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Sample records for iodine contrast agent

  1. Frequently asked questions: iodinated contrast agents.

    PubMed

    Bettmann, Michael A

    2004-10-01

    Although iodinated contrast agents are safe and widely used, adverse events occur and questions remain about their use, safety, and interactions. Some questions are easily answered and others still require extensive investigation. For one frequent question--is informed consent necessary before all contrast media injections--the simple answer is no. Another question concerns use of contrast media in patients with prior reactions or allergies. Contrast agents can be safely used in such patients, but special care must be taken to be aware of what the previous reaction was and to be ready to treat any reaction. The protective role of pre-treatment with steroids is well established for minor reactions, but they may not prevent major reactions. It is important to realize that even life-threatening, anaphylactoid reactions are not the result of a true allergy to contrast media. Many questions arise about contrast agent-induced nephropathy. Baseline serum creatinine values should be obtained in patients who are at risk, not all patients. The incidence and natural history of contrast agent-induced nephropathy remain unclear. It occurs only in patients with compromised renal function before contrast agent injection, but even patients with normal serum creatinine levels can have renal dysfunction. Calculated creatinine clearance is a better way to determine risk and to follow this complication. The outcome in almost all patients is benign, with progression to end-stage renal disease being rare. The major risk factors, in addition to renal dysfunction, are long-standing diabetes mellitus, dehydration, and use of other nephrotoxic medications. Recent work in preventing and ameliorating contrast agent-induced nephropathy with N-acetyl cysteine, substitution of an isosmolal nonionic contrast agent, and various hydration regimens has been promising. Another common concern is use of iodinated contrast agents in pregnant or breast-feeding women. In both cases, there is no evidence

  2. [Iodinated contrast agents used in Radiology].

    PubMed

    Ramírez Ribelles, C; Sánchez Fuster, M A; Pamies Guilabert, J

    2014-06-01

    Iodinated contrast media are widely used in Radiology practices with a very low rate of adverse effects, being contrast-induced nephropathy the most serious one. In the majority of cases it is temporary and reversible, even though it can increase the inhospital morbidity and mortality in patients with risk factors. We will describe the various measures of prevention, being hydration and use of non-ionic contrast low osmolality those which have demonstrated greater effectiveness. Precautions to be taken in some risk situations, as patients treated with metformin or with impaired renal function, are also discussed. PMID:25267147

  3. Biodegradable Iodinated Polydisulfides as Contrast Agents for CT Angiography

    PubMed Central

    Jin, Erlei; Zheng-Rong, Lu

    2014-01-01

    Current clinical CT contrast agents are mainly small molecular iodinated compounds, which often suffer from short blood pool retention for more comprehensive cardiovascular CT imaging and may cause contrast-induced nephropathy. In this work, we prepared polydisulfides containing a traditional iodinated CT contrast agent in order to optimize the pharmacokinetics of the agent and improve its safety. Initially acting as a macromolecular agent and achieving sharp blood vessel delineation, the polydisulfides can be reduced by endogenous thiols via disulfide-thiol exchange reaction to oligomers that can be readily excreted via renal filtration. Short polyethylene glycol (PEG) chain was also introduced to the polymers to further modify the in vivo properties of the agents. Strong and prolonged vascular enhancement has been generated with two new agents in mice (5–10 times higher blood pool enhancement than iodinaxol). The polydisulfide agents gradually degraded and excreted via renal filtration. The gradual excretion process could prevent contrast induced nephropathy. These results suggest that the biodegradable macromolecular CT contrast agents are promising safe and effective blood contrast agents for CT angiography and image-guided interventions. PMID:24768156

  4. [Immediate allergy to iodinated contrast agents and prevention of reactions].

    PubMed

    Dewachter, P; Mouton-Faivre, C; Laroche, D; Clément, O

    2009-10-01

    The incidence and morbimortality of immediate hypersensitivity reactions following iodinated contrast media (ICM) injection remain unknown. The diagnosis of an immediate hypersensitivity reaction relies on a triad associating the precise description of the initial clinical manifestations and their delay of onset, the results of the biological assessment performed after the reaction including histamine and tryptase serum level measurements, and the results of skin testing with the culprit agent. Analysis of these data allows identification of the pathophysiologic mechanism of the reaction and the allergen involved in case of allergic hypersensitivity. Skin tests should be performed according to strict criteria. Cross-reactivity with ICM has to be investigated in order to propose a nonreactive ICM for future procedures. Allergic hypersensitivity to a given ICM imposes its definitive avoidance but not the avoidance of all iodinated drugs. The allergenic sequence has not yet been identified but is not the iodine atom itself. Asthma and treatment with beta-blockers are not risk factors of immediate allergic reactions to ICM per se, but may increase their severity. The various published protocols of premedication do not prevent the occurrence of an allergic/anaphylactic reaction to an ICM. The avoidance of the culprit ICM is the only way to prevent further reactions. PMID:19375199

  5. Characterization of liposomes containing iodine-125-labeled radiographic contrast agents

    SciTech Connect

    Zalutsky, M.R.; Noska, M.A.; Seltzer, S.E.

    1987-02-01

    Multilamellar liposomes were prepared containing either iodine-125-labeled (/sup 125/I) diatrizoate or /sup 125/I labeled iotrol in their aqueous phase. The in vitro permeabilities of liposomes containing both contrast agents were measured in the presence of saline and serum at 37 degrees C. Two different phospholipid compositions were studied: phosphatidylcholine/cholesterol/stearylamine (PC/C/S, 8: 1:1 molar ratio) and distearoylphosphatidylcholine/sphingomyelin (DSPC/SM, 5:2 mole ratio). In saline, similar permeabilities were observed for the four phospholipid-contrast agent combinations. In serum, however, leakage of /sup 125/I activity was 2 to 3 times greater from PC/C/S liposomes than from vesicles composed of DSPC/SM. When PC/C/S liposomes that contained /sup 125/I-diatrizoate were injected into rats, the clearance half-times for /sup 125/I activity from the liver, spleen, and whole body were 4.4 hours, 4.5 hours, and 2.8 hours, respectively. Liposomes composed of DSPC/SM cleared at a significantly slower rate from the liver, spleen, and whole body with half-times of 24.0 hours, 18.4 hours, and 17.2 hours observed from these tissues, respectively.

  6. Synthesis and characterization of ethosomal contrast agents containing iodine for computed tomography (CT) imaging applications.

    PubMed

    Shin, Hanjin; Cho, Young-Min; Lee, Kangtaek; Lee, Chang-Ha; Choi, Byoung Wook; Kim, Bumsang

    2014-06-01

    As a first step in the development of novel liver-specific contrast agents using ethosomes for computed tomography (CT) imaging applications, we entrapped iodine within ethosomes, which are phospholipid vesicular carriers containing relatively high alcohol concentrations, synthesized using several types of alcohol, such as methanol, ethanol, and propanol. The iodine containing ethosomes that were prepared using methanol showed the smallest vesicle size (392 nm) and the highest CT density (1107 HU). The incorporation of cholesterol into the ethosomal contrast agents improved the stability of the ethosomes but made the vesicle size large. The ethosomal contrast agents were taken up well by macrophage cells and showed no cellular toxicity. The results demonstrated that ethosomes containing iodine, as prepared in this study, have potential as contrast agents for applications in CT imaging. PMID:24188576

  7. [Immediate and delayed hypersensitivity reactions to iodinated radiographic contrast agents: an update].

    PubMed

    Khachman, Dalia; Gandia, Peggy; Sallerin, François; Mailly, Nicolas

    2009-01-01

    Diagnostic and interventional radiology of patients is nowadays crucial with increasing requirement for iodinated contrast agents infusion. Besides adverse reactions after administration of the iodinated contrast agents due to their toxicity, immediate hypersensitivity reactions and reactions resembling delayed hypersensitivity appearing from 1 hour to several days later, have been reported. Patients at high risk to develop such adverse events have to be detected on the basis of their risk factors in order to prevent or limit serious outcomes. Previous reactions to contrast media, asthma, atopy and cardiovascular disorders are risk factors for anaphylactic or anaphylactoid reactions. Female gender, age and beta-blockers increase the severity. This article aims to summarize the risk of allergic reactions related to the use of iodinated contrast agents and to suggest a way for diagnosis, treatment and prevention according to each clinical situation. PMID:19863909

  8. Experimental and theoretical x-ray imaging performance comparison of iodine and lanthanide contrast agents.

    PubMed

    Cardinal, H N; Holdsworth, D W; Drangova, M; Hobbs, B B; Fenster, A

    1993-01-01

    Contrast agents based on the lanthanide elements gadolinium and holmium have recently been developed for magnetic resonance imaging (MRI). Because of the increased atomic number of these elements relative to iodine, these new compounds, used as x-ray contrast agents, may yield higher radiographic contrast, and hence improved x-ray image quality, relative to conventional iodinated compounds, for clinically useful x-ray spectra. This possibility has been investigated, in independent experimental and theoretical studies, for two x-ray imaging systems: a digital radiographic system, using an x-ray image intensifier (XRII) and charge-coupled device (CCD) detector; and a conventional screen/film system, using a Lanex Regular screen. Iodine, gadolinium, and holmium contrast agents were investigated over a wide range of concentration-thickness products (0.1-0.6 M cm) and diagnostic x-ray spectra (60-120 kVp). A simple theoretical model of x-ray detector response predicts the experimental radiographic contrast measurements with a mean absolute error of 8.0% for the XRII/CCD system and 5.9% for the screen/film system, and shows that the radiographic contrast for these two systems is representative of all XRII and screen/film systems. An index of image quality is defined, and its dependence on radiographic contrast, x-ray fluence per unit dose, and detective quantum efficiency (DQE) is shown. Theoretical values of the index, predicted by our model, are then used to compare the performance of the three contrast agents for the two systems investigated. In general, iodine performance decreases steadily with increasing kVp, gadolinium performance has a broad maximum near 85 kVp, and gadolinium outperforms holmium. Gadolinium outperforms iodine for spectra above (and vice versa below) about 72 kVp, depending slightly on spectrum filtration, object thickness, and detector type. Thus, raising the kVp to shorten exposure times or reduce x-ray tube heat loading results in a loss of

  9. Absolute perfusion measurements and associated iodinated contrast agent time course in brain metastasis: a study for contrast-enhanced radiotherapy

    PubMed Central

    Obeid, Layal; Deman, Pierre; Tessier, Alexandre; Balosso, Jacques; Estève, François; Adam, Jean- François

    2014-01-01

    Contrast-enhanced radiotherapy is an innovative treatment that combines the selective accumulation of heavy elements in tumors with stereotactic irradiations using medium energy X-rays. The radiation dose enhancement depends on the absolute amount of iodine reached in the tumor and its time course. Quantitative, postinfusion iodine biodistribution and associated brain perfusion parameters were studied in human brain metastasis as key parameters for treatment feasibility and quality. Twelve patients received an intravenous bolus of iodinated contrast agent (CA) (40 mL, 4 mL/s), followed by a steady-state infusion (160 mL, 0.5 mL/s) to ensure stable intratumoral amounts of iodine during the treatment. Absolute iodine concentrations and quantitative perfusion maps were derived from 40 multislice dynamic computed tomography (CT) images of the brain. The postinfusion mean intratumoral iodine concentration (over 30 minutes) reached 1.94±0.12 mg/mL. Reasonable correlations were obtained between these concentrations and the permeability surface area product and the cerebral blood volume. To our knowledge, this is the first quantitative study of CA biodistribution versus time in brain metastasis. The study shows that suitable and stable amounts of iodine can be reached for contrast-enhanced radiotherapy. Moreover, the associated perfusion measurements provide useful information for the patient recruitment and management processes. PMID:24447951

  10. MCNP simulation of absorbed energy and dose by iodinated contrast agent

    NASA Astrophysics Data System (ADS)

    He, Wenjun; Mah, Eugene; Huda, Walter; Yao, Hai

    2012-03-01

    The purpose of this study is to investigate the absorbed dose and energy by iodinated contrast medium in diagnostic radiology. A simulation geometry in which an inner sphere (d = 0.2cm, 1cm, 5cm) filled with iodinated contrast medium (or water) is located at the center of a 20cm diameter water sphere was used in simulations performed with MCNP5 codes. Monoenergetic x-rays with energies ranging from 40 to 80keV from a cone beam source were utilized and contrast medium concentration ranged from 100 to 1mg/ml. Absorbed dose ratio (RD) to inner sphere and total absorbed energies ratio (RE) to the whole phantom with and without iodinated contrast medium were investigated. The maximum RD was ~13 for the 0.2cm diameter sphere with 100mg/ml contrast medium. The maximum RE was ~1.05 for the 5cm diameter contrast sphere at 80keV with 100mg/ml contrast medium. Under the same incident photon energy, increasing the inner sphere size from 0.2cm to 5cm caused a ~63% increase in the RD on average. Decreasing the contrast medium concentration from 100 to 10 mg/ml caused a decrease of RD of ~ 76%. A conclusion was reached that although local absorbed dose increase caused by iodinated contrast agent could be high; the increase in total absorbed energy is negligible.

  11. Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods

    PubMed Central

    Bernstein, Ally Leigh; Dhanantwari, Amar; Jurcova, Martina; Cheheltani, Rabee; Naha, Pratap Chandra; Ivanc, Thomas; Shefer, Efrat; Cormode, David Peter

    2016-01-01

    Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used. PMID:27185492

  12. Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods

    NASA Astrophysics Data System (ADS)

    Bernstein, Ally Leigh; Dhanantwari, Amar; Jurcova, Martina; Cheheltani, Rabee; Naha, Pratap Chandra; Ivanc, Thomas; Shefer, Efrat; Cormode, David Peter

    2016-05-01

    Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used.

  13. Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods.

    PubMed

    Bernstein, Ally Leigh; Dhanantwari, Amar; Jurcova, Martina; Cheheltani, Rabee; Naha, Pratap Chandra; Ivanc, Thomas; Shefer, Efrat; Cormode, David Peter

    2016-01-01

    Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used. PMID:27185492

  14. Determination of free iodine concentration in an X-ray contrast agent

    NASA Astrophysics Data System (ADS)

    Kljubin, V. V.; Kljubina, K. A.; Makovetskaya, K. N.

    2016-04-01

    Based on the analysis of the absorption spectra of solutions of iodine in ethanol, we propose a simple and sensitive (at a level of 1 μg/g) method for determination of the concentration of free (not bound to polymer) iodine in substances synthesized from ether oils and iodine. The method uses absorption of molecular iodine in the UV region. Iodine dissolved in alcohols has a rather large absorption cross section in the UV region. These absorption bands can be used to detect very small quantities of iodine. It is shown that, for iodine concentrations in the 1-50 μg/g range, the intensity of absorption band at a wavelength of 359 nm depends linearly on the iodine concentration, which allows one to use this band to determine the concentration of iodine not bound with the polymer in the X-ray contrast material.

  15. The study of N-isopropylacrylamide gel dosimeter doped iodinated contrast agents

    NASA Astrophysics Data System (ADS)

    Chang, Y. J.; Hsieh, L. L.; Liu, M. H.; Liu, J. S.; Hsieh, B. T.

    2013-06-01

    Low toxicity of N-isopropylacrylamide (NIPAM) dosimeter was doped with clinical iodinated contrast medium agents(Iobitridol (Xenetix® 350) and organically bound iodine (Conray® 60) as radiation sensitizers; The suitable gel dosimeter preparation formula in this research was 5 w/w% gelatin, 5 w/w% N-isopropylacrylamide, 3 w/w% N,N-methylene-bis-acrylamide, and 5 mM Tetrakis phosphonium chloride. The spiral CT was irradiator, and 120 kVp was the operating tube voltage. The maximum radiation dose was 0.6 Gy, and optical CT was the gel measurement device used. The results showed SERs with the addition of radiosensitizers were 10.70 (Xenetix® 350) and 9.67 (Conray® 60), respectively. Thus, the polymerized gel dosimeter could be used in the efficacy evaluation of low-energy and low-radiation dose.

  16. Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study*

    PubMed Central

    da Silva, Yvana Lopes Pinheiro; Costa, Rita Zanlorensi Visneck; Pinho, Kátia Elisa Prus; Ferreira, Ricardo Rabello; Schuindt, Sueliton Miyamoto

    2015-01-01

    Objective To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality. Materials and Methods Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration. Results As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions. Conclusion Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography. PMID:25987746

  17. [Immediate hypersensitivity reactions to iodinated contrast agents used in radiology: a review].

    PubMed

    Moussa, Lina Menassa; Nabhane, Linda; Smayra, Tarek; Zebouni, Soha Haddad; Mohanna, Assaad; Abi Khalil, Samer; Aoun, Noel

    2012-01-01

    The use of iodinated contrast agents (IC) has become common practice nowadays in the daily diagnostic and therapeutic procedures in radiology. Immediate hypersensitivity reactions occurring up to the first hour after injection of IC, can be of serious consequences, occasionally leading to death. This justifies the establishment of a prevention algorithm, including a sharp identification of those at risk and the implementation of premedication with corticosteroids. A history of previous reaction to IC is the major risk factor of a new reaction. Other risk factors include asthma, atopy and cardiomyopathy. The factors that influence the severity of the hypersensitivity allergic reactions are female gender, age, and taking beta blockers or ACE inhibitor drugs. PMID:23198457

  18. In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel.

    PubMed

    Rathnayake, Samira; Mongan, John; Torres, Andrew S; Colborn, Robert; Gao, Dong-Wei; Yeh, Benjamin M; Fu, Yanjun

    2016-07-01

    To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (-100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30-44% and 36-45%, both p < 0.001) higher for double-contrast DECT than for conventional CT with enteric tungsten and tantalum contrast, respectively. Median small bowel wall visualization for double-contrast DECT was scored 29 and 35 percentage points (95% CI 20-35% and 33-39%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Median completeness of intraluminal enteric contrast subtraction in double-contrast DECT iodine density maps was scored 28 and 29 percentage points (95% CI 15-31% and 28-33%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Results suggest that in vivo double-contrast DECT with iodinated intravenous and either tantalum- or tungsten-based enteric contrast provides better visualization of small bowel than conventional CT. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26892945

  19. Iodinated α-tocopherol nano-emulsions as non-toxic contrast agents for preclinical X-ray imaging.

    PubMed

    Li, Xiang; Anton, Nicolas; Zuber, Guy; Zhao, Minjie; Messaddeq, Nadia; Hallouard, François; Fessi, Hatem; Vandamme, Thierry F

    2013-01-01

    Micro-computed tomography (micro-CT) is an emerging imaging modality, due to the low cost of the imagers as well as their efficiency in establishing high-resolution (1-100 μm) three-dimensional images of small laboratory animals and facilitating rapid, structural and functional in vivo visualization. However use of a contrast agent is absolutely necessary when imaging soft tissues. The main limitation of micro-CT is the low efficiency and toxicity of the commercially available blood pool contrast agents. This study proposes new, efficient and non-toxic contrast agents for micro-CT imaging. This formulation consists of iodinated vitamin E (α-tocopheryl 2,3,5-triiodobenzoate) as an oily phase, formulated as liquid nano-emulsion droplets (by low-energy nano-emulsification), surrounded by a hairy PEG layer to confer stealth properties. The originality and strength of these new contrast agents lie not only in their outstanding contrasting properties, biocompatibility and low toxicity, but also in the simplicity of their fabrication: one-step synthesis of highly iodinated oil (iodine constitutes 41.7% of the oil molecule weight) and its spontaneous emulsification. After i.v. administration in mice (8.5% of blood volume), the product shows stealth properties towards the immune system and thus acts as an efficient blood pool contrast agent (t(1/2) = 9.0 h), exhibiting blood clearance following mono-exponential decay. A gradual accumulation predominantly due to hepatocyte uptake is observed and measured in the liver, establishing a strong hepatic contrast, persistent for more than four months. To summarize, in the current range of available or developed contrast agents for preclinical X-ray imaging, this agent appears to be one of the most efficient. PMID:23083930

  20. Investigation of the use of iodinated contrast agent in a proposed flat-panel CT mammography system

    NASA Astrophysics Data System (ADS)

    Didier, Clay; Glick, Stephen; Gong, Xing; Chen, Yu; Mahd, Mufeed

    2007-03-01

    In considering a breast CT system, it is important to note that the spectral attenuation profile of a tumor is very similar to that of fibro-glandular tissue. Preliminary evidence based on imaging breast specimens suggest that the CT number of a malignant breast tumor is very similar to that of surrounding fibro-glandular tissue. Therefore, it is expected that radiologists will probably rely more on tumor morphology to distinguish a malignant tumor from fibro-glandular tissue than an increase in contrast per se. Previous studies have shown that iodinated contrast agents can increase the effective attenuation coefficient yielded by a breast tumor thereby providing increased CT tumor contrast. In order to characterize how the intravenous administration of an iodinated contrast agent can affect the performance of CT breast imaging, a computer simulation of such a system was conducted. The two primary goals of this investigation were first to determine how mean glandular dose, choice of x-ray energy spectrum, and iodine contrast agent density affect tumor detection, and second to determine what effect Compton and Rayleigh scattering have on the variability of the attenuation coefficient yielded by CT mammography. The first goal was achieved by making use of a modified version of the Bakic (Med. Phys. 2003) digital breast phantom to model the uncompressed breast, and a 0.5 cm sphere representing a breast tumor was digitally inserted into the ductal region of this phantom. Several projection sets were generated with the tumor containing various densities of iodine contrast agent, different x-ray energy spectra, and different mean glandular dosage (MGD) levels . Slices through the tumor were extracted from the reconstructions of these projections and were used in human observer studies to determine tumor detectability. The second goal was achieved by using the GATE (Geant 4 Application for Tomographic Emission) Monte-Carlo software package to compute the scattering

  1. Arterial double-contrast dual-energy MDCT: in-vivo rabbit atherosclerosis with iodinated nanoparticles and gadolinium agents

    NASA Astrophysics Data System (ADS)

    Carmi, Raz; Kafri, Galit; Altman, Ami; Goshen, Liran; Planer, David; Sosna, Jacob

    2010-03-01

    An in-vivo feasibility study of potentially improved atherosclerosis CT imaging is presented. By administration of two different contrast agents to rabbits with induced atherosclerotic plaques we aim at identifying both soft plaque and vessel lumen simultaneously. Initial injection of iodinated nanoparticle (INP) contrast agent (N1177 - Nanoscan Imaging), two to four hours before scan, leads to its later accumulation in macrophage-rich soft plaque, while a second gadolinium contrast agent (Magnevist) injected immediately prior to the scan blends with the aortic blood. The distinction between the two agents in a single scan is achieved with a double-layer dual-energy MDCT (Philips Healthcare) following material separation analysis using the reconstructed images of the different x-ray spectra. A single contrast agent injection scan, where only INP was injected two hours prior to the scan, was compared to a double-contrast scan taken four hours after INP injection and immediately after gadolinium injection. On the single contrast agent scan we observed along the aorta walls, localized iodine accumulation which can point on INP uptake by atherosclerotic plaque. In the double-contrast scan the gadolinium contributes a clearer depiction of the vessel lumen in addition to the lasting INP presence. The material separation shows a good correlation to the pathologies inferred from the conventional CT images of the two different scans while performing only a single scan prevents miss-registration problems and reduces radiation dose. These results suggest that a double-contrast dual-energy CT may be used for advanced clinical diagnostic applications.

  2. Environmental risk assessment for the widely used iodinated X-ray contrast agent iopromide (Ultravist).

    PubMed

    Steger-Hartmann, T; Länge, R; Schweinfurth, H

    1999-03-01

    Iodinated X-ray contrast media are diagnostic pharmaceuticals that are applied to enhance the contrast between organs or vessels examined and surrounding tissues during radiography. These substances are applied in doses up to ca. 200 g per person (corresponding to approx 100 g iodine) and are rapidly excreted. In the sewage system they contribute to the burden of adsorbable organic halogens (AOX). To assess the potential environmental impact of this release, studies on environmental fate and effects were conducted for a risk assessment of the frequently used X-ray contrast medium iopromide (brand name: Ultravist). A screening test for biological degradation (OECD Screening Test 301 E) led to iopromide being classified as not readily biodegradable. Therefore, the predicted environmental concentration (PEC) in surface water was calculated in a first step. The resulting concentration of 2 microgram/liter was then compared in a second step with the predicted no-effect concentration as derived from a battery of ecotoxicity tests. In short-term toxicity tests with bacteria (Vibrio fisheri, Pseudomonas putida), algae (Scenedesmus subspicatus), crustaceans (Daphnia magna), and fish (Danio rerio, Leuciscus idus) no toxic effects were detected at the highest tested concentration of 10 g/liter. In a chronic toxicity test with D. magna no effect was observed at the highest tested concentration of 1 g/liter. Using an assessment factor of 100 the ratio between the predicted environmental concentration (PEC) and the predicted no-effect concentration (PNEC) was calculated to be

  3. Computed Tomography Imaging of Solid Tumors Using a Liposomal-Iodine Contrast Agent in Companion Dogs with Naturally Occurring Cancer

    PubMed Central

    Ghaghada, Ketan B.; Sato, Amy F.; Starosolski, Zbigniew A.; Berg, John; Vail, David M.

    2016-01-01

    Objectives Companion dogs with naturally occurring cancer serve as an important large animal model in translational research because they share strong similarities with human cancers. In this study, we investigated a long circulating liposomal-iodine contrast agent (Liposomal-I) for computed tomography (CT) imaging of solid tumors in companion dogs with naturally occurring cancer. Materials and Methods The institutional animal ethics committees approved the study and written informed consent was obtained from all owners. Thirteen dogs (mean age 10.1 years) with a variety of masses including primary and metastatic liver tumors, sarcomas, mammary carcinoma and lung tumors, were enrolled in the study. CT imaging was performed pre-contrast and at 15 minutes and 24 hours after intravenous administration of Liposomal-I (275 mg/kg iodine dose). Conventional contrast-enhanced CT imaging was performed in a subset of dogs, 90 minutes prior to administration of Liposomal-I. Histologic or cytologic diagnosis was obtained for each dog prior to admission into the study. Results Liposomal-I resulted in significant (p < 0.05) enhancement and uniform opacification of the vascular compartment. Non-renal, reticulo-endothelial systemic clearance of the contrast agent was demonstrated. Liposomal-I enabled visualization of primary and metastatic liver tumors. Sub-cm sized liver lesions grossly appeared as hypo-enhanced compared to the surrounding normal parenchyma with improved lesion conspicuity in the post-24 hour scan. Large liver tumors (> 1 cm) demonstrated a heterogeneous pattern of intra-tumoral signal with visibly higher signal enhancement at the post-24 hour time point. Extra-hepatic, extra-splenic tumors, including histiocytic sarcoma, anaplastic sarcoma, mammary carcinoma and lung tumors, were visualized with a heterogeneous enhancement pattern in the post-24 hour scan. Conclusions The long circulating liposomal-iodine contrast agent enabled prolonged visualization of small

  4. Iodinated NanoClusters as an inhaled CT contrast agent for lung visualization

    PubMed Central

    Aillon, Kristin L.; El-Gendy, Nashwa; Norenberg, Jeffery P.; McDonald, Jacob; Dennis, Connor; Berkland, Cory

    2014-01-01

    Improvements to contrast media formulations may be an effective way to increase the accuracy and effectiveness of thoracic computed tomography (CT) imaging in disease evaluation. To achieve contrast enhancement in the lungs, a relatively large localized concentration of contrast media must be delivered. Inhalation offers a non-invasive alternative to intrapleural injections for local lung delivery, but effective aerosolization may deter successful imaging strategies. Here, NanoCluster technology was applied to N1177, a diatrizoic acid derivative, to formulate low density nanoparticle agglomerates with aerodynamic diameters ≤ 5 µm. Excipient-free N1177 NanoCluster powders were delivered to rats by insufflation or inhalation and scanned using CT up to 2 h post dose. CT images after inhalation showed a ~120 HU contrast increase in the lungs, which was more than sufficient contrast for thoracic CT imaging. Lung tissue histology demonstrated that N1177 NanoClusters did not damage the lungs. NanoCluster particle engineering technology offers a novel approach to safely and efficiently disseminate high concentrations of contrast agents to the lung periphery. PMID:20575527

  5. Allergy-like reactions to iodinated contrast agents. A critical analysis.

    PubMed

    Idée, Jean-Marc; Pinès, Emmanuelle; Prigent, Philippe; Corot, Claire

    2005-06-01

    Allergy-like reactions may occur following administration of iodinated contrast media (CM), mostly in at-risk patients (patients with history of previous reaction, history of allergy, co-treated with interleukin-2 or beta-blockers, etc.) but remain generally unpredictable. Severe and fatal reactions are very rare events. All categories of CM may induce such reactions, although first generation (high osmolar CM) have been found to induce a higher rate of adverse events than low osmolar CM. However, no differences were found between the two categories of CM with respect to mortality. Delayed reactions can also occur. There are no differences between the various categories of CM except for non-ionic dimers, which are more likely to induce such effect. Numerous clinical studies have evaluated the prophylactic value of drugs (mostly antihistamines and corticosteroids). Results are unclear and highly variable. Any prevention depends upon the mechanism involved. However, the mechanism of CM-induced allergy-like reaction remains disputed. Relatively recent data revived the hypothesis of a type-I hypersensitivity mechanism. Positive skin tests to CM have been reported. However, the affinity of IgE towards CM has been found to be very low in the only study which actually evaluated it. Other pathophysiological mechanisms (involving direct secretory effects on mast cells or basophils, or activation of the complement system associated or not with the plasma contact system) are also much debated. Anaphylaxis and anaphylactoid reactions are, in the end, clinically undistinguishable. PMID:15910651

  6. Dose distributions using kilovoltage x-rays and dose enhancement from iodine contrast agents

    NASA Astrophysics Data System (ADS)

    Mesa, A. V.; Norman, A.; Solberg, T. D.; Demarco, J. J.; Smathers, J. B.

    1999-08-01

    In x-ray phototherapy of brain tumours, the tumour is loaded with iodine and exposed to kilovoltage x-rays. Due to the high photoelectric cross sections of iodine, substantial photoelectric interactions occur. The flux of photoelectrons, characteristic x-rays and Auger electrons produce a localized dose enhancement. A modified computed tomography scanner, CTRx, can be used both for tumour localization and delivery of the dose enhancement therapy. Monte Carlo methods were employed to simulate the treatment of iodinated brain tumours with a CTRx. The calculated results reveal the effect of tumour iodine concentration on dose distribution, the degree of skull bone sparing with the application of multiple arcs, and the homogeneity of tumour dose distribution versus iodine concentration. A comparison with 10 MV stereotactic radiosurgery treatment shows the potential of CTRx treatment relative to conventional treatment modalities.

  7. Size and CT density of iodine-containing ethosomal vesicles obtained by membrane extrusion: potential for use as CT contrast agents.

    PubMed

    Na, Bomin; Choi, Byoung Wook; Kim, Bumsang

    2013-11-01

    Computed tomography (CT) is the primary non-invasive imaging technique used for most patients with suspected liver disease. In order to improve liver-specific imaging properties and prevent toxic effects in patients with compromised renal function, we investigated the encapsulation of iodine within ethosomal vesicles. As a first step in the development of novel contrast agents using ethosomes for CT imaging applications, iodine was entrapped within ethosomes and iodine-containing ethosomes of the desired size were obtained by extrusion using a polycarbonate membrane with a defined pore size. Ethosomes containing iodine showed a relatively high CT density, which decreased when they were extruded, due to the rupture and re-formation of the lipid bilayer of the ethosome. However, when a solution with a high iodine concentration was used as a dispersion media during the extrusion process, the decrease in CT density could be prevented. In addition, ethosomes containing iodine were taken up efficiently by macrophages, which are abundant in the liver, and these ethosomes exhibited no cellular toxicity. These results demonstrate that iodine could be entrapped within ethosomal vesicles, giving the ethosomes a relatively high CT density, and that the extrusion technique used in this study could conveniently and reproducibly produce ethosomal vesicles with a desired size. Therefore, ethosomes containing iodine, as prepared in this study, have potential as contrast agents with applications in CT imaging. PMID:23857905

  8. Borate complexes of x-ray iodinated contrast agents: characterization and sorption studies for their removal from aqueous media.

    PubMed

    Rustighi, Isabella; Donati, Ivan; Ferluga, Matteo; Campa, Cristiana; Pasqua, Adele E; Rossi, Marco; Paoletti, Sergio

    2012-02-29

    Iodinated contrast media (ICM) are persistent and ubiquitous water pollutants. Because of their high water solubility and biochemical stability, their phase-separation and recovery from the aquatic environment is very difficult. Here, borate was chosen as a complexing agent of the two diagnostic aids iomeprol and iopamidol in order to provide them with a negative charge and to fix the resulting adducts on Dowex 1X4 ion exchangers. A systematic characterization study of the complex by means of capillary zone electrophoresis and 11B NMR revealed that iomeprol and iopamidol interact with borate anions in aqueous solutions giving a 1:1 single-charged adduct and that the association constant at 25 °C for both contrast agents is highest at pH 10.5. These findings allowed the proper calibration of experimental parameters for further batch adsorption-desorption trials, where the two ICM were shown to be almost completely removed from the water phase and released from the solid sorbents in mild conditions, enabling the recovery of functional resin. PMID:22245510

  9. SU-E-QI-21: Iodinated Contrast Agent Time Course In Human Brain Metastasis: A Study For Stereotactic Synchrotron Radiotherapy Clinical Trials

    SciTech Connect

    Obeid, L; Esteve, F; Adam, J; Tessier, A; Balosso, J

    2014-06-15

    Purpose: Synchrotron stereotactic radiotherapy (SSRT) is an innovative treatment combining the selective accumulation of heavy elements in tumors with stereotactic irradiations using monochromatic medium energy x-rays from a synchrotron source. Phase I/II clinical trials on brain metastasis are underway using venous infusion of iodinated contrast agents. The radiation dose enhancement depends on the amount of iodine in the tumor and its time course. In the present study, the reproducibility of iodine concentrations between the CT planning scan day (Day 0) and the treatment day (Day 10) was assessed in order to predict dose errors. Methods: For each of days 0 and 10, three patients received a biphasic intravenous injection of iodinated contrast agent (40 ml, 4 ml/s, followed by 160 ml, 0.5 ml/s) in order to ensure stable intra-tumoral amounts of iodine during the treatment. Two volumetric CT scans (before and after iodine injection) and a multi-slice dynamic CT of the brain were performed using conventional radiotherapy CT (Day 0) or quantitative synchrotron radiation CT (Day 10). A 3D rigid registration was processed between images. The absolute and relative differences of absolute iodine concentrations and their corresponding dose errors were evaluated in the GTV and PTV used for treatment planning. Results: The differences in iodine concentrations remained within the standard deviation limits. The 3D absolute differences followed a normal distribution centered at zero mg/ml with a variance (∼1 mg/ml) which is related to the image noise. Conclusion: The results suggest that dose errors depend only on the image noise. This study shows that stable amounts of iodine are achievable in brain metastasis for SSRT treatment in a 10 days interval.

  10. Successful transfemoral aortic Edwards(®) SAPIEN(®) bioprosthesis implantation without using iodinated contrast media in a woman with severe allergy to contrast agent.

    PubMed

    Leroux, Lionel; Dijos, Marina; Dos Santos, Pierre

    2013-12-01

    Severe anaphylactoid reaction after the use of iodinated contrast media are rare but can contraindicate the use of contrast agent. It was the case of a 53-year-old woman suffering from symptomatic severe aortic stenosis, recused for cardiac surgery because of deleterious effects of chest-wall irradiation, with porcelain aorta. We decided to implant a 23-mm Edwards(®) SAPIEN(®) transcatheter aortic valve via a femoral route without using any contrast media. The implantation was successful after surgical approach of the femoral artery, transesophageal echocardiography guiding, and localization of native leaflets and coronary trunk with catheters. Immediate and one month post-interventional follow-up was favorable and echocardiography showed a good functioning of the aortic bioprosthesis. Although conventional angiography is the best way to visualize the good positioning of the valve before deployment, our case suggests that, in special situations, transfemoral implantation of an Edwards(®) SAPIEN(®) aortic bioprosthesis is feasible without any contrast injection. PMID:23197475

  11. Dual-Energy Computed Tomography Imaging of Atherosclerotic Plaques in a Mouse Model Using a Liposomal-Iodine Nanoparticle Contrast Agent

    PubMed Central

    Bhavane, Rohan; Badea, Cristian; Ghaghada, Ketan B.; Clark, Darin; Vela, Deborah; Moturu, Anoosha; Annapragada, Akshaya; Johnson, G. Allan; Willerson, James T.; Annapragada, Ananth

    2013-01-01

    Background The accumulation of macrophages in inflamed atherosclerotic plaques has been long recognized. In an attempt to develop an imaging agent for detection of vulnerable plaques, we evaluated the feasibility of a liposomal-iodine nanoparticle contrast agent for computed tomography (CT) imaging of macrophage-rich atherosclerotic plaques in a mouse model. Methods and Results Liposomal-iodine formulations varying in particle size and polyethylene glycol coating were fabricated, and shown to stably encapsulate the iodine compound. In vitro uptake studies using optical and CT imaging in the RAW264.7 macrophage cell line identified the formulation that promoted maximal uptake. Dual-energy CT imaging using this formulation in Apolipoprotein E deficient (ApoE−/−) mice (n=8) and control C57BL/6 mice (n=6) followed by spectral decomposition of the dual-energy images enabled imaging of the liposomes localized in the plaque. Imaging cytometry confirmed the presence of liposomes in the plaque and their co-localization with a small fraction (~2%) of the macrophages in the plaque. Conclusions The results demonstrate the feasibility of imaging macrophage-rich atherosclerotic plaques using a liposomal-iodine nanoparticle contrast agent and dual-energy CT. PMID:23349231

  12. Double-low protocol for hepatic dynamic CT scan: Effect of low tube voltage and low-dose iodine contrast agent on image quality.

    PubMed

    Zhang, Xiuli; Li, Shaodong; Liu, Wenlou; Huang, Ning; Li, Jingjing; Cheng, Li; Xu, Kai

    2016-06-01

    The radiation-induced carcinogenesis from computed tomography (CT) and iodine contrast agent induced nephropathy has attracted international attention. The reduction of the radiation dose and iodine intake in CT scan is always a direction for researchers to strive. The purpose of this study was to evaluate the feasibility of a "double-low" (i.e., low tube voltage and low-dose iodine contrast agent) scanning protocol for dynamic hepatic CT with the adaptive statistical iterative reconstruction (ASIR) in patients with a body mass index (BMI) of 18.5 to 27.9 kg/m.A total of 128 consecutive patients with a BMI between 18.5 and 27.9 kg/m were randomly assigned into 3 groups according to tube voltage, iodine contrast agent, and reconstruction algorithms. Group A (the "double-low" protocol): 100 kVp tube voltage with 40% ASIR, iodixanol at 270 mg I/mL, group B: 120 kVp tube voltage with filtered back projection (FBP), iodixanol at 270 mg I/ mL, and group C: 120 kVp tube voltage with FBP, ioversol at 350 mg I/ mL.The volume CT dose index (CTDIvol) and effective dose (ED) in group A were lower than those in group B and C (all P < 0.01). The iodine intake in group A was decreased by approximately 26.5% than group C, whereas no statistical difference was observed between group A and B (P > 0.05). There was no significant difference of the CT values between group A and C (P > 0.05), which both showed higher CT values than that in group B (P < 0.001). However, no statistic difference was observed in the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and image-quality scores among the 3 groups (all P > 0.05). Near-perfect consistency of the evaluation for group A, B, and C (Kenall's W = 0.921, 0.874, and 0.949, respectively) was obtained by the 4 readers with respect to the overall image quality.These results suggested that the "double-low" protocol with ASIR algorithm for multi-phase hepatic CT scan can dramatically decrease

  13. [Complications related to the administration of iodinated contrast media].

    PubMed

    Cappeliez, O; Lemort, M; Dagnelie, J

    1997-12-01

    Improvement brought to iodinated molecules aims to obtain an optimal enhancement effect together with a lower toxicity. However, benign adverse events remain a common risk, and anaphylactoid reactions from the intravascular administration of iodinated contrast media may occur at random and are unpredictable. Although most contrast reactions are mild and self-limited, severe and even life-threatening reactions can occur at any time and for any kind of agent. Physicians must be aware of possible complications related to administration of this kind of agents and must be able to identify patients at risk, to care for prevention and prescribe an appropriate premedication regimen. PMID:9481156

  14. Renal Safety of Iodinated Contrast Media Depending on Their Osmolarity – Current Outlooks

    PubMed Central

    Mruk, Bartosz

    2016-01-01

    Summary Iodinated contrast media (ICM) are commonly administered pharmaceutical agents. Most often they are used intravenously and intraarterially. Although iodinated contrast agents are relatively safe and widely used, adverse events occur and questions remain about their use, safety, and interactions. The most important adverse effects of contrast media include hypersensitivity reactions, thyroid dysfunction, and contrast-induced nephropathy. Radiologists must be aware of the risk factors for reactions to contrast media. Nonionic iodinated contrast agents can be divided into monomeric, low-osmolar, and dimeric, iso-osmolar classes. The osmotic characteristics of contrast media have been a significant focus in many investigations of contrast-induced nephropathy. PMID:27141236

  15. [Suggestions for prevention of adverse reactions after intravasal administration of iodinated contrast media].

    PubMed

    Kuefner, Michael A; Heinrich, Marc; Bautz, Werner; Uder, Michael

    2008-01-01

    Iodinated contrast media are widely used in computed tomography and angiography. Adverse reactions such as contrast-medium induced nephropathy (CIN), anaphylactoid reactions and iodine-induced thyrotoxicosis are associated with intravasal administration of contrast agents. Iodinated contrast agents are generally considered to be safe, but in rare cases they can cause severe life threatening situations. In this review we present an overview about the incidence, pathways, and risk factors of adverse reactions. Simple schemes including hydration protocols for prevention of CIN, medication for prophylaxis of iodine-induced thyrotoxicosis with thyreostatics and anaphylactoid reactions with histamine antagonists and corticosteroids are suggested. PMID:19294866

  16. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  17. Contrast agent choice for intravenous coronary angiography

    SciTech Connect

    Zeman, H.D.; Siddons, D.P.

    1989-01-01

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with monochromatic synchrotron radiation x-rays and an iodine containing contrast agent at the Stanford Synchrotron Radiation Laboratory have shown that such an intravenous angiography procedure would be possible with an adequately intense monochromatic x-ray source. Because of the size and cost of synchrotron radiation facilities it would be desirable to make the most efficient use of the intensity available, while reducing as much as possible the radiation dose experienced by the patient. By choosing contrast agents containing elements with a higher atomic number than iodine, it is possible to both improve the image quality and reduce the patient radiation dose, while using the same synchrotron source. By using Si monochromator crystals with a small mosaic spread, it is possible to increase the x-ray flux available for imaging by over an order of magnitude, without any changes in the storage ring or wiggler magnet. The most critical imaging task for intravenous coronary angiography utilizing synchrotron radiation x-rays is visualizing a coronary artery through the left ventricle or aorta which also contains a contrast agent. Calculations have been made of the signal to noise ratio expected for this imaging task for various contrast agents with atomic numbers between that of iodine and bismuth.

  18. A Review: Radiographic Iodinated Contrast Media-Induced Thyroid Dysfunction

    PubMed Central

    Leung, Angela M.; Braverman, Lewis E.; Brent, Gregory A.; Pearce, Elizabeth N.

    2015-01-01

    Context: Thyroid hormone production is dependent on adequate iodine intake. Excess iodine is generally well-tolerated, but thyroid dysfunction can occur in susceptible individuals after excess iodine exposure. Radiological iodinated contrast media represent an increasingly common source of excess iodine. Objective: This review will discuss the thyroidal response after acute exposure to excess iodine; contrast iodine-induced thyroid dysfunction; risks of iodine-induced thyroid dysfunction in vulnerable populations, such as the fetus, neonate, and patients with impaired renal function; and recommendations for the assessment and treatment of contrast iodine-induced thyroid dysfunction. Methods: Data for this review were identified by searching PubMed, Google Scholar, and references from relevant articles from 1948 to 2014. Conclusions: With the increase in the use of computed tomography scans in the United States, there is increasing risk of contrast-induced thyroid dysfunction. Patients at risk of developing iodine-induced thyroid dysfunction should be closely monitored after receiving iodinated contrast media and should be treated as needed. PMID:25375985

  19. Contrast agent choice for intravenous coronary angiography

    NASA Astrophysics Data System (ADS)

    Zeman, H. D.; Siddons, D. P.

    1990-05-01

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with monochromatic synchrotron radiation X-rays and an iodine-containing contrast agent at the Stanford Synchrotron Radiation Laboratory have shown that such an intravenous angiography procedure would be possible with an adequately intense monochromatic X-ray source. Because of the size and cost of synchrotron radiation facilities it would be desirable to make the most efficient use of the intensity available, while reducing as much as possible the radiation dose experienced by the patient. By choosing contrast agents containing elements with a higher atomic number than iodine, it is possible to both improve the image quality and reduce the patient radiation dose, while using the same synchrotron radiation source. By using Si monochromator crystals with a small mosaic spread, it is possible to increase the X-ray flux available for imaging by over an order of magnitude, without any changes in the storage ring or wiggler magnet. The most critical imaging task for intravenous coronary angiography utilizing synchrotron radiation X-rays is visualizing a coronary artery through the left ventricle or aorta which also contain contrast agent. Calculations have been made of the signal to noise ratio expected for this imaging task for various contrast agents with atomic numbers between that of iodine and bismuth. The X-ray energy spectrum of the X-17 superconduction wiggler beam line at the National Synchrotron Light Source at Brookhaven National Laboratory has been used for these calculations. Both perfect Si crystals and Si crystals with a small mosaic spread are considered as monochromators. Contrast agents containing Gd or Yb seem to have about the optimal calculated signal to noise ratio. Gd-DTPA is already approved for use as a contrast agent for

  20. Intravascular iodinated contrast media and the anaesthetist.

    PubMed

    Dickinson, M C; Kam, P C A

    2008-06-01

    The use of intravascular iodinated contrast media (ICM) in radiological investigations is common. Increasingly, anaesthetists and intensivists are involved in the care of patients undergoing these investigations. Whilst the use of ICM is generally safe there are important adverse effects that need to be recognised and measures instigated to prevent or treat these effects. In patients at risk of developing adverse reactions it is important to consider alternative modes of imaging so that ICM can be avoided. Strategies for the prevention of ICM nephropathy should be considered in all patients receiving ICM. Currently intravascular volume expansion with 0.9% saline has the strongest evidence base. The use of isotonic sodium bicarbonate combined with N-acetylcysteine appears promising in providing further benefits. Although the use of N-acetylcysteine alone has not been shown to significantly reduce the incidence of ICM nephropathy it is cheap, has few adverse effects and it would seem reasonable to continue its use in conjunction with intravascular volume expansion. The routine use of corticosteroid and antihistamine premedication is not always effective in preventing general adverse reactions. PMID:18477275

  1. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, Paul H.; Brainard, James R.; Jarvinen, Gordon D.; Ryan, Robert R.

    1997-01-01

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

  2. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  3. The use of iodinated and gadolinium contrast media during pregnancy and lactation.

    PubMed

    Webb, Judith A W; Thomsen, Henrik S; Morcos, Sameh K

    2005-06-01

    The use of iodinated or gadolinium-based contrast media in pregnant or lactating women often causes concerns in the radiology department because of the principle of not exposing a fetus or neonate to any drugs. Because of the uncertainty about the use of contrast media during pregnancy and lactation, the Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines. An extensive literature search was carried out and summarized in a report. Based on the limited information available, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. Mutagenic and teratogenic effects have not been described after administration of gadolinium or iodinated contrast media. Free iodide in radiographic contrast medium given to the mother has the potential to depress fetal/neonatal thyroid function. Neonatal thyroid function should be checked during the 1st week if iodinated contrast media have been given during pregnancy. No effect on the fetus has been seen after gadolinium contrast media. Only tiny amounts of iodinated or gadolinium-based contrast medium given to a lactating mother reach the milk, and only a minute proportion entering the baby's gut is absorbed. The very small potential risk associated with absorption of contrast medium may be considered insufficient to warrant stopping breast-feeding for 24 h following either iodinated or gadolinium contrast agents. PMID:15609057

  4. Reduction of iodinated contrast medium in CT: feasibility study

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Mei, Kai; Kopp, Felix K.; Penchev, Petar; Rummeny, Ernst J.; Fiebich, Martin; Noël, Peter B.

    2015-03-01

    In CT, the magnitude of enhancement is proportional to the amount of contrast medium (CM) injected. However, high doses of iodinated CM pose health risks, ranging from mild side effects to serious complications such as contrast-induced nephropathy (CIN). This work presents a method that enables the reduction of CM dosage, without affecting the diagnostic image quality. The technique proposed takes advantage of the additional spectral information provided by photon-counting CT systems. In the first step, we apply a material decomposition technique on the projection data to discriminate iodine from other materials. Then, we estimated the noise of the decomposed image by calculating the Cramér-Rao lower bound of the parameter estimator. Next, we iteratively reconstruct the iodine-only image by using the decomposed image and the estimation of noise as an input into a maximum-likelihood iterative reconstruction algorithm. Finally, we combine the iodine-only image with the original image to enhance the contrast of low iodine concentrations. The resulting reconstructions show a notably improved contrast in the final images. Quantitatively, the combined image has a significantly improved CNR, while the measured concentrations are closer to the actual concentrations of the iodine. The preliminary results from our technique show the possibility of reducing the clinical dosage of iodine, without affecting the diagnostic image quality.

  5. Nanoparticle Contrast Agents for Computed Tomography: A Focus on Micelles

    PubMed Central

    Cormode, David P.; Naha, Pratap C.; Fayad, Zahi A.

    2014-01-01

    Computed tomography (CT) is an X-ray based whole body imaging technique that is widely used in medicine. Clinically approved contrast agents for CT are iodinated small molecules or barium suspensions. Over the past seven years there has been a great increase in the development of nanoparticles as CT contrast agents. Nanoparticles have several advantages over small molecule CT contrast agents, such as long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Furthermore, there is a need for novel CT contrast agents, due to the growing population of renally impaired patients and patients hypersensitive to iodinated contrast. Micelles and lipoproteins, a micelle-related class of nanoparticle, have notably been adapted as CT contrast agents. In this review we discuss the principles of CT image formation and the generation of CT contrast. We discuss the progress in developing non-targeted, targeted and cell tracking nanoparticle CT contrast agents. We feature agents based on micelles and used in conjunction with spectral CT. The large contrast agent doses needed will necessitate careful toxicology studies prior to clinical translation. However, the field has seen tremendous advances in the past decade and we expect many more advances to come in the next decade. PMID:24470293

  6. Environmentally responsive MRI contrast agents

    PubMed Central

    Davies, Gemma-Louise; Kramberger, Iris; Davis, Jason J.

    2015-01-01

    Biomedical imaging techniques can provide a vast amount of anatomical information, enabling diagnosis and the monitoring of disease and treatment profile. MRI uniquely offers convenient, non-invasive, high resolution tomographic imaging. A considerable amount of effort has been invested, across several decades, in the design of non toxic paramagnetic contrast agents capable of enhancing positive MRI signal contrast. Recently, focus has shifted towards the development of agents capable of specifically reporting on their local biochemical environment, where a switch in image contrast is triggered by a specific stimulus/biochemical variable. Such an ability would not only strengthen diagnosis but also provide unique disease-specific biochemical insight. This feature article focuses on recent progress in the development of MRI contrast switching with molecular, macromolecular and nanoparticle-based agents. PMID:24040650

  7. Polycatechol Nanoparticle MRI Contrast Agents.

    PubMed

    Li, Yiwen; Huang, Yuran; Wang, Zhao; Carniato, Fabio; Xie, Yijun; Patterson, Joseph P; Thompson, Matthew P; Andolina, Christopher M; Ditri, Treffly B; Millstone, Jill E; Figueroa, Joshua S; Rinehart, Jeffrey D; Scadeng, Miriam; Botta, Mauro; Gianneschi, Nathan C

    2016-02-01

    Amphiphilic triblock copolymers containing Fe(III) -catecholate complexes formulated as spherical- or cylindrical-shaped micellar nanoparticles (SMN and CMN, respectively) are described as new T1-weighted agents with high relaxivity, low cytotoxicity, and long-term stability in biological fluids. Relaxivities of both SMN and CMN exceed those of established gadolinium chelates across a wide range of magnetic field strengths. Interestingly, shape-dependent behavior is observed in terms of the particles' interactions with HeLa cells, with CMN exhibiting enhanced uptake and contrast via magnetic resonance imaging (MRI) compared with SMN. These results suggest that control over soft nanoparticle shape will provide an avenue for optimization of particle-based contrast agents as biodiagnostics. The polycatechol nanoparticles are proposed as suitable for preclinical investigations into their viability as gadolinium-free, safe, and effective imaging agents for MRI contrast enhancement. PMID:26681255

  8. Contrast-Medium-Enhanced Digital Mammography: Contrast vs. Iodine Concentration Phantom Calibration

    SciTech Connect

    Rosado-Mendez, I.; Brandan, M. E.; Villasenor, Y.; Benitez-Bribiesca, L.

    2008-08-11

    This work deals with the application of the contrast-medium-enhanced digital subtraction mammography technique in order to calibrate the contrast level in subtracted phantom images as function of iodine concentration to perform dynamic studies of the contrast-medium uptake in the breast. Previously optimized dual-energy temporal subtraction modalities were used (a) to determine radiological parameters for a dynamic clinical study composed of 1 mask+3 post-contrast images limiting the total mean glandular dose to 2.5 mGy, and (b) to perform a contrast vs iodine concentration calibration using a custom-made phantom. Calculated exposure values were applied using a commercial full-field digital mammography unit. Contrast in subtracted phantom images (one mask and one post-CM) is linear as function of iodine concentration, although the sensitivity (contrast per iodine concentration) decreases beyond 8 mg/mL. This calibration seems to apply only to thin and normal thickness breasts.

  9. Does iodinated contrast medium amplify DNA damage during exposure to radiation.

    PubMed

    Riley, Peter

    2015-01-01

    There is a recognized increased risk of cancer following exposure of humans to ionizing radiation; this is felt to be most likely due to damage to DNA strands during exposure. Damage to DNA strands can be demonstrated microscopically following exposure to X-rays, and new evidence is emerging that this effect may be compounded by administration of iodinated contrast agents. PMID:26234959

  10. Contrast agents in diagnostic imaging: Present and future.

    PubMed

    Caschera, Luca; Lazzara, Angelo; Piergallini, Lorenzo; Ricci, Domenico; Tuscano, Bruno; Vanzulli, Angelo

    2016-08-01

    Specific contrast agents have been developed for x ray examinations (mainly CT), sonography and Magnetic Resonance Imaging. Most of them are extracellular agents which create different enhancement on basis of different vascularization or on basis of different interstitial network in tissues, but some can be targeted to a particular cell line (e.g. hepatocyte). Microbubbles can be used as carrier for therapeutic drugs which can be released in specific targets under sonographic guidance, decreasing systemic toxicity and increasing therapeutic effect. Radiologists have to choose a particular contrast agent knowing its physical and chemical properties and the possibility of adverse reactions and balancing them with the clinical benefits of a more accurate diagnosis. As for any drug, contrast agents can cause adverse events, which are more frequent with Iodine based CA, but also with Gd based CA and even with sonographic contrast agents hypersensitivity reaction can occur. PMID:27168225

  11. S-Nitrosylation in Organs of Mice Exposed to Low or High Doses of γ-Rays: The Modulating Effect of Iodine Contrast Agent at a Low Radiation Dose

    PubMed Central

    Nicolas, Fadia; Wu, Changgong; Bukhari, Salwa; de Toledo, Sonia M.; Li, Hong; Shibata, Masayuki; Azzam, Edouard I.

    2015-01-01

    The covalent addition of nitric oxide (NO•) onto cysteine thiols, or S-nitrosylation, modulates the activity of key signaling proteins. The dysregulation of normal S-nitrosylation contributes to degenerative conditions and to cancer. To gain insight into the biochemical changes induced by low-dose ionizing radiation, we determined global S-nitrosylation by the “biotin switch” assay coupled with mass spectrometry analyses in organs of C57BL/6J mice exposed to acute 0.1 Gy of 137Cs γ-rays. The dose of radiation was delivered to the whole body in the presence or absence of iopamidol, an iodinated contrast agent used during radiological examinations. To investigate whether similar or distinct nitrosylation patterns are induced following high-dose irradiation, mice were exposed in parallel to acute 4 Gy of 137Cs γ rays. Analysis of modulated S-nitrosothiols (SNO-proteins) in freshly-harvested organs of animals sacrificed 13 days after irradiation revealed radiation dose- and contrast agent-dependent changes. The major results were as follows: (i) iopamidol alone had significant effects on S-nitrosylation in brain, lung and liver; (ii) relative to the control, exposure to 0.1 Gy without iopamidol resulted in statistically-significant SNO changes in proteins that differ in molecular weight in liver, lung, brain and blood plasma; (iii) iopamidol enhanced the decrease in S-nitrosylation induced by 0.1 Gy in brain; (iv) whereas a decrease in S-nitrosylation occurred at 0.1 Gy for proteins of ~50 kDa in brain and for proteins of ~37 kDa in liver, an increase was detected at 4 Gy in both organs; (v) mass spectrometry analyses of nitrosylated proteins in brain revealed differential modulation of SNO proteins (e.g., sodium/potassium-transporting ATPase subunit beta-1; beta tubulins; ADP-ribosylation factor 5) by low- and high-dose irradiation; and (vi) ingenuity pathway analysis identified major signaling networks to be modulated, in particular the neuronal nitric oxide

  12. [Adverse reactions to iodinated contrast media: how to prevent them?].

    PubMed

    Berner, Jeanne; Poletti, Pierre-Alexandre; Becker, Christoph D; Nendaz, Mathieu

    2009-10-14

    The incidence of acute iodine contrast media reactions, appearing within the first hour after the procedure, is low but clinically important due to their daily use. Previous adverse reactions to iodinated contrast media, asthma and a history of allergic reaction are the most recognized risk factors, but the identification of patients at risk remains difficult. The efficacy of preventive measures such as corticosteroid and/or antihistaminic administration rests on low-level evidence. Practical recommendations are presented in this article. Rather than relying on the sole administration of a premedication, the importance of other measures must be stressed: assessing the relevance of the indication to the radiologic exam, use of low osmolarity contrast media, and ensuring a proper monitoring of the patient during and after the procedure. PMID:19911686

  13. Iodine vapor staining for atomic number contrast in backscattered electron and X-ray imaging.

    PubMed

    Boyde, Alan; Mccorkell, Fergus A; Taylor, Graham K; Bomphrey, Richard J; Doube, Michael

    2014-12-01

    Iodine imparts strong contrast to objects imaged with electrons and X-rays due to its high atomic number (53), and is widely used in liquid form as a microscopic stain and clinical contrast agent. We have developed a simple technique which exploits elemental iodine's sublimation-deposition state-change equilibrium to vapor stain specimens with iodine gas. Specimens are enclosed in a gas-tight container along with a small mass of solid I2 . The bottle is left at ambient laboratory conditions while staining proceeds until empirically determined completion (typically days to weeks). We demonstrate the utility of iodine vapor staining by applying it to resin-embedded tissue blocks and whole locusts and imaging them with backscattered electron scanning electron microscopy (BSE SEM) or X-ray microtomography (XMT). Contrast is comparable to that achieved with liquid staining but without the consequent tissue shrinkage, stain pooling, or uneven coverage artefacts associated with immersing the specimen in iodine solutions. Unmineralized tissue histology can be read in BSE SEM images with good discrimination between tissue components. Organs within the locust head are readily distinguished in XMT images with particularly useful contrast in the chitin exoskeleton, muscle and nerves. Here, we have used iodine vapor staining for two imaging modalities in frequent use in our laboratories and on the specimen types with which we work. It is likely to be equally convenient for a wide range of specimens, and for other modalities which generate contrast from electron- and photon-sample interactions, such as transmission electron microscopy and light microscopy. PMID:25219801

  14. Iodine Vapor Staining for Atomic Number Contrast in Backscattered Electron and X-ray Imaging

    PubMed Central

    Boyde, Alan; Mccorkell, Fergus A; Taylor, Graham K; Bomphrey, Richard J; Doube, Michael

    2014-01-01

    Iodine imparts strong contrast to objects imaged with electrons and X-rays due to its high atomic number (53), and is widely used in liquid form as a microscopic stain and clinical contrast agent. We have developed a simple technique which exploits elemental iodine's sublimation-deposition state-change equilibrium to vapor stain specimens with iodine gas. Specimens are enclosed in a gas-tight container along with a small mass of solid I2. The bottle is left at ambient laboratory conditions while staining proceeds until empirically determined completion (typically days to weeks). We demonstrate the utility of iodine vapor staining by applying it to resin-embedded tissue blocks and whole locusts and imaging them with backscattered electron scanning electron microscopy (BSE SEM) or X-ray microtomography (XMT). Contrast is comparable to that achieved with liquid staining but without the consequent tissue shrinkage, stain pooling, or uneven coverage artefacts associated with immersing the specimen in iodine solutions. Unmineralized tissue histology can be read in BSE SEM images with good discrimination between tissue components. Organs within the locust head are readily distinguished in XMT images with particularly useful contrast in the chitin exoskeleton, muscle and nerves. Here, we have used iodine vapor staining for two imaging modalities in frequent use in our laboratories and on the specimen types with which we work. It is likely to be equally convenient for a wide range of specimens, and for other modalities which generate contrast from electron- and photon-sample interactions, such as transmission electron microscopy and light microscopy. Microsc. Res. Tech. 77:1044–1051, 2014. © 2014 The Authors. Microscopy Research Technique published by Wiley Periodocals, Inc. PMID:25219801

  15. Renal Artery Stenting Using CO2 Gas Angiography in Combination with Iodinated Contrast Angiography.

    PubMed

    Adachi, Yuya; Endo, Akihiro; Nakashima, Ryuma; Sugamori, Takashi; Takahashi, Nobuyuki; Kinoshita, Yoshihisa; Tanabe, Kazuaki

    2016-01-01

    A 76-year-old woman was hospitalized repeatedly due to unexplained heart failure. On admission, she had hypertensive acute heart failure. Her symptoms disappeared promptly after the initial treatment; however, her systolic blood pressure remained at over 160 mmHg despite her taking three antihypertensive drugs. Closer examination revealed hemodynamically significant right renal artery stenosis and a lack of left kidney function. We performed percutaneous transluminal renal angioplasty using CO2 angiography in combination with iodinated contrast agents. The patient's renal function and blood pressure improved, however, CO2 gas-induced mild ischemic colitis occurred. We discuss the possibility of the use of combined iodinated contrast angiography and CO2 angiography to avoid contrast-induced nephropathy and the complications peculiar to CO2 angiography. PMID:27580543

  16. Optimal exposure techniques for iodinated contrast enhanced breast CT

    NASA Astrophysics Data System (ADS)

    Glick, Stephen J.; Makeev, Andrey

    2016-03-01

    Screening for breast cancer using mammography has been very successful in the effort to reduce breast cancer mortality, and its use has largely resulted in the 30% reduction in breast cancer mortality observed since 1990 [1]. However, diagnostic mammography remains an area of breast imaging that is in great need for improvement. One imaging modality proposed for improving the accuracy of diagnostic workup is iodinated contrast-enhanced breast CT [2]. In this study, a mathematical framework is used to evaluate optimal exposure techniques for contrast-enhanced breast CT. The ideal observer signal-to-noise ratio (i.e., d') figure-of-merit is used to provide a task performance based assessment of optimal acquisition parameters under the assumptions of a linear, shift-invariant imaging system. A parallel-cascade model was used to estimate signal and noise propagation through the detector, and a realistic lesion model with iodine uptake was embedded into a structured breast background. Ideal observer performance was investigated across kVp settings, filter materials, and filter thickness. Results indicated many kVp spectra/filter combinations can improve performance over currently used x-ray spectra.

  17. "Basic MR Relaxation Mechanisms & Contrast Agent Design"

    PubMed Central

    De León-Rodríguez, Luis M.; Martins, André F.; Pinho, Marco; Rofsky, Neil; Sherry, A. Dean

    2015-01-01

    The diagnostic capabilities of magnetic resonance imaging (MRI) have undergone continuous and substantial evolution by virtue of hardware and software innovations and the development and implementation of exogenous contrast media. Thirty years since the first MRI contrast agent was approved for clinical use, a reliance on MR contrast media persists largely to improve image quality with higher contrast resolution and to provide additional functional characterization of normal and abnormal tissues. Further development of MR contrast media is an important component in the quest for continued augmentation of diagnostic capabilities. In this review we will detail the many important considerations when pursuing the design and use of MR contrast media. We will offer a perspective on the importance of chemical stability, particularly kinetic stability, and how this influences one's thinking about the safety of metal-ligand based contrast agents. We will discuss the mechanisms involved in magnetic resonance relaxation in the context of probe design strategies. A brief description of currently available contrast agents will be accompanied by an in-depth discussion that highlights promising MRI contrast agents in development for future clinical and research applications. Our intention is to give a diverse audience an improved understanding of the factors involved in developing new types of safe and highly efficient MR contrast agents and, at the same time, provide an appreciation of the insights into physiology and disease that newer types of responsive agents can provide. PMID:25975847

  18. Iodinated Contrast Does Not Alter Clotting Dynamics in Acute Ischemic Stroke as Measured by Thromboelastography

    PubMed Central

    McDonald, Mark M; Archeval-Lao, Joancy M; Cai, Chunyan; Peng, Hui; Sangha, Navdeep; Parker, Stephanie A; Wetzel, Jeremy; Riney, Stephen A; Cherches, Matt F; Guthrie, Greer J; Roper, Tiffany C; Kawano-Castillo, Jorge F; Pandurengan, Renga; Rahbar, Mohammad H; Grotta, James C

    2014-01-01

    Background and Purpose Iodinated contrast agents used for computed tomography angiography (CTA) may alter fibrin fiber characteristics and decrease fibrinolysis by tissue plasminogen activator (tPA). Thromboelastography (TEG™) measures the dynamics of coagulation and correlates with thrombolysis in acute ischemic stroke (AIS) patients. We hypothesized that receiving CTA prior to tPA will not impair thrombolysis as measured by TEG™. Methods AIS patients receiving 0.9 mg/kg tPA within 4.5 hours of symptom onset were prospectively enrolled. For CTA, 350 mg/dL of iohexol or 320 mg/dL of iodixanol at a dose of 2.2 ml/kg was administered. TEG™ was measured prior to tPA and 10-minutes after tPA bolus. CTA timing was left to the discretion of the treating physician. Results Of 136 AIS patients who received tPA, 47 had CTA prior to tPA bolus, and 42 had either CTA following tPA and post-tPA TEG™ draw or no CTA (non-contrast group). The median change in clot lysis (LY30) following tPA was 95.3% in the contrast group vs. 95.0% in the non-contrast group (p = 0.74). Thus, tPA-induced thrombolysis did not differ between contrast and non-contrast groups. Additionally, there was no effect of contrast on any pre-tPA TEG™ value. Conclusions Our data do not support an effect of iodinated contrast agents on clot formation or tPA activity. PMID:24370757

  19. Intravascular ultrasound-guided central vein angioplasty and stenting without the use of radiographic contrast agents.

    PubMed

    Matthews, Ray; Thomas, Joseph

    2008-05-01

    Patients with contraindications to iodinated radiographic contrast agents present a significant challenge during endovascular intervention. A 46-year-old man with end-stage renal disease and a normally functioning left upper extremity arteriovenous fistula presented with severe left arm edema. The patient's history included repeated severe anaphylactoid reactions with severe respiratory distress upon exposure to iodinated contrast. In an attempt to avoid the use of iodinated contrast, angioplasty and stent placement of a severe central venous stenosis were performed using only fluoroscopy and intravascular sonography. In patients unable to receive iodinated contrast secondary to anaphylactoid reactions, intravascular sonography can be used to guide angioplasty and stenting of central venous stenosis. PMID:18286503

  20. Contrast medium usage reduction in abdominal computed tomography by using high-iodinated concentration contrast medium

    NASA Astrophysics Data System (ADS)

    Suwannasri, A.; Kaewlai, R.; Asavaphatiboon, S.

    2016-03-01

    This study was to determine if administration of a low volume high-concentration iodinated contrast medium can preserve image quality in comparison with regular-concentration intravenous contrast medium in patient undergoing contrast-enhancement abdominal computed tomography (CT). Eighty-four patients were randomly divided into 3 groups of similar iodine delivery rate; A: 1.2 cc/kg of iomeprol-400, B: 1.0 cc/kg of iomeprol-400 and C: 1.5 cc/kg of ioversol-350. Contrast enhancement of the liver parenchyma, pancreas and aorta was quantitatively measured in Hounsfield units and qualitative assessed by a radiologist. T-test was used to evaluate contrast enhancement, and Chi-square test was used to evaluate qualitative image assessment, at significance level of 0.05 with 95% confidence intervals. There were no statistically significant differences in contrast enhancement of liver parenchyma and pancreas between group A and group C in both quantitative and qualitative analyses. Group C showed superior vascular enhancement to group A and B on quantitative analysis.

  1. Development and production of a prototype iodine contrast phantom for CEDEM

    NASA Astrophysics Data System (ADS)

    Leithner, Robert; Knogler, Thomas; Homolka, Peter

    2013-02-01

    Phantoms containing iodine details with clinically relevant iodine concentrations are required to systematically study dose requirements, for quality assurance and optimizing exposure parameters and protocols for contrast enhanced dual energy mammography (CEDEM) applications. Most such phantoms use liquid iodine solutions, challenging the user with air inclusions, evaporation or the necessity for changing the iodine concentration through refilling. A prototype phantom with an array of sintered solid iodine-containing platelets with iodine area weights of 0, 0.25, 0.5, 1, 1.5 and 2 mg cm-2 is described. Disks containing various iodine concentrations were produced using polymer sintering of Iopamidol embedded into a polystyrene/graphite matrix. Iopamidol-containing platelets with a diameter of 0.5 cm and thickness of 550 µm forming an array with gradually increasing iodine area weight, were embedded in PMMA to allow statistical analysis of contrast and contrast-to-noise ratio (CNR). The homogeneity of the plates was tested and images of the phantom were acquired to assess the iodine area density progression and to evaluate phantom accuracy. The phantom was imaged on a mammography system applying low and high energy spectra as used for CEDEM. The disks show good homogeneity. Uncertainties in absolute iodine area weight were estimated ±5%. The iodine CNR showed a linear correlation with R2 > 0.99. Polymer powder sintering works well for producing stable iodine contrast phantoms without the necessity to handle liquid iodine solutions. Thus, it is a promising approach to construct phantoms not only for CEDEM but also angiography or other contrast enhanced methods with iodine details for quality control or research purposes and optimization.

  2. Small-animal microangiography using phase-contrast X-ray imaging and gas as contrast agent

    NASA Astrophysics Data System (ADS)

    Lundström, Ulf; Larsson, Daniel H.; Westermark, Ulrica K.; Burvall, Anna; Hertz, Hans M.

    2014-03-01

    We use propagation-based phase-contrast X-ray imaging with gas as contrast agent to visualize the microvasculature in small animals like mice and rats. The radiation dose required for absorption X-ray imaging is proportional to the minus fourth power of the structure size to be detected. This makes small vessels impossible to image at reasonable radiation doses using the absorption of conventional iodinated contrast agents. Propagation-based phase contrast gives enhanced contrast for high spatial frequencies by moving the detector away from the sample to let phase variations in the transmitted X-rays develop into intensity variations at the detector. Blood vessels are normally difficult to observe in phase contrast even with iodinated contrast agents as the density difference between blood and most tissues is relatively small. By injecting gas into the blood stream this density difference can be greatly enhanced giving strong phase contrast. One possible gas to use is carbon dioxide, which is a clinically accepted X-ray contrast agent. The gas is injected into the blood stream of patients to temporarily displace the blood in a region and thereby reduce the X-ray absorption in the blood vessels. We have shown that this method can be used to image blood vessels down to 8 μm in diameter in mouse ears. The low dose requirements of this method indicate a potential for live small-animal imaging and longitudinal studies of angiogenesis.

  3. Contrast-induced acute kidney injury following iodine opacification other than by intravascular injection

    PubMed Central

    Perrin, Tilman; Hemett, Ould Maouloud; Menth, Markus; Descombes, Eric

    2012-01-01

    Contrast-induced acute kidney injury (CI-AKI) classically occurs following the intravascular administration of iodinated contrast medium (CM). However, some cases of iodine-induced nephrotoxicity have been reported in patients who did not receive intravascular CM, as a consequence of iodine absorption through mucosae, burned skin or interstitial tissues. Recently, we observed the first case of CI-AKI occurring after an enteroclysis without any direct intravascular injection of CM. Here, we report this case, and review other clinical situations in which renal toxicity has been reported following the non-intravascular use of iodinated compounds. PMID:24175084

  4. Anaphylactoid and anaphylactic reactions to iodinated contrast material.

    PubMed

    Laroche, D; Namour, F; Lefrançois, C; Aimone-Gastin, I; Romano, A; Sainte-Laudy, J; Laxenaire, M C; Guéant, J L

    1999-01-01

    Some adverse reactions to iodinated contrast material (ICM) are considered allergy-like, with cutaneous, cardiovascular, respiratory, and digestive symptoms. Allergy-like reactions are usually unpredictable. Reactions are more frequent with ionic than with nonionic material, but the frequency of deaths is almost identical. In a recent study, 20 severe unexpected reactions to ICM, including 10 life-threatening reactions and one death, were investigated by measuring mediators in blood, within the first minutes or hours of reaction. The responsible ICMs were mostly ionic materials. Histamine and tryptase release correlated with the severity of the reaction. Specific IgE against the responsible ICM was significantly higher in reactors than in controls. A few patients had positive skin tests to the administered ICM, suggesting type-I allergic reaction. Only 2.4% and 3.1% of the cases yielded a positive IgE-RIA, in a second retrospective study which included 165 patients recruited during a 4-year period. In conclusion, IgE-mediated anaphylaxis is rare, but it may be one of the possible mechanisms of severe adverse reactions to ICM. PMID:10735643

  5. Carbon dioxide as a substitute for iodine contrast in arteriography during embolectomy

    PubMed Central

    Wolosker, Nelson; Teivelis, Marcelo Passos; Mendes, Cynthia de Almeida; Nishinari, Kenji; Ribeiro, Mariângela de Freitas; Kuzniec, Sergio

    2015-01-01

    Acute limb ischemia can be potentially harmful to the limb and life threatening. Renal failure is a possible outcome associated with release of products of ischemic limb reperfusion. Some authors reported the benefit of performing angiography after embolectomy, even though iodine contrast is also nephrotoxic. We report a case of embolectomy on a patient with renal insufficiency in whom carbon dioxide was used as a substitute for iodine contrast. PMID:26061074

  6. Multifunctional nanoparticles as coupled contrast agents

    PubMed Central

    Jin, Yongdong; Jia, Congxian; Huang, Sheng-Wen; O’Donnell, Matthew; Gao, Xiaohu

    2011-01-01

    Engineering compact imaging probes with highly integrated modalities is a key focus in bionanotechnology and will have profound impact on molecular diagnostics, imaging, and therapeutics. However, combining multiple components on a nanometer scale to create new imaging modalities unavailable from individual components has proven challenging. Here, we demonstrate iron oxide and gold coupled core-shell nanoparticles with well defined structural characteristics (e.g., size, shell thickness, and core-shell separation) and physical properties (e.g., electronic, magnetic, optical, thermal, and acoustic). The resulting multifunctional nanoprobes not only offer contrast for electron microscopy, magnetic resonance imaging, and scattering-based imaging, but more importantly, enable a new imaging mode, magnetomotive photoacoustic (mmPA) imaging, with remarkable contrast enhancement compared to PA images using conventional nanoparticle contrast agents. PMID:20975706

  7. Micro-radiography of biological samples with medical contrast agents

    NASA Astrophysics Data System (ADS)

    Dammer, J.; Weyda, F.; Benes, J.; Sopko, V.; Gelbic, I.

    2013-12-01

    Micro-radiography is an imaging technique that uses X-rays to study the internal structures of objects. This fast and easy imaging tool is based on differential X-ray attenuation by various tissues and structures within biological samples. The experimental setup described is based on the semiconductor pixel X-ray detector Medipix2 and X-ray micro-focus tube. Our micro-radiographic system has been recently used not only for the examination of internal structures of various arthropods and other biological objects but also for tracing some processes in selected model species (we used living larvae of mosquito Culex quinquefasciatus). Low concentrations of iodine, lanthanum or gold particles were used as a tracer (contrast agent). Such contrast agents increase the absorption of X-rays and allow a better visibility of internal structures of model organisms (especially the various cavities, pores, etc.). In addition, the movement of tracers in selected timing experiments demonstrates some physiological functions of digestive and excretory system.

  8. Optical imaging with dynamic contrast agents.

    PubMed

    Wei, Qingshan; Wei, Alexander

    2011-01-24

    Biological imaging applications often employ molecular probes or nanoparticles for enhanced contrast. However, resolution and detection are still often limited by the intrinsic heterogeneity of the sample, which can produce high levels of background that obscure the signals of interest. Herein, we describe approaches to overcome this obstacle based on the concept of dynamic contrast: a strategy for elucidating signals by the suppression or removal of background noise. Dynamic contrast mechanisms can greatly reduce the loading requirement of contrast agents, and may be especially useful for single-probe imaging. Dynamic contrast modalities are also platform-independent, and can enhance the performance of sophisticated biomedical imaging systems or simple optical microscopes alike. Dynamic contrast is performed in two stages: 1) a signal modulation scheme to introduce time-dependent changes in amplitude or phase, and 2) a demodulation step for signal recovery. Optical signals can be coupled with magnetic nanoparticles, photoswitchable probes, or plasmon-resonant nanostructures for modulation by magnetomotive, photonic, or photothermal mechanisms, respectively. With respect to image demodulation, many of the strategies developed for signal processing in electronics and communication technologies can also be applied toward the editing of digital images. The image-processing step can be as simple as differential imaging, or may involve multiple reference points for deconvolution by using cross-correlation algorithms. Periodic signals are particularly amenable to image demodulation strategies based on Fourier transform; the contrast of the demodulated signal increases with acquisition time, and modulation frequencies in the kHz range are possible. Dynamic contrast is an emerging topic with considerable room for development, both with respect to molecular or nanoscale probes for signal modulation, and also to methods for more efficient image processing and editing. PMID

  9. Optimal Contrast Agent Staining of Ligaments and Tendons for X-Ray Computed Tomography.

    PubMed

    Balint, Richard; Lowe, Tristan; Shearer, Tom

    2016-01-01

    X-ray computed tomography has become an important tool for studying the microstructures of biological soft tissues, such as ligaments and tendons. Due to the low X-ray attenuation of such tissues, chemical contrast agents are often necessary to enhance contrast during scanning. In this article, the effects of using three different contrast agents-iodine potassium iodide solution, phosphotungstic acid and phosphomolybdic acid-are evaluated and compared. Porcine anterior cruciate ligaments, patellar tendons, medial collateral ligaments and lateral collateral ligaments were used as the basis of the study. Three samples of each of the four ligament/tendon types were each assigned a different contrast agent (giving a total of twelve samples), and the progression of that agent through the tissue was monitored by performing a scan every day for a total period of five days (giving a total of sixty scans). Since the samples were unstained on day one, they had been stained for a total of four days by the time of the final scans. The relative contrast enhancement and tissue deformation were measured. It was observed that the iodine potassium iodide solution penetrated the samples fastest and caused the least sample shrinkage on average (although significant deformation was observed by the time of the final scans), whereas the phosphomolybdic acid caused the greatest sample shrinkage. Equations describing the observed behaviour of the contrast agents, which can be used to predict optimal staining times for ligament and tendon X-ray computed tomography, are presented. PMID:27078030

  10. Iodine-125 metaraminol: A new platelet specific labeling agent

    SciTech Connect

    Ohmomo, Y.; Yokoyama, A.; Kawaii, K.; Horiuchi, K.; Saji, H.; Torizuka, K.

    1984-01-01

    In the search for a platelet specific labeling agent, Metaraminol (MA), which is a sympatomimetic amine used for the treatment of hypotension, cardiogenic shock and well recognized as a drug actively incorporated and accumulated in platelet, attracted the authors' attention. Using the classical chloramine-T iodination method, a high labeling efficiency near 98%, reaching a specific activity up to about 1000 Ci/mmole was obtained. Upon the harvest of platelet, only as platelet rich plasma (PRP), the labeling with this radiopharmaceutical was easily performed by incubation at 37/sup 0/C for 10 min. Labeling efficiency as high as 63.0 +- 3.1% at 24 x 10/sup 8/ cells/ml was obtained. In in-vitro studies, the unaltered state of I-125 MA labeled platelet, with their cellular functions fully retained was demonstrated. Pharmacological study indicated a specific incorporation of I-125 MA by active transport system similar to that of 5-HT, along with passive diffusion. Then the in-vivo study carried out in rabbits with induced thrombi on the femoral artery, showed rather rapid disappearance of the I-125 MA labeled autologous platelet radioactivity, from circulating blood reaching as high thrombus-to-blood activity ratio as 19.8+-4.3 within 30 min post-administration. This new platelet labeling agent, I-125 MA, has many advantages over the use of IN-111 oxine and holds considerable promise for thrombus imaging with single photon emission CT upon the availability of I-123 MA.

  11. Dual energy iodine contrast CT with monochromatic x-rays

    SciTech Connect

    Dilmanian, F.A.; Wu, X.Y.; Kress, J.

    1995-12-31

    Computed tomography (CT) with monochromatic x-ray beams was used to image phantoms and a live rabbit using the preclinical Multiple Energy Computed Tomography (MECT) system at the National Synchrotron Light Source. MECT has a horizontal fan beam with a subject apparatus rotating about a vertical axis. Images were obtained at 43 keV for single-energy studies, and at energies immediately below and above the 33.17 keV iodine K-edge for dual-energy subtraction CT. Two CdWO{sub 4}-photodiode array detectors were used. The high-resolution detector (0.5 mm pitch, uncollimated) provided 14 line pair/cm in-plane spatial resolution, with lower image noise than conventional CT. Images with the low-resolution detector (1.844-mm pitch, collimated to 0.922 mm detector elements) had a sensitivity for iodine of {approx} 60 {micro}g/cc in 11-mm channels inside a 135 mm-diameter acrylic cylindrical phantom for a slice height of 2.5 mm and a surface does of {approx} 4 cGy. The image noise was {approx} 1 Hounsfield Unit (HU); it was {approx} 3 HU for the same phantom imaged with conventional CT at approximately the same dose, slice height, and spatial resolution ({approx} 7 lp/cm). These results show the potential advantage of MECT, despite present technical limitations.

  12. Nanoparticle contrast agents for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Gabriele, Michelle Lynn

    Optical coherence tomography (OCT) provides real-time, objective, in-vivo, optical cross-sectional representations of the retina and optic nerve. Recent innovations in image acquisition, including the incorporation of Fourier/spectral-domain detection, have improved imaging speed, sensitivity and resolution. Still, there remain specific structures within ocular OCT images, such as retinal ganglion cells (RGCs), which are of clinical interest but consistently have low contrast. This makes it difficult to differentiate between surrounding layers and structures. The objectives of this project were: (1) To establish a reliable method for OCT imaging of the healthy and diseased mouse eye in order to provide a platform for testing the utility of OCT contrast agents for ocular imaging, (2) To develop antibody-conjugated gold nanoparticles suitable for targeting specific structures and enhancing OCT image contrast in the mouse eye, and (3) To examine the localized contrast-enhancing ability and biocompatibility of gold nanoparticle contrast agents in-vivo. Our organizing hypotheses were that nanoparticles could improve contrast by modulating the intensity of backscattered light detected by OCT and that they could be directed to ocular structures of interest using antibodies specific to cellular markers. A reproducible method for imaging the mouse retina and quantifying retinal thickness was developed and this technique was then applied to a mouse model for retinal ganglion cell loss, optic nerve crush. Gold nanorods were designed specifically to augment the backscattering OCT signal at the same wavelengths of light used in current ophthalmic OCT imaging schemes (resonant wavelength lambda = 840 nm). Anti-CD90.1 (Thy1.1) antibodies were conjugated to the gold nanorods and a protocol for characterization of the success of antibody conjugation was developed. Upon injection, the gold nanorods were found to remain in the vitreous post-injection, with many consumed by an early

  13. Photoacoustic cell for ultrasound contrast agent characterization.

    PubMed

    Alippi, A; Bettucci, A; Biagioni, A; D'Orazio, A; Germano, M; Passeri, D

    2010-10-01

    Photoacoustics has emerged as a tool for the study of liquid gel suspension behavior and has been recently employed in a number of new biomedical applications. In this paper, a photoacoustic sensor is presented which was designed and realized for analyzing photothermal signals from solutions filled with microbubbles, commonly used as ultrasound contrast agents in echographic imaging techniques. It is a closed cell device, where photothermal volume variation of an aqueous solution produces the periodic deflection of a thin membrane closing the cell at the end of a short pipe. The cell then acts as a Helmholtz resonator, where the displacement of the membrane is measured through a laser probe interferometer, whereas photoacoustic signal is generated by a laser chopped light beam impinging onto the solution through a glass window. Particularly, the microbubble shell has been modeled through an effective surface tension parameter, which has been then evaluated from experimental data through the shift of the resonance frequencies of the photoacoustic sensor. This shift of the resonance frequencies of the photoacoustic sensor caused by microbubble solutions is high enough for making such a cell a reliable tool for testing ultrasound contrast agent, particularly for bubble shell characterization. PMID:21034110

  14. Photoacoustic cell for ultrasound contrast agent characterization

    NASA Astrophysics Data System (ADS)

    Alippi, A.; Bettucci, A.; Biagioni, A.; D'Orazio, A.; Germano, M.; Passeri, D.

    2010-10-01

    Photoacoustics has emerged as a tool for the study of liquid gel suspension behavior and has been recently employed in a number of new biomedical applications. In this paper, a photoacoustic sensor is presented which was designed and realized for analyzing photothermal signals from solutions filled with microbubbles, commonly used as ultrasound contrast agents in echographic imaging techniques. It is a closed cell device, where photothermal volume variation of an aqueous solution produces the periodic deflection of a thin membrane closing the cell at the end of a short pipe. The cell then acts as a Helmholtz resonator, where the displacement of the membrane is measured through a laser probe interferometer, whereas photoacoustic signal is generated by a laser chopped light beam impinging onto the solution through a glass window. Particularly, the microbubble shell has been modeled through an effective surface tension parameter, which has been then evaluated from experimental data through the shift of the resonance frequencies of the photoacoustic sensor. This shift of the resonance frequencies of the photoacoustic sensor caused by microbubble solutions is high enough for making such a cell a reliable tool for testing ultrasound contrast agent, particularly for bubble shell characterization.

  15. Contrast Agents for Quantitative MicroCT of Lung Tumors in Mice

    PubMed Central

    Lalwani, Kush; Giddabasappa, Anand; Li, Danan; Olson, Peter; Simmons, Brett; Shojaei, Farbod; Arsdale, Todd Van; Christensen, James; Jackson-Fisher, Amy; Wong, Anthony; Lappin, Patrick B; Eswaraka, Jeetendra

    2013-01-01

    The identification and quantitative evaluation of lung tumors in mouse models is challenging and an unmet need in preclinical arena. In this study, we developed a noninvasive contrast-enhanced microCT (μCT) method to longitudinally evaluate and quantitate lung tumors in mice. Commercially available μCT contrast agents were compared to determine the optimal agent for visualization of thoracic blood vessels and lung tumors in naïve mice and in non-small-cell lung cancer models. Compared with the saline control, iopamidol and iodinated lipid agents provided only marginal increases in contrast resolution. The inorganic nanoparticulate agent provided the best contrast and visualization of thoracic vascular structures; the density contrast was highest at 15 min after injection and was stable for more than 4 h. Differential contrast of the tumors, vascular structures, and thoracic air space by the nanoparticulate agent enabled identification of tumor margins and accurate quantification. μCT data correlated closely with traditional histologic measurements (Pearson correlation coefficient, 0.995). Treatment of ELM4–ALK mice with crizotinib yielded 65% reduction in tumor size and thus demonstrated the utility of quantitative μCT in longitudinal preclinical trials. Overall and among the 3 agents we tested, the inorganic nanoparticulate product was the best commercially available contrast agent for visualization of thoracic blood vessels and lung tumors. Contrast-enhanced μCT imaging is an excellent noninvasive method for longitudinal evaluation during preclinical lung tumor studies. PMID:24326223

  16. Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection

    PubMed Central

    Sinharay, Sanhita; Pagel, Mark D.

    2016-01-01

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized 13C to detect the agent with outstanding sensitivity. These hyperpolarized 13C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection. PMID:27049630

  17. Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection

    NASA Astrophysics Data System (ADS)

    Sinharay, Sanhita; Pagel, Mark D.

    2016-06-01

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized 13C to detect the agent with outstanding sensitivity. These hyperpolarized 13C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection.

  18. Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection.

    PubMed

    Sinharay, Sanhita; Pagel, Mark D

    2016-06-12

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized (13)C to detect the agent with outstanding sensitivity. These hyperpolarized (13)C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection. PMID:27049630

  19. MMP-14 Triggered Fluorescence Contrast Agent.

    PubMed

    Nguyen, Mai-Dung; Kang, Kyung A

    2016-01-01

    Matrix metalloproteinase-14 (MMP-14) is involved in cancer invasion, metastasis, and angiogenesis. Therefore, it is considered to be a biomarker for aggressive cancer types, including some of the triple-negative breast cancer. Accurate (i.e., specific) and sensitive detection of MMP-14 can, thus, be important for the early diagnosis of and accurate prognosis for aggressive cancer, including the breast cancer caused by cell line MDA-MB 231. Fluorophore-mediated molecular sensing has been used for detecting biomarkers, for a long time. One way to increase the specificity of the sensing is designing the fluorophore to emit its fluorescence only when it encounters the biomarker of interest. When a fluorophore is placed on the surface of, or very close to a gold nanoparticle (GNP), its fluorescence is quenched. Applying this relationship between the GNP and fluorophore, we have developed a GNP-based, near-infrared fluorescent contrast agent that is highly specific for MMP-14. This agent normally emits only 14-17 % fluorescence of the free fluorophore. When the agent encounters MMP-14, its fluorescence gets fully restored, allowing MMP-14 specific optical signal emission. PMID:27526171

  20. Optimal Contrast Agent Staining of Ligaments and Tendons for X-Ray Computed Tomography

    PubMed Central

    Balint, Richard; Lowe, Tristan

    2016-01-01

    X-ray computed tomography has become an important tool for studying the microstructures of biological soft tissues, such as ligaments and tendons. Due to the low X-ray attenuation of such tissues, chemical contrast agents are often necessary to enhance contrast during scanning. In this article, the effects of using three different contrast agents—iodine potassium iodide solution, phosphotungstic acid and phosphomolybdic acid—are evaluated and compared. Porcine anterior cruciate ligaments, patellar tendons, medial collateral ligaments and lateral collateral ligaments were used as the basis of the study. Three samples of each of the four ligament/tendon types were each assigned a different contrast agent (giving a total of twelve samples), and the progression of that agent through the tissue was monitored by performing a scan every day for a total period of five days (giving a total of sixty scans). Since the samples were unstained on day one, they had been stained for a total of four days by the time of the final scans. The relative contrast enhancement and tissue deformation were measured. It was observed that the iodine potassium iodide solution penetrated the samples fastest and caused the least sample shrinkage on average (although significant deformation was observed by the time of the final scans), whereas the phosphomolybdic acid caused the greatest sample shrinkage. Equations describing the observed behaviour of the contrast agents, which can be used to predict optimal staining times for ligament and tendon X-ray computed tomography, are presented. PMID:27078030

  1. Iodine

    MedlinePlus

    ... of iodine are POSSIBLY UNSAFE. Adults should avoid prolonged use of doses higher than 1100 mcg per ... enlarged thyroid gland (goiter), or a thyroid tumor: Prolonged use or high doses of iodine might make ...

  2. Iodine

    MedlinePlus

    ... 6 weeks increases the healing rate. Also, applying povidone-iodine in addition to compression seems help heal ... Catheter-related infection. Some evidence suggests that applying povidone-iodine reduces the risk of blood stream infections ...

  3. Iodine

    MedlinePlus

    ... the amount depends on the iodine in the soil where they grew and in any fertilizer that ... babies. People living in regions with iodine-deficient soils who eat mostly local foods. These soils produce ...

  4. Iodine

    USGS Publications Warehouse

    Krukowski, S.T.

    2006-01-01

    In descending order, Chile, Japan and the United States have the largest iodine reserves. Chile produces iodine from iodate minerals while Japan and the United States produce it from sodium iodide solutions found in underground iodide solutions. Iodine is also produced from subterranean brines in Azerbaijan, Russia, Turkmenista, Indonesia and Uzbekistan. In 2005, iodine prices increased sharply to US$19 to US$23 then leveled off at US$23 to US$25.

  5. 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

  6. Gene transfection by echo contrast agent microbubbles

    NASA Astrophysics Data System (ADS)

    Tachibana, Katsuro

    2002-11-01

    In vitro and in vivo experiments have demonstrated that various echo contrast agent microbubbles can be intentionally ruptured by diagnostic and therapeutic ultrasound. Violent microstreaming are produced during microbubble collapse. Researchers have hypothesized that these microjets or microstreaming could be applied to promote diffusion of drugs into various tissues and lesions. The most exciting application of this method is probably delivery of genes into cells. As various genes are currently under investigation for the purpose of treating diseases, ultrasound and microbubbles may be used as a modality to promote better outcome for gene therapy. Recent studies have shown that different gases contained within the bubbles greatly influence the degree of gene transfection. Also, the outer layer of the microbubbles can be custom-made for binding to target tissue. Recent advance on this topic will be discussed.

  7. Intraoperative imaging using intravascular contrast agent

    NASA Astrophysics Data System (ADS)

    Watson, Jeffrey R.; Martirosyan, Nikolay; Garland, Summer; Lemole, G. Michael; Romanowski, Marek

    2016-03-01

    Near-infrared (NIR) contrast agents are becoming more frequently studied in medical imaging due to their advantageous characteristics, most notably the ability to capture near-infrared signal across the tissue and the safety of the technique. This produces a need for imaging technology that can be specific for both the NIR dye and medical application. Indocyanine green (ICG) is currently the primary NIR dye used in neurosurgery. Here we report on using the augmented microscope we described previously for image guidance in a rat glioma resection. Luc-C6 cells were implanted in a rat in the left-frontal lobe and grown for 22 days. Surgical resection was performed by a neurosurgeon using augmented microscopy guidance with ICG contrast. Videos and images were acquired to evaluate image quality and resection margins. ICG accumulated in the tumor tissue due to enhanced permeation and retention from the compromised bloodbrain- barrier. The augmented microscope was capable of guiding the rat glioma resection and intraoperatively highlighted tumor tissue regions via ICG fluorescence under normal illumination of the surgical field.

  8. Allergic reactions to iodinated contrast media: premedication considerations for patients at risk.

    PubMed

    Schopp, Jennifer G; Iyer, Ramesh S; Wang, Carolyn L; Petscavage, Jonelle M; Paladin, Angelisa M; Bush, William H; Dighe, Manjiri K

    2013-08-01

    The objectives of this article are to review allergy-type reactions to iodinated contrast media and the protocols utilized to prevent or reduce the occurrence of these adverse reactions in high-risk patients. We will begin by discussing the types or classifications of the adverse reactions to iodinated contrast media. We will then discuss reaction mechanisms, identify the patients at highest risk for adverse reactions, and clarify common misperceptions about the risk. Finally, we will discuss the actions of the medications used to help reduce or prevent allergy-type reactions to iodinated contrast media, the protocols used to help reduce or prevent contrast reactions in high-risk patients, and the potential side effects of these medications. We will also discuss the high-risk patient who has received premedication due to a prior index reaction and discuss the risk of having a subsequent reaction, termed "breakthrough reaction." Identifying patient at high risk for an "allergy-type" reaction to contrast media is an essential task of the radiologist. Prevention of or reduction of the risk of an adverse reaction is critical to patient safety. If an examination can be performed without contrast in a patient at high risk for an allergy-type reaction, it may be appropriate to avoid contrast. However, there are situations where contrast media is necessary, and the radiologist plays a vital role in preventing or mitigating an allergy-type reaction. PMID:23430296

  9. Role of iodinated contrast material in the evaluation of myocardial infarction by computerized transmission tomography.

    PubMed

    Higgins, C B; Siemers, P T; Newell, J D; Schmidt, W

    1980-01-01

    In vivo and in vitro studies have shown that areas of myocardial infarctions can be delineated on CT scans after intravenous administration of iodinated contrast material to dogs with experimental myocardial infarctions. Within the first minute after intravenous administration of contrast material (initial myocardial perfusion phase), the infarct appears an as area of decreased x-ray attenuation (cold spot image). Studies using radiolabeled microspheres indicate that the relative attenuation numbers throughout the myocardium in this phase reflect myocardial perfusion (Hessel et al, 1978). Delayed scans obtained at 5 minutes and later showed a reversal in the attenuation values of normal and infarcted myocardium with the infarct appearing as an area of homogeneous or mottled increase in x-ray density compared to normal myocardium. (Siemers et al, 1978; Carlsson et al, 1977; Higgins et al, 1979). This phenomenon of delayed contrast enhancement of myocardial infarctions ensues as early as 8 hours after coronary occlusion (Higgins et al, 1979) and is present in evolved infarcts as old as 51 days (Newell et al, 1979). Direct measurements of iodine concentration in infarcts, normal myocardium, and organs surrounding the heart were performed in dogs with 48-hour-old myocardial infarctions using fluorescent excitation analysis (Higgins et al, 1978, 1979). These measurements of iodine concentration in tissue samples obtained at 10-180 minutes after intravenous administration of contrast material indicated that the highest iodine concentration in the infarct was at 10 minutes, but the highest ratio of iodine concentration of the infarct to normal myocardium was at 180 minutes. At all time intervals, the concentration of iodine within the infarct was fivefold greater than in the normal myocardium. PMID:7203920

  10. SU-E-I-45: Feasibility for Using Iodine Quantification to Assist Diagnosis in Dual Energy Contrast-Enhanced Digital Mammography

    SciTech Connect

    Hwang, Y; Lin, Y; Tsai, C; Cheung, Y

    2015-06-15

    Purpose: The objective of this study is to develop quantitative calibration between image quality indexes and iodine concentration with dual-energy (DE) contrast-enhanced digital mammography (CEDM) techniques and further serve as the assistance for diagnosis. Methods: Custom-made acrylic phantom with dimensions of 24×30 cm{sup 2} simulated breast thickness from 2 to 6 cm was used in the calibration. The phantom contained matrix of four times four holes of 3 mm deep with a diameter of 15 mm for filling contrast agent with area density ranged from 0.1 to 10 mg/cm{sup 2}. All the image acquisitions were performed on a full-field digital mammography system (Senographe Essential, GE) with dual energy acquisitions. Mean pixel value (MPV), and contrast-to-noise ratio (CNR) were used for evaluating the relationship between image quality indexes and iodine concentration. Iodine map and CNR map could further be constructed with these calibration curves applied pixel by pixel utilized MATLAB software. Minimum iodine concentration could also be calculated with the visibility threshold of CNR=5 according the Rose model. Results: When evaluating the DE subtraction images, MPV increased linearly as the iodine concentration increased with all the phantom thickness surveyed (R{sup 2} between 0.989 and 0.992). Lesions with increased iodine uptake could thus be enhanced in the color-encoded iodine maps, and the mean iodine concentration could be obtained through the ROI measurements. As for investigating CNR performance, linear relationships were also shown between the iodine concentration and CNR (R{sup 2} between 0.983 and 0.990). Minimum iodine area density of 1.45, 1.73, 1.80, 1.73 and 1.72 mg/cm{sup 2} for phantom thickness of 2, 3, 4, 5, 6 cm were calculated based on Rose’s visualization criteria. Conclusion: Quantitative calibration between image quality indexes and iodine concentrations may further serving as the assistance for analyzing contrast enhancement for patient

  11. Dual-energy coronary angiography in pigs using a Gd contrast agent

    NASA Astrophysics Data System (ADS)

    Fiedler, Stefan; Elleaume, Helene; Le Duc, Geraldine; Nemoz, Christian; Brochard, Thierry; Renier, Michel; Bertrand, Bernard; Esteve, Francois; Le Bas, Jean-Francois; Suortti, Pekka; Thomlinson, William C.

    2000-04-01

    The European Synchrotron Radiation Facility Medical Research Beamline is now fully operational. One of the primary programs is the development of dual-energy transvenous coronary angiography for in vivo human research protocols. Previous work at this and other synchrotrons has been entirely devoted to the use of the dual-energy digital subtraction technique at the iodine k-absorption edge at 33.17 keV. The images are recorded in a line scan mode following venous injection of the contrast agent. Considerations of the patient dose, the dilution of the contrast agent in the pulmonary system and the arteries overlying the filled ventricles have limited the image quality. The ESRF facility was designed to allow dual- energy imaging at higher energies, for example at the gadolinium k-absorption edge at 50.24 keV. The advantages have been theoretically known for many years, with the higher energy promising higher image quality with less radiation dose. During the commissioning phase of the ESRF angiography program, the opportunity presented itself to image adult pigs in vivo with Gd contrast agent. This paper presents some initial results of the image quality in the Gd studies in comparison with iodine contrast agent studies, also carried out in adult pigs at the ESRF.

  12. Shellfish allergy and relation to iodinated contrast media: United Kingdom survey

    PubMed Central

    Baig, Mudassar; Farag, Ahmad; Sajid, Jamal; Potluri, Rahul; Irwin, R Bruce; Khalid, Hafiz Mohammed Idrees

    2014-01-01

    AIM: To assess current practice of United Kingdom cardiologists with respect to patients with reported shellfish/iodine allergy, and in particular the use of iodinated contrast for elective coronary angiography. Moreover we have reviewed the current evidence-base and guidelines available in this area. METHODS: A questionnaire survey was send to 500 senior United Kingdom cardiologists (almost 50% cardiologists registered with British Cardiovascular Society) using email and first 100 responses used to analyze practise. We involved cardiologists performing coronary angiograms routinely both at secondary and tertiary centres. Three specific questions relating to allergy were asked: (1) History of shellfish/iodine allergy in pre-angiography assessment; (2) Treatments offered for shellfish/iodine allergy individuals; and (3) Any specific treatment protocol for shellfish/iodine allergy cases. We aimed to establish routine practice in United Kingdom for patients undergoing elective coronary angiography. We also performed comprehensive PubMed search for the available evidence of relationship between shellfish/iodine allergy and contrast media. RESULTS: A total of 100 responses were received, representing 20% of all United Kingdom cardiologists. Ninety-three replies were received from consultant cardiologists, 4 from non-consultant grades and 3 from cardiology specialist nurses. Amongst the respondents, 66% routinely asked about a previous history of shellfish/iodine allergy. Fifty-six percent would pre-treat these patients with steroids and anti-histamines. The other 44% do nothing, or do nonspecific testing based on their personal experience as following: (1) Skin test with 1 mL of subcutaneous contrast before intravenous contrast; (2) Test dose 2 mL contrast before coronary injection; (3) Close observation for shellfish allergy patients; and (4) Minimal evidence that the steroid and anti-histamine regime is effective but it makes us feel better. CONCLUSION: There is no

  13. Successful stent implantation guided by intravascular ultrasound and a Doppler guidewire without contrast injection in a patient with allergy to iodinated contrast media.

    PubMed

    Okura, Hiroyuki; Nezuo, Shintaro; Yoshida, Kiyoshi

    2011-07-01

    Presence of allergy to iodinated contrast may prevent percutaneous coronary intervention (PCI) to be performed. We present a 76-year-old male with a history of allergic reaction to iodinated contrast who successfully underwent intravascular ultrasound (IVUS) and a Doppler guidewire-guided PCI. Stent size was determined based on IVUS. After PCI, stent expansion and a lack of edge dissection or incomplete apposition were confirmed by IVUS and a good antegrade coronary flow was confirmed by a Doppler guidewire. Thus, PCI without contrast injection under IVUS and a Doppler guidewire-guidance may be feasible in selected patients with allergy to iodinated contrast. PMID:21725127

  14. Tumor-specific fluorescent contrast agents

    NASA Astrophysics Data System (ADS)

    Achilefu, Samuel I.; Dorshow, Richard B.; Bugaj, Joseph E.; Rajagopalan, Raghavan

    2000-04-01

    Several dyes are currently used for various biomedical applications due to their biocompatibility and high molar absorptivity. Localization of dyes in tumors may be mediated by several factors such as leaky vasculature and high metabolic activity in proliferating cells. However, these mechanisms of action make it difficult to differentiate inflammation from benign or malignant tumors. In order to enhance their tumor specificity, dyes have been conjugated to biomolecules that target unique factors in various diseased state. However, such large biomolecules can elicit adverse immunogenic reactions in humans, and are often preferentially taken up by the liver. Furthermore, for solid tumors which may rely on diffusion of the biomarkers from the vascular, penetration of large dye conjugates is not favorable. To overcome these problems, we designed and synthesized novel dye-peptide conjugates that are receptor specific. The efficacy of these new fluorescent contrast agents was tested in vivo in well-characterized rat tumor lines. The resulting optical images demonstrate that successful specific tumor targeting was achieved.

  15. A method to evaluate the dose increase in CT with iodinated contrast medium

    SciTech Connect

    Amato, Ernesto; Lizio, Domenico; Settineri, Nicola; Di Pasquale, Andrea; Salamone, Ignazio; Pandolfo, Ignazio

    2010-08-15

    Purpose: The objective of this study is to develop a method to calculate the relative dose increase when a computerized tomography scan (CT) is carried out after administration of iodinated contrast medium, with respect to the same CT scan in absence of contrast medium. Methods: A Monte Carlo simulation in GEANT4 of anthropomorphic neck and abdomen phantoms exposed to a simplified model of CT scanner was set up in order to calculate the increase of dose to thyroid, liver, spleen, kidneys, and pancreas as a function of the quantity of iodine accumulated; a series of experimental measurements of Hounsfield unit (HU) increment for known concentrations of iodinated contrast medium was carried out on a Siemens Sensation 16 CT scanner in order to obtain a relationship between the increment in HU and the relative dose increase in the organs studied. The authors applied such a method to calculate the average dose increase in three patients who underwent standard CT protocols consisting of one native scan in absence of contrast, followed by a contrast-enhanced scan in venous phase. Results: The authors validated their GEANT4 Monte Carlo simulation by comparing the resulting dose increases for iodine solutions in water with the ones presented in literature and with their experimental data obtained through a Roentgen therapy unit. The relative dose increases as a function of the iodine mass fraction accumulated and as a function of the Hounsfield unit increment between the contrast-enhanced scan and the native scan are presented. The data shown for the three patients exhibit an average relative dose increase between 22% for liver and 74% for kidneys; also, spleen (34%), pancreas (28%), and thyroid (48%) show a remarkable average increase. Conclusions: The method developed allows a simple evaluation of the dose increase when iodinated contrast medium is used in CT scans, basing on the increment in Hounsfield units observed on the patients' organs. Since many clinical protocols

  16. Adverse reactions to intravenous iodinated contrast media: a primer for radiologists.

    PubMed

    Namasivayam, Saravanan; Kalra, Mannudeep K; Torres, William E; Small, William C

    2006-07-01

    Adverse reactions to intravenous iodinated contrast media may be classified as general and organ-specific, such as contrast-induced nephrotoxicity. General adverse reactions may be subclassified into acute and delayed types. Acute general adverse reactions can range from transient minor reactions to life-threatening severe reactions. Non-ionic contrast media have lower risk of mild and moderate adverse reactions. However, the risk of fatal reactions is similar for ionic and non-ionic contrast media. Adequate preprocedure evaluation should be performed to identify predisposing risk factors. Prompt recognition and treatment of acute adverse reactions is crucial. Risk of contrast induced nephrotoxicity can be reduced by use of non-ionic contrast media, less volume of contrast, and adequate hydration. The radiologist can play a pivotal role by being aware of predisposing factors, clinical presentation, and management of adverse reactions to contrast media. PMID:16688432

  17. Taxanes as a Risk Factor for Acute Adverse Reactions to Iodinated Contrast Media in Cancer Patients

    PubMed Central

    Farolfi, Alberto; Della Luna, Corradina; Ragazzini, Angela; Carretta, Elisa; Gentili, Nicola; Casadei, Carla; Aquilina, Michele; Barone, Domenico; Minguzzi, Martina; Amadori, Dino; Nanni, Oriana

    2014-01-01

    Background. The impact of cytotoxic agents on the risk of acute allergy-like adverse reactions (ARs) to intravenous iodinated contrast media (ICM) injections is unknown. Methods. We retrospectively reviewed 13,565 computed tomography (CT) scans performed in a consecutive cohort of cancer patients from January 1, 2010 to December 31, 2012. Episodes of acute ICM-related ARs were reported to the pharmacovigilance officer. The following matched comparisons were made: tax code, gender, primary tumor, antineoplastic therapy, and date of last cycle. Concomitant antineoplastic treatment was classified into five groups: platinum, taxane, platinum plus taxane, other, and no treatment group (no therapy had been administered in the previous 24 months). Logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI) to evaluate the risk of acute ICM-related ARs. Results. Of 10,472 contrast-enhanced CT scans, 97 (0.93%; 95% CI: 0.74–1.11) ICM-related ARs were reported, 11 of which (0.1%) were severe, including one fatality. The overall incidence was significantly higher in patients aged <65 years (p = .0062) and in the platinum plus taxane and taxane groups (p = .007), whereas no correlation was found with gender, number of previous CT scans, site of disease, or treatment setting. Multivariate analysis confirmed an increased risk for patients aged <65 years (OR: 1.73; 95% CI: 1.14–2.63) and for the taxane group (in comparison with the no treatment group; OR: 2.06; 95% CI: 1.02–4.16). Conclusion. Among cancer patients, concomitant treatment with taxanes and younger age would seem to be risk factors for ICM-related ARs. PMID:25063226

  18. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    NASA Astrophysics Data System (ADS)

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm‑1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm‑1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm‑1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility

  19. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    PubMed

    Wu, Po-Hung; Brace, Chris L

    2016-08-21

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm(-1)), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm(-1)) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm(-1)). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility

  20. Adverse reactions to iodinated contrast media administered at the time of endoscopic retrograde cholangiopancreatography (ERCP).

    PubMed

    Pan, Jen-Jung; Draganov, Peter V

    2009-03-01

    Adverse reactions after intravascular administration of iodine contrast media are common and prophylactic regiments consisting of the use of steroids and low osmolality contrast media are highly effective in significantly decreasing the adverse reactions rate. The same type of contrast media are also used for opacification of the biliary tree and the pancreatic duct at the time of endoscopic retrograde cholangiopancreatography (ERCP). Systemic absorption of contrast media after ERCP routinely occurs. Although the adverse reaction rate appears to be very low the exact incidence remains unknown due to the retrospective nature of all reports. Despite the lack of formal recommendations, numerous prophylactic regiments are routinely used prior to ERCP in patients with history of prior reaction to intravascular contrast media. Moreover, the use of prophylaxis has even expanded to patients with no prior reaction to intravascular contrast media who are somehow perceived to be at increase risk (e.g. shellfish allergy). Recently, the first large scale prospective study reported exceedingly low incidence of adverse reaction to high oslmolality iodine-containing contrast media administered at the time of ERCP done without prophylactic premedication even in patients considered to be at the highest risk (prior severe reaction to intravascular contrast media administration). These data suggest that the use of prophylactic regiments prior to ERCP appears to be unnecessary. PMID:19275689

  1. Non-toxic lead sulfide nanodots as efficient contrast agents for visualizing gastrointestinal tract.

    PubMed

    Liu, Zhen; Ran, Xiang; Liu, Jianhua; Du, Yingda; Ren, Jinsong; Qu, Xiaogang

    2016-09-01

    Non-invasive imaging of gastrointestinal (GI) tract using novel but efficient contrast agents is of the most important issues in the diagnosis and prognosis of GI diseases. Here, for the first time, we reported the design and synthesis of biothiol-decorated lead sulfide nanodots, as well as their usages in functional dual-modality imaging of GI tract in vivo. Due to the presence of glutathione on the surface of the nanodots, these well-prepared contrast agents could decrease the unwanted ion leakage, withstand the harsh conditions in GI tract, and avoid the systemic absorption after oral administration. Compared with clinical barium meal and iodine-based contrast agents, these nanodots exhibited much more significant enhancement in contrast efficiency during both 2D X-ray imaging and 3D CT imaging. Different from some conventional invasive imaging modalities, such as gastroscope and enteroscope, non-invasive imaging strategy by using glutathione modified PbS nanodots as contrast agents could reduce the painfulness towards patients, facilitate the imaging procedure, and economize the manipulation period. Moreover, long-term toxicity and bio-distribution of these nanodots after oral administration were evaluated in detail, which indicated their overall safety. Based on our present study, these nanodots could act as admirable contrast agents to integrate X-ray imaging and CT imaging for the direct visualization of GI tract. PMID:27240159

  2. Effect of Intravascular Iodinated Contrast Media on Natural Course of End-Stage Renal Disease Progression in Hemodialysis Patients: A Prospective Study

    SciTech Connect

    Janousek, Radim; Krajina, Antonin; Peregrin, Jan H.; Dusilova-Sulkova, Sylvie; Renc, Ondrej; Hajek, Jan; Dvorak, Kamil; Fixa, Petr; Cermakova, Eva

    2010-02-15

    We evaluated the impact of intravascular iodinated contrast medium on residual diuresis in hemodialyzed patients. Two groups of clinically stable hemodialyzed patients with residual diuresis minimally 500 ml of urine per day were studied. The patients from the first group were given iso-osmolal contrast agent iodixanol (Visipaque, GE Healthcare, United Kingdom) in concentration of iodine 320 mg/ml with osmolality 290 mOsm/kg of water during the endovascular procedure. The second control group was followed without contrast medium administered. Residual diuresis and residual renal excretory capacity expressed as 24-h calculated creatinine clearance were evaluated in the both groups after 6 months. The evaluated group included 42 patients who were given 99.3 ml of iodixanol in average (range, 60-180 ml). The control group included 45 patients. There was no statistically significant difference found between both groups in daily volume of urine (P = 0.855) and calculated clearance of creatinine (P = 0.573). We can conclude that residual diuresis is not significantly influenced by intravascular administration of iso-osmolal iodinated contrast agent (iodixanol) in range of volume from 60 to 180 ml in comparison to natural course of urinary output and residual renal function during end-stage renal disease. This result can help the nephrologist to decide which imaging method/contrast medium to use in dialyzed patients in current practice.

  3. A simple method to estimate the optimum iodine concentration of contrast material through microcatheters: hydrodynamic calculation with spreadsheet software

    NASA Astrophysics Data System (ADS)

    Yamauchi, Teiyu; Furui, Shigeru; Suzuki, Shigeru; Mimura, Kohshiro; Hayashi, Toshihiko; Yamada, Takeshi; Futami, Choichiro; Tsukiyama, Yumiko; Harada, Motoko

    2008-03-01

    It is important to increase the iodine delivery rate (I), that is the iodine concentration of the contrast material (C) × the flow rate of the contrast material (Q), through microcatheters to obtain arteriograms of the highest contrast. It is known that C is an important factor that influences I. The purpose of this study is to establish a method of hydrodynamic calculation of the optimum iodine concentration (i.e., the iodine concentration at which I becomes maximum) of the contrast material and its flow rate through commercially available microcatheters. Iopamidol, ioversol and iohexol of ten iodine concentrations were used. Iodine delivery rates (I meas) of each contrast material through ten microcatheters were measured. The calculated iodine delivery rate (I cal) and calculated optimum iodine concentration (calculated C opt) were obtained with spreadsheet software. The agreement between I cal and I meas was studied by correlation and logarithmic Bland-Altman analyses. The value of the calculated C opt was within the optimum range of iodine concentrations (i.e. the range of iodine concentrations at which I meas becomes 90% or more of the maximum) in all cases. A good correlation between I cal and I meas (I cal = 1.08 I meas, r = 0.99) was observed. Logarithmic Bland-Altman analysis showed that the 95% confidence interval of I cal/I meas was between 0.82 and 1.29. In conclusion, hydrodynamic calculation with spreadsheet software is an accurate, generally applicable and cost-saving method to estimate the value of the optimum iodine concentration and its flow rate through microcatheters.

  4. The effect of bilipolinum (Adipiodon), an iodine contrast medium on erythrocyte enzymes.

    PubMed

    Kwiatkowska, J; Kwiatkowska, D; Dawiskiba, J

    1980-01-01

    Bilipolinum (Adipiodon), iodine contrast medium used in cholangiography, showed an inhibitory effect on the activity of human erythrocyte phosphohexoseisomerase, phosphofructokinase, aldolase and glucose-6-phosphate dehydrogenase. The addition of glucose metabolites (glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bis-phosphate, pyruvate and lactate) abolished the inhibitory effect of Bilipolinum. In the presence of Bilipolinum purified erythrocyte phosphofructokinase showed a decreased affinity towards substrate, modified allosteric properties and reduced stability at pH below 7.5. Purified erythrocyte glucose-6-phosphate dehydrogenase was also affected by Bilipolinum and its affinity for NADP was decreased. Testing of erythrocyte enzymes in the evaluation of toxicity of iodine contrast media is discussed. PMID:6452104

  5. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues.

    PubMed

    Gignac, Paul M; Kley, Nathan J; Clarke, Julia A; Colbert, Matthew W; Morhardt, Ashley C; Cerio, Donald; Cost, Ian N; Cox, Philip G; Daza, Juan D; Early, Catherine M; Echols, M Scott; Henkelman, R Mark; Herdina, A Nele; Holliday, Casey M; Li, Zhiheng; Mahlow, Kristin; Merchant, Samer; Müller, Johannes; Orsbon, Courtney P; Paluh, Daniel J; Thies, Monte L; Tsai, Henry P; Witmer, Lawrence M

    2016-06-01

    Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT-based research is the use of chemical agents to render visible, and differentiate between, soft-tissue structures in X-ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine-based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine-based, contrast-enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting-edge applications of diffusible iodine-based contrast-enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward. PMID:26970556

  6. [Prophylaxis and treatment of side effects due to iodinated contrast media relevant to radiological practice].

    PubMed

    Becker, C

    2007-09-01

    Increased utilization of iodinated contrast media may be associated with increased incidence of adverse events. The most important side effects include contrast-induced nephropathy, anaphylactoid reaction, thyrotoxicosis, and extravasation. In patients with moderate renal dysfunction, saline hydration and reduction of contrast media volume are recommended. No regime to prevent anaphylactoid reactions has yet proven to be efficient. If subclinical hyperthyroidism has been determined, prophylaxis with sodium perchlorate is advised. Contrast-induced nephropathy is commonly transient and needs to be followed over time. Mild general anaphylactoid reactions may be treated with antihistaminic drugs and corticosteroids. Furthermore the choice of the X-ray contrast media might influence the risk of any adverse effects. PMID:17768601

  7. Dense iodine-rich compounds with low detonation pressures as biocidal agents.

    PubMed

    He, Chunlin; Zhang, Jiaheng; Shreeve, Jean'ne M

    2013-06-01

    Fifteen iodo compounds and six iodyl compounds with an iodine content between 45.3 and 89.0 % were prepared. The mono, di, and triiodyl compounds were obtained from the corresponding iodo compound by employing Oxone. All the compounds were characterized by IR, (1)H and (13)C NMR, elemental analysis, and differential scanning calorimetry (DSC). The impact sensitivity was measured by using BAM (Bundesamt für Materialforschung) methodology. Based on the calculated heats of formation and experimental densities, the detonation properties and detonation products were predicted by employing Cheetah 6.0. A total percentage of iodine-containing species in wt % (I2, HI, and I in gas phase) ranged from 46.7 (21) to 88.94 % (11) was found in the detonation products. The high concentration and easy accessibility of iodine and/or iodine-containing species is very important in developing materials suitable as Agent Defeat Weapons (ADWs). PMID:23576298

  8. Modified natural nanoparticles as contrast agents for medical imaging

    PubMed Central

    Cormode, David P.; Jarzyna, Peter A.; Mulder, Willem J. M.; Fayad, Zahi A.

    2009-01-01

    The development of novel and effective contrast agents is one of the drivers of the ongoing improvement in medical imaging. Many of the new agents reported are nanoparticle-based. There are a variety of natural nanoparticles known, e.g. lipoproteins, viruses or ferritin. Natural nanoparticles have advantages as delivery platforms such as biodegradability. In addition, our understanding of natural nanoparticles is quite advanced, allowing their adaptation as contrast agents. They can be labeled with small molecules or ions such as Gd3+ to act as contrast agents for magnetic resonance imaging, 18F to act as positron emission tomography contrast agents or fluorophores to act as contrast agents for fluorescence techniques. Additionally, inorganic nanoparticles such as iron oxide, gold nanoparticles or quantum dots can be incorporated to add further contrast functionality. Furthermore, these natural nanoparticle contrast agents can be rerouted from their natural targets via the attachment of targeting molecules. In this review, we discuss the various modified natural nanoparticles that have been exploited as contrast agents. PMID:19900496

  9. Basic MR relaxation mechanisms and contrast agent design.

    PubMed

    De León-Rodríguez, Luis M; Martins, André F; Pinho, Marco C; Rofsky, Neil M; Sherry, A Dean

    2015-09-01

    The diagnostic capabilities of magnetic resonance imaging (MRI) have undergone continuous and substantial evolution by virtue of hardware and software innovations and the development and implementation of exogenous contrast media. Thirty years since the first MRI contrast agent was approved for clinical use, a reliance on MR contrast media persists, largely to improve image quality with higher contrast resolution and to provide additional functional characterization of normal and abnormal tissues. Further development of MR contrast media is an important component in the quest for continued augmentation of diagnostic capabilities. In this review we detail the many important considerations when pursuing the design and use of MR contrast media. We offer a perspective on the importance of chemical stability, particularly kinetic stability, and how this influences one's thinking about the safety of metal-ligand-based contrast agents. We discuss the mechanisms involved in MR relaxation in the context of probe design strategies. A brief description of currently available contrast agents is accompanied by an in-depth discussion that highlights promising MRI contrast agents in the development of future clinical and research applications. Our intention is to give a diverse audience an improved understanding of the factors involved in developing new types of safe and highly efficient MR contrast agents and, at the same time, provide an appreciation of the insights into physiology and disease that newer types of responsive agents can provide. PMID:25975847

  10. Inorganic nanoparticle-based contrast agents for molecular imaging

    PubMed Central

    Cho, Eun Chul; Glaus, Charles; Chen, Jingyi; Welch, Michael J.; Xia, Younan

    2010-01-01

    Inorganic nanoparticles including semiconductor quantum dots, iron oxide nanoparticles, and gold nanoparticles have been developed as contrast agents for diagnostics by molecular imaging. Compared to traditional contrast agents, nanoparticles offer several advantages: their optical and magnetic properties can be tailored by engineering the composition, structure, size, and shape; their surfaces can be modified with ligands to target specific biomarkers of disease; the contrast enhancement provided can be equivalent to millions of molecular counterparts; and they can be integrated with a combination of different functions for multi-modal imaging. Here, we review recent advances in the development of contrast agents based on inorganic nanoparticles for molecular imaging, with a touch on contrast enhancement, surface modification, tissue targeting, clearance, and toxicity. As research efforts intensify, contrast agents based on inorganic nanoparticles that are highly sensitive, target-specific, and safe to use are expected to enter clinical applications in the near future. PMID:21074494

  11. INTRAARTERIAL INJECTION OF IODINATED CONTRAST MEDIUM FOR CONTRAST ENHANCED COMPUTED TOMOGRAPHY OF THE EQUINE HEAD.

    PubMed

    Carmalt, James L; Montgomery, James

    2015-01-01

    Minimizing the volume of contrast administered for contrast-enhanced computed tomography (CT) of the equine head is desirable for reducing costs and risks of adverse reactions, however evidence-based studies on the effects of varying volumes on image quality are currently lacking. The objective of the current study was to determine whether low-volume intraarterial administration of contrast medium would result in an equivalent image quality and tissue attenuation vs. high-volume intravenous bolus administration. A prospective cross-over experimental design was used in a sample of six horses. After anesthetic induction, the right carotid artery was exposed surgically and catheterized. Four CT scans of the cranium were performed for each horse: baseline, immediately following intraarterial contrast injection, five-min postinjection (return to baseline) and a final scan after intravenous contrast administration. Soft tissue attenuation in predetermined regions of interest (ROI); and length, width, and height measurements of the pituitary gland were recorded at each time point. Horses were euthanized and measurements of the pituitary gland were repeated postmortem. No adverse reactions to contrast administration were observed. Intraarterial and intravenous administration of contrast medium resulted in significantly greater soft tissue enhancement of some brain ROI's and the pituitary gland vs. baseline values. Pituitary gland measurements made on postcontrast CT images did not differ from those obtained during postmortem examination. Findings indicated that low-dose intraarterial administration of contrast material in the equine head resulted in comparable soft tissue enhancement vs. high volume intravenous administration. PMID:25782997

  12. Diagnostic image quality of hysterosalpingography: ionic versus non ionic water soluble iodinated contrast media

    PubMed Central

    Mohd Nor, H; Jayapragasam, KJ; Abdullah, BJJ

    2009-01-01

    Objective To compare the diagnostic image quality between three different water soluble iodinated contrast media in hysterosalpingography (HSG). Material and method In a prospective randomised study of 204 patients, the diagnostic quality of images obtained after hysterosalpingography were evaluated using Iopramide (106 patients) and Ioxaglate (98 patients). 114 patients who had undergone HSG examination using Iodamide were analysed retrospectively. Image quality was assessed by three radiologists independently based on an objective set of criteria. The obtained results were statistically analysed using Kruskal-Wallis and Mann-Whitney U test. Results Visualisation of fimbrial rugae was significantly better with Iopramide and Ioxaglate than Iodamide. All contrast media provided acceptable diagnostic image quality with regard to uterine, fallopian tubes outline and peritoneal spill. Uterine opacification was noted to be too dense in all three contrast media and not optimal for the assessment of intrauterine pathology. Higher incidence of contrast intravasation was noted in the Iodamide group. Similarly, the numbers of patients diagnosed with bilateral blocked fallopian tubes were also higher in the Iodamide group. Conclusion HSG using low osmolar contrast media (Iopramide and Ioxaglate) demonstrated diagnostic image qualities similar to HSG using conventional high osmolar contrast media (Iodamide). However, all three contrast media were found to be too dense for the detection of intrauterine pathology. Better visualisation of the fimbrial outline using Ioxaglate and Iopramide were attributed to their low contrast viscosity. The increased incidence of contrast media intravasation and bilateral tubal blockage using Iodamide are probably related to the high viscosity. PMID:21611058

  13. Superparamagnetic nanoparticle-inclusion microbubbles for ultrasound contrast agents

    NASA Astrophysics Data System (ADS)

    Yang, Fang; Li, Ling; Li, Yixin; Chen, Zhongping; Wu, Junru; Gu, Ning

    2008-11-01

    We have developed a new type of ultrasound (US) contrast agent, consisting of a gas core, a layer of superparamagnetic iron oxide Fe3O4 nanoparticles (SPIO) and an oil in water outermost layer. The newly developed US contrast agent microbubbles have a mean diameter of 760 nm with a polydisperity index (PI) of 0.699. Our in vitro and in vivo experiments have shown that they have the following advantages compared to gas-encapsulated microbbubbles without SPIO inclusion: (1) they provide better contrast for US images; (2) the SPIO-inclusion microbubbles generate a higher backscattering signal; the mean grey scale is 97.9, which is 38.6 higher than that of microbubbles without SPIO; and (3) since SPIO can also serve as a contrast agent of magnetic resonance images (MRI) in vitro, they can be potentially used as contrast agents for double-modality (MRI and US) clinical studies.

  14. Investigation of optimal parameters for penalized maximum-likelihood reconstruction applied to iodinated contrast-enhanced breast CT

    NASA Astrophysics Data System (ADS)

    Makeev, Andrey; Ikejimba, Lynda; Lo, Joseph Y.; Glick, Stephen J.

    2016-03-01

    Although digital mammography has reduced breast cancer mortality by approximately 30%, sensitivity and specificity are still far from perfect. In particular, the performance of mammography is especially limited for women with dense breast tissue. Two out of every three biopsies performed in the U.S. are unnecessary, thereby resulting in increased patient anxiety, pain, and possible complications. One promising tomographic breast imaging method that has recently been approved by the FDA is dedicated breast computed tomography (BCT). However, visualizing lesions with BCT can still be challenging for women with dense breast tissue due to the minimal contrast for lesions surrounded by fibroglandular tissue. In recent years there has been renewed interest in improving lesion conspicuity in x-ray breast imaging by administration of an iodinated contrast agent. Due to the fully 3-D imaging nature of BCT, as well as sub-optimal contrast enhancement while the breast is under compression with mammography and breast tomosynthesis, dedicated BCT of the uncompressed breast is likely to offer the best solution for injected contrast-enhanced x-ray breast imaging. It is well known that use of statistically-based iterative reconstruction in CT results in improved image quality at lower radiation dose. Here we investigate possible improvements in image reconstruction for BCT, by optimizing free regularization parameter in method of maximum likelihood and comparing its performance with clinical cone-beam filtered backprojection (FBP) algorithm.

  15. Computed tomography lung iodine contrast mapping by image registration and subtraction

    NASA Astrophysics Data System (ADS)

    Goatman, Keith; Plakas, Costas; Schuijf, Joanne; Beveridge, Erin; Prokop, Mathias

    2014-03-01

    Pulmonary embolism (PE) is a relatively common and potentially life threatening disease, affecting around 600,000 people annually in the United States alone. Prompt treatment using anticoagulants is effective and saves lives, but unnecessary treatment risks life threatening haemorrhage. The specificity of any diagnostic test for PE is therefore as important as its sensitivity. Computed tomography (CT) angiography is routinely used to diagnose PE. However, there are concerns it may over-report the condition. Additional information about the severity of an occlusion can be obtained from an iodine contrast map that represents tissue perfusion. Such maps tend to be derived from dual-energy CT acquisitions. However, they may also be calculated by subtracting pre- and post-contrast CT scans. Indeed, there are technical advantages to such a subtraction approach, including better contrast-to-noise ratio for the same radiation dose, and bone suppression. However, subtraction relies on accurate image registration. This paper presents a framework for the automatic alignment of pre- and post-contrast lung volumes prior to subtraction. The registration accuracy is evaluated for seven subjects for whom pre- and post-contrast helical CT scans were acquired using a Toshiba Aquilion ONE scanner. One hundred corresponding points were annotated on the pre- and post-contrast scans, distributed throughout the lung volume. Surface-to-surface error distances were also calculated from lung segmentations. Prior to registration the mean Euclidean landmark alignment error was 2.57mm (range 1.43-4.34 mm), and following registration the mean error was 0.54mm (range 0.44-0.64 mm). The mean surface error distance was 1.89mm before registration and 0.47mm after registration. There was a commensurate reduction in visual artefacts following registration. In conclusion, a framework for pre- and post-contrast lung registration has been developed that is sufficiently accurate for lung subtraction

  16. Iron Oxide as an MRI Contrast Agent for Cell Tracking

    PubMed Central

    Korchinski, Daniel J.; Taha, May; Yang, Runze; Nathoo, Nabeela; Dunn, Jeff F.

    2015-01-01

    Iron oxide contrast agents have been combined with magnetic resonance imaging for cell tracking. In this review, we discuss coating properties and provide an overview of ex vivo and in vivo labeling of different cell types, including stem cells, red blood cells, and monocytes/macrophages. Furthermore, we provide examples of applications of cell tracking with iron contrast agents in stroke, multiple sclerosis, cancer, arteriovenous malformations, and aortic and cerebral aneurysms. Attempts at quantifying iron oxide concentrations and other vascular properties are examined. We advise on designing studies using iron contrast agents including methods for validation. PMID:26483609

  17. Iodinated contrast media electro-degradation: process performance and degradation pathways.

    PubMed

    Del Moro, Guido; Pastore, Carlo; Di Iaconi, Claudio; Mascolo, Giuseppe

    2015-02-15

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm(2) with energy consumption higher than 370 kWh/m(3). Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. PMID:25433384

  18. Photodecomposition of iodinated contrast media and subsequent formation of toxic iodinated moieties during final disinfection with chlorinated oxidants.

    PubMed

    Allard, Sébastien; Criquet, Justine; Prunier, Anaïs; Falantin, Cécilia; Le Person, Annaïg; Yat-Man Tang, Janet; Croué, Jean-Philippe

    2016-10-15

    Large amount of iodinated contrast media (ICM) are found in natural waters (up to μg.L(-)(1) levels) due to their worldwide use in medical imaging and their poor removal by conventional wastewater treatment. Synthetic water samples containing different ICM and natural organic matter (NOM) extracts were subjected to UV254 irradiation followed by the addition of chlorine (HOCl) or chloramine (NH2Cl) to simulate final disinfection. In this study, two new quantum yields were determined for diatrizoic acid (0.071 mol.Einstein(-1)) and iotalamic acid (0.038 mol.Einstein(-1)) while values for iopromide (IOP) (0.039 mol.Einstein(-1)), iopamidol (0.034 mol.Einstein(-1)) and iohexol (0.041 mol.Einstein(-1)) were consistent with published data. The photodegradation of IOP led to an increasing release of iodide with increasing UV doses. Iodide is oxidized to hypoiodous acid (HOI) either by HOCl or NH2Cl. In presence of NOM, the addition of oxidant increased the formation of iodinated disinfection by-products (I-DBPs). On one hand, when the concentration of HOCl was increased, the formation of I-DBPs decreased since HOI was converted to iodate. On the other hand, when NH2Cl was used the formation of I-DBPs was constant for all concentration since HOI reacted only with NOM to form I-DBPs. Increasing the NOM concentration has two effects, it decreased the photodegradation of IOP by screening effect but it increased the number of reactive sites available for reaction with HOI. For experiments carried out with HOCl, increasing the NOM concentration led to a lower formation of I-DBPs since less IOP are photodegraded and iodate are formed. For NH2Cl the lower photodegradation of IOP is compensated by the higher amount of NOM reactive sites, therefore, I-DBPs concentrations were constant for all NOM concentrations. 7 different NOM extracts were tested and almost no differences in IOP degradation and I-DBPs formation was observed. Similar behaviour was observed for the 5 ICM

  19. In vivo small animal micro-CT using nanoparticle contrast agents

    PubMed Central

    Ashton, Jeffrey R.; West, Jennifer L.; Badea, Cristian T.

    2015-01-01

    Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research. PMID:26581654

  20. Torsten Almén (1931-2016): the father of non-ionic iodine contrast media.

    PubMed

    Nyman, Ulf; Ekberg, Olle; Aspelin, Peter

    2016-09-01

    The Swedish radiologist Torsten Almén is the first clinical radiologist ever to have made a fundamental contribution to intravascular contrast medium design, the development of non-ionic contrast media. He became emotionally triggered by the patients' severe pain each time he injected the ionic "high-osmolar" contrast media when performing peripheral arteriographies in the early 1960s. One day he got a flash of genius that combined the observation of pain, a pathophysiological theory and how to eliminate it with suitable contrast media chemistry. After self-studies in chemistry he developed the concept of iodine contrast media not dissociating into ions in solution to reduce their osmolality and even reach plasma isotonicity. He offered several pharmaceutical companies his concept of mono- and polymeric non-ionic agents but without response, since it was considered against the chemical laws of that time. Contrast media constructed as salts and dissociating into ions in solution was regarded an absolute necessity to achieve high enough water solubility and concentration for diagnostic purposes. Finally a small Norwegian company, Nyegaard & Co., took up his idea 1968 and together they developed the essentially painless "low-osmolar" monomeric non-ionic metrizamide (Amipaque) released in 1974 and iohexol (Omipaque) in 1982 followed by the "iso-osmolar" dimeric non-ionic iodixanol (Visipaque) released in 1993. This has implied a profound paradigm shift with regard to reduction of both hypertonic and chemotoxic side effects, which have been a prerequisite for the today's widespread use of contrast medium-enhanced CT and advanced endovascular interventional techniques even in fragile patients. PMID:27225455

  1. Microbubbles as contrast agent for in-line x-ray phase-contrast imaging

    SciTech Connect

    Xi Yan; Zhao Jun; Tang Rongbiao; Wang Yujie

    2011-07-04

    In the present study, we investigated the potential of gas-filled microbubbles as contrast agents for in-line x-ray phase-contrast imaging (PCI) in biomedical applications. When imaging parameters are optimized, the microbubbles function as microlenses that focus the incoming x-rays to form bright spots, which can significantly enhance the image contrast. Since microbubbles have been shown to be safe contrast agents in clinical ultrasonography, this contrast-enhancement procedure for PCI may have promising utility in biomedical applications, especially when the dose of radiation is a serious concern. In this study, we performed both numerical simulations and ex vivo experiments to investigate the formation of the contrast and the effectiveness of microbubbles as contrast agents in PCI.

  2. A brief account of nanoparticle contrast agents for photoacoustic imaging.

    PubMed

    Pan, Dipanjan; Kim, Benjamin; Wang, Lihong V; Lanza, Gregory M

    2013-01-01

    Photoacoustic imaging (PAI) is a hybrid, nonionizing modality offering excellent spatial resolution, deep penetration, and high soft tissue contrast. In PAI, signal is generated based on the absorption of laser-generated optical energy by endogenous tissues or exogenous contrast agents leading to acoustic emissions detected by an ultrasound transducer. Research in this area over the years has shown that PAI has the ability to provide both physiological and molecular imaging, which can be viewed alone or used in a hybrid modality fashion to extend the anatomic and hemodynamic sensitivities of clinical ultrasound. PAI may be performed using inherent contrast afforded by light absorbing molecules such as hemoglobin, myoglobin, and melanin or exogenous small molecule contrast agent such as near infrared dyes and porphyrins. However, this review summarizes the potential of exogenous nanoparticle-based agents for PAI applications including contrast based on gold particles, carbon nanotubes, and encapsulated copper compounds. PMID:23983210

  3. MRI contrast agent concentration and tumor interstitial fluid pressure.

    PubMed

    Liu, L J; Schlesinger, M

    2016-10-01

    The present work describes the relationship between tumor interstitial fluid pressure (TIFP) and the concentration of contrast agent for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). We predict the spatial distribution of TIFP based on that of contrast agent concentration. We also discuss the cases for estimating tumor interstitial volume fraction (void fraction or porosity of porous medium), ve, and contrast volume transfer constant, K(trans), by measuring the ratio of contrast agent concentration in tissue to that in plasma. A linear fluid velocity distribution may reflect a quadratic function of TIFP distribution and lead to a practical method for TIFP estimation. To calculate TIFP, the parameters or variables should preferably be measured along the direction of the linear fluid velocity (this is in the same direction as the gray value distribution of the image, which is also linear). This method may simplify the calculation for estimating TIFP. PMID:27343032

  4. A Brief Account of Nanoparticle Contrast Agents for Photoacoustic Imaging

    PubMed Central

    Pan, Dipanjan; Kim, Benjamin; Wang, Lihong V.; Lanza, Gregory M

    2014-01-01

    Photoacoustic imaging (PAI) is a hybrid, nonionizing modality offering excellent spatial resolution, deep penetration, and high soft tissue contrast. In PAI, signal is generated based on the absorption of laser-generated optical energy by endogenous tissues or exogenous contrast agents leading to acoustic emissions detected by an ultrasound transducer. Research in this area over the years has shown that PAI has the ability to provide both physiological and molecular imaging, which can be viewed alone or used in a hybrid modality fashion to extend the anatomic and hemodynamic sensitivities of clinical ultrasound. PAI may be performed using inherent contrast afforded by light absorbing molecules such as hemoglobin, myoglobin, and melanin or exogenous small molecule contrast agent such as near infrared dyes and porphyrins. However, this review summarizes the potential of exogenous nanoparticle-based agents for PAI applications including contrast based on gold particles, carbon nanotubes, and encapsulated copper compounds. PMID:23983210

  5. [Allergy to iodinated drugs and to foods rich in iodine: Iodine is not the allergenic determinant].

    PubMed

    Dewachter, Pascale; Mouton-Faivre, Claudie

    2015-11-01

    "Iodine allergy" does not exist. The concept of "iodine allergy" should be abandoned since it may result in inappropriate measures such as drug, food or environmental eviction. Immediate or non-immediate allergic hypersensitivity to iodinated contrast media is not infrequent. The corresponding allergens have not been identified. Iodine is not involved. Immediate or non-immediate allergic hypersensitivity to povidone iodine is rare. The corresponding allergen is povidone in case of immediate hypersensitivity while nonoxynol might be involved during non-immediate hypersensitivity. Seafood allergens belong to a group of muscle proteins. Immediate drug hypersensitivity or food hypersensitivity is assessed by immediate-reading skin tests while non-immediate drug hypersensitivity is investigated by delayed-reading skin testing. Combined histamine and tryptase measurement is invaluable during the diagnostic approach of immediate hypersensitivity. Other biological tests are being evaluated. Allergic hypersensitivity to iodinated contrast agents does not contraindicate the use of other iodinated drugs. PMID:26387623

  6. Multiwalled carbon nanotube hybrids as MRI contrast agents.

    PubMed

    Kuźnik, Nikodem; Tomczyk, Mateusz Michał

    2016-01-01

    Magnetic resonance imaging (MRI) is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs), their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories. PMID:27547627

  7. Multiwalled carbon nanotube hybrids as MRI contrast agents

    PubMed Central

    Tomczyk, Mateusz Michał

    2016-01-01

    Summary Magnetic resonance imaging (MRI) is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs), their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories. PMID:27547627

  8. Gadolinium-Based Contrast Agent Accumulation and Toxicity: An Update.

    PubMed

    Ramalho, J; Semelka, R C; Ramalho, M; Nunes, R H; AlObaidy, M; Castillo, M

    2016-07-01

    In current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition. PMID:26659341

  9. Optical characterization of contrast agents for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Lee, Tin-Man; Toublan, Farah J.; Oldenburg, Amy; Sitafalwalla, Shoeb; Luo, Wei; Marks, Daniel L.; Suslick, Kenneth S.; Boppart, Stephen A.

    2003-07-01

    The use of contrast agents in almost every imaging modality has been known to enhance the sensitivity of detection and improve diagnostic capabilities by site-specifically labeling tissues or cells of interest. The imaging capabilities of Optical Coherence Tomography (OCT) need to be improved in order to detect early neoplastic changes in medicine and tumor biology. We introduce and characterize the optical properties of several types of optical contrast agents in OCT, namely encapsulating microspheres that incorporate materials including melanin, gold, and carbon. Micron-sized microspheres have been fabricated by state-of-the-art sonicating and ultrasound technology. The optical properties of optical contrast agents have been characterized according to their scattering and absorption coefficients and lifetimes using OCT and the oblique incidence reflectometry method. Finally, we demonstrate the use of these optical contrast agents in in vitro mice liver and analyze the contrast improvement from the OCT images. These optical contrast agents have the potential to improve the detection of in vivo pathologies in the future.

  10. Micro-Radiography of Living Biological Organisms with MEDIPIX2 Detector and Application of Various Contrast Agents

    NASA Astrophysics Data System (ADS)

    Dammer, Jiri; Sopko, Vit; Jakubek, Jan; Weyda, Frantisek; Benes, Jiri; Zahorovsky, Julian

    2012-08-01

    We describe a newly developed radiographic system equipped with Medipix2 semiconductor pixel detector and a micro-focus FeinFocus X-ray tube tabletop. The detector is used as an imager that counts individual photons of ionizing radiation, emitted by the X-ray tube. The digital pixel detectors of the Medipix family represent a highly efficient type of imaging devices with high spatial resolution better than 1μm, and unlimited dynamic range allowing single particle of radiation and to determine their energies. The setup is particularly suitable for radiographic imaging of small biological samples, including in vivo observations with various contrast agents (iodine and lanthanum nitrate). Along with the description of the apparatus we provide examples of application of iodine and lanthanum nitrate contrast agents as tracers in various insects as model organisms. The iodine contrast agent increases the absorption of X-rays and this leads to better resolution of internal structures of biological organisms, and especially the various cavities, pores, etc. Micro-radiographic imaging helps to detect organisms living in a not visible environment, visualize internal biological processes and also to resolve the details of their body (morphology). Tiny live insects are an ideal object for our studies.

  11. Targeting cancer chemotherapeutic agents by use of lipiodol contrast medium

    SciTech Connect

    Konno, T. )

    1990-11-01

    Arterially administered Lipiodol Ultrafluid contrast medium selectively remained in various malignant solid tumors because of the difference in time required for the removal of Lipiodol contrast medium from normal capillaries and tumor neovasculature. Although blood flow was maintained in the tumor, even immediately after injection Lipiodol contrast medium remained in the neovasculature of the tumor. To target anti-cancer agents to tumors by using Lipiodol contrast medium as a carrier, the characteristics of the agents were examined. Anti-cancer agents had to be soluble in Lipiodol, be stable in it, and separate gradually from it so that the anti-cancer agents would selectively remain in the tumor. These conditions were found to be necessary on the basis of the measurement of radioactivity in VX2 tumors implanted in the liver of 16 rabbits that received arterial injections of 14C-labeled doxorubicin. Antitumor activities and side effects of arterial injections of two types of anti-cancer agents were compared in 76 rabbits with VX2 tumors. Oily anti-cancer agents that had characteristics essential for targeting were compared with simple mixtures of anti-cancer agents with Lipiodol contrast medium that did not have these essential characteristics. Groups of rabbits that received oily anti-cancer agents responded significantly better than groups that received simple mixtures, and side effects were observed more frequently in the groups that received the simple mixtures. These results suggest that targeting of the anti-cancer agent to the tumor is important for treatment of solid malignant tumors.

  12. Chlorotoxin-modified macromolecular contrast agent for MRI tumor diagnosis.

    PubMed

    Huang, Rongqin; Han, Liang; Li, Jianfeng; Liu, Shuhuan; Shao, Kun; Kuang, Yuyang; Hu, Xing; Wang, Xuxia; Lei, Hao; Jiang, Chen

    2011-08-01

    Clinical diagnosis of cancers using magnetic resonance imaging (MRI) is highly dependent on contrast agents, especially for brain tumors which contain blood-brain barrier (BBB) at the early stage. However, currently mostly used low molecular weight contrast agents such as Gd-DTPA suffer from rapid renal clearance, non-specificity, and low contrast efficiency. The aim of this paper is to investigate the potential of a macromolecular MRI contrast agent based on dendrigraft poly-l-lysines (DGLs), using chlorotoxin (CTX) as a tumor-specific ligand. The contrast agent using CTX-modified conjugate as the main scaffold and Gd-DTPA as the payload was successfully synthesized. The results of fluorescent microscopy showed that the modification of CTX could markedly enhance the cellular uptake in C6 glioma and liver tumor cell lines, but not in normal cell line. Significantly increased accumulation of CTX-modified conjugate within glioma and liver tumor was further demonstrated in tumor-bearing nude mice using in vivo imaging system. The MRI results showed that the signal enhancement of mice treated with CTX-modified contrast reached peak level at 5 min for both glioma and liver tumor, 144.97% ± 19.54% and 158.69% ± 12.41%, respectively, significantly higher than that of unmodified counterpart and commercial control. And most importantly, the signal enhancement of CTX-modified contrast agent maintained much longer compared to that of controls, which might be useful for more exact diagnosis for tumors. CTX-modified dendrimer-based conjugate might be applied as an efficient MRI contrast agent for targeted and accurate tumor diagnosis. This finding is especially important for tumors such as brain glioma which is known hard to be diagnosed due to the presence of BBB. PMID:21531455

  13. Contrast Agents for Photoacoustic and Thermoacoustic Imaging: A Review

    PubMed Central

    Wu, Dan; Huang, Lin; Jiang, Max S.; Jiang, Huabei

    2014-01-01

    Photoacoustic imaging (PAI) and thermoacoustic imaging (TAI) are two emerging biomedical imaging techniques that both utilize ultrasonic signals as an information carrier. Unique advantages of PAI and TAI are their abilities to provide high resolution functional information such as hemoglobin and blood oxygenation and tissue dielectric properties relevant to physiology and pathology. These two methods, however, may have a limited detection depth and lack of endogenous contrast. An exogenous contrast agent is often needed to effectively resolve these problems. Such agents are able to greatly enhance the imaging contrast and potentially break through the imaging depth limit. Furthermore, a receptor-targeted contrast agent could trace the molecular and cellular biological processes in tissues. Thus, photoacoustic and thermoacoustic molecular imaging can be outstanding tools for early diagnosis, precise lesion localization, and molecular typing of various diseases. The agents also could be used for therapy in conjugation with drugs or in photothermal therapy, where it functions as an enhancer for the integration of diagnosis and therapy. In this article, we present a detailed review about various exogenous contrast agents for photoacoustic and thermoacoustic molecular imaging. In addition, challenges and future directions of photoacoustic and thermoacoustic molecular imaging in the field of translational medicine are also discussed. PMID:25530615

  14. Selective imaging of adherent targeted ultrasound contrast agents

    PubMed Central

    Zhao, S; Kruse, D E; Ferrara, K W; Dayton, P A

    2007-01-01

    The goal of ultrasonic molecular imaging is the detection of targeted contrast agents bound to receptors on endothelial cells. We propose imaging methods that can distinguish adherent microbubbles from tissue and from freely circulating microbubbles, each of which would otherwise obscure signal from molecularly targeted adherent agents. The methods are based on a harmonic signal model of the returned echoes over a train of pulses. The first method utilizes an ‘image–push–image’ pulse sequence where adhesion of contrast agents is rapidly promoted by acoustic radiation force and the presence of adherent agents is detected by the signal change due to targeted microbubble adhesion. The second method rejects tissue echoes using a spectral high-pass filter. Free agent signal is suppressed by a pulse-to-pulse low-pass filter in both methods. An overlay of the adherent and/or flowing contrast agents on B-mode images can be readily created for anatomical reference. Contrast-to-tissue ratios from adherent microbubbles exceeding 30 dB and 20 dB were achieved for the two methods proposed, respectively. The performance of these algorithms is compared, emphasizing the significance and potential applications in ultrasonic molecular imaging. PMID:17404455

  15. Prevention and Management of Adverse Reactions Induced by Iodinated Contrast Media.

    PubMed

    Wu, Yi Wei; Leow, Kheng Song; Zhu, Yujin; Tan, Cher Heng

    2016-04-01

    Iodinated radiocontrast media (IRCM) is widely used in current clinical practice. Although IRCM is generally safe, serious adverse drug reactions (ADRs) may still occur. IRCM-induced ADRs may be subdivided into chemotoxic and hypersensitivity reactions. Several factors have been shown to be associated with an increased risk of ADRs, including previous contrast media reactions, history of asthma and allergic disease, etc. Contrast media with lower osmolality is generally recommended for at-risk patients to prevent ADRs. Current premedication prophylaxis in at-risk patients may reduce the risk of ADRs. However, there is still a lack of consensus on the prophylactic role of premedication. Contrast-induced nephropathy (CIN) is another component of IRCM-related ADRs. Hydration remains the mainstay of CIN prophylaxis in at-risk patients. Despite several preventive measures, ADRs may still occur. Treatment strategies for potential contrast reactions are also summarised in this article. This article summarises the pathophysiology, epidemiology and risk factors of ADRs with emphasis on prevention and treatment strategies. This will allow readers to understand the rationale behind appropriate patient preparation for diagnostic imaging involving IRCM. PMID:27292007

  16. Exogenous contrast agents for thermoacoustic imaging: An investigation into the underlying sources of contrast

    SciTech Connect

    Ogunlade, Olumide 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 substance 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

  17. Graphene-based contrast agents for photoacoustic and thermoacoustic tomography☆

    PubMed Central

    Lalwani, Gaurav; Cai, Xin; Nie, Liming; Wang, Lihong V.; Sitharaman, Balaji

    2013-01-01

    In this work, graphene nanoribbons and nanoplatelets were investigated as contrast agents for photoacoustic and thermoacoustic tomography (PAT and TAT). We show that oxidized single- and multi-walled graphene oxide nanoribbons (O-SWGNRs, O-MWGNRs) exhibit approximately 5–10 fold signal enhancement for PAT in comparison to blood at the wavelength of 755 nm, and approximately 10–28% signal enhancement for TAT in comparison to deionized (DI) water at 3 GHz. Oxidized graphite microparticles (O-GMPs) and exfoliated graphene oxide nanoplatelets (O-GNPs) show no significant signal enhancement for PAT, and approximately 12–29% signal enhancement for TAT. These results indicate that O-GNRs show promise as multi-modal PAT and TAT contrast agents, and that O-GNPs are suitable contrast agents for TAT. PMID:24490141

  18. Ultrasound contrast agents and their use in monitoring therapy

    NASA Astrophysics Data System (ADS)

    Ferrara, Katherine; Dayton, Paul; Shortencarrier, Michaelann; Kruse, Dustin

    2003-10-01

    The shell of ultrasound contrast agents can be modified to include a molecular targeting ligand, and the properties of the agent with and without molecular targeting can be used to monitor changes produced by a therapy. We have investigated the use of ligands targeted to an integrin expressed in cancer, whose expression correlates with tumor grade. Acoustic studies illustrate a 3- to 20-fold increase in echo amplitude from integrin-expressing cells exposed to the targeted contrast agent, as compared to controls, and depending on cell type, stimulation, and targeting ligand. Changes in integrin expression with therapy may be important in future studies. We have also developed a system to quantify small changes in vascular parameters due to effects of new anti-angiogenic drugs using the intrinsic properties of contrast agents. Regions containing intravascular contrast agents are identified using a strategy that combines subharmonic and phase inversion imaging. As predicted by a Rayleigh-Plesset analysis, this strategy can successfully detect flow over a range of transmission frequencies from 4-6 MHz. We demonstrate that regions of viable tumor as small as 1 mm, as verified by histology, can be detected and show similar morphology to images acquired with computed tomography (CT).

  19. Influence of radiographic contrast agents on quantitative coronary angiography

    SciTech Connect

    Jost, Stefan; Hausmann, Dirk; Lippolt, Peter; Gerhardt, Uwe; Lichtlen, Paul R.

    1997-01-15

    Purpose. Quantitative angiographic studies on the vasomotility of epicardial coronary arteries are gaining increasing relevance. We investigated whether radiographic contrast agents might influence coronary vasomotor tone and thereby the results of such studies. Methods. Coronary angiograms were taken in 12 patients with coronary artery disease at intervals of 5, 3, 2, and 1 min with the low-osmolar, nonionic contrast agent iopamidol 300, and were repeated at identical intervals with the high-osmolar, ionic agent diatrizoate 76%. Results. Quantitative cine film analysis demonstrated no significant diameter changes in angiographically normal and stenotic coronary arteries with iopamidol. With diatrizoate, however, normal segments were dilated 2%{+-}2% (p<0.01) after 2 min and 10%{+-}3% after the 1 min interval (p<0.001). Stenoses showed no uniform responses to diatrizoate. Conclusion. Low-osmolar, nonionic contrast agents should be preferred for quantitative angiographic studies on epicardial coronary vasomotility. When using ionic contrast agents, injection intervals of at least 3 min are required.

  20. Gd-HOPO Based High Relaxivity MRI Contrast Agents

    SciTech Connect

    Datta, Ankona; Raymond, Kenneth

    2008-11-06

    Tris-bidentate HOPO-based ligands developed in our laboratory were designed to complement the coordination preferences of Gd{sup 3+}, especially its oxophilicity. The HOPO ligands provide a hexadentate coordination environment for Gd{sup 3+} in which all he donor atoms are oxygen. Because Gd{sup 3+} favors eight or nine coordination, this design provides two to three open sites for inner-sphere water molecules. These water molecules rapidly exchange with bulk solution, hence affecting the relaxation rates of bulk water olecules. The parameters affecting the efficiency of these contrast agents have been tuned to improve contrast while still maintaining a high thermodynamic stability for Gd{sup 3+} binding. The Gd- HOPO-based contrast agents surpass current commercially available agents ecause of a higher number of inner-sphere water molecules, rapid exchange of inner-sphere water molecules via an associative mechanism, and a long electronic relaxation time. The contrast enhancement provided by these agents is at least twice that of commercial contrast gents, which are based on polyaminocarboxylate ligands.

  1. Microfabricated High-Moment Micrometer-sized MRI Contrast Agents

    PubMed Central

    Zabow, Gary; Dodd, Stephen J.; Shapiro, Erik; Moreland, John; Koretsky, Alan P.

    2010-01-01

    While chemically synthesized superparamagnetic microparticles have enabled much new research based on MRI-tracking of magnetically labeled cells, signal-to-noise levels still limit the potential range of applications. Here it is shown how, through top-down microfabrication, contrast agent relaxivity can be increased several-fold, which should extend the sensitivity of such cell tracking studies. Microfabricated agents can benefit from both higher magnetic moments and higher uniformity than their chemically synthesized counterparts, implying increased label visibility and more quantitative image analyses. To assess the performance of microfabricated micrometer-sized contrast agent particles, analytic models and numerical simulations are developed and tested against new microfabricated agents described in this paper, as well as against results of previous imaging studies of traditional chemically synthesized microparticle agents. Experimental data showing signal effects of 500-nanometer thick, 2-micrometer diameter, gold-coated iron and gold-coated nickel disks verify the simulations. Additionally, it is suggested that measures of location better than the pixel resolution can be obtained and that these are aided using well-defined contrast agent particles achievable through microfabrication techniques. PMID:20928829

  2. Bismuth@US-tubes as a Potential Contrast Agent for X-ray Imaging Applications

    PubMed Central

    Rivera, Eladio J.; Tran, Lesa A.; Hernández-Rivera, Mayra; Yoon, Diana; Mikos, Antonios G.; Rusakova, Irene A.; Cheong, Benjamin Y.; Cabreira-Hansen, Maria da Graça; Willerson, James T.; Perin, Emerson C.; Wilson, Lon J.

    2013-01-01

    The encapsulation of bismuth as BiOCl/Bi2O3 within ultra-short (ca. 50 nm) single-walled carbon nanocapsules (US-tubes) has been achieved. The Bi@US-tubes have been characterized by high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Bi@US-tubes have been used for intracellular labeling of pig bone marrow-derived mesenchymal stem cells (MSCs) to show high X-ray contrast in computed tomography (CT) cellular imaging for the first time. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US-tubes and without compromising cell viability. X-ray CT imaging of Bi@US-tubes-labeled MSCs showed a nearly two-fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US-tubes is 500 times greater than polymer-coated Bi2S3 nanoparticles and several-fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US-tubes can be used as a potential new class of X-ray CT agent for stem cell labeling and possibly in vivo tracking. PMID:24288589

  3. Revisiting an old friend: manganese-based MRI contrast agents

    PubMed Central

    Pan, Dipanjan; Caruthers, Shelton D.; Senpan, Angana; Schmieder, Ann H.; Wickline, Samuel A.; Lanza, Gregory M.

    2011-01-01

    Non-invasive cellular and molecular imaging techniques are emerging as a multidisciplinary field that offers promise in understanding the components, processes, dynamics and therapies of disease at a molecular level. Magnetic resonance imaging (MRI) is an attractive technique due to the absence of radiation and high spatial resolution which makes it advantageous over techniques involving radioisotopes. Typically paramagnetic and superparamagnetic metals are used as contrast materials for MR based techniques. Gadolinium has been the predominant paramagnetic contrast metal until the discovery and association of the metal with nephrogenic systemic fibrosis (NSF) in some patients with severe renal or kidney disease. Manganese was one of the earliest reported examples of paramagnetic contrast material for MRI because of its efficient positive contrast enhancement. In this review manganese based contrast agent approaches will be presented with a particular emphasis on nanoparticulate agents. We have discussed both classically used small molecule based blood pool contrast agents and recently developed innovative nanoparticle-based strategies highlighting a number of successful molecular imaging examples. PMID:20860051

  4. Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease

    PubMed Central

    Fernandes, Sheila Marques; Martins, Daniel Malisani; da Fonseca, Cassiane Dezoti; Watanabe, Mirian; Vattimo, Maria de Fátima Fernandes

    2016-01-01

    Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI. PMID:27034930

  5. Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease.

    PubMed

    Fernandes, Sheila Marques; Martins, Daniel Malisani; da Fonseca, Cassiane Dezoti; Watanabe, Mirian; Vattimo, Maria de Fátima Fernandes

    2016-01-01

    Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI. PMID:27034930

  6. Sonophoresis Using Ultrasound Contrast Agents: Dependence on Concentration

    PubMed Central

    Park, Donghee; Song, Gillsoo; Jo, Yongjun; Won, Jongho; Son, Taeyoon; Cha, Ohrum; Kim, Jinho; Jung, Byungjo; Park, Hyunjin; Kim, Chul-Woo; Seo, Jongbum

    2016-01-01

    Sonophoresis can increase skin permeability to various drugs in transdermal drug delivery. Cavitation is recognized as the predominant mechanism of sonophoresis. Recently, a new logical approach to enhance the efficiency of transdermal drug delivery was tried. It is to utilize the engineered microbubble and its resonant frequency for increase of cavitation activity. Actively-induced cavitation with low-intensity ultrasound (less than ~1 MPa) causes disordering of the lipid bilayers and the formation of aqueous channels by stable cavitation which indicates a continuous oscillation of bubbles. Furthermore, the mutual interactions of microbubble determined by concentration of added bubble are also thought to be an important factor for activity of stable cavitation, even in different characteristics of drug. In the present study, we addressed the dependence of ultrasound contrast agent concentration using two types of drug on the efficiency of transdermal drug delivery. Two types of experiment were designed to quantitatively evaluate the efficiency of transdermal drug delivery according to ultrasound contrast agent concentration. First, an experiment of optical clearing using a tissue optical clearing agent was designed to assess the efficiency of sonophoresis with ultrasound contrast agents. Second, a Franz diffusion cell with ferulic acid was used to quantitatively determine the amount of drug delivered to the skin sample by sonophoresis with ultrasound contrast agents. The maximum enhancement ratio of sonophoresis with a concentration of 1:1,000 was approximately 3.1 times greater than that in the ultrasound group without ultrasound contrast agent and approximately 7.5 times greater than that in the control group. These results support our hypothesis that sonophoresis becomes more effective in transdermal drug delivery due to the presence of engineered bubbles, and that the efficiency of transdermal drug delivery using sonophoresis with microbubbles depends on the

  7. Sonophoresis Using Ultrasound Contrast Agents: Dependence on Concentration.

    PubMed

    Park, Donghee; Song, Gillsoo; Jo, Yongjun; Won, Jongho; Son, Taeyoon; Cha, Ohrum; Kim, Jinho; Jung, Byungjo; Park, Hyunjin; Kim, Chul-Woo; Seo, Jongbum

    2016-01-01

    Sonophoresis can increase skin permeability to various drugs in transdermal drug delivery. Cavitation is recognized as the predominant mechanism of sonophoresis. Recently, a new logical approach to enhance the efficiency of transdermal drug delivery was tried. It is to utilize the engineered microbubble and its resonant frequency for increase of cavitation activity. Actively-induced cavitation with low-intensity ultrasound (less than ~1 MPa) causes disordering of the lipid bilayers and the formation of aqueous channels by stable cavitation which indicates a continuous oscillation of bubbles. Furthermore, the mutual interactions of microbubble determined by concentration of added bubble are also thought to be an important factor for activity of stable cavitation, even in different characteristics of drug. In the present study, we addressed the dependence of ultrasound contrast agent concentration using two types of drug on the efficiency of transdermal drug delivery. Two types of experiment were designed to quantitatively evaluate the efficiency of transdermal drug delivery according to ultrasound contrast agent concentration. First, an experiment of optical clearing using a tissue optical clearing agent was designed to assess the efficiency of sonophoresis with ultrasound contrast agents. Second, a Franz diffusion cell with ferulic acid was used to quantitatively determine the amount of drug delivered to the skin sample by sonophoresis with ultrasound contrast agents. The maximum enhancement ratio of sonophoresis with a concentration of 1:1,000 was approximately 3.1 times greater than that in the ultrasound group without ultrasound contrast agent and approximately 7.5 times greater than that in the control group. These results support our hypothesis that sonophoresis becomes more effective in transdermal drug delivery due to the presence of engineered bubbles, and that the efficiency of transdermal drug delivery using sonophoresis with microbubbles depends on the

  8. Tumor Characterization with Dynamic Contrast Enhanced Magnetic Resonance Imaging and Biodegradable Macromolecular Contrast Agents in Mice

    PubMed Central

    Wu, Xueming; Feng, Yi; Jeong, Eun-Kee; Emerson, Lyska; Lu, Zheng-Rong

    2009-01-01

    Purpose To investigate the efficacy of polydisulfide-based biodegradable macromolecular contrast agents of different degradability and molecular weight for tumor characterization based on angiogenesis using dynamic contrast enhanced MRI (DCE-MRI). Methods Biodegradable macromolecular MRI contrast agents, GDCC and GDCP, with molecular weight of 20 and 70 KDa were evaluated for tumor characterization. The DCE-MRI studies were performed in nude mice bearing MDA PCa 2b and PC-3 human prostate tumor xenografts. Tumor angiogenic kinetic parameters, endothelium transfer coefficient (Ktrans) and fractional tumor plasma volume (fPV), were calculated from the DCE-MRI data using a two-compartment model. Results There was no significant difference in the fPV values between two tumor models estimated with the same agent except for GDCC-70. The Ktrans values in both tumor models decreased with increasing molecular weight of the agents. GDCC-70 showed a higher Ktrans values than GDCP-70 due to high degradability of the former in both tumor models (p < 0.05). The Ktrans values of MDA PCa 2b tumors were significantly higher than those of PC-3 tumors estimated by Gd(DTPA-BMA), GDCC-20, GDCC-70, GDCP-70, and albumin-(Gd-DTPA) (p < 0.05). Conclusions The polydisulfide based biodegradable macromolecular MRI contrast agents are promising in tumor characterization with dynamic contrast enhanced MRI. PMID:19597972

  9. Molecular Imaging and Contrast Agent Database (MICAD): Evolution and Progress

    PubMed Central

    Chopra, Arvind; Shan, Liang; Eckelman, W. C.; Leung, Kam; Latterner, Martin; Bryant, Stephen H.; Menkens, Anne

    2011-01-01

    The purpose of writing this review is to showcase the Molecular Imaging and Contrast Agent Database (MICAD; www.micad.nlm.nih.gov) to students, researchers and clinical investigators interested in the different aspects of molecular imaging. This database provides freely accessible, current, online scientific information regarding molecular imaging (MI) probes and contrast agents (CA) used for positron emission tomography, single-photon emission computed tomography, magnetic resonance imaging, x-ray/computed tomography, optical imaging and ultrasound imaging. Detailed information on >1000 agents in MICAD is provided in a chapter format and can be accessed through PubMed. Lists containing >4250 unique MI probes and CAs published in peer-reviewed journals and agents approved by the United States Food and Drug Administration (FDA) as well as a CSV file summarizing all chapters in the database can be downloaded from the MICAD homepage. Users can search for agents in MICAD on the basis of imaging modality, source of signal/contrast, agent or target category, preclinical or clinical studies, and text words. Chapters in MICAD describe the chemical characteristics (structures linked to PubChem), the in vitro and in vivo activities and other relevant information regarding an imaging agent. All references in the chapters have links to PubMed. A Supplemental Information Section in each chapter is available to share unpublished information regarding an agent. A Guest Author Program is available to facilitate rapid expansion of the database. Members of the imaging community registered with MICAD periodically receive an e-mail announcement (eAnnouncement) that lists new chapters uploaded to the database. Users of MICAD are encouraged to provide feedback, comments or suggestions for further improvement of the database by writing to the editors at: micad@nlm.nih.gov PMID:21989943

  10. Surface Modified Gadolinium Phosphate Nanoparticles as MRI Contrast Agents

    NASA Astrophysics Data System (ADS)

    Dumont, Matthieu F.; Baligand, Celine; Knowles, Elisabeth S.; Meisel, Mark W.; Walter, Glenn A.; Talham, Daniel R.

    2012-02-01

    Nanoparticles of GdPO4H2O were synthesized in a water/oil microemulsion using IGEPAL CO-520 as surfactant resulting in 50 nm to 100 nm particles that are dispersible and stable in water. Using surface modification chemistry previously established for zirconium phosphonate surfaces,ootnotetext J. Monot et al., J. Am. Chem. Soc. 130 (2008) 6243. the particles are directly modified with 5'-phosphate terminated oligonucleotides, and the specific interaction of the divalent phosphate with Gd^3+ sites at the surface is demonstrated. The ability of the modified nanoparticles to act as MRI contrast agents was determined by performing MR relaxivity measurements at 14 T. Solutions of nanopure water, Feridex and Omniscan (FDA cleared contrast agents) in 0.25% agarose were used for comparison and control purposes. MRI data confirm that GdPO4H2O nanoparticles have relaxivities (r1,r2) comparable to commercially available contrast agents.ootnotetext H. Hifumi et al., J. Am. Chem. Soc. 128 (2006) 15090. In addition, biofunctionalization of the surface of the nanoparticles does not prevent their function as MRI contrast agents.

  11. Cell-Permeable MR Contrast Agents with Increased Intracellular Retention

    PubMed Central

    Endres, Paul J.; MacRenaris, Keith W.; Vogt, Stefan; Meade, Thomas J.

    2009-01-01

    Magnetic resonance imaging (MRI) is a technique used in both clinical and experimental settings to produce high resolution images of opaque organisms without ionizing radiation. Currently, MR imaging is augmented by contrast agents and the vast majority these small molecule Gd(III) chelates are confined to the extracellular regions. As a result, contrast agents are confined to vascular regions reducing their ability to provide information about cell physiology or molecular pathology. We have shown that polypeptides of arginine have the capacity to transport Gd(III) contrast agents across cell membranes. However, this transport is not unidirectional and once inside the cell the arginine-modified contrast agents efflux rapidly, decreasing the intracellular Gd(III) concentration and corresponding MR image intensity. By exploiting the inherent disulfide reducing environment of cells, thiol compounds, Gd(III)-DOTA-SS-Arg8 and Gd(III)-DTPA-SS-Arg8, are cleaved from their cell penetrating peptide transduction domains upon cell internalization. This reaction prolongs the cell-associated lifetime of the chelated Gd(III) by cleaving it from the cell transduction domain. PMID:18803414

  12. Assessment of DNA double-strand breaks induced by intravascular iodinated contrast media following in vitro irradiation and in vivo, during paediatric cardiac catheterization.

    PubMed

    Gould, Richard; McFadden, Sonyia L; Horn, Simon; Prise, Kevin M; Doyle, Philip; Hughes, Ciara M

    2016-01-01

    Paediatric cardiac catheterizations may result in the administration of substantial amounts of iodinated contrast media and ionizing radiation. The aim of this work was to investigate the effect of iodinated contrast media in combination with in vitro and in vivo X-ray radiation on lymphocyte DNA. Six concentrations of iodine (15, 17.5, 30, 35, 45, and 52.5 mg of iodine per mL blood) represented volumes of iodinated contrast media used in the clinical setting. Blood obtained from healthy volunteers was mixed with iodinated contrast media and exposed to radiation doses commonly used in paediatric cardiac catheterizations (0 mGy, 70 mGy, 140 mGy, 250 mGy and 450 mGy). Control samples contained no iodine. For in vivo experimentation, pre and post blood samples were collected from children undergoing cardiac catheterization, receiving iodine concentrations of up to 51 mg of iodine per mL blood and radiation doses of up to 400 mGy. Fluorescence microscopy was performed to assess γH2AX-foci induction, which corresponded to the number of DNA double-strand breaks. The presence of iodine in vitro resulted in significant increases of DNA double-strand breaks beyond that induced by radiation for ≥ 17.5 mg/mL iodine to blood. The in vivo effects of contrast media on children undergoing cardiac catheterization resulted in a 19% increase in DNA double-strand breaks in children receiving an average concentration of 19 mg/mL iodine to blood. A larger investigation is required to provide further information of the potential benefit of lowering the amount of iodinated contrast media received during X-ray radiation investigations. PMID:26549792

  13. Macromolecular and Dendrimer Based Magnetic Resonance Contrast Agents

    PubMed Central

    Bumb, Ambika; Brechbiel, Martin W.; Choyke, Peter

    2010-01-01

    Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20–25 years, a number of gadolinium based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution and targeting of dendrimer-based MR contrast agents are also discussed. PMID:20590365

  14. Paramagnetic self-assembled nanoparticles as supramolecular MRI contrast agents.

    PubMed

    Besenius, Pol; Heynens, Joeri L M; Straathof, Roel; Nieuwenhuizen, Marko M L; Bomans, Paul H H; Terreno, Enzo; Aime, Silvio; Strijkers, Gustav J; Nicolay, Klaas; Meijer, E W

    2012-01-01

    Nanometer-sized materials offer a wide range of applications in biomedical technologies, particularly imaging and diagnostics. Current scaffolds in the nanometer range predominantly make use of inorganic particles, organic polymers or natural peptide-based macromolecules. In contrast we hereby report a supramolecular approach for the preparation of self-assembled dendritic-like nanoparticles for applications as MRI contrast agents. This strategy combines the benefits from low molecular weight imaging agents with the ones of high molecular weight. Their in vitro properties are confirmed by in vivo measurements: post injection of well-defined and meta-stable nanoparticles allows for high-resolution blood-pool imaging, even at very low Gd(III) doses. These dynamic and modular imaging agents are an important addition to the young field of supramolecular medicine using well-defined nanometer-sized assemblies. PMID:22539406

  15. Evaluation of Intrarenal Oxygenation in Iodinated Contrast-Induced Acute Kidney Injury–Susceptible Rats by Blood Oxygen Level–Dependent Magnetic Resonance Imaging

    PubMed Central

    Li, Lu-Ping; Lu, Jing; Zhou, Ying; Papadopoulou, Maria V.; Franklin, Tammy; Bokhary, Ujala; Solomon, Richard; Sen, Anindya; Prasad, Pottumarthi V.

    2016-01-01

    Objectives The objectives of this study were to evaluate differences in intrarenal oxygenation as assessed by blood oxygen level–dependent (BOLD) magnetic resonance imaging in contrast-induced acute kidney injury (CIAKI)–susceptible rats when using 4 contrast media with different physicochemical properties and to demonstrate the feasibility of acquiring urinary neutrophil gelatinase–associated lipocalin (NGAL) levels as a marker of CIAKI in this model. Materials and Methods Our institutional animal care and use committee approved the study. Sixty-six Sprague-Dawley rats were divided into CIAKI-susceptible groups (received nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester [10 mg/kg] and cycloxygenase inhibitor indomethacin [10mg/kg]) and control groups (received saline instead). One of the 4 iodinated contrast agents (iothalamate, iohexol, ioxaglate, or iodixanol) was then administered (1600-mg organic iodine per kilogram of body weight). Multiple blood oxygen level–dependent magnetic resonance images were acquired on a Siemens 3.0-T scanner using a multiple gradient recalled echo sequence at baseline, after N-nitro-L-arginine methyl ester (or saline), indomethacin (or saline), and iodinated contrast agent (or placebo). R2* (R2* = 1/T2*) maps were generated inline on the scanner. A mixed-effects growth curve model with first-order autoregressive variance-covariance was used to analyze the temporal data. Urinary NGAL, a marker of kidney injury (unlike serum creatinine), was measured 4 hours after contrast injection in the 2 subgroups. Results Differences in blood oxygen level–dependent magnetic resonance imaging results between the contrast media were observed in all 4 renal regions. However, the inner stripe of the outer medulla (ISOM) showed the most pronounced changes in the CIAKI-susceptible group and R2* increased significantly (P < 0.01) over time with all 4 contrast media. In the control groups, only iodixanol showed an increase in R2

  16. Novel design of multimodal MRI/NIR optical contrast agent

    NASA Astrophysics Data System (ADS)

    Guo, Kevin; Lin, Franck; Akers, Walter; Zheng, Jie; Teng, Bao; Vasalatiy, Olga; Griffiths, Gary L.; Gandjbakhche, Amir; Berezin, Mikhail Y.; Achilefu, Samuel

    2011-03-01

    We present a novel, dual modality gadolinium based MRI/near-infrared optical probe. Utilizing a fluorescent dye as a scaffold with attached Gd-chelating moiety, we demonstrated a substantial shortening of T1 relaxation time of water protons in vitro. The probe was compared to the commonly used MRI Gd-based contrast agents Magnevist® and Multihance® and showed superior contrast properties. The enhancement was due to strong albumin binding of the hydrophobic fluorophore and overall rigidification of the contrast agent. Due to the near-infrared optical properties of the probe and excellent MRI activity the proposed construct can be potentially utilized as a dual probe in multimodal MRI/NIR optical imaging.

  17. Extracardiac applications of MR blood pool contrast agent in children.

    PubMed

    Farmakis, Shannon G; Khanna, Geetika

    2014-12-01

    Magnetic resonance (MR) angiography has significantly reduced the need for diagnostic conventional angiography and is preferred over CT angiography in children because of its lack of ionizing radiation. The availability of gadofosveset trisodium (the only clinically approved blood pool MR contrast agent) has led to an increase in applications of MR for vascular imaging and an improvement in diagnostic quality of MR angiography. Gadofosveset is a gadolinium-based contrast agent that binds reversibly to albumin, resulting in increased paramagnetic effect and longer intravascular residence. This allows for high-resolution arterial and venous MR angiography, assessment of flow characteristics of vascular malformations, dynamic vascular imaging, and multi-station imaging with a single low-dose gadolinium contrast injection. The purpose of this pictorial essay is to facilitate understanding of the kinetics and safety profile of gadofosveset trisodium, discuss technical aspects of imaging, and illustrate advantages and extracardiac applications in pediatric body imaging. PMID:25408135

  18. Ultrasound Imaging Beyond the Vasculature with New Generation Contrast Agents

    PubMed Central

    Perera, Reshani H.; Hernandez, Christopher; Zhou, Haoyan; Kota, Pavan; Burke, Alan

    2015-01-01

    Current commercially available ultrasound contrast agents are gas-filled, lipid- or protein-stabilized microbubbles larger than 1 μm in diameter. Because the signal generated by these agents is highly dependent on their size, small yet highly echogenic particles have been historically difficult to produce. This has limited the molecular imaging applications of ultrasound to the blood pool. In the area of cancer imaging, microbubble applications have been constrained to imaging molecular signatures of tumor vasculature and drug delivery enabled by ultrasound-modulated bubble destruction. Recently, with the rise of sophisticated advancements in nanomedicine, ultrasound contrast agents, which are an order of magnitude smaller (100-500 nm) than their currently utilized counterparts, have been undergoing rapid development. These agents are poised to greatly expand the capabilities of ultrasound in the field of targeted cancer detection and therapy by taking advantage of the enhanced permeability and retention phenomenon of many tumors and can extravasate beyond the leaky tumor vasculature. Agent extravasation facilitates highly sensitive detection of cell surface or microenvironment biomarkers, which could advance early cancer detection. Likewise, when combined with appropriate therapeutic agents and ultrasound-mediated deployment on demand, directly at the tumor site, these nanoparticles have been shown to contribute to improved therapeutic outcomes. Ultrasound's safety profile, broad accessibility and relatively low cost make it an ideal modality for the changing face of healthcare today. Aided by the multifaceted nano-sized contrast agents and targeted theranostic moieties described herein, ultrasound can considerably broaden its reach in future applications focused on the diagnosis and staging of cancer. PMID:25580914

  19. Dual-Energy Computed Tomography Arthrography of the Shoulder Joint Using Virtual Monochromatic Spectral Imaging: Optimal Dose of Contrast Agent and Monochromatic Energy Level

    PubMed Central

    An, Chansik; Chun, Yong-Min; Kim, Sungjun; Lee, Young Han; Yun, Min Jeong; Suh, Jin-Suck

    2014-01-01

    Objective To optimize the dose of contrast agent and the level of energy for dual-energy computed tomography (DECT) arthrography of the shoulder joint and to evaluate the benefits of the optimized imaging protocol. Materials and Methods Dual-energy scans with monochromatic spectral imaging mode and conventional single energy scans were performed on a shoulder phantom with 10 concentrations from 0 to 210 mg/mL of iodinated contrast medium at intervals of 15 or 30 mg/mL. Image noise, tissue contrast, and beam hardening artifacts were assessed to determine the optimum dose of contrast agent and the level of monochromatic energy for DECT shoulder arthrography in terms of the lowest image noise and the least beam hardening artifacts while good tissue contrast was maintained. Material decomposition (MD) imaging for bone-iodine differentiation was qualitatively assessed. The optimized protocol was applied and evaluated in 23 patients. Results The optimal contrast dose and energy level were determined by the phantom study at 60 mg/mL and 72 keV, respectively. This optimized protocol for human study reduced the image noise and the beam-hardening artifacts by 35.9% and 44.5%, respectively. Bone-iodine differentiation by MD imaging was not affected by the iodine concentration or level of energy. Conclusion Dual-energy scan with monochromatic spectral imaging mode results in reduced image noise and beam hardening artifacts. PMID:25469086

  20. Redox- and Hypoxia-Responsive MRI Contrast Agents

    PubMed Central

    Do, Quyen N.; Ratnakar, James S.; Kovács, Zoltán

    2014-01-01

    The development of responsive or “smart” magnetic resonance imaging (MRI) contrast agents that can report specific biomarker or biological events has been the focus of MRI contrast agent research over the past 20 years. Among various biological hallmarks of interest, tissue redox and hypoxia are particularly important owing to their roles in disease states and metabolic consequences. Herein we review the development of redox-/hypoxia-sensitive T1 shortening and paramagnetic chemical exchange saturation transfer (PARACEST) MRI contrast agents. Traditionally, the relaxivity of redox-sensitive Gd3+-based complexes is modulated through changes in the ligand structure or molecular rotation, while PARACEST sensors exploit the sensitivity of the metal-bound water exchange rate to electronic effects of the ligand-pendant arms and alterations in the coordination geometry. Newer designs involve complexes of redox-active metal ions in which the oxidation states have different magnetic properties. The challenges of translating redox- and hypoxia-sensitive agents in vivo are also addressed. PMID:24825674

  1. Redox- and hypoxia-responsive MRI contrast agents.

    PubMed

    Do, Quyen N; Ratnakar, James S; Kovács, Zoltán; Sherry, A Dean

    2014-06-01

    The development of responsive or "smart" magnetic resonance imaging (MRI) contrast agents that can report specific biomarker or biological events has been the focus of MRI contrast agent research over the past 20 years. Among various biological hallmarks of interest, tissue redox and hypoxia are particularly important owing to their roles in disease states and metabolic consequences. Herein we review the development of redox-/hypoxia-sensitive T1 shortening and paramagnetic chemical exchange saturation transfer (PARACEST) MRI contrast agents. Traditionally, the relaxivity of redox-sensitive Gd(3+) -based complexes is modulated through changes in the ligand structure or molecular rotation, while PARACEST sensors exploit the sensitivity of the metal-bound water exchange rate to electronic effects of the ligand-pendant arms and alterations in the coordination geometry. Newer designs involve complexes of redox-active metal ions in which the oxidation states have different magnetic properties. The challenges of translating redox- and hypoxia-sensitive agents in vivo are also addressed. PMID:24825674

  2. Effects of ultrasound and ultrasound contrast agent on vascular tissue

    PubMed Central

    2012-01-01

    Background Ultrasound (US) imaging can be enhanced using gas-filled microbubble contrast agents. Strong echo signals are induced at the tissue-gas interface following microbubble collapse. Applications include assessment of ventricular function and virtual histology. Aim While ultrasound and US contrast agents are widely used, their impact on the physiological response of vascular tissue to vasoactive agents has not been investigated in detail. Methods and results In the present study, rat dorsal aortas were treated with US via a clinical imaging transducer in the presence or absence of the US contrast agent, Optison. Aortas treated with both US and Optison were unable to contract in response to phenylephrine or to relax in the presence of acetylcholine. Histology of the arteries was unremarkable. When the treated aortas were stained for endothelial markers, a distinct loss of endothelium was observed. Importantly, terminal deoxynucleotidyl transferase mediated dUTP nick-end-labeling (TUNEL) staining of treated aortas demonstrated incipient apoptosis in the endothelium. Conclusions Taken together, these ex vivo results suggest that the combination of US and Optison may alter arterial integrity and promote vascular injury; however, the in vivo interaction of Optison and ultrasound remains an open question. PMID:22805356

  3. Biodegradable Polydisulfide Dendrimer Nanoclusters as MRI Contrast Agents

    PubMed Central

    Huang, Ching-Hui; Nwe, Kido; Zaki, Ajlan Al; Brechbiel, Martin W.; Tsourkas, Andrew

    2012-01-01

    Gd-conjugated dendrimer nanoclusters (DNCs) are a promising platform for the early detection of disease; however, their clinical utility is potentially limited due to safety concerns related to nephrogenic systemic fibrosis (NSF). In this paper, biodegradable DNCs were prepared with polydisulfide linkages between the individual dendrimers to facilitate excretion. Further, DNCs were labeled with pre-metalated Gd chelates to eliminate the risk of free Gd becoming entrapped in dendrimer cavities. The biodegradable polydisulfide DNCs possessed a circulation half-life of > 1.6 h in mice and produced significant contrast enhancement in the abdominal aorta and kidneys for as long as 4 h. The DNCs were reduced in circulation as a result of thiol-disulfide exchange and the degradation products were rapidly excreted via renal filtration. These agents demonstrated effective and prolonged in vivo contrast enhancement and yet minimized Gd tissue retention. Biodegradable polydisulfide DNCs represent a promising biodegradable macromolecular MRI contrast agent for magnetic resonance angiography and can potentially be further developed into target specific MRI contrast agents. PMID:23098069

  4. Dual-frequency transducer for nonlinear contrast agent imaging.

    PubMed

    Guiroy, Axel; Novell, Anthony; Ringgaard, Erling; Lou-Moeller, Rasmus; Grégoire, Jean-Marc; Abellard, André-Pierre; Zawada, Tomasz; Bouakaz, Ayache; Levassort, Franck

    2013-12-01

    Detection of high-order nonlinear components issued from microbubbles has emerged as a sensitive method for contrast agent imaging. Nevertheless, the detection of these high-frequency components, including the third, fourth, and fifth harmonics, remains challenging because of the lack of transducer sensitivity and bandwidth. In this context, we propose a new design of imaging transducer based on a simple fabrication process for high-frequency nonlinear imaging. The transducer is composed of two elements: the outer low-frequency (LF) element was centered at 4 MHz and used in transmit mode, whereas the inner high-frequency (HF) element centered at 14 MHz was used in receive mode. The center element was pad-printed using a lead zirconate titanate (PZT) paste. The outer element was molded using a commercial PZT, and curved porous unpoled PZT was used as backing. Each piezoelectric element was characterized to determine the electromechanical performance with thickness coupling factor around 45%. After the assembly of the two transducer elements, hydrophone measurements (electroacoustic responses and radiation patterns) were carried out and demonstrated a large bandwidth (70% at -3 dB) of the HF transducer. Finally, the transducer was evaluated for contrast agent imaging using contrast agent microbubbles. The results showed that harmonic components (up to the sixth harmonic) of the microbubbles were successfully detected. Moreover, images from a flow phantom were acquired and demonstrated the potential of the transducer for high-frequency nonlinear contrast imaging. PMID:24297028

  5. Molecular nanomagnets as contrast agents for Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Rodríguez, Elisenda; Roig, Anna; Molins, Elies; Arús, Carles; Cabañas, Miquel; Quintero, María Rosa; Cerdán, Sebastián; Sanfeliu, Coral

    2003-03-01

    Magnetic resonance imaging (MRI) is a non-invasive technique used in medicine to produce high quality images of human body slices. In order to enhance the contrast between different organs or to reveal altered portions of them such necrosis or tumors, the administration of a contrast agent is highly convenient. Currently Gd-DTPA, a paramagnetic complex, is the most widely administered compound. In this context, we have assayed molecular nanomagnets as MRI contrast agents. The complex [(tacn)_6Fe_8(μ_3-O)_2(μ_2-OH)_12]Br_8·9H_2O^1(Fe8 in brief) has been evaluated and shorter relaxation times, T1 and T_2, have been obtained for Fe8 than those obtained for the commercial Gd-DTPA. No toxic effects have been observed at concentrations up to 1 mM of Fe8 in cultured cells. Phantom studies with T_1-weighted MRI at 9.4 Tesla suggest that Fe8 can have potentiality as T_1-contrast agent. ^1Wieghardt K Angew Chem Intl Ed Engl 23 1 (1984) 77

  6. Cardiac arrhythmias produced by ultrasound and contrast agents

    NASA Astrophysics Data System (ADS)

    Rota, Claudio

    Ultrasound is used widely in medicine for both diagnostic and therapeutic applications. Ultrasound contrast agents are suspensions of gas-filled microbubbles used to enhance diagnostic imaging. Microbubble contrast agents can increase the likelihood of bioeffects of ultrasound associated with acoustic cavitation. Under certain exposure conditions, the interaction of ultrasound with cardiac tissues can produce cardiac arrhythmias. The general objective of this thesis was to develop a greater understanding of ultrasound-induced premature cardiac beats. The hypothesis guiding this work was that acoustic cavitation is the physical mechanism for the production of arrhythmias with ultrasound. This hypothesis was tested through a series of experiments with mice in vivo and theoretical investigations. Results of this research supported the acoustic cavitation hypothesis. The acoustic pressure threshold for premature beats was significantly lower with microbubble contrast agents present in the blood than without. With microbubbles, the threshold for premature beats was below the current output limits of diagnostic devices. The threshold was not significantly dependent upon contrast agent type and was not influenced by contrast agent dose over three orders of magnitude. Furthermore, the dependence of the threshold on acoustic frequency was consistent with the frequency dependence of acoustic cavitation. Experimentally determined thresholds for premature beats in vivo were in excellent agreement with theoretically estimated thresholds for inertial cavitation. A passive cavitation detector (PCD) was used to measure the acoustic emissions produced by cavitating microbubbles in vivo. A direct correlation between the amplitude of the PCD and the percentage of ultrasound pulses producing a premature beat was consistent with cavitation as a mechanism for this bioeffect. Although this thesis focused on the mechanistic understanding of ultrasound-induced arrhythmias, more persistent

  7. Screening CEST contrast agents using ultrafast CEST imaging

    NASA Astrophysics Data System (ADS)

    Xu, Xiang; Yadav, Nirbhay N.; Song, Xiaolei; McMahon, Michael T.; Jerschow, Alexej; van Zijl, Peter C. M.; Xu, Jiadi

    2016-04-01

    A chemical exchange saturation transfer (CEST) experiment can be performed in an ultrafast fashion if a gradient field is applied simultaneously with the saturation pulse. This approach has been demonstrated for studying dia- and para-magnetic CEST agents, hyperpolarized Xe gas and in vivo spectroscopy. In this study we present a simple method for the simultaneous screening of multiple samples. Furthermore, by interleaving a number of saturation and readout periods within the TR, a series of images with different saturation times can be acquired, allowing for the quantification of exchange rates using the variable saturation time (QUEST) approach in a much accelerated fashion, thus enabling high throughput screening of CEST contrast agents.

  8. Nanoshells as an optical coherence tomography contrast agent

    NASA Astrophysics Data System (ADS)

    Barton, Jennifer K.; Halas, Naomi J.; West, Jennifer L.; Drezek, Rebekah A.

    2004-07-01

    Nanoshells are a layered dielectric core/metal shell composite nanostructure with an optical resonance geometrically tunable through the visible and near infrared. Due to their small size, ability to generate a strong backscattering signal, and potential for surface modification, they may be an ideal in vivo optical coherence tomography contrast agent. We performed a pilot study to assess their capabilities. Images of a cuvette filled with dilute nanoshells, 2 μm polystyrene microspheres, or a combination were obtained. When compared to microspheres, images of the nanoshells where much brighter and attenuation of the bottom cuvette interface less. Injection of micropheres into the tail vein of mice and hamsters caused a noticeable brightening of OCT images of the dorsal skin. These pilot studies indicate that nanoshells may be an excellent OCT contrast agent; work is continuing to determine optimum nanoshell parameters and applications.

  9. Tunable Diacetylene Polymerized Shell Microbubbles as Ultrasound Contrast Agents

    PubMed Central

    Park, Yoonjee; Luce, Adam C.; Whitaker, Ragnhild D.; Amin, Bhumica; Cabodi, Mario; Nap, Rikkert J.; Szleifer, Igal; Cleveland, Robin O.; Nagy, Jon O.; Wong, Joyce Y.

    2012-01-01

    Monodisperse gas microbubbles, encapsulated with a shell of photopolymerizable diacetylene lipids and phospholipids, were produced by microfluidic flow focusing, for use as ultrasound contrast agents. The stability of the polymerized shell microbubbles against both aggregation and gas dissolution under physiological conditions was studied. Polyethylene glycol (PEG) 5000, which was attached to the diacetylene lipids, was predicted by molecular theory to provide more steric hindrance against aggregation than PEG 2000 and this was confirmed experimentally. The polymerized shell microbubbles were found to have higher shell-resistance than nonpolymerizable shell microbubbles and commercially available microbubbles (Vevo MicroMarker). The acoustic stability under 7.5 MHz ultrasound insonation was significantly greater than for the two comparison microbubbles. The acoustic stability was tunable by varying the amount of diacetylene lipid. Thus, our polymerized shell microbubbles are a promising platform for ultrasound contrast agents. PMID:22260537

  10. Towards MRI T2 contrast agents of increased efficiency

    NASA Astrophysics Data System (ADS)

    Branca, Marlène; Marciello, Marzia; Ciuculescu-Pradines, Diana; Respaud, Marc; Morales, Maria del Puerto; Serra, Raphael; Casanove, Marie-José; Amiens, Catherine

    2015-03-01

    Magnetic nanoparticles can be efficient contrast agents for T2 weighted magnetic resonance imaging (MRI) after tuning of some key parameters such as size, surface state, colloidal stability and magnetization, thus motivating the development of new synthetic pathways. In this paper we report the effects of surface coating on the efficiency of two different types of iron based nanoparticles (NPs) as MRI contrast agents. Starting from well-defined hydrophobic iron oxide nanospheres and iron nanocubes of 13 nm size, we have used three methods to increase their hydrophilicity and transfer them into water: surface ligand modification, ligand exchange or encapsulation. The NPs obtained have been characterized by dynamic light scattering and transmission electron microscopy, and the relaxivities of their stable colloidal solutions in water have been determined. Among all samples prepared, iron nanocubes coated by silica display the highest relaxivity (r2) value: 628 s-1 mM-1.

  11. The in vivo relaxivity of MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Shuter, Borys

    1999-11-01

    Post-contrast clinical 1H Magnetic Resonance Images have to date been interpreted with little regard for possible variations in the in-vivo properties of injected magnetic pharmaceuticals (contrast agents), particularly in their relaxivity or ability to alter tissue relaxation rates, T2-1 and T 2-1, per unit concentration. The relaxivities of contrast agents have only rarely been measured in-vivo, measurements usually being performed on excised tissues and at magnetic field strengths lower than used in clinical practice. Some researchers have simply assumed that relaxivities determined in homogeneous tissue phantoms were applicable in-vivo. In this thesis, the relaxivities of two contrast agents, Gd-DTPA and Gd-EOB-DTPA, were measured in simple tissue phantoms and in the kidney and liver of intact, but sacrificed, Wistar rats using a clinical MR scanner with a magnetic field of 1.5 Tesla. T1 and T2 were determined from sets of images acquired using a standard clinical spin-echo pulse sequence. The contrast agent concentration in tissue was assessed by radioassay of 153Gd-DTPA or 153Gd-EOB-DTPA, mixed with the normal compound prior to injection. Relaxivity was taken as the slope of a linear regression fit of relaxation rate against Gd concentration. The relaxivities of Gd-EOB-DTPA were similarly determined in normal and biliary- obstructed guinea pigs. Relaxivities in tissue differed significantly from values obtained in simple phantoms. Kidney T1 relaxivity was reduced for both compounds in normal animals. Three days or more of biliary obstruction produced further reductions in kidney T1 relaxivity of Gd-EOB-DTPA, providing strong evidence that disease affects contrast agent relaxivity. Kidney T2 relaxivity was much greater than T1 relaxivity and was also depressed by biliary obstruction. Liver T1 and T 2 relaxivites were increased above phantom values, but were not affected by the biliary obstruction. Water compartmentalisation, macromolecular binding, proton

  12. [Anaphylactic shock from an iodine contrast medium: role of the allergy check-up in one case].

    PubMed

    Halna du Fretay, X; Gaillet, G; Hoarau, C; Blanchard-Lemoine, B

    2012-12-01

    Anaphylactoid reactions to iodine contrast media are rare but serious, possibly life-threatening and calling an appropriate and urgent care. The physiopathological mechanism of these reactions remains to be fully elucidated. This reaction is still mostly called "pseudoallergic" in the literature. However, recent papers emphasise that a true allergic process is more frequent than previously expected. They also insist on the interest of running allergy tests including skin testing. We report the case of an anaphylactic shock to iodine contrast media, occurring during coronary angiography. We performed an allergy check-up and found the culprit allergen. We also evidenced a cross-reaction to another contrast media from the similar group. On the other hand, there was no reaction to contrast media of other types. With these results, another coronary angiography could be performed without any adverse event. When hypersensitivity reactions to iodine contrast media occur, it is mandatory to perform a complete allergy check-up. This will help determine the precise mechanism of the reaction and find the culprit allergen. PMID:23102513

  13. Beat frequency ultrasonic microsphere contrast agent detection system

    NASA Technical Reports Server (NTRS)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  14. Potential of high-Z contrast agents in clinical contrast-enhanced computed tomography

    SciTech Connect

    Nowak, Tristan; Hupfer, Martin; Brauweiler, Robert; Eisa, Fabian; Kalender, Willi A.

    2011-12-15

    Purpose: Currently, only iodine- and barium-based contrast media (CM) are used in clinical contrast-enhanced computed tomography (CE-CT). High-Z metals would produce a higher contrast at equal mass density for the x-ray spectra used in clinical CT. Using such materials might allow for significant dose reductions in CE-CT. The purpose of this study was to quantify the potential for dose reduction when using CM based on heavy metals. Methods: The contrast-to-noise ratio weighted by dose (CNRD) was determined as a function of scan protocol by means of measurements and simulations on a clinical CT scanner. For simulations, water cylinders with diameters 160, 320, 480, and 640 mm were used to cover a broad range of patient sizes. Measurements were conducted with 160 and 320 mm water-equivalent plastic cylinders. A central bore of 13 mm diameter was present in all phantoms. The tube voltage was varied from 80 to 140 kV for measurements and from 60 to 180 kV for simulations. Additional tin filtration of thicknesses 0.4, 0.8, and 1.2 mm was applied in the simulation to evaluate a range of spectral hardness. The bore was filled with a mixture of water and 10 mg/ml of pure iodine, holmium, gadolinium, ytterbium, osmium, tungsten, gold, and bismuth for the simulations and with aqueous solutions of ytterbium, tungsten, gold, and bismuth salts as well as Iopromid containing 10 mg/ml of the pure materials for the measurements. CNRDs were compared to iodine at phantom size-dependent reference voltages for all high-Z materials and the resulting dose reduction was calculated for equal contrast-to-noise ratio. Results: Dose reduction potentials strongly depended on phantom size, spectral hardness, and tube voltage. Depending on the added filtration, a dose reduction of 19%-60% could be reached at 80 kV with gadolinium for the 160 mm phantom, 52%-69% at 100 kV with holmium for the 320 mm phantom, 62%-78% with 120 kV for hafnium and the 480 mm phantom and 74%-86% with 140 kV for gold

  15. X-ray computed tomography contrast agents prepared by seeded growth of gold nanoparticles in PEGylated dendrimer

    NASA Astrophysics Data System (ADS)

    Kojima, Chie; Umeda, Yasuhito; Ogawa, Mikako; Harada, Atsushi; Magata, Yasuhiro; Kono, Kenji

    2010-06-01

    Gold nanoparticles (Au NPs) are a potential x-ray computed tomography (CT) contrast agent. A biocompatible and bioinactive surface is necessary for application of gold nanoparticle to CT imaging. Polyethylene glycol (PEG)-attached dendrimers have been used as a drug carrier with long blood circulation. In this study, the Au NPs were grown in the PEGylated dendrimer to produce a CT contrast agent. The Au NPs were grown by adding gold ions and ascorbic acid at various equivalents to the Au NP-encapsulated dendrimer solution. Both size and surface plasmon absorption of the grown Au NPs increased with adding a large number of gold ions. The x-ray attenuation of the Au NPs also increased after the seeded growth. The Au NPs grown in the PEG-attached dendrimer at the maximum under our conditions exhibited a similar CT value to a commercial iodine agent, iopamidol, in vitro. The Au NP-loaded PEGylated dendrimer and iopamidol were injected into mice and CT images were obtained at different times. The Au NP-loaded PEGylated dendrimer achieved a blood pool imaging, which was greater than a commercial iodine agent. Even though iopamidol was excreted rapidly, the PEGylated dendrimer loading the grown Au NP was accumulated in the liver.

  16. Acoustic properties of organic powders as ultrasonic contrast agents

    NASA Astrophysics Data System (ADS)

    Burov, V. A.; Loginov, S. V.; Dmitriev, K. V.

    2011-11-01

    The results of experiments on measuring attenuation and the effective acoustic nonlinear parameter of the second order are given for a suspension of cocoa-powder in water at different concentrations of the suspension. In the process of evaluating the value of the nonlinear parameter the attenuation in the suspension and generation of the second harmonic not only in the suspension but also in water are taken into account. The obtained results are evidence of the possibility of using a suspension of cocoa-powder in water as a technical substitute for ultrasonic contrast agents. The values of attenuation (up to 60 m-1 at the concentration of 1 g of the powder per 1 l of water) and the nonlinear parameter (up to 120 m-1 at the same concentration) mean that the suspension of cocoa-powder in water has smaller attenuation and the nonlinear parameter than ultrasonic contrast agents at the same concentration. However, these values for the suspension differ considerably from corresponding values for water or blood and, therefore, a suspension of cocoa-powder in water is a promising "substitute" for ultrasonic contrast agents in the case of technical testing of systems for nonlinear tomography of a blood flow, but cannot replace them in medical studies.

  17. Target-specific contrast agents for magnetic resonance microscopy

    PubMed Central

    Blackwell, Megan L.; Farrar, Christian T.; Fischl, Bruce; Rosen, Bruce R.

    2009-01-01

    High-resolution ex vivo magnetic resonance (MR) imaging can be used to delineate prominent architectonic features in the human brain, but increased contrast is required to visualize more subtle distinctions. To aid MR sensitivity to cell density and myelination, we have begun the development of target-specific paramagnetic contrast agents. This work details the first application of luxol fast blue (LFB), an optical stain for myelin, as a white matter-selective MR contrast agent for human ex vivo brain tissue. Formalin-fixed human visual cortex was imaged with an isotropic resolution between 80 and 150 μm at 4.7 and 14 T before and after en bloc staining with LFB. Longitudinal (R1) and transverse (R2) relaxation rates in LFB-stained tissue increased proportionally with myelination at both field strengths. Changes in R1 resulted in larger contrast-to-noise ratios (CNR), per unit time, on T1-weighted images between more myelinated cortical layers (IV–VI) and adjacent, superficial layers (I–III) at both field strengths. Specifically, CNR for LFB-treated samples increased by 229±13% at 4.7 T and 269±25% at 14 T when compared to controls. Also, additional cortical layers (IVca, IVd, and Va) were resolvable in 14T-MR images of LFB-treated samples but not in control samples. After imaging, samples were sliced in 40-micron sections, mounted, and photographed. Both the macroscopic and microscopic distributions of LFB were found to mimic those of traditional histological preparations. Our results suggest target-specific contrast agents will enable more detailed MR images with applications in imaging pathological ex vivo samples and constructing better MR atlases from ex vivo brains. PMID:19385012

  18. Hepatobiliary MR Imaging with Gadolinium Based Contrast Agents

    PubMed Central

    Frydrychowicz, Alex; Lubner, Meghan G.; Brown, Jeffrey J.; Merkle, Elmar M.; Nagle, Scott K.; Rofsky, Neil M.; Reeder, Scott B.

    2011-01-01

    The advent of gadolinium-based “hepatobiliary” contrast agents offers new opportunities for diagnostic MRI and has triggered a great interest for innovative imaging approaches to the liver and bile ducts. In this review article we will discuss the imaging properties of the two gadolinium-based hepatobiliary contrast agents currently available in the USA, gadobenate dimeglumine and gadoxetic acid, as well as important pharmacokinetic differences that affect their diagnostic performance. We will review potential applications, protocol optimization strategies, as well as diagnostic pitfalls. A variety of illustrative case examples will be used to demonstrate the role of these agents in detection and characterization of liver lesions as well as for imaging the biliary system. Changes in MR protocols geared towards optimizing workflow and imaging quality will also be discussed. It is our aim that the information provided in this article will facilitate the optimal utilization of these agents, and will stimulate the reader‘s pursuit of new applications for future benefit. PMID:22334493

  19. The Paramagnetic Pillared Bentonites as Digestive Tract MRI Contrast Agents

    NASA Astrophysics Data System (ADS)

    Mojović, Miloš; Daković, Marko; Omerašević, Mia; Mojović, Zorica; Banković, Predrag; Milutinović-Nikolić, Aleksandra; Jovanović, Dušan

    The increased use of imaging techniques in diagnostic studies, such as MRI, has contributed to the development of the wide range of new materials which could be successfully used as image improving agents. However, there is a lack of such substances in the area of gastrointestinal tract MRI. Many of the traditionally popular relaxation altering agents show poor results and disadvantages provoking black bowel, side effects of diarrhea and the presence of artifacts arising from clumping. Paramagnetic species seem to be potentially suitable agents for these studies, but contrast opacification has been reported and less than 60% of the gastrointestinal tract magnetic resonance scans showed improved delineation of abdominal pathologies. The new solution has been proposed as zeolites or smectite clays (hectorite and montmorillonite) enclosing of paramagnetic metal ions obtained by ion-exchange methods. However, such materials have problems of leakage of paramagnetic ions causing the appearance of the various side-effects. In this study we show that Co+2 and Dy+3 paramagnetic-pillared bentonites could be successfully used as MRI digestive tract non-leaching contrast agents, altering the longitudinal and transverse relaxation times of fluids in contact with the clay minerals.

  20. Removal of the iodinated X-ray contrast medium diatrizoate by anaerobic transformation.

    PubMed

    Redeker, Maria; Wick, Arne; Meermann, Björn; Ternes, Thomas A

    2014-09-01

    The iodinated X-ray contrast medium diatrizoate is known to be very persistent in current wastewater treatment as well as in environmental compartments. In this study, the potential of anaerobic processes in soils, sediments, and during wastewater treatment to remove and transform diatrizoate was investigated. In anaerobic batch experiments with soil and sediment seven biologically formed transformation products (TPs) as well as the corresponding transformation pathway were identified. The TPs resulted from successive deiodinations and deacetylations. The final TP 3,5-diaminobenzoic acid (DABA) was stable under anaerobic conditions. However, DABA was further transformed under air atmosphere, indicating the potential for the mineralization of diatrizoate by combining anaerobic and aerobic conditions. With the development of a methodology using complementary liquid chromatography-electrospray ionization-tandem mass spectrometry and liquid chromatography-inductively coupled plasma-mass spectrometry techniques, all identified TPs were quantified and the mass balance could be closed without having authentic standards for four of the TPs available. The detection and quantification of diatrizoate TPs in groundwater, in technical wetlands with anaerobic zones, and in a pilot wastewater treatment plant established for anaerobic treatment highlights the transferability and up-scaling of the results attained by laboratory experiments to environmental conditions. PMID:25140788

  1. Ex vivo micro-CT imaging of murine brain models using non-ionic iodinated contrast

    NASA Astrophysics Data System (ADS)

    Salas Bautista, N.; Martínez-Dávalos, A.; Rodríguez-Villafuerte, M.; Murrieta-Rodríguez, T.; Manjarrez-Marmolejo, J.; Franco-Pérez, J.; Calvillo-Velasco, M. E.

    2014-11-01

    Preclinical investigation of brain tumors is frequently carried out by means of intracranial implantation of brain tumor xenografts or allografts, with subsequent analysis of tumor growth using conventional histopathology. However, very little has been reported on the use contrast-enhanced techniques in micro-CT imaging for the study of malignant brain tumors in small animal models. The aim of this study has been to test a protocol for ex vivo imaging of murine brain models of glioblastoma multiforme (GBM) after treatment with non-ionic iodinated solution, using an in-house developed laboratory micro-CT. We have found that the best compromise between acquisition time and image quality is obtained using a 50 kVp, 0.5 mAs, 1° angular step on a 360 degree orbit acquisition protocol, with 70 μm reconstructed voxel size using the Feldkamp algorithm. With this parameters up to 4 murine brains can be scanned in tandem in less than 15 minutes. Image segmentation and analysis of three sample brains allowed identifying tumor volumes as small as 0.4 mm3.

  2. Biocompatible Nanocomplexes for Molecular Targeted MRI Contrast Agent

    NASA Astrophysics Data System (ADS)

    Chen, Zhijin; Yu, Dexin; Wang, Shaojie; Zhang, Na; Ma, Chunhong; Lu, Zaijun

    2009-07-01

    Accurate diagnosis in early stage is vital for the treatment of Hepatocellular carcinoma. The aim of this study was to investigate the potential of poly lactic acid-polyethylene glycol/gadolinium-diethylenetriamine-pentaacetic acid (PLA-PEG/Gd-DTPA) nanocomplexes using as biocompatible molecular magnetic resonance imaging (MRI) contrast agent. The PLA-PEG/Gd-DTPA nanocomplexes were obtained using self-assembly nanotechnology by incubation of PLA-PEG nanoparticles and the commercial contrast agent, Gd-DTPA. The physicochemical properties of nanocomplexes were measured by atomic force microscopy and photon correlation spectroscopy. The T1-weighted MR images of the nanocomplexes were obtained in a 3.0 T clinical MR imager. The stability study was carried out in human plasma and the distribution in vivo was investigated in rats. The mean size of the PLA-PEG/Gd-DTPA nanocomplexes was 187.9 ± 2.30 nm, and the polydispersity index was 0.108, and the zeta potential was -12.36 ± 3.58 mV. The results of MRI test confirmed that the PLA-PEG/Gd-DTPA nanocomplexes possessed the ability of MRI, and the direct correlation between the MRI imaging intensities and the nano-complex concentrations was observed ( r = 0.987). The signal intensity was still stable within 2 h after incubation of the nanocomplexes in human plasma. The nanocomplexes gave much better image contrast effects and longer stagnation time than that of commercial contrast agent in rat liver. A dose of 0.04 mmol of gadolinium per kilogram of body weight was sufficient to increase the MRI imaging intensities in rat livers by five-fold compared with the commercial Gd-DTPA. PLA-PEG/Gd-DTPA nanocomplexes could be prepared easily with small particle sizes. The nanocomplexes had high plasma stability, better image contrast effect, and liver targeting property. These results indicated that the PLA-PEG/Gd-DTPA nanocomplexes might be potential as molecular targeted imaging contrast agent.

  3. Hexameric Mn(II) Dendrimer as MRI Contrast Agent

    PubMed Central

    Zhu, Jiang; Gale, Eric M.; Atanasova, Iliyana; Rietz, Tyson A.

    2014-01-01

    A Mn(II) chelating dendrimer was prepared as a contrast agent for MRI applications. The dendrimer comprises six tyrosine-derived [Mn(EDTA)(H2O)]2− moieties coupled to a cyclotriphosphazene core. Variable temperature 17O NMR revealed a single water co-ligand per Mn(II) that undergoes fast water exchange (kex = (3.0±0.1) × 108 s−1 at 37 °C). The 37 °C per Mn(II) relaxivity ranged from 8.2 to 3.8 mM−1s−1 from 0.47 to 11.7T, and is 6-fold higher on a per molecule basis. From this field dependence a rotational correlation time was estimated as 0.45±0.02 ns. The imaging and pharmacokinetic properties of the dendrimer were compared to clinically used [Gd(DTPA)(H2O)]2− in mice at 4.7T. On first pass, the higher per ion relaxivity of the dendrimer resulted in 2-fold greater blood signal than for [Gd(DTPA)(H2O)]2−. Blood clearance was fast and elimination occurred through both the renal and hepatobiliary routes. This Mn(II) containing dendrimer represents potential alternative to Gd-based contrast agents, especially in patients with chronic kidney disease where the use of current Gd-based agents may be contraindicated. PMID:25224391

  4. Multifunctional Photosensitizer-Based Contrast Agents for Photoacoustic Imaging

    PubMed Central

    Ho, Chris Jun Hui; Balasundaram, Ghayathri; Driessen, Wouter; McLaren, Ross; Wong, Chi Lok; Dinish, U. S.; Attia, Amalina Binte Ebrahim; Ntziachristos, Vasilis; Olivo, Malini

    2014-01-01

    Photoacoustic imaging is a novel hybrid imaging modality combining the high spatial resolution of optical imaging with the high penetration depth of ultrasound imaging. Here, for the first time, we evaluate the efficacy of various photosensitizers that are widely used as photodynamic therapeutic (PDT) agents as photoacoustic contrast agents. Photoacoustic imaging of photosensitizers exhibits advantages over fluorescence imaging, which is prone to photobleaching and autofluorescence interference. In this work, we examined the photoacoustic activity of 5 photosensitizers: zinc phthalocyanine, protoporphyrin IX, 2,4-bis [4-(N,N-dibenzylamino)-2,6-dihydroxyphenyl] squaraine, chlorin e6 and methylene blue in phantoms, among which zinc phthalocyanine showed the highest photoacoustic activity. Subsequently, we evaluated its tumor localization efficiency and biodistribution at multiple time points in a murine model using photoacoustic imaging. We observed that the probe localized at the tumor within 10 minutes post injection, reaching peak accumulation around 1 hour and was cleared within 24 hours, thus, demonstrating the potential of photosensitizers as photoacoustic imaging contrast agents in vivo. This means that the known advantages of photosensitizers such as preferential tumor uptake and PDT efficacy can be combined with photoacoustic imaging capabilities to achieve longitudinal monitoring of cancer progression and therapy in vivo. PMID:24938638

  5. Nanostructured thermites based on iodine pentoxide for bio agent defeat systems.

    NASA Astrophysics Data System (ADS)

    Hobosyan, Mkhitar; Kazansky, Alexander; Martirosyan, Karen

    2011-10-01

    The risk for bioterrorist events involving the intentional airborne release of contagious agents has led to development of new approaches for bio agent defeat technologies both indoors and outdoors. Novel approaches to defeat harmful biological agents have generated a strong demand for new active materials. The preferred solutions are to neutralize the biological agents within the immediate target area by using aerosolized biocidal substances released in situ by high energetic reactions. By using nano-thermite reactions, with energy release up to 25 kJ/cc, based on I2O5/Al nanoparticles we intend to generate high quantity of vaporized iodine for spatial deposition onto harmful bacteria for their destruction. In this report, the effect of reaction product on growth and survival of Escherichia coli (E-coli) expressing GFP (Green Fluorescent Protein) was investigated. Moreover, we developed an approach to increase sensitivity of the detection. The study has shown that I2O5/Al nanosystem is extremely effective to disinfect harmful biological agents such (E-coli) bacteria in seconds.

  6. Simultaneous imaging of multiple contrast agents using full-spectrum micro-CT

    NASA Astrophysics Data System (ADS)

    Clark, D. P.; Touch, M.; Barber, W.; Badea, C. T.

    2015-03-01

    One of the major challenges for in vivo, micro-computed tomography (CT) imaging is poor soft tissue contrast. To increase contrast, exogenous contrast agents can be used as imaging probes. Combining these probes with a photon counting x-ray detector (PCXD) allows energy-sensitive CT and probe material decomposition from a series of images associated with different x-ray energies. We have implemented full-spectrum micro-CT using a PCXD and 2 keV energy sampling. We then decomposed multiple k-edge contrast materials present in an object (iodine, barium, and gadolinium) from water. Since the energy bins were quite narrow, the projection data was very noisy. This noise and further spectral distortions amplify errors in post-reconstruction material decompositions. Here, we propose and demonstrate a novel post-reconstruction denoising scheme which jointly enforces local and global gradient sparsity constraints, improving the contrast-to-noise ratio in full-spectrum micro-CT data and resultant material decompositions. We performed experiments using both calibration phantoms and ex vivo mouse data. Denoising increased the material contrast-to-noise ratio by an average of 13 times relative to filtered backprojection reconstructions. The relative decomposition error after denoising was 21%. To further improve material decomposition accuracy in future work, we also developed a model of the spectral distortions caused by PCXD imaging using known spectra from radioactive isotopes (109Cd, 133Ba). In future work, we plan to combine this model with the proposed denoising algorithm, enabling material decomposition with higher sensitivity and accuracy.

  7. What We Can Really Do with Bioresponsive MRI Contrast Agents.

    PubMed

    Angelovski, Goran

    2016-06-13

    Bioresponsive MRI contrast agents hold great promise for monitoring major physiological and pathological processes in a non-invasive manner. They are capable of altering the acquired MRI signal as a consequence of changes in their microenvironment, thus allowing real-time functional reporting in living organisms. Importantly, chemistry offers diverse solutions for the design of agents which respond to a great number of specific targets. However, the path to the successful utilization of these biomarkers in the desired functional MRI studies involves careful consideration of multiple scientific, technical, and practical issues across various research disciplines. This Minireview highlights the critical steps for planning and executing such multidisciplinary projects with an aim to substantially improve our knowledge of essential biological processes. PMID:27112329

  8. Screening CEST contrast agents using ultrafast CEST imaging.

    PubMed

    Xu, Xiang; Yadav, Nirbhay N; Song, Xiaolei; McMahon, Michael T; Jerschow, Alexej; van Zijl, Peter C M; Xu, Jiadi

    2016-04-01

    A chemical exchange saturation transfer (CEST) experiment can be performed in an ultrafast fashion if a gradient field is applied simultaneously with the saturation pulse. This approach has been demonstrated for studying dia- and para-magnetic CEST agents, hyperpolarized Xe gas and in vivo spectroscopy. In this study we present a simple method for the simultaneous screening of multiple samples. Furthermore, by interleaving a number of saturation and readout periods within the TR, a series of images with different saturation times can be acquired, allowing for the quantification of exchange rates using the variable saturation time (QUEST) approach in a much accelerated fashion, thus enabling high throughput screening of CEST contrast agents. PMID:26969814

  9. Gadolinium nanoparticles and contrast agent as radiation sensitizers.

    PubMed

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-01

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist(®) in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL(-1)), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly 'energy dependent' for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs. PMID:25988839

  10. Gadolinium nanoparticles and contrast agent as radiation sensitizers

    NASA Astrophysics Data System (ADS)

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F.; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-01

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist® in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL-1), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly ‘energy dependent’ for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs.

  11. The Incidence, Classification, and Management of Acute Adverse Reactions to the Low-Osmolar Iodinated Contrast Media Isovue and Ultravist in Contrast-Enhanced Computed Tomography Scanning.

    PubMed

    Zhang, Bin; Dong, Yuhao; Liang, Long; Lian, Zhouyang; Liu, Jing; Luo, Xiaoning; Chen, Wenbo; Li, Xinyu; Liang, Changhong; Zhang, Shuixing

    2016-03-01

    Some epidemiologic surveillance studies have recorded adverse drug reactions to radiocontrast agents. We aimed to investigate the incidence and management of acute adverse reactions (AARs) to Ultravist-370 and Isovue-370 in patients who underwent contrast-enhanced computed tomography (CT) scanning.Data from 137,473 patients were analyzed. They had undergone enhanced CT scanning with intravenous injection of Ultravist-370 or Isovue-370 during the period of January 1, 2006 to December 31, 2012 in our hospital. We investigated and classified AARs according to the American College of Radiology and the Chinese Society of Radiology (CSR) guidelines for iodinated contrast media. We analyzed risk factors for AARs and compared the AARs induced by Ultravist-370 and Isovue-370.Four hundred and twenty-eight (0.31%) patients experienced AARs, which included 330 (0.24%) patients with mild AARs, 82 (0.06%) patients with moderate AARs, and 16 (0.01%) patients with severe AARs (including 3 cases of cardiac arrest and one case of death). The incidence of AARs was higher with Ultravist-370 than with Isovue-370 (0.38% vs 0.24%, P < 0.001), but only for mild AARs (0.32% vs 0.16%, P < 0.001). Analyses on risk factors indicated that female patients (n = 221, 0.43%, P < 0.001), emergency patients (n = 11, 0.51%, P < 0.001), elderly patients aged 50 to 60 years (n = 135, 0.43%, P < 0.001), and patients who underwent coronary computed tomography angiography (CTA) (n = 55, 0.51%, P < 0.001) had a higher risk of AARs. Cutaneous manifestations (50.52%)-especially rash (59.74%)-were the most frequent mild AARs. Cardiovascular manifestations accounted for most moderate and severe AARs (62.91% and 48.28%, respectively). After proper management, the symptoms and signs of 96.5% of the AARs resolved within 24 hours without sequelae.Ultravist-370 and Isovue-370 are safe for patients undergoing enhanced CT scanning. The incidence of AARs is higher with Ultravist

  12. The Incidence, Classification, and Management of Acute Adverse Reactions to the Low-Osmolar Iodinated Contrast Media Isovue and Ultravist in Contrast-Enhanced Computed Tomography Scanning

    PubMed Central

    Zhang, Bin; Dong, Yuhao; Liang, Long; Lian, Zhouyang; Liu, Jing; Luo, Xiaoning; Chen, Wenbo; Li, Xinyu; Liang, Changhong; Zhang, Shuixing

    2016-01-01

    Abstract Some epidemiologic surveillance studies have recorded adverse drug reactions to radiocontrast agents. We aimed to investigate the incidence and management of acute adverse reactions (AARs) to Ultravist-370 and Isovue-370 in patients who underwent contrast-enhanced computed tomography (CT) scanning. Data from 137,473 patients were analyzed. They had undergone enhanced CT scanning with intravenous injection of Ultravist-370 or Isovue-370 during the period of January 1, 2006 to December 31, 2012 in our hospital. We investigated and classified AARs according to the American College of Radiology and the Chinese Society of Radiology (CSR) guidelines for iodinated contrast media. We analyzed risk factors for AARs and compared the AARs induced by Ultravist-370 and Isovue-370. Four hundred and twenty-eight (0.31%) patients experienced AARs, which included 330 (0.24%) patients with mild AARs, 82 (0.06%) patients with moderate AARs, and 16 (0.01%) patients with severe AARs (including 3 cases of cardiac arrest and one case of death). The incidence of AARs was higher with Ultravist-370 than with Isovue-370 (0.38% vs 0.24%, P < 0.001), but only for mild AARs (0.32% vs 0.16%, P < 0.001). Analyses on risk factors indicated that female patients (n = 221, 0.43%, P < 0.001), emergency patients (n = 11, 0.51%, P < 0.001), elderly patients aged 50 to 60 years (n = 135, 0.43%, P < 0.001), and patients who underwent coronary computed tomography angiography (CTA) (n = 55, 0.51%, P < 0.001) had a higher risk of AARs. Cutaneous manifestations (50.52%)—especially rash (59.74%)—were the most frequent mild AARs. Cardiovascular manifestations accounted for most moderate and severe AARs (62.91% and 48.28%, respectively). After proper management, the symptoms and signs of 96.5% of the AARs resolved within 24 hours without sequelae. Ultravist-370 and Isovue-370 are safe for patients undergoing enhanced CT scanning. The incidence of AARs is

  13. Modified Gadonanotubes as a promising novel MRI contrasting agent

    PubMed Central

    2013-01-01

    Background and purpose of the study Carbon nanotubes (CNTs) are emerging drug and imaging carrier systems which show significant versatility. One of the extraordinary characteristics of CNTs as Magnetic Resonance Imaging (MRI) contrasting agent is the extremely large proton relaxivities when loaded with gadolinium ion (Gdn3+) clusters. Methods In this study equated Gdn3+ clusters were loaded in the sidewall defects of oxidized multiwalled (MW) CNTs. The amount of loaded gadolinium ion into the MWCNTs was quantified by inductively coupled plasma (ICP) method. To improve water solubility and biocompatibility of the system, the complexes were functionalized using diamine-terminated oligomeric poly (ethylene glycol) via a thermal reaction method. Results Gdn3+ loaded PEGylated oxidized CNTs (Gdn3+@CNTs-PEG) is freely soluble in water and stable in phosphate buffer saline having particle size of about 200 nm. Transmission electron microscopy (TEM) images clearly showed formation of PEGylated CNTs. MRI analysis showed that the prepared solution represents 10% more signal intensity even in half concentration of Gd3+ in comparison with commerciality available contrasting agent Magnevist®. In addition hydrophilic layer of PEG at the surface of CNTs could prepare stealth nanoparticles to escape RES. Conclusion It was shown that Gdn3+@CNTs-PEG was capable to accumulate in tumors through enhanced permeability and retention effect. Moreover this system has a potential for early detection of diseases or tumors at the initial stages. PMID:23815852

  14. Repositioning Clofazimine as a Macrophage-Targeting Photoacoustic Contrast Agent

    PubMed Central

    Keswani, Rahul K.; Tian, Chao; Peryea, Tyler; Girish, Gandikota; Wang, Xueding; Rosania, Gus R.

    2016-01-01

    Photoacoustic Tomography (PAT) is a deep-tissue imaging modality, with potential clinical applications in the diagnosis of arthritis, cancer and other disease conditions. Here, we identified Clofazimine (CFZ), a red-pigmented dye and anti-inflammatory FDA-approved drug, as a macrophage-targeting photoacoustic (PA) imaging agent. Spectroscopic experiments revealed that CFZ and its various protonated forms yielded optimal PAT signals at wavelengths −450 to 540 nm. CFZ’s macrophage-targeting chemical and structural forms were detected with PA microscopy at a high contrast-to-noise ratio (CNR > 22 dB) as well as with macroscopic imaging using synthetic gelatin phantoms. In vivo, natural and synthetic CFZ formulations also demonstrated significant anti-inflammatory activity. Finally, the injection of CFZ was monitored via a real-time ultrasound-photoacoustic (US-PA) dual imaging system in a live animal and clinically relevant human hand model. These results demonstrate an anti-inflammatory drug repurposing strategy, while identifying a new PA contrast agent with potential applications in the diagnosis and treatment of arthritis. PMID:27000434

  15. Photoacoustic microscopy using Evans Blue dye as a contrast agent

    NASA Astrophysics Data System (ADS)

    Yao, Junjie; Maslov, Konstantin I.; Hu, Song; Wang, Lihong V.

    2010-02-01

    Complete and continuous imaging of microvascular networks is crucial for a wide variety of biomedical applications. Photoacoustic tomography can provide high resolution microvascular imaging using hemoglobin within red blood cells (RBC) as an endogenous contrast agent. However, intermittent RBC flow in capillaries results in discontinuous and fragmentary capillary images. To overcome this problem, we used Evans Blue (EB) dye as a contrast agent for in vivo photoacoustic imaging. EB has strong optical absorption at 610 nm and distributes uniformly in the blood stream by chemically binding to albumin. By intravenous injection of EB (6%, 200 μL), complete and continuous microvascular networks-especially capillaries-of the ears of nude mice were imaged. The diffusion of EB (3%, 100 μL) leaving the blood stream was monitored for 2 hours. At lower administration dose of EB (3%, 50 μL), the clearance of the EB-albumin complex was imaged for 10 days and quantitatively investigated using a two-compartment model.

  16. Repositioning Clofazimine as a Macrophage-Targeting Photoacoustic Contrast Agent.

    PubMed

    Keswani, Rahul K; Tian, Chao; Peryea, Tyler; Girish, Gandikota; Wang, Xueding; Rosania, Gus R

    2016-01-01

    Photoacoustic Tomography (PAT) is a deep-tissue imaging modality, with potential clinical applications in the diagnosis of arthritis, cancer and other disease conditions. Here, we identified Clofazimine (CFZ), a red-pigmented dye and anti-inflammatory FDA-approved drug, as a macrophage-targeting photoacoustic (PA) imaging agent. Spectroscopic experiments revealed that CFZ and its various protonated forms yielded optimal PAT signals at wavelengths -450 to 540 nm. CFZ's macrophage-targeting chemical and structural forms were detected with PA microscopy at a high contrast-to-noise ratio (CNR > 22 dB) as well as with macroscopic imaging using synthetic gelatin phantoms. In vivo, natural and synthetic CFZ formulations also demonstrated significant anti-inflammatory activity. Finally, the injection of CFZ was monitored via a real-time ultrasound-photoacoustic (US-PA) dual imaging system in a live animal and clinically relevant human hand model. These results demonstrate an anti-inflammatory drug repurposing strategy, while identifying a new PA contrast agent with potential applications in the diagnosis and treatment of arthritis. PMID:27000434

  17. A sensitive multi-residue method for the determination of 35 micropollutants including pharmaceuticals, iodinated contrast media and pesticides in water.

    PubMed

    Valls-Cantenys, Carme; Scheurer, Marco; Iglesias, Mònica; Sacher, Frank; Brauch, Heinz-Jürgen; Salvadó, Victoria

    2016-09-01

    A sensitive, multi-residue method using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to determine a representative group of 35 analytes, including corrosion inhibitors, pesticides and pharmaceuticals such as analgesic and anti-inflammatory drugs, five iodinated contrast media, β-blockers and some of their metabolites and transformation products in water samples. Few other methods are capable of determining such a broad range of contrast media together with other analytes. We studied the parameters affecting the extraction of the target analytes, including sorbent selection and extraction conditions, their chromatographic separation (mobile phase composition and column) and detection conditions using two ionisation sources: electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI). In order to correct matrix effects, a total of 20 surrogate/internal standards were used. ESI was found to have better sensitivity than APCI. Recoveries ranging from 79 to 134 % for tap water and 66 to 144 % for surface water were obtained. Intra-day precision, calculated as relative standard deviation, was below 34 % for tap water and below 21 % for surface water, groundwater and effluent wastewater. Method quantification limits (MQL) were in the low ng L(-1) range, except for the contrast agents iomeprol, amidotrizoic acid and iohexol (22, 25.5 and 17.9 ng L(-1), respectively). Finally, the method was applied to the analysis of 56 real water samples as part of the validation procedure. All of the compounds were detected in at least some of the water samples analysed. Graphical Abstract Multi-residue method for the determination of micropollutants including pharmaceuticals, iodinated contrast media and pesticides in waters by LC-MS/MS. PMID:27382969

  18. Case Report: Atrial Fibrillation After Intravenous Administration of Iodinated Contrast Medium in a Patient With Hepatocellular Carcinoma.

    PubMed

    Maimone, Sergio; Filomia, Roberto; Saitta, Carlo; Raimondo, Giovanni; Squadrito, Giovanni

    2015-09-01

    We describe the case of a 73-year-old woman with liver cirrhosis and hepatocellular carcinoma (HCC) who developed 2 distinct episodes of paroxystic atrial fibrillation (AF) each of which occurred 1 to 4 hours after iodine medium contrast-enhanced computed tomography. Sinus rhythm was restored by amiodarone therapy after the first AF episode and by electrical cardioversion after the second one. A careful clinical, biochemical, and instrumental examination showed that the patient had subclinical hyperthyroidism and moderate mitral insufficiency with mild atrial enlargement.Thus, the coexistence of both subclinical disthyroidism and of cardiac anatomical alterations may have predisposed the patient to AF that in fact occurred when exogenous iodine administration triggered a hyperthyroidism status. PMID:26334896

  19. Case Report: Atrial Fibrillation After Intravenous Administration of Iodinated Contrast Medium in a Patient With Hepatocellular Carcinoma

    PubMed Central

    Maimone, Sergio; Filomia, Roberto; Saitta, Carlo; Raimondo, Giovanni; Squadrito, Giovanni

    2015-01-01

    Abstract We describe the case of a 73-year-old woman with liver cirrhosis and hepatocellular carcinoma (HCC) who developed 2 distinct episodes of paroxystic atrial fibrillation (AF) each of which occurred 1 to 4 hours after iodine medium contrast-enhanced computed tomography. Sinus rhythm was restored by amiodarone therapy after the first AF episode and by electrical cardioversion after the second one. A careful clinical, biochemical, and instrumental examination showed that the patient had subclinical hyperthyroidism and moderate mitral insufficiency with mild atrial enlargement. Thus, the coexistence of both subclinical disthyroidism and of cardiac anatomical alterations may have predisposed the patient to AF that in fact occurred when exogenous iodine administration triggered a hyperthyroidism status. PMID:26334896

  20. Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging

    PubMed Central

    Velroyen, Astrid; Bech, Martin; Tapfer, Arne; Yaroshenko, Andre; Müller, Mark; Paprottka, Philipp; Ingrisch, Michael; Cyran, Clemens C.; Auweter, Sigrid D.; Nikolaou, Konstantin; Reiser, Maximilian F.; Pfeiffer, Franz

    2015-01-01

    The investigation of dedicated contrast agents for x-ray dark-field imaging, which exploits small-angle scattering at microstructures for contrast generation, is of strong interest in analogy to the common clinical use of high-atomic number contrast media in conventional attenuation-based imaging, since dark-field imaging has proven to provide complementary information. Therefore, agents consisting of gas bubbles, as used in ultrasound imaging for example, are of particular interest. In this work, we investigate an experimental contrast agent based on microbubbles consisting of a polyvinyl-alcohol shell with an iron oxide coating, which was originally developed for multimodal imaging and drug delivery. Its performance as a possible contrast medium for small-animal angiography was examined using a mouse carcass to realistically consider attenuating and scattering background signal. Subtraction images of dark field, phase contrast and attenuation were acquired for a concentration series of 100%, 10% and 1.3% to mimic different stages of dilution in the contrast agent in the blood vessel system. The images were compared to the gold-standard iodine-based contrast agent Solutrast, showing a good contrast improvement by microbubbles in dark-field imaging. This study proves the feasibility of microbubble-based dark-field contrast-enhancement in presence of scattering and attenuating mouse body structures like bone and fur. Therefore, it suggests a strong potential of the use of polymer-based microbubbles for small-animal dark-field angiography. PMID:26134130

  1. Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging.

    PubMed

    Velroyen, Astrid; Bech, Martin; Tapfer, Arne; Yaroshenko, Andre; Müller, Mark; Paprottka, Philipp; Ingrisch, Michael; Cyran, Clemens C; Auweter, Sigrid D; Nikolaou, Konstantin; Reiser, Maximilian F; Pfeiffer, Franz

    2015-01-01

    The investigation of dedicated contrast agents for x-ray dark-field imaging, which exploits small-angle scattering at microstructures for contrast generation, is of strong interest in analogy to the common clinical use of high-atomic number contrast media in conventional attenuation-based imaging, since dark-field imaging has proven to provide complementary information. Therefore, agents consisting of gas bubbles, as used in ultrasound imaging for example, are of particular interest. In this work, we investigate an experimental contrast agent based on microbubbles consisting of a polyvinyl-alcohol shell with an iron oxide coating, which was originally developed for multimodal imaging and drug delivery. Its performance as a possible contrast medium for small-animal angiography was examined using a mouse carcass to realistically consider attenuating and scattering background signal. Subtraction images of dark field, phase contrast and attenuation were acquired for a concentration series of 100%, 10% and 1.3% to mimic different stages of dilution in the contrast agent in the blood vessel system. The images were compared to the gold-standard iodine-based contrast agent Solutrast, showing a good contrast improvement by microbubbles in dark-field imaging. This study proves the feasibility of microbubble-based dark-field contrast-enhancement in presence of scattering and attenuating mouse body structures like bone and fur. Therefore, it suggests a strong potential of the use of polymer-based microbubbles for small-animal dark-field angiography. PMID:26134130

  2. Characterizing Galbumin as a high molecular weight contrast agent in MRI - A novel dual contrast agent protocol

    NASA Astrophysics Data System (ADS)

    Moosvi, Firas; Reinsberg, Stefan; Baker, Jennifer

    2009-05-01

    In studying cancer and tumours, traditional biochemical methods call for analyzing frozen cross sections of tumour tissues, staining and then fluorescently imaging them at high resolution. While this method has served its purpose for decades, situations and conditions are arising that require dynamic imaging in live animals. Recent advances in the field of Biophysics have allowed researchers the ability to correlate images taken with Magnetic Resonance Imaging (MRI) to those using high- resolution fluorescent microscopy. While live imaging is possible using MRI, it is certainly not possible to reproduce much of the biologically relevant data acquired by fluorescent microscopy. In this proposal, we set the stage for the biological problem, cover some basic tumour biology then outline the basic principles of imaging with NMR. Finally, we characterize the use of a new contrast agent, Galbumin, to conduct a pilot study for a new class of animal MRI experiments.Finally, we present a novel protocol for a dual contrast agent MR protocol to extract permeability and flow information to improve characterization of drug delivery. Our over-arching goal is to use the live imaging capabilities of MR, and combine them with traditional fluorescent microscopy techniques to get a more accurate biological picture of a tumour.

  3. Cellulose nanoparticles: photoacoustic contrast agents that biodegrade to simple sugars

    NASA Astrophysics Data System (ADS)

    Jokerst, Jesse V.; Bohndiek, Sarah E.; Gambhir, Sanjiv S.

    2014-03-01

    In photoacoustic imaging, nanoparticle contrast agents offer strong signal intensity and long-term stability, but are limited by poor biodistribution and clearance profiles. Conversely, small molecules offer renal clearance, but relatively low photoacoustic signal. Here we describe a cellulose-based nanoparticle with photoacoustic signal superior to gold nanorods, but that undergoes enzymatic cleavage into constituent glucose molecules for renal clearance. Cellulose nanoparticles (CNPs) were synthesized through acidic cleavage of cellulose linters and purified with centrifugation. TEM indicated that the nanoparticles were 132 +/- 46 nm; the polydispersity index was 0.138. Ex vivo characterization showed a photoacoustic limit of detection of 0.02 mg/mL CNPs, and the photoacoustic signal of CNPs was 1.5- to 3.0-fold higher than gold nanorods (also at 700 nm resonance) on a particle-to-particle basis. Cell toxicity assays suggested that overnight doses below 0.31 mg/mL CNPs produced no significant (p>0.05) impact on cell metabolism. Intravenous doses up to 0.24 mg were tolerated well in nude mice. Subcutaneous and orthotopic tumor xenografts of the OV2008 ovarian cancer cell line were then created in nude mice. Data was collected with a Nexus128 scanner from Endra LifeSciences. Spectral data used a LAZR system from Visualsonics both at 700 nm excitation. We injected CNPs (0.024 mg, 0.048 mg, and 0.80 mg) via tail vein and showed that the tumor photoacoustic signal reached maximum increase between 10 and 20 minutes. All injected concentrations were statistically (p<0.05) elevated relative to the control group with n=3 mice in each group, and dose and signal had a linear relationship at R2>0.96 suggesting quantitative signal. CNP biodegradation was demonstrated ex vivo with a glucose assay. CNPs in the presence of cellulase were reduced to free glucose in under than four hours. The glucose concentration before addition of cellulase was not detectable, but increased to

  4. Hafnia (HfO2) nanoparticles as an X-ray contrast agent and mid-infrared biosensor.

    PubMed

    McGinnity, Tracie L; Dominguez, Owen; Curtis, Tyler E; Nallathamby, Prakash D; Hoffman, Anthony J; Roeder, Ryan K

    2016-07-14

    The interaction of hafnium oxide (HfO2) nanoparticles (NPs) with X-ray and mid-infrared radiation was investigated to assess the potential as a multifunctional diagnostic probe for X-ray computed tomography (CT) and/or mid-infrared biosensing. HfO2 NPs of controlled size were prepared by a sol-gel process and surface functionalized with polyvinylpyrrolidone, resulting in relatively spherical and monodispersed NPs with a tunable mean diameter in the range of ∼7-31 nm. The X-ray attenuation of HfO2 NPs was measured over 0.5-50 mM concentration and compared with Au NPs and iodine, which are the most prominent X-ray contrast agents currently used in research and clinical diagnostic imaging, respectively. At clinical CT tube potentials >80 kVp, HfO2 NPs exhibited superior or similar X-ray contrast compared to Au NPs, while both exhibited significantly greater X-ray contrast compared to iodine, due to the favorable location of the k-shell absorption edge for hafnium and gold. Moreover, energy-dependent differences in X-ray attenuation enabled simultaneous quantitative molecular imaging of each agent using photon-counting spectral (multi-energy) CT. HfO2 NPs also exhibited a strong mid-infrared absorption in the Reststrahlen band from ∼250-800 cm(-1) and negative permittivity below 695 cm(-1), which can enable development of mid-infrared biosensors and contrast agents, leveraging surface enhanced mid-infrared and/or phonon polariton absorption. PMID:27364973

  5. Hafnia (HfO2) nanoparticles as an X-ray contrast agent and mid-infrared biosensor

    NASA Astrophysics Data System (ADS)

    McGinnity, Tracie L.; Dominguez, Owen; Curtis, Tyler E.; Nallathamby, Prakash D.; Hoffman, Anthony J.; Roeder, Ryan K.

    2016-07-01

    The interaction of hafnium oxide (HfO2) nanoparticles (NPs) with X-ray and mid-infrared radiation was investigated to assess the potential as a multifunctional diagnostic probe for X-ray computed tomography (CT) and/or mid-infrared biosensing. HfO2 NPs of controlled size were prepared by a sol-gel process and surface functionalized with polyvinylpyrrolidone, resulting in relatively spherical and monodispersed NPs with a tunable mean diameter in the range of ~7-31 nm. The X-ray attenuation of HfO2 NPs was measured over 0.5-50 mM concentration and compared with Au NPs and iodine, which are the most prominent X-ray contrast agents currently used in research and clinical diagnostic imaging, respectively. At clinical CT tube potentials >80 kVp, HfO2 NPs exhibited superior or similar X-ray contrast compared to Au NPs, while both exhibited significantly greater X-ray contrast compared to iodine, due to the favorable location of the k-shell absorption edge for hafnium and gold. Moreover, energy-dependent differences in X-ray attenuation enabled simultaneous quantitative molecular imaging of each agent using photon-counting spectral (multi-energy) CT. HfO2 NPs also exhibited a strong mid-infrared absorption in the Reststrahlen band from ~250-800 cm-1 and negative permittivity below 695 cm-1, which can enable development of mid-infrared biosensors and contrast agents, leveraging surface enhanced mid-infrared and/or phonon polariton absorption.

  6. Biological in situ characterization of polymeric microbubble contrast agents.

    PubMed

    Wan, Sha; Egri, Gabriella; Oddo, Letizia; Cerroni, Barbara; Dähne, Lars; Paradossi, Gaio; Salvati, Anna; Lynch, Iseult; Dawson, Kenneth A; Monopoli, Marco P

    2016-06-01

    Polymeric microbubbles (MBs) are gas filled particles composed of a thin stabilized polymer shell that have been recently developed as valid contrast agents for the combined use of ultrasonography (US), magnetic resonance imaging (MRI) and single photon emission computer tomography (SPECT) imaging. Due to their buoyancy, the commonly available approaches to study their behaviour in complex media are not easily applicable and their use in modern medicine requires such behaviour to be fully elucidated. Here we have used for the first time flow cytometry as a new high throughput approach that allows characterisation of the MB dispersion, prior to and after exposure in different biological media and we have additionally developed a method that allows characterisation of the strongly bound proteins adsorbed on the MBs, to fully predict their biological behaviour in biological milieu. PMID:26993210

  7. Superparamagnetic FePt nanoparticles as excellent MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Maenosono, Shinya; Suzuki, Toshimasa; Saita, Soichiro

    Chemically disordered face-centered cubic (fcc) FePt nanoparticles (NPs) with a mean diameter of 9 nm were synthesized via pyrolysis of iron(III) ethoxide and platinum(II) acetylacetonate. The surface ligands of these NPs were then exchanged from oleic acid to tetramethylammonium hydroxide (TMAOH) to measure the longitudinal ( T1) and transverse ( T2) proton relaxation times of aqueous dispersion of FePt NPs. Magnetic resonance relaxometry reveals that TMAOH-capped FePt NPs have a higher T2-shortening effect than conventional superparamagnetic iron oxide NPs, indicating that fcc-phase FePt NPs might be superior negative contrast agents for magnetic resonance imaging.

  8. Biodistribution of gadolinium-based contrast agents, including gadolinium deposition

    PubMed Central

    Aime, Silvio; Caravan, Peter

    2010-01-01

    The biodistribution of approved gadolinium (Gd) based contrast agents (GBCA) is reviewed. After intravenous injection GBCA distribute in the blood and the extracellular space and transiently through the excretory organs. Preclinical animal studies and the available clinical literature indicate that all these compounds are excreted intact. Elimination tends to be rapid and for the most part, complete. In renally insufficient patients the plasma elimination half-life increases substantially from hours to days depending on renal function. In patients with impaired renal function and nephrogenic systemic fibrosis (NSF), the agents gadodiamide, gadoversetamide, and gadopentetate dimeglumine have been shown to result in Gd deposition in the skin and internal organs. In these cases, it is likely that the Gd is no longer present as the GBCA, but this has still not been definitively shown. In preclinical models very small amounts of Gd are retained in the bone and liver, and the amount retained correlates with the kinetic and thermodynamic stability of the GBCA with respect to Gd release in vitro. The pattern of residual Gd deposition in NSF subjects may be different than that observed in preclinical rodent models. GBCA are designed to be used via intravenous administration. Altering the route of administration and/or the formulation of the GBCA can dramatically alter the biodistribution of the GBCA and can increase the likelihood of Gd deposition. PMID:19938038

  9. Mechanically Tunable Hollow Silica Ultrathin Nanoshells for Ultrasound Contrast Agents

    PubMed Central

    Liberman, A.; Wang, J.; Lu, N.; Viveros, R.D.; Allen, C. A.; Mattrey, R.F.; Blair, S.L.; Trogler, W.C.; Kim, M. J.; Kummel, A.C.

    2015-01-01

    Perfluoropentane (PFP) gas filled biodegradable iron-doped silica nanoshells have been demonstrated as long-lived ultrasound contrast agents. Nanoshells are synthesized by a sol-gel process with tetramethyl orthosilicate (TMOS) and iron ethoxide. Substituting a fraction of the TMOS with R-substituted trialkoxysilanes produces ultrathin nanoshells with varying shell thicknesses and morphologies composed of fused nanoflakes. The ultrathin nanoshells had continuous ultrasound Doppler imaging lifetimes exceeding 3 hours, were twice as bright using contrast specific imaging, and had decreased pressure thresholds compared to control nanoshells synthesized with just TMOS. Transmission electron microscopy (TEM) showed that the R-group substituted trialkoxysilanes could reduce the mechanically critical nanoshell layer to 1.4 nm. These ultrathin nanoshells have the mechanical behavior of weakly linked nanoflakes but the chemical stability of silica. The synthesis can be adapted for general fabrication of three-dimensional nanostructures composed of nanoflakes, which have thicknesses from 1.4–3.8 nm and diameters from 2–23 nm. PMID:26955300

  10. Successful balloon pulmonary angioplasty with gadolinium contrast media for a patient with chronic thromboembolic pulmonary hypertension and iodine allergy

    PubMed Central

    Nakamura, Tomohisa; Ogo, Takeshi; Tsuji, Akihiro; Fukui, Shigefumi; Fukuda, Tetsuya; Tahara, Nobuhiro; Fukumoto, Yoshihiro; Yasuda, Satoshi; Ogawa, Hisao; Nakanishi, Norifumi

    2016-01-01

    A 28-year-old male was referred to our hospital with dyspnea. He was diagnosed as having chronic thromboembolic pulmonary hypertension, and a pulmonary endarterectomy (PEA) was performed. However, exertional dyspnea remained because of residual pulmonary hypertension; therefore, the patient was re-admitted to our hospital 1 year after PEA. We performed computed tomography and pulmonary angiography and found web and band lesions in the distal pulmonary artery with a high pulmonary artery pressure. Although further management was complicated because the patient had an anaphylactic shock to iodine-based contrast media, we eventually completed five sessions of balloon pulmonary angioplasty (BPA) using gadolinium contrast medium. His symptoms and hemodynamics dramatically improved after a series of BPA. After 15 months, mean pulmonary arterial pressure reduced from 67 mmHg to 20 mmHg, and subjective symptoms improved from stage Ⅳ to I as per the WHO classification system. BPA is a potential procedure for residual pulmonary hypertension after PEA and could be safely performed using gadolinium contrast medium for patients with iodine allergy. PMID:27141436

  11. Contrast Induced Nephropathy with Intravenous Iodinated Contrast Media in Routine Diagnostic Imaging: An Initial Experience in a Tertiary Care Hospital

    PubMed Central

    Bhatt, Shuchi; Rajpal, Nipun; Rathi, Vineeta; Avasthi, Rajneesh

    2016-01-01

    Background. Contrast induced nephropathy (CIN) is common cause of hospital acquired renal failure, defined as iatrogenic deterioration of renal function following intravascular contrast administration in the absence of another nephrotoxic event. Objectives. Objectives were to calculate incidence of CIN with routine IV contrast usage and to identify its risk factors. Materials and Methods. Study was conducted on 250 patients (having eGFR ≥ 45 mL/min/1.73 m2) receiving intravenous contrast. Various clinical risk factors and details of contrast media were recorded. Patients showing 25% increase in postprocedural serum creatinine value or an absolute increase of 0.5 mg/dL (44.2 mmol/L) were diagnosed as having CIN. Results and Conclusions. Postprocedural serum creatinine showed significant increase from baseline levels. 25 patients (10%) developed CIN. CIN was transient in 21 (84%) patients developing CIN. One patient (4%) developed renal failure and another died due to unknown cause. Dehydration, preexisting renal disease, cardiac failure, previous contrast administration, and volume of contrast had significant correlation with development of CIN (p < 0.05); whereas demographic variables, baseline serum creatinine/eGFR, previous renal surgery, diabetes mellitus, hypertension, nephrotoxic drug intake, abnormal routine hematology, and contrast characteristics had no correlation with CIN. CIN is a matter of concern even in routine imaging requiring intravenous contrast media, in our set-up. PMID:27069686

  12. Comparison of iodinated trihalomethanes formation during aqueous chlor(am)ination of different iodinated X-ray contrast media compounds in the presence of natural organic matter.

    PubMed

    Ye, Tao; Xu, Bin; Wang, Zhen; Zhang, Tian-Yang; Hu, Chen-Yan; Lin, Lin; Xia, Sheng-Ji; Gao, Nai-Yun

    2014-12-01

    Iodinated trihalomethanes (I-THMs) formation during chlorination and chloramination of five iodinated X-ray contrast media (ICM) compounds (iopamidol, iopromide, iodixanol, histodenz, and diatrizoate) in the presence of natural organic matter (NOM) was evaluated and compared. Chlorination and chloramination of ICM in the absence of NOM yielded only a trace amount of I-THMs, while levels of I-THMs were enhanced substantially in raw water samples. With the presence of NOM, the order with respect to the maximum yield of I-THMs observed during chlorination was iopamidol > histodenz > iodixanol > diatrizoate > iopromide. During chloramination, I-THM formation was enhanced for hisodenz, iodixanol, diatrizoate, and iopromide. The order with respect to the maximum yield of I-THMs observed during chloramination was iopamidol > diatrizoate > iodixanol > histodenz > iopromide. With the exception of iopamidol, I-THM formation was favored at relatively low chlorine doses (≤100 μM) during ICM chlorination, and significant suppression was observed with high chlorine doses applied (>100 μM). However, during chloramination, increasing monochloramine dose monotonously increased the yield of I-THMs for the five ICM. During chlorination of iodixanol, histodenz, and diatrizoate, the yields of I-THMs exhibited three distinct trends as the pH increased from 5 to 9, while peak I-THM formation was found at circumneutral pH for chloramination. Increasing bromide concentration not only considerably enhanced the yield of I-THMs but also shifted the I-THMs towards bromine-containing ones and increased the formation of higher bromine-incorporated species (e.g., CHBrClI and CHBr2I), especially in chloramination. These results are of particular interest to understand I-THM formation mechanisms during chlorination and chloramination of waters containing ICM. PMID:25240119

  13. Optical contrast agents to visualize molecular expression in breast cancer

    NASA Astrophysics Data System (ADS)

    Langsner, Robert James

    Breast cancer is the second leading cause of death of women in the United States. Improvements in screening technology have increased the breast cancer incidence rate, as smaller lesions are being detected. Due to the small size of lesions, patients can choose to receive breast conservation therapy (BCT) rather than a modified radical mastectomy. Even though the breast retains cosmesis after BCT, there is an increased risk of the patient having residual microscopic disease, known as positive margins. Patients with positive margins receive increased radiation and have an increased chance of second surgery. Pathology with hematoxylin and eosin (H&E) remains the gold standard for diagnosing margin status in patients. Intraoperative pathology has been shown to reduce the rate of positive margins in BCT. However, a minority of surgery centers have intraoperative pathology centers, limiting the number of patients that receive this standard of care. The expression profiles of surface receptors such as ErbB2 (HER2-positive) and epidermal growth factor receptor (EGFR) provide information about the aggressiveness of a particular tumor. Recent research has shown that there was elevated EGFR expression in patients with a local recurrence even though the biopsies were assessed to be disease free using standard H&E. If the physicians had known the molecular expression of these biopsies, a different treatment regimen or excision of more tissue might have prevented the recurrence. This thesis investigates targeted molecular contrast agents that enhance the visualization of molecular markers such as glucose transporters (GLUTs) and growth factor receptors in tissue specimens. First, application of 2-NBDG, a fluorescent deoxyglucose, enhances signal in cancerous tissue with a 20-minute incubation. Then, antibody functionalized silica-gold nanoshells enhance the visualization of ErbB2 overexpression in specimens with a 5-minute incubation. To image these contrast agents in cancerous

  14. Synthesis, Characterization, In Vitro Phantom Imaging, and Cytotoxicity of A Novel Graphene-Based Multimodal Magnetic Resonance Imaging - X-Ray Computed Tomography Contrast Agent.

    PubMed

    Lalwani, Gaurav; Sundararaj, Joe Livingston; Schaefer, Kenneth; Button, Terry; Sitharaman, Balaji

    2014-06-14

    Graphene nanoplatelets (GNPs), synthesized using potassium permanganate-based oxidation and exfoliation followed by reduction with hydroiodic acid (rGNP-HI), have intercalated manganese ions within the graphene sheets, and upon functionalization with iodine, show excellent potential as biomodal contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT). Structural characterization of rGNP-HI nanoparticles with low- and high-resolution transmission electron microscope (TEM) showed disc-shaped nanoparticles (average diameter, 200 nm, average thickness, 3 nm). Energy dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of intercalated manganese. Raman spectroscopy and X-ray diffraction (XRD) analysis of rGNP-HI confirmed the reduction of oxidized GNPs (O-GNPs), absence of molecular and physically adsorbed iodine, and the functionalization of graphene with iodine as polyiodide complexes (I3 (-) and I5 (-)). Manganese and iodine content were quantified as 5.1 ± 0.5 and 10.54 ± 0.87 wt% by inductively-coupled plasma optical emission spectroscopy and ion-selective electrode measurements, respectively. In vitro cytotoxicity analysis, using absorbance (LDH assay) and fluorescence (calcein AM) based assays, performed on NIH3T3 mouse fibroblasts and A498 human kidney epithelial cells, showed CD50 values of rGNP-HI between 179-301 µg/ml, depending on the cell line and the cytotoxicity assay. CT and MRI phantom imaging of rGNP-HI showed high CT (approximately 3200% greater than HI at equimolar iodine concentration) and MRI (approximately 59% greater than equimolar Mn(2+) solution) contrast. These results open avenues for further in vivo safety and efficacy studies towards the development of carbon nanostructure-based multimodal MRI-CT contrast agents. PMID:24999431

  15. Synthesis, Characterization, In Vitro Phantom Imaging, and Cytotoxicity of A Novel Graphene-Based Multimodal Magnetic Resonance Imaging - X-Ray Computed Tomography Contrast Agent

    PubMed Central

    Lalwani, Gaurav; Sundararaj, Joe Livingston; Schaefer, Kenneth; Button, Terry; Sitharaman, Balaji

    2014-01-01

    Graphene nanoplatelets (GNPs), synthesized using potassium permanganate-based oxidation and exfoliation followed by reduction with hydroiodic acid (rGNP-HI), have intercalated manganese ions within the graphene sheets, and upon functionalization with iodine, show excellent potential as biomodal contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT). Structural characterization of rGNP-HI nanoparticles with low- and high-resolution transmission electron microscope (TEM) showed disc-shaped nanoparticles (average diameter, 200 nm, average thickness, 3 nm). Energy dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of intercalated manganese. Raman spectroscopy and X-ray diffraction (XRD) analysis of rGNP-HI confirmed the reduction of oxidized GNPs (O-GNPs), absence of molecular and physically adsorbed iodine, and the functionalization of graphene with iodine as polyiodide complexes (I3− and I5−). Manganese and iodine content were quantified as 5.1 ± 0.5 and 10.54 ± 0.87 wt% by inductively-coupled plasma optical emission spectroscopy and ion-selective electrode measurements, respectively. In vitro cytotoxicity analysis, using absorbance (LDH assay) and fluorescence (calcein AM) based assays, performed on NIH3T3 mouse fibroblasts and A498 human kidney epithelial cells, showed CD50 values of rGNP-HI between 179-301 µg/ml, depending on the cell line and the cytotoxicity assay. CT and MRI phantom imaging of rGNP-HI showed high CT (approximately 3200% greater than HI at equimolar iodine concentration) and MRI (approximately 59% greater than equimolar Mn2+ solution) contrast. These results open avenues for further in vivo safety and efficacy studies towards the development of carbon nanostructure-based multimodal MRI-CT contrast agents. PMID:24999431

  16. Section 6—Mechanical Bioeffects in the Presence of Gas-Carrier Ultrasound Contrast Agents

    PubMed Central

    2007-01-01

    This review addresses the issue of mechanical ultrasound-induced bioeffects in the presence of gas carrier contrast agents (GCAs). Here, the term “contrast agent” refers to those agents that provide ultrasound contrast by being composed of microbubbles, encapsulated or not, containing one or more gases. Provided in this section are summaries on how contrast agents work, some of their current uses, and the potential for bio-effects associated with their presence in an ultrasonic field. PMID:10680618

  17. Ultrasound Induced Fluorescence of Nanoscale Liposome Contrast Agents

    PubMed Central

    Zhang, Qimei; Morgan, Stephen P.; O’Shea, Paul; Mather, Melissa L.

    2016-01-01

    A new imaging contrast agent is reported that provides an increased fluorescent signal upon application of ultrasound (US). Liposomes containing lipids labelled with pyrene were optically excited and the excimer fluorescence emission intensity was detected in the absence and presence of an ultrasound field using an acousto-fluorescence setup. The acousto-fluorescence dynamics of liposomes containing lipids with pyrene labelled on the fatty acid tail group (PyPC) and the head group (PyPE) were compared. An increase in excimer emission intensity following exposure to US was observed for both cases studied. The increased intensity and time constants were found to be different for the PyPC and PyPE systems, and dependent on the applied US pressure and exposure time. The greatest change in fluorescence intensity (130%) and smallest rise time constant (0.33 s) are achieved through the use of PyPC labelled liposomes. The mechanism underlying the observed increase of the excimer emission intensity in PyPC labelled liposomes is proposed to arise from the “wagging” of acyl chains which involves fast response and requires lower US pressure. This is accompanied by increased lipid lateral diffusivity at higher ultrasound pressures, a mechanism that is also active in the PyPE labelled liposomes. PMID:27467748

  18. BROADBAND ATTENUATION MEASUREMENTS OF PHOSPHOLIPID-SHELLED ULTRASOUND CONTRAST AGENTS

    PubMed Central

    Raymond, Jason L.; Haworth, Kevin J.; Bader, Kenneth B.; Radhakrishnan, Kirthi; Griffin, Joseph K.; Huang, Shao-Ling; McPherson, David D.; Holland, Christy K.

    2014-01-01

    The aim of this study was to characterize the frequency-dependent acoustic attenuation of three phospholipid-shelled ultrasound contrast agents (UCAs): Definity, MicroMarker and echogenic liposomes. A broadband through-transmission technique allowed for measurement over 2 to 25 MHz with a single pair of transducers. Viscoelastic shell parameters of the UCAs were estimated using a linearized model developed by N. de Jong, L. Hoff, T. Skotland and N. Bom (Ultrasonics 1992; 30:95–103). The effect of diluent on the attenuation of these UCA suspensions was evaluated by performing attenuation measurements in 0.5% (w/v) bovine serum albumin and whole blood. Changes in attenuation and shell parameters of the UCAs were investigated at room temperature (25°C) and physiologic temperature (37°C). The attenuation of the UCAs diluted in 0.5% (w/v) bovine serum albumin was found to be identical to the attenuation of UCAs in whole blood. For each UCA, attenuation was higher at 37°C than at 25°C, underscoring the importance of conducting characterization studies at physiologic temperature. Echogenic liposomes exhibited a larger increase in attenuation at 37°C versus 25°C than either Definity or MicroMarker. PMID:24262056

  19. Proposal of a skin tests based approach for the prevention of recurrent hypersensitivity reactions to iodinated contrast media.

    PubMed

    Della-Torre, E; Berti, A; Yacoub, M R; Guglielmi, B; Tombetti, E; Sabbadini, M G; Voltolini, S; Colombo, G

    2015-05-01

    The purpose of the present work is to evaluate the efficacy of an approach that combines clinical history, skin tests results, and premedication, in preventing recurrent hypersensitivity reactions to iodinated contrast media (ICM). Skin Prick tests, Intradermal tests, and Patch tests were performed in 36 patients with a previous reaction to ICM. All patients underwent a second contrast enhanced radiological procedure with an alternative ICM selected on the basis of the proposed approach. After alternative ICM re-injection, only one patient presented a mild NIR. The proposed algorithm, validated in clinical settings where repeated radiological exams are needed, offers a safe and practical approach for protecting patients from recurrent hypersensitivity reactions to ICM. PMID:25951145

  20. Complex interfaces in "phase-change" contrast agents.

    PubMed

    Capece, Sabrina; Domenici, Fabio; Brasili, Francesco; Oddo, Letizia; Cerroni, Barbara; Bedini, Angelico; Bordi, Federico; Chiessi, Ester; Paradossi, Gaio

    2016-03-28

    In this paper we report on the study of the interface of hybrid shell droplets encapsulating decafluoropentane (DFP), which exhibit interesting potentialities for ultrasound (US) imaging. The fabrication of the droplets is based on the deposition of a dextran methacrylate layer onto the surface of surfactants. The droplets have been stabilized against coalescence by UV curing, introducing crosslinks in the polymer layer and transforming the shell into an elastomeric membrane with a thickness of about 300 nm with viscoelastic behaviour. US irradiation induces the evaporation of the DFP core of the droplets transforming the particles into microbubbles (MBs). The presence of a robust crosslinked polymer shell introduces an unusual stability of the droplets also during the core phase transition and allows the recovery of the initial droplet state after a few minutes from switching off US. The interfacial tension of the droplets has been investigated by two approaches, the pendant drop method and an indirect method, based on the determination of the liquid ↔ gas transition point of DFP confined in the droplet core. The re-condensation process has been followed by capturing images of single MBs by confocal microscopy. The time evolution of MB relaxation to droplets was analysed in terms of a modified Church model to account for the structural complexity of the MB shell, i.e. a crosslinked polymer layer over a layer of surfactants. In this way the microrheology parameters of the shell were determined. In a previous paper (Chem. Commun., 2013, 49, 5763-5765) we showed that these systems could be used as ultrasound contrast agents (UCAs). In this work we substantiate this view assessing some key features offered by the viscoelastic nature of the droplet shell. PMID:26931337

  1. Experimental characterization, comparison and image quality assessment of two ultrasound contrast agents: Optison and Definity

    NASA Astrophysics Data System (ADS)

    Hughes, Amy C.; Day, Steven W.; Linte, Cristian A.; Schwarz, Karl Q.

    2016-04-01

    Microbubble-based contrast agents are commonly used in ultrasound imaging to help differentiate the blood pool from the endocardial wall. It is essential to use an agent which produces high image intensity relative to the surrounding tissue, commonly referred to contrast effect. When exposed to ultrasound waves, microbubbles produce an intense backscatter signal in addition to the contrast produced by the fluctuating size of the microbubbles. However, over time, the microbubble concentration depletes, leading to reduced visual enhancement. The retention time associated with contrast effect varies according to the frequency and power level of the ultrasound wave, as well as the contrast agent used. The primary objective of this study was to investigate and identify the most appropriate image acquisition parameters that render optimal contrast effect for two intravenous contrast agents, Optison™ and Definity™. Several controlled in vitro experiments were conducted using an experimental apparatus that featured a perfused tissue-emulating phantom. A continuous flow of contrast agent was imaged using ultrasound at different frequencies and power levels, while a pulse wave Doppler device was used to monitor the concentration of the contrast agent solution. The contrast effect was determined based on the image intensity inside the flow pipe mimicking the blood-pool relative to the intensity of the surrounding phantom material mimicking cardiac tissue. To identify the combination of parameters that yielded optimal visualization for each contrast agent tested, the contrast effect was assessed at different microbubble concentrations and different ultrasound imaging frequencies and transmission power levels.

  2. A Novel Procedure for Rapid Imaging of Adult Mouse Brains with MicroCT Using Iodine-Based Contrast

    PubMed Central

    Anderson, Ryan; Maga, A. Murat

    2015-01-01

    High-resolution Magnetic Resonance Imaging (MRI) has been the primary modality for obtaining 3D cross-sectional anatomical information in animals for soft tissue, particularly brain. However, costs associated with MRI can be considerably high for large phenotypic screens for gross differences in the structure of the brain due to pathology and/or experimental manipulations. MicroCT (mCT), especially benchtop mCT, is becoming a common laboratory equipment with throughput rates equal or faster than any form of high-resolution MRI at lower costs. Here we explore adapting previously developed contrast based mCT to image adult mouse brains in-situ. We show that 2% weight per volume (w/v) iodine-potassium iodide solution can be successfully used to image adult mouse brains within 48 hours post-mortem when a structural support matrix is used. We demonstrate that hydrogel can be effectively used as a perfusant which limits the tissue shrinkage due to iodine. PMID:26571123

  3. Is Non-Contrast CT Adequate for the Evaluation of Hepatic Metastasis in Patients Who Cannot Receive Iodinated Contrast Media?

    PubMed Central

    Jee, Han Bum; Park, Min Jung; Lee, Hye Sun; Park, Mi-Suk; Kim, Myeong-Jin; Chung, Yong Eun

    2015-01-01

    Objective To evaluate the appropriateness of follow-up with only non-enhanced CT (NECT) in patients with gastrointestinal cancer. Subjects and Methods This retrospective study included 323 patients with colorectal and gastric cancer who underwent two consecutive CT examinations (CT1 and CT2), including non-contrast and portal venous phase CT images, with an interval of 1 year. Patients were divided into 2 groups: Group A included patients with no hepatic metastasis on CT1 and with or without newly developed metastasis on CT2 to evaluate the diagnostic performance of NECT for detecting newly developed hepatic metastasis; Group B included patients with known hepatic metastasis both on CT1 and CT2 to evaluate the accuracy of NECT for the assessment of hepatic metastasis based on RECIST criteria (version 1.1). Contrast-enhanced CT (CECT) images were considered as reference standards. Results Group A included 172 patients (M:F = 107:65; mean age, 62.6 years). Among them, 57 patients had 95 metastases (mean size, 2.2 ± 1.3 cm). Per patient and per lesion sensitivity for diagnosing newly developed hepatic metastasis was 56.1–66.7% and 52.6–56.8%, respectively. In terms of small metastases (<1.5 cm), per lesion sensitivity was significantly decreased to 28.1–34.4% (P < 0.05). Metastasis size measurements were significantly smaller on NECT (P < 0.001) compared with reference standards. In Group B, the accuracy of response evaluation based on RECIST criteria was 65.6–72.2%. Conclusions NECT showed inadequate diagnostic performances in both detecting newly developed hepatic metastasis and evaluating the response of hepatic metastasis based on RECIST criteria. PMID:26218533

  4. Do Iodine Contrast Media Compounds Used for Medical Imaging Contribute to the Formation of Iodinated Disinfection By-Products in Drinking Water?

    EPA Science Inventory

    Iodinated disinfection byproducts (DBPs) have recently gained attention due to their cyto- and genotoxicity and increased formation in drinking water treated with chloramine, which has become an increasingly popular disinfectant in the United States. One of these—iodoacetic acid...

  5. Avoidable errors in dealing with anaphylactoid reactions to iodinated contrast media.

    PubMed

    Segal, Arthur J; Bush, William H

    2011-03-01

    Contrast reactions are much less common today than in the past. This is principally because of the current and predominant use of low and iso-osmolar contrast media compared with the prior use of high osmolality contrast media. As a result of the significantly diminished frequency, there are now fewer opportunities for physicians to recognize and appropriately treat such adverse reactions. In review of the literature combined with our own clinical and legal experience, 12 potential errors were identified and these are reviewed in detail so that they can be avoided by the physician-in-charge. Basic treatment considerations are presented along with a plan to systematize an approach to contrast reactions, simplify treatment options and plans, and schedule periodic drills. PMID:21150793

  6. 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. PMID:27317202

  7. Engineering of Nanoscale Contrast Agents for Optical Coherence Tomography

    PubMed Central

    Gordon, Andrew Y; Jayagopal, Ashwath

    2014-01-01

    Optical coherence tomography has emerged as valuable imaging modalityin ophthalmology and other fields by enabling high-resolution three-dimensional imaging of tissue. In this paper, we review recent progress in the field of contrast-enhanced optical coherence tomography (OCT). We discuss exogenous and endogenous sources of OCT contrast, focusing on their use with standard OCT systems as well as emerging OCT-based imaging modalities. We include advances in the processing of OCT data that generate improved tissue contrast, including spectroscopic OCT (SOCT), as well as work utilizing secondary light sources and/or detection mechanisms to create and detect enhanced contrast, including photothermal OCT (PTOCT) and photoacoustic OCT (PAOCT). Finally, we conclude with a discussion of the translational potential of these developments as well as barriers to their clinical use. PMID:25009761

  8. Intravascular contrast agent improves magnetic resonance angiography of carotid arteries in minipigs.

    PubMed

    Lin, W; Abendschein, D R; Celik, A; Dolan, R P; Lauffer, R B; Walovitch, R C; Haacke, E M

    1997-01-01

    This study was designed to optimize three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequences and to determine whether contrast-enhanced MRA could improve the accuracy of lumen definition in stenosed carotid arteries of minipigs. 3D TOF MRA was acquired with use of either an intravascular (n = 13) and/or an extravascular contrast agent (n = 5) administrated at 2 to 4 weeks after balloon-induced injury to a carotid artery in 16 minipigs. Vascular contrast, defined as signal intensity differences between blood vessels and muscle normalized to the signal intensity of muscle, was compared before and after the injection of each contrast agent and between the two agents. Different vascular patencies were observed among the animals, including completely occluded vessels (n = 5), stenotic vessels (n = 3), and vessels with no visible stenosis (n = 8). Superior vascular contrast improvement was observed for small arteries and veins and for large veins with the intravascular contrast agent when compared with the extravascular contrast agent. In addition, preliminary studies in two of the animals showed a good correlation for the extent of luminal stenosis defined by digital subtraction angiography compared with MRA obtained after administration of the intravascular contrast agent (R2 = .71, with a slope of .96 +/- .04 by a linear regression analysis). We concluded that use of an intravascular contrast agent optimizes 3D TOF MRA and may improve its accuracy compared with digital subtraction angiography. PMID:9400838

  9. Impact of iodinated contrast injections on percent diameter coronary arterial stenosis and implications for trials of intracoronary pharmacotherapies in patients with ST-elevation myocardial infarction.

    PubMed

    Gibson, C Michael; Buros, Jacqueline; Ciaglo, Lauren N; Southard, Matthew C; Takao, Shaun; Harrigan, Caitlin; Filopei, Jason; Lew, Michelle; Marble, Susan J; Murphy, Sabina A; Cohen, Mauricio G

    2007-07-01

    Administration of fibrinolytic, antiplatelet, and antithrombotic agents by the intracoronary route may disaggregate clot, but the potential role of the mechanical force of the injection itself in decreasing clot burden has not been studied. Patients with ST-segment elevation myocardial infarction who were pretreated in the emergency room (ER) with unfractionated heparin and aspirin in the TITAN-TIMI 34 study were randomized to treatment with eptifibatide in the ER (n = 131) versus after diagnostic catheterization (n = 150). Quantitative coronary angiography was used to assess change in diameter stenosis from time of first contrast injection to injection before percutaneous coronary intervention (PCI) immediately preceding wire placement down the culprit artery in a matching view. Successful perfusion of the myocardium was assessed after PCI by the presence of Thrombolysis In Myocardial Infarction myocardial perfusion grade of 2 or 3. In patients treated with eptifibatide in the ER, there was a 1.3% absolute improvement in diameter stenosis from the first injection to the injection before PCI (p = 0.02), whereas there was no change in diameter stenosis in patients not treated with eptifibatide in the ER (0.0%, p = NS). Each 1% improvement in percent diameter stenosis during diagnostic injections before PCI was strongly correlated with an open muscle after PCI (adjusted odds ratio 1.09, 95% confidence interval 1.02 to 1.16, p = 0.012). In conclusion, the mechanical force of a contrast injection decreases thrombotic burden in patients with ST-segment elevation myocardial infarction pretreated with eptifibatide but not with placebo. Future trials of intracoronary pharmacotherapies should include a control arm in which saline is injected to account for the potential clot disaggregation that occurs as a result of iodinated contrast injections, particularly if the patient has been pretreated with aggressive pharmacotherapy. PMID:17599433

  10. Synthetic Ni3S2/Ni hybrid architectures as potential contrast agents in MRI

    NASA Astrophysics Data System (ADS)

    Ma, J.; Chen, K.

    2016-04-01

    Traditional magnetic resonance imaging (MRI) contrast agents mainly include superparamagnetic (SPM) iron oxide nanoparticle as T 2 contrast agent for liver and paramagnetic Gd (III)-chelate as T 1 contrast agent for all organs. In this work, weak ferromagnetic kale-like and SPM cabbage-like Ni3S2@Ni hybrid architectures were synthesized and evaluated as potential T 1 MRI contrast agents. Their relatively small r 2/r 1 ratios of 2.59 and 2.38, and high r 1 values of 11.27 and 4.89 mmol‑1 L s‑1 (for the kale-like and cabbage-like Ni3S2@Ni, respectively) will shed some light on the development of new-type MRI contrast agents.

  11. X-ray spatial frequency heterodyne imaging of protein-based nanobubble contrast agents.

    PubMed

    Rand, Danielle; Uchida, Masaki; Douglas, Trevor; Rose-Petruck, Christoph

    2014-09-22

    Spatial Frequency Heterodyne Imaging (SFHI) is a novel x-ray scatter imaging technique that utilizes nanoparticle contrast agents. The enhanced sensitivity of this new technique relative to traditional absorption-based x-ray radiography makes it promising for applications in biomedical and materials imaging. Although previous studies on SFHI have utilized only metal nanoparticle contrast agents, we show that nanomaterials with a much lower electron density are also suitable. We prepared protein-based "nanobubble" contrast agents that are comprised of protein cage architectures filled with gas. Results show that these nanobubbles provide contrast in SFHI comparable to that of gold nanoparticles of similar size. PMID:25321797

  12. X-ray spatial frequency heterodyne imaging of protein-based nanobubble contrast agents

    PubMed Central

    Rand, Danielle; Uchida, Masaki; Douglas, Trevor; Rose-Petruck, Christoph

    2014-01-01

    Spatial Frequency Heterodyne Imaging (SFHI) is a novel x-ray scatter imaging technique that utilizes nanoparticle contrast agents. The enhanced sensitivity of this new technique relative to traditional absorption-based x-ray radiography makes it promising for applications in biomedical and materials imaging. Although previous studies on SFHI have utilized only metal nanoparticle contrast agents, we show that nanomaterials with a much lower electron density are also suitable. We prepared protein-based “nanobubble” contrast agents that are comprised of protein cage architectures filled with gas. Results show that these nanobubbles provide contrast in SFHI comparable to that of gold nanoparticles of similar size. PMID:25321797

  13. Noninvasive visualization of in vivo release and intratumoral distribution of surrogate MR contrast agent using the dual MR contrast technique.

    PubMed

    Onuki, Yoshinori; Jacobs, Igor; Artemov, Dmitri; Kato, Yoshinori

    2010-09-01

    A direct evaluation of the in vivo release profile of drugs from carriers is a clinical demand in drug delivery systems, because drug release characterized in vitro correlates poorly with in vivo release. The purpose of this study is to demonstrate the in vivo applicability of the dual MR contrast technique as a useful tool for noninvasive monitoring of the stability and the release profile of drug carriers, by visualizing in vivo release of the encapsulated surrogate MR contrast agent from carriers and its subsequent intratumoral distribution profile. The important aspect of this technique is that it incorporates both positive and negative contrast agents within a single carrier. GdDTPA, superparamagnetic iron oxide nanoparticles, and 5-fluorouracil were encapsulated in nano- and microspheres composed of poly(D,L-lactide-co-glycolide), which was used as a model carrier. In vivo studies were performed with orthotopic xenograft of human breast cancer. The MR-based technique demonstrated here has enabled visualization of the delivery of carriers, and release and intratumoral distribution of the encapsulated positive contrast agent. This study demonstrated proof-of-principle results for the noninvasive monitoring of in vivo release and distribution profiles of MR contrast agents, and thus, this technique will make a great contribution to the field. PMID:20580427

  14. Iodinated contrast media cause direct tubular cell damage, leading to oxidative stress, low nitric oxide, and impairment of tubuloglomerular feedback

    PubMed Central

    Liu, Zhi Zhao; Schmerbach, Kristin; Lu, Yuan; Perlewitz, Andrea; Nikitina, Tatiana; Cantow, Kathleen; Seeliger, Erdmann; Persson, Pontus B.; Liu, Ruisheng; Sendeski, Mauricio M.

    2014-01-01

    Iodinated contrast media (CM) have adverse effects that may result in contrast-induced acute kidney injury. Oxidative stress is believed to play a role in CM-induced kidney injury. We test the hypothesis that oxidative stress and reduced nitric oxide in tubules are consequences of CM-induced direct cell damage and that increased local oxidative stress may increase tubuloglomerular feedback. Rat thick ascending limbs (TAL) were isolated and perfused. Superoxide and nitric oxide were quantified using fluorescence techniques. Cell death rate was estimated using propidium iodide and trypan blue. The function of macula densa and tubuloglomerular feedback responsiveness were measured in isolated, perfused juxtaglomerular apparatuses (JGA) of rabbits. The expression of genes related to oxidative stress and the activity of superoxide dismutase (SOD) were investigated in the renal medulla of rats that received CM. CM increased superoxide concentration and reduced nitric oxide bioavailability in TAL. Propidium iodide fluorescence and trypan blue uptake increased more in CM-perfused TAL than in controls, indicating increased rate of cell death. There were no marked acute changes in the expression of genes related to oxidative stress in medullary segments of Henle's loop. SOD activity did not differ between CM and control groups. The tubuloglomerular feedback in isolated JGA was increased by CM. Tubular cell damage and accompanying oxidative stress in our model are consequences of CM-induced direct cell damage, which also modifies the tubulovascular interaction at the macula densa, and may therefore contribute to disturbances of renal perfusion and filtration. PMID:24431205

  15. Feasibility of iodine contrast enhanced CT-scan during a 18F-fluorodeoxyglucose Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Houzard, C.; Tychyj, C.; Morelec, I.; Ricard, F.; Got, P.; Cotton, F.; Giammarile, F.; Maintas, D.

    2009-06-01

    OBJECTIVE: this prospective study evaluates the feasibility in current clinical practice of contrast enhanced CT-scan for diagnosis purpose, performed during 18FDG PET-CT study with a PET/CT tomography. METHOD: 25 patients underwent FDG imaging for lymphoma staging. The PET scan was done immediately after the usual low dose CT (lCT). A second CT scan was consequently acquired, by using classical diagnosis CT parameters (dCT) and iodinated contrast. For each patient, all CT attenuation correction (CTAC) PET images were visually compared. Density in Hounsfield units (HU) and maximum Standardized Uptake Value (SUVmax) were then measured on different organs and up to 5 specific lymphoma localizations (total of 294 measurements). RESULTS: Visual analysis was similar for the 2 modalities, without discordant interpretation for the pathologic sites. SUVmax means and standard deviation of each organ for lCTAC and dCTAC were comparable. The equation of the fitted multiple linear regression model was: dCT=0.0748191 + 1.17024*lCT (98.71%; p < 0.01). CONCLUSION: These first results allow the use of injected CT scan, before the PET scan acquisition for lymphoma staging with this PET-CT scan, not affected by the height atomic number and elevated density. A great benefit is therefore obtained on diagnostic, logistic and radioprotection purposes.

  16. Development and characterization of a nano-scale contrast agent.

    PubMed

    Oeffinger, Brian E; Wheatley, Margaret A

    2004-04-01

    Agents injected parenterally must be less than approximately 8 microm diameter in order to traverse the capillaries in the pulmonary bed, but these agents remain in the vasculature until they are eliminated from the body by a variety of mechanisms. Targeting of cells outside the capillaries requires agent diameters of less than approximately 700 nm to enable escape through the larger-than-usual pores that have been noted in the leaky vasculature of a tumor. The objective of this study was to test the feasibility of creating a surfactant-stabilized nano-bubble with favorable acoustic properties, and identify the key parameters that influence size, yield and stability. Size distribution was characterized using laser light scattering. In vitro acoustic enhancement was assessed by generation of dose and time response curves. We previously developed a successful protocol to generate gas-filled microbubbles (containing perfluorocarbon, sulfur hexafluoride or air) with mean diameter of 1.5 microm, using sonication of carefully selected surfactant mixtures. This presentation describes generation of nano-bubbles with mean diameters ranging from 700 to 450 nm, depending on process variables. In all cases a centrifugation step was employed to separate the nano-sized particles. The in vitro dose response curves gave a maximum of 23-27 dB enhancement compared to buffer in the absence of agent, with the maximum enhancement and presence of shadowing at higher doses being dependent on the fabrication protocol. The effect of sonication time for solutions containing a mixture of the surfactants (Span 60 and Tween 80) was also tested, but was determined not to be an influencing factor. Future studies will involve development of a mathematical model characterizing the mean size as a function of centrifugal force, spin time and initial size distribution. Future work will also include imaging of tumor-bearing mice and measuring imaging potential in vivo in New Zealand white rabbits

  17. Diffusion coefficients of articular cartilage for different CT and MRI contrast agents.

    PubMed

    Kulmala, K A M; Korhonen, R K; Julkunen, P; Jurvelin, J S; Quinn, T M; Kröger, H; Töyräs, J

    2010-10-01

    In contrast enhanced magnetic resonance imaging (MRI) and computed tomography (CT), the equilibrium distribution of anionic contrast agent is expected to reflect the fixed charged density (FCD) of articular cartilage. Diffusion is mainly responsible for the transport of contrast agents into cartilage. In osteoarthritis, cartilage composition changes at early stages of disease, and solute diffusion is most likely affected. Thus, investigation of contrast agent diffusion could enable new methods for imaging of cartilage composition. The aim of this study was to determine the diffusion coefficient of four contrast agents (ioxaglate, gadopentetate, iodide, gadodiamide) in bovine articular cartilage. The contrast agents were different in molecular size and charge. In peripheral quantitative CT experiments, penetration of contrast agent into the tissue was allowed either through the articular surface or through deep cartilage. To determine diffusion coefficients, a finite element model based on Fick's law was fitted to experimental data. Diffusion through articular surface was faster than through deep cartilage with every contrast agent. Iodide, being of atomic size, diffused into the cartilage significantly faster (q<0.05) than the other three contrast agents, for either transport direction. The diffusion coefficients of all clinical contrast agents (ioxaglate, gadopentetate and gadodiamide) were relatively low (142.8-253.7 μm(2)/s). In clinical diagnostics, such slow diffusion may not reach equilibrium and this jeopardizes the determination of FCD by standard methods. However, differences between diffusion through articular surface and deep cartilage, that are characterized by different tissue composition, suggest that diffusion coefficients may correlate with cartilage composition. Present method could therefore enable image-based assessment of cartilage composition by determination of diffusion coefficients within cartilage tissue. PMID:20594900

  18. K-edge ratio method for identification of multiple nanoparticulate contrast agents by spectral CT imaging

    PubMed Central

    Ghadiri, H; Ay, M R; Shiran, M B; Soltanian-Zadeh, H

    2013-01-01

    Objective: Recently introduced energy-sensitive X-ray CT makes it feasible to discriminate different nanoparticulate contrast materials. The purpose of this work is to present a K-edge ratio method for differentiating multiple simultaneous contrast agents using spectral CT. Methods: The ratio of two images relevant to energy bins straddling the K-edge of the materials is calculated using an analytic CT simulator. In the resulting parametric map, the selected contrast agent regions can be identified using a thresholding algorithm. The K-edge ratio algorithm is applied to spectral images of simulated phantoms to identify and differentiate up to four simultaneous and targeted CT contrast agents. Results: We show that different combinations of simultaneous CT contrast agents can be identified by the proposed K-edge ratio method when energy-sensitive CT is used. In the K-edge parametric maps, the pixel values for biological tissues and contrast agents reach a maximum of 0.95, whereas for the selected contrast agents, the pixel values are larger than 1.10. The number of contrast agents that can be discriminated is limited owing to photon starvation. For reliable material discrimination, minimum photon counts corresponding to 140 kVp, 100 mAs and 5-mm slice thickness must be used. Conclusion: The proposed K-edge ratio method is a straightforward and fast method for identification and discrimination of multiple simultaneous CT contrast agents. Advances in knowledge: A new spectral CT-based algorithm is proposed which provides a new concept of molecular CT imaging by non-iteratively identifying multiple contrast agents when they are simultaneously targeting different organs. PMID:23934964

  19. Diffusion and near-equilibrium distribution of MRI and CT contrast agents in articular cartilage.

    PubMed

    Silvast, Tuomo S; Kokkonen, Harri T; Jurvelin, Jukka S; Quinn, Thomas M; Nieminen, Miika T; Töyräs, Juha

    2009-11-21

    Charged contrast agents have been used both in vitro and in vivo for estimation of the fixed charge density (FCD) in articular cartilage. In the present study, the effects of molecular size and charge on the diffusion and equilibrium distribution of several magnetic resonance imaging (MRI) and computed tomography (CT) contrast agents were investigated. Full thickness cartilage disks (Ø = 4.0 mm, n = 64) were prepared from fresh bovine patellae. Contrast agent (gadopentetate: Magnevist((R)), gadodiamide: Omniscan, ioxaglate: Hexabrix or sodium iodide: NaI) diffusion was allowed either through the articular surface or through the deep cartilage. CT imaging of the samples was conducted before contrast agent administration and after 1, 5, 9, 16, 25 and 29 h (and with three samples after 2, 3, 4 and 5 days) diffusion using a clinical peripheral quantitative computed tomography (pQCT) instrument. With all contrast agents, the diffusion through the deep cartilage was slower when compared to the diffusion through the articular surface. With ioxaglate, gadopentetate and gadodiamide it took over 29 h for diffusion to reach the near-equilibrium state. The slow diffusion of the contrast agents raise concerns regarding the validity of techniques for FCD estimation, as these contrast agents may not reach the equilibrium state that is assumed. However, since cartilage composition, i.e. deep versus superficial, had a significant effect on diffusion, imaging of the nonequilibrium diffusion process might enable more accurate assessment of cartilage integrity. PMID:19864699

  20. Intraarterial CT Angiography Using Ultra Low Volume of Iodine Contrast – Own Experiences

    PubMed Central

    Garcarek, Jerzy; Kurcz, Jacek; Guziński, Maciej; Banasik, Mirosław; Miś, Marcin; Gołębiowski, Tomasz

    2015-01-01

    Summary Background High volume of intravenous contrast in CT-angiography may result in contrast-induced nephropathy. Intraarterial ultra-low volume of contrast medium results in its satisfactory blood concentration with potentially good image quality. The first main purpose was to assess the influence of the method on function of transplanted kidney in patients with impaired graft function. The second main purpose of the study was to evaluate the usefulness of this method for detection of gastrointestinal and head-and-neck haemorrhages. Material/Methods Between 2010 and 2013 intraarterial CT-angiography was performed in 56 patients, including 28 with chronic kidney disease (CKD). There were three main subgroups: 18 patients after kidney transplantation, 10 patients with gastrointestinal hemorrhage, 8 patients with head-and-neck hemorrhage. Contralateral or ipsilateral inguinal arterial approach was performed. The 4-French vascular sheaths and 4F-catheters were introduced under fluoroscopy. Intraarterial CT was performed using 64-slice scanner. The scanning protocol was as follows: slice thickness 0.625 mm, pitch 1.3, gantry rotation 0.6 sec., scanning delay 1–2 sec. The extent of the study was established on the basis of scout image. In patients with CKD 6–8 mL of Iodixanol (320 mg/mL) diluted with saline to 18–24 mL was administered at a speed of 4–5 mL/s. Results Vasculature was properly visualized in all patients. In patients with impaired renal function creatinine/eGFR levels remained stable in all but one case. Traditional arteriography failed and CT-angiography demonstrated the site of bleeding in 3 of 10 patients with symptoms of gastrointestinal bleeding (30%). In 8 patients with head-and-neck bleeding CT-angiography did not prove beneficial when compared to traditional arteriography. Conclusions 1. Ultra-low contrast intraarterial CT-angiography does not deteriorate the function of transplanted kidneys in patients with impaired graft function. 2. 3

  1. Synthesis, Characterization, and X-ray Attenuation Properties of Ultrasmall BiOI Nanoparticles: Toward Renal Clearable Particulate CT Contrast Agents

    PubMed Central

    2015-01-01

    A unique decelerated hydrolytic procedure is developed and reported here for the preparation of ultrasmall nanoparticles (NPs) of PVP-coated BiOI with a narrow size distribution, i.e., 2.8 ± 0.5 nm. The crystal structure of this compound is determined by X-ray powder diffraction using the bulk materials. The stability, cytotoxicity, and potential use of the PVP-coated ultrasmall BiOI NPs as a CT contrast agent are investigated. Because of the combined X-ray attenuation effect of bismuth and iodine, such NPs exhibit a CT value that is among the best of those of the inorganic nanoparticle-based CT contrast agents reported in the literature. PMID:25283335

  2. Liver-specific agents for contrast-enhanced MRI: role in oncological imaging

    PubMed Central

    Thian, Yee Liang; Riddell, Angela M.

    2013-01-01

    Abstract Liver-specific magnetic resonance (MR) contrast agents are increasingly used in evaluation of the liver. They are effective in detection and morphological characterization of lesions, and can be useful for evaluation of biliary tree anatomy and liver function. The typical appearances and imaging pitfalls of various tumours at MR imaging performed with these agents can be understood by the interplay of pharmacokinetics of these contrast agents and transporter expression of the tumour. This review focuses on the applications of these agents in oncological imaging. PMID:24434892

  3. Motion corrected photoacoustic difference imaging of fluorescent contrast agents

    NASA Astrophysics Data System (ADS)

    Märk, Julia; Wagener, Asja; Pönick, Sarah; Grötzinger, Carsten; Zhang, Edward; Laufer, Jan

    2016-03-01

    In fluorophores, such as exogenous dyes and genetically expressed proteins, the excited state lifetime can be modulated using pump-probe excitation at wavelengths corresponding to the absorption and fluorescence spectra. Simultaneous pump-probe pulses induce stimulated emission (SE) which, in turn, modulates the thermalized energy, and hence the photoacoustic (PA) signal amplitude. For time-delayed pulses, by contrast, SE is suppressed. Since this is not observed in endogenous chromophores, the location of the fluorophore can be determined by subtracting images acquired using simultaneous and time-delayed pump-probe excitation. This simple experimental approach exploits a fluorophorespecific contrast mechanism, and has the potential to enable deep-tissue molecular imaging at fluences below the MPE. In this study, some of the challenges to its in vivo implementation are addressed. First, the PA signal amplitude generated in fluorophores in vivo is often much smaller than that in blood. Second, tissue motion can give rise to artifacts that correspond to endogenous chromophores in the difference image. This would not allow the unambiguous detection of fluorophores. A method to suppress motion artifacts based on fast switching between simultaneous and time-delayed pump-probe excitation was developed. This enables the acquisition of PA signals using the two excitation modes with minimal time delay (20 ms), thus minimizing the effects of tissue motion. The feasibility of this method is demonstrated by visualizing a fluorophore (Atto680) in tissue phantoms, which were moved during the image acquisition to mimic tissue motion.

  4. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J.; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G.-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T. C.; Kim, Ki Hean

    2016-06-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence.

  5. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

    PubMed Central

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J.; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T. C.; Kim, Ki Hean

    2016-01-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence. PMID:27283889

  6. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging.

    PubMed

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T C; Kim, Ki Hean

    2016-01-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence. PMID:27283889

  7. Tailored Near-Infrared