemoembolization or Radiofrequency Ablation.

PubMed

Ippolito, Davide; Trattenero, Chiara; Talei Franzesi, Cammillo; Casiraghi, Alessandra; Lombardi, Sophie; Vacirca, Francesco; Corso, Rocco; Sironi, Sandro

2016-01-01

The aim of this study was to investigate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in evaluation of blood flow changes related to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) procedures in patients with hepatocellular carcinoma (HCC) lesions. Fifty-four patients, with biopsy-proven HCC, who underwent TACE or RFA, were evaluated, 1 month after treatment, with upper abdominal MRI examination. Multiplanar T2-weighted, T1-weighted, and dynamic contrast-enhanced sequences were acquired. Dedicated perfusion software (T1 Perfusion Package, Viewforum; Philips Medical Systems, The Netherlands) was used to generate color permeability maps. After placing regions of interest in normal hepatic parenchyma, in successfully treated lesions, and in area of recurrence, the following perfusion parameters were calculated and statistically analyzed: relative arterial, venous, and late enhancement; maximum enhancement; maximum relative enhancement, and time to peak. Twenty-one of 54 patients had residual disease, and perfusion parameters values measured within tumor tissue were: relative arterial enhancement median, 42%; relative venous enhancement median, 69%; relative late enhancement median, 57.7%; maximum enhancement median, 749.6%; maximum relative enhancement median, 69%; time to peak median, 81.1 seconds. As for all the evaluated parameters, a significant difference (P < 0.05) was found between residual viable tumor tissue and effective treated lesions. Dynamic contrast-enhanced MRI represents a complementary noninvasive tool that may offer quantitative and qualitative information about HCC lesions treated with TACE and RFA.

The diffusion of organ transplantation in Western Europe.

PubMed

Rigter, H; Bos, M A

1990-11-01

The moment of introduction of clinical organ transplantations varied in Western Europe from country to country. In retrospect, one can distinguish pioneering countries (most notably the U.K. and France), and countries that were early or late adopters of the new technologies. An early start did not necessarily lead to extensive diffusion of organ transplantations, as shown by the example of the U.K. In general, Western Europe is lagging behind the U.S.A. In diffusion of organ transplantation technologies. With few exceptions, the introduction and diffusion of organ transplantations in Western Europe have been largely autonomous developments, not regulated by government or third party payers and only slowed down by lack of organs, facilities or funds. The lack of organs has been reduced by the activities of organ procurement and exchange organisations, and perhaps by legislation promoting organ donation. Nevertheless, the growth of the number of patients waiting for an organ is in almost all countries outpacing the increase in availability of organs.

Compositional Zoning in Kilauea Olivine: A Geochemical Tool for Investigating Magmatic Processes at Hawaiian Volcanoes

NASA Astrophysics Data System (ADS)

Lynn, Kendra J.

Olivine compositions and zoning patterns have been widely used to investigate the evolution of magmas from their source to the Earthfs surface. Modeling the formation of compositional zoning in olivine crystals has been used to retrieve timescales of magma residence, mixing, and transit. This dissertation is composed of three projects that apply diffusion chronometry principles to investigate how zoned olivine phenocrysts record magmatic processes at Hawaiian volcanoes. Olivine phenocrysts from K.lauea, the most active and thoroughly studied volcano in Hawaiei, are used to develop a better understanding of how Hawaiian olivine crystals record magmatic histories. This work begins by examining how crustal processes such as magma mixing and diffusive reequilibration can modify olivine compositions inherited from growth in parental magmas (Chapter 2). Diffusive re-equilibration of Fe-Mg, Mn, and Ni in olivine crystals overprints the chemical relationships inherited during growth, which strongly impacts interpretations about mantle processes and source components. These issues are further complicated by sectioning effects, where small (400 ƒEm along the c-axis) olivine crystals are more susceptible to overprinting compared to large (800 ƒEm) crystals. Olivine compositions and zoning patterns are then used to show that magmas during K.laueafs explosive Keanak.koei Tephra period (1500-1823 C.E.) were mixed and stored in crustal reservoirs for weeks to months prior to eruption (Chapter 3). Fe-Mg disequilibrium between olivine rims and their surrounding glasses show that a late-stage mixing event likely occurred hours to days prior to eruption, but the exact timescale is difficult to quantify using Fe-Mg and Ni diffusion. Lithium, a rapidly diffusing trace element in olivine, is modeled for the first time in a natural volcanic system to quantify this late-stage, short-duration mixing event (Chapter 4). Lithium zoning in olivine records both growth and diffusion processes that are affected by charge balancing requirements with growth zoning of P. Timescales from modeling diffuse Li zoning range from a few hours to three weeks, but most record short storage durations of four days or less. These timescales correspond to short storage periods after mixing. Thus, Li probably records the final perturbation of a magmatic system prior to eruption.

Caustic Precipitation of Plutonium Using Gadolinium as the Neutron Poison for Disposition to High Level Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bronikowski, M.G.

2002-06-24

Nuclear Materials Management Division (NMMD) has proposed that up to 100 kg of the plutonium (Pu) solutions stored in H-Canyon be precipitated with a nuclear poison and dispositioned to H-Area Tank Farm. The use of gadolinium (Gd) as the poison would greatly reduce the number of additional glass logs resulting from this disposition. This report summarizes the characteristics of the precipitation process and addresses criticality concerns in the Nuclear Criticality Safety Evaluation. No problems were found with the nature of the precipitate or the neutralization process.

Measuring θ13 in the Double Chooz experiment

NASA Astrophysics Data System (ADS)

Crum, Keith

2013-04-01

Double Chooz measures θ13 by searching for the disappearance of reactor electron antineutrinos (νe) interacting via inverse beta decay (IBD) in a liquid scintillator-based detector. The signature of IBD is the coincidence of positron annihilation followed by the capture of a neutron. Although Double Chooz was primarily designed to detect νe by searching for neutron capture on gadolinium, we can also search for neutron capture on hydrogen. We developed separate analyses for neutron capture on hydrogen and gadolinium as the two elements have different capture energies, capture lifetimes, and spatial distributions within our detector.

Active extravasation of gadolinium-based contrast agent into the subdural space following lumbar puncture.

PubMed

Kothari, Pranay D; Hanser, Evelyn M; Wang, Harrison; Farid, Nikdokht

2016-01-01

A 38year-old male presented with cauda equina syndrome following multiple lumbar puncture attempts. Lumbar spine magnetic resonance imaging (MRI) showed a subdural hematoma and an area of apparent contrast enhancement in the spinal canal on sagittal post-contrast images. Axial post-contrast images obtained seven minutes later demonstrated an increase in size and change in shape of the region of apparent contrast enhancement, indicating active extravasation of the contrast agent. This is the first reported case of active extravasation of gadolinium-based contrast agent in the spine. Copyright © 2016 Elsevier Inc. All rights reserved.

Gadolinium(III)-sensitized fluorescence of europium in its mixed-metal compounds with trifluroacetate

NASA Astrophysics Data System (ADS)

Kalinovskaya, I. V.; Zadorozhnaya, A. N.

2017-04-01

The fluorescence properties of mixed-metal compounds of Eu(III) and Gd(III) with trifluoroacetic acid, Eu1-хGdx(С2F3O2)3·yD·zH2O, where D - 1,10-phenanthroline, 2,2-dipyridil, diphenylguanidine, x = 0, 0.25, 0.5, or 0.7, were studied. Luminescence spectroscopic evidence and the examination of excitation spectra indicate the occurrence of efficient energy transfer from the gadolinium to the europium ion. The greatest promotion of Eu3+ photoluminescence at 615 nm is observed when Eu:Gd = 1:1.

Practical and efficient magnetic heat pump

NASA Technical Reports Server (NTRS)

Brown, G. V.

1978-01-01

Method for pumping heat magnetically at room temperature is more economical than existing refrigeration systems. Method uses natural magneto-thermal effect of gadolinium metal to establish temperature gradient across length of tube. Regenerative cyclic process in which gadolinium sample is magnetized and gives off heat at one end of tube, and then is demagnetized at other end to absorb heat has established temperature gradients of 144 degrees F in experiments near room temperature. Other materials with large magnetothermal effects can be used below room temperature. Possible commercial applications include freeze-drying and food processing, cold storage, and heating and cooling of buildings, plants, and ships.

Band-gap modulation via gallium substitution in cerium doped gadolinium aluminum garnet using a mixed fuel combustion approach

NASA Astrophysics Data System (ADS)

Tyagi, Mohit; Pitale, Shreyas S.; Ghosh, Manoranjan; Shinde, Seema

2014-04-01

Cerium doped Gadolinium garnets (Gd3AlxGa5-xO12 where 0≤x≤5) are synthesized via combustion synthesis using mixture of urea and glycine fuels. A 4h Post annealing at 1400 oC is found to be necessary for pure phase formation. Lattice spacing variation as a result of partial or total Ga substitution at Al site was mapped by X-ray diffraction. Photoluminescence emission of Ce shifts as a consequence of Ga substitution and therefore suggests a local re-adjustment of crystal field around activator site.

Highly transparent cerium doped gadolinium gallium aluminum garnet ceramic prepared with precursors fabricated by ultrasonic enhanced chemical co-precipitation.

PubMed

Zhang, Ji-Yun; Luo, Zhao-Hua; Jiang, Hao-Chuan; Jiang, Jun; Chen, Chun-Hua; Zhang, Jing-Xian; Gui, Zhen-Zhen; Xiao, Na

2017-11-01

Cerium doped gadolinium gallium aluminum garnet (GGAG:Ce) ceramic precursors have been synthesized with an ultrasonic chemical co-precipitation method (UCC) and for comparison with a traditional chemical co-precipitation method (TCC). The effect of ultra-sonication on the morphology of powders and the transmittance of GGAG:Ce ceramics are studied. The results indicate that the UCC method can effectively improve the homogenization and sinterability of GGAG:Ce powders, which contribute to obtain high transparent GGAG ceramic with the highest transmittance of 81%. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification of early and distinct glioblastoma response patterns treated by boron neutron capture therapy not predicted by standard radiographic assessment using functional diffusion map

PubMed Central

2013-01-01

Background Radiologic response of brain tumors is traditionally assessed according to the Macdonald criteria 10 weeks from the start of therapy. Because glioblastoma (GB) responds in days rather than weeks after boron neutron capture therapy (BNCT) that is a form of tumor-selective particle radiation, it is inconvenient to use the Macdonald criteria to assess the therapeutic efficacy of BNCT by gadolinium-magnetic resonance imaging (Gd-MRI). Our study assessed the utility of functional diffusion map (fDM) for evaluating response patterns in GB treated by BNCT. Methods The fDM is an image assessment using time-dependent changes of apparent diffusion coefficient (ADC) in tumors on a voxel-by-voxel approach. Other than time-dependent changes of ADC, fDM can automatically assess minimum/maximum ADC, Response Evaluation Criteria In Solid Tumors (RECIST), and the volume of enhanced lesions on Gd-MRI over time. We assessed 17 GB patients treated by BNCT using fDM. Additionally, in order to verify our results, we performed a histopathological examination using F98 rat glioma models. Results Only the volume of tumor with decreased ADC by fDM at 2 days after BNCT was a good predictor for GB patients treated by BNCT (P value = 0.022 by log-rank test and 0.033 by wilcoxon test). In a histopathological examination, brain sections of F98 rat glioma models treated by BNCT showed cell swelling of both the nuclei and the cytoplasm compared with untreated rat glioma models. Conclusions The fDM could identify response patterns in BNCT-treated GB earlier than a standard radiographic assessment. Early detection of treatment failure can allow a change or supplementation before tumor progression and might lead to an improvement of GB patients’ prognosis. PMID:23915330

Imaging Biomarker Dynamics in an Intracranial Murine Glioma Study of Radiation and Antiangiogenic Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Caroline, E-mail: caroline.chung@rmp.uhn.on.ca; Jalali, Shahrzad; Foltz, Warren

2013-03-01

Purpose: There is a growing need for noninvasive biomarkers to guide individualized spatiotemporal delivery of radiation therapy (RT) and antiangiogenic (AA) therapy for brain tumors. This study explored early biomarkers of response to RT and the AA agent sunitinib (SU), in a murine intracranial glioma model, using serial magnetic resonance imaging (MRI). Methods and Materials: Mice with MRI-visible tumors were stratified by tumor size into 4 therapy arms: control, RT, SU, and SU plus RT (SURT). Single-fraction conformal RT was delivered using MRI and on-line cone beam computed tomography (CT) guidance. Serial MR images (T2-weighted, diffusion, dynamic contrast-enhanced and gadolinium-enhancedmore » T1-weighted scans) were acquired biweekly to evaluate tumor volume, apparent diffusion coefficient (ADC), and tumor perfusion and permeability responses (K{sub trans}, K{sub ep}). Results: Mice in all treatment arms survived longer than those in control, with a median survival of 35 days for SURT (P<.0001) and 30 days for RT (P=.009) and SU (P=.01) mice vs 26 days for control mice. At Day 3, ADC rise was greater with RT than without (P=.002). Sunitinib treatment reduced tumor perfusion/permeability values with mean K{sub trans} reduction of 27.6% for SU (P=.04) and 26.3% for SURT (P=.04) mice and mean K{sub ep} reduction of 38.1% for SU (P=.01) and 27.3% for SURT (P=.02) mice. The magnitude of individual mouse ADC responses at Days 3 and 7 correlated with subsequent tumor growth rate R values of −0.878 (P=.002) and −0.80 (P=.01), respectively. Conclusions: Early quantitative changes in diffusion and perfusion MRI measures reflect treatment responses soon after starting therapy and thereby raise the potential for these imaging biomarkers to guide adaptive and potentially individualized therapy approaches in the future.« less

Localized malignant pleural mesothelioma: report of two cases.

PubMed

Tanzi, Silvia; Tiseo, Marcello; Internullo, Eveline; Cacciani, Giancarlo; Capra, Roberto; Carbognani, Paolo; Rusca, Michele; Rindi, Guido; Ardizzoni, Andrea

2009-08-01

Localized malignant pleural mesothelioma is very rare tumor disease. There are sporadic reports in the literature showing that this entity has a different biologic behavior compared with diffuse pleural mesothelioma. We report two cases of radically resected localized pleural malignant mesothelioma, with a previous history of asbestos exposure. Both cases showed a microscopic and immunohistochemical findings of malignant mesothelioma, biphasic and sarcomatoid lympho-histiocitoid variant type, respectively, without evidence of diffuse pleural spread. The first is very peculiar case of bilateral localized malignant pleural mesothelioma with complete response to chemotherapy and localized late recurrence, radically resected and treated with adjuvant radiotherapy. The second case revealed as a solitary localized mass, underwent a complete en bloc resection and adjuvant radiotherapy. Both cases demonstrate that the localized malignant mesothelioma should be distinguished from diffuse form and that complete resection is associated with good prognosis.

Testing the Dark Matter Scenario for PeV Neutrinos Observed in IceCube.

PubMed

Murase, Kohta; Laha, Ranjan; Ando, Shin'ichiro; Ahlers, Markus

2015-08-14

Late time decay of very heavy dark matter is considered as one of the possible explanations for diffuse PeV neutrinos observed in IceCube. We consider implications of multimessenger constraints, and show that proposed models are marginally consistent with the diffuse γ-ray background data. Critical tests are possible by a detailed analysis and identification of the sub-TeV isotropic diffuse γ-ray data observed by Fermi and future observations of sub-PeV γ rays by observatories like HAWC or Tibet AS+MD. In addition, with several-year observations by next-generation telescopes such as IceCube-Gen2, muon neutrino searches for nearby dark matter halos such as the Virgo cluster should allow us to rule out or support the dark matter models, independently of γ-ray and anisotropy tests.

Reconnection in the Post-impulsive Phase of Solar Flares

NASA Astrophysics Data System (ADS)

Forbes, Terry G.; Seaton, Daniel B.; Reeves, Katharine K.

2018-05-01

Using a recently developed analytical procedure, we determine the rate of magnetic reconnection in the “standard” model of eruptive solar flares. During the late phase, the neutral line is located near the lower tip of the reconnection current sheet, and the upper region of the current sheet is bifurcated into a pair of Petschek-type shocks. Despite the presence of these shocks, the reconnection rate remains slow if the resistivity is uniform and the flow is laminar. Fast reconnection is achieved only if there is some additional mechanism that can shorten the length of the diffusion region at the neutral line. Observations of plasma flows by the X-ray telescope on Hinode imply that the diffusion region is, in fact, quite short. Two possible mechanisms for reducing the length of the diffusion region are localized resistivity and MHD turbulence.

Pebble pile-up and planetesimal formation at the snow line

NASA Astrophysics Data System (ADS)

Drazkowska, J.

2017-09-01

The planetesimal formation stage represents a major gap in our understanding of planet formation process. Because of this, the late-stage planet accretion models typically make arbitrary assumptions about planetesimals and pebbles distribution, while the state-of-the-art dust evolution models predict no or little planetesimal formation. With this contribution, I present a step toward bridging the gap between the early and late stages of planet formation by models that connect dust coagulation and planetesimal formation. With the aid of evaporation, outward diffusion, and re-condensation of water vapor, pile-up of large pebbles is formed outside of the snow line that facilitates planetesimal formation by streaming instability.

Organ involvement in Argentinian systemic sclerosis patients with "late" pattern as compared to patients with "early/active" pattern by nailfold capillaroscopy.

PubMed

Marino Claverie, Lucila; Knobel, Elizabeth; Takashima, Lorena; Techera, Lorena; Oliver, Marina; Gonzalez, Paula; Romanini, Félix E; Fonseca, María L; Mamani, Marta N

2013-06-01

Changes in nailfold capillaroscopy in systemic sclerosis patients could be related to the disease severity. The aim of this study was to investigate whether patients with "late" scleroderma (SD) pattern have more organ involvement than patients with "early/active" SD pattern. Forty-six Argentinian patients (44 women and 2 men), with a diagnosis of systemic sclerosis, were distributed in two groups based on the presence of late and early/active patterns. Organ involvement was assessed as follows: pulmonary function by chest radiography, high-resolution chest tomography (HRCT), lung volume tests, and diffusing capacity for carbon monoxide (DLCO); esophageal involvement by manometry; and pulmonary arterial hypertension (PAH) by Doppler echocardiography and six-minute walk test. Honeycombing of the lungs evaluated by HRCT was more frequently present in patients with late pattern compared with early/active patients (p = 0.01). We also found statistically significant differences in lung volume tests (p = 0.03) and DLCO (p = 0.02) between the two SD pattern groups. Esophageal manometry showed a significantly higher frequency of motility disorders in the group with late pattern (p = 0.0024). In this study, patients with late pattern had higher frequency of pulmonary and esophageal involvement compared with patients with early/active pattern.

White matter microstructure in transsexuals and controls investigated by diffusion tensor imaging.

PubMed

Kranz, Georg S; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

2014-11-12

Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects' sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. Copyright © 2014 the authors 0270-6474/14/3415466-10$15.00/0.

Safety assessment of nanoparamagnetic contrast agents with different coatings for molecular MRI

NASA Astrophysics Data System (ADS)

Azizian, Gholamreza; Riyahi-Alam, Nader; Haghgoo, Soheila; Saffari, Mojtaba; Zohdiaghdam, Reza; Gorji, Ensieh

2013-04-01

Despite the wide application of gadolinium as a contrast agent for magnetic resonance imaging (MRI), there is a serious lack of information on its toxicity. Gadolinium and gadolinium oxide (Gd-oxide) are used as contrast agents for magnetic resonance imaging (MRI). There are methods for reducing toxicity of these materials, such as core nanoparticles coating or conjugating. Therefore, for toxicity evaluation, we compared the viability of commercial contrast agents in MRI (Gd-DTPA) and three nanoparticles with the same core Gd2O3 and small particulate gadolinium oxide or SPGO (< 40 nm) but different coatings of diethyleneglycol (DEG) as Gd2O3-DEG and methoxy polyethylene glycol-silane (mPEG-silane: 550 and 2000 Dalton) as SPGO-mPEG-silane550 and SPGO-mPEG-silane2000, respectively, in the SK-MEL3 cell line, by light microscopy, MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity. The viability values were not statistically different between the three nanoparticles and Gd-DTPA. The MTT and LDH assay results showed that Gd2O3-DEG nanoparticles were more toxic than Gd-DTPA and other nanoparticles. Also, SPGO-mPEG-silane2000 was more biocompatible than other nanoparticles. The obtained results did not show any significant increase in cytotoxicity of the nanoparticles and Gd-DTPA, neither dose-dependent nor time-dependent. Therefore, DEG and PEG, due to their considerable properties and irregular sizes (different molecular weights), were selected as the useful surface covering materials of nanomagnetic particles that could reveal noticeable relaxivity and biocompatibility characteristics.

A novel cryogenic magnetic refrigerant metal-organic framework based on 1D gadolinium(III) chain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Qun; Li, Peng-Fei; Zou, Zhi-Ming, E-mail: 2014005@glut.edu.cn

2017-02-15

A metal-organic framework (MOF) based on gadolinium ion (Gd{sup 3+}) and tricarboxylate ligand, [Gd(BTPCA)(H{sub 2}O)]·2DMF·3H{sub 2}O (Gd-BTPCA) (H{sub 3}BTPCA =1,1′,1′-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid; DMF=dimethylformamide), was synthesized and structurally characterized. The adjacent Gd{sup 3+} ions are intraconnected by the carboxylate groups of the BTPCA{sup 3-} ligands to form a 1D Gd{sup 3+} ion chain. The 1D Gd{sup 3+} ion chains are interconnected by the BTPCA{sup 3-} ligands, giving rise to a 3D framework with 1D open channel. The magnetic studies indicate that Gd-BTPCA exhibits weak ferromagnetic interactions, and acts as a cryogenic magnetic refrigerant having the magnetic entropy change (−ΔS{sub m}) of 20.40more » J kg{sup −1} K{sup −1} for ΔH =7 T at 3 K. - Graphical abstract: A 1D gadolinium(III) chains-based metal-organic framework performed ferromagnetic coupling on the magnetic property. Magnetic investigation reveals that Gd-BTPCA exhibits the entropy change (−ΔS{sub m}) of 20.40 J kg{sup −1} K{sup −1} for ΔH =7 T at 3 K. - Highlights: • The MOF based on gadolinium ion and tricarboxylate ligand was synthesized. • This MOF is connected with 1D Gd{sup 3+} ions chain and the carboxylate groups of BTPCA{sup 3-} ligands. • The magnetic studies indicate that the MOF exhibits the weak ferromagnetic interactions. • Magnetic investigation reveals that the MOF exhibits the high entropy change.« less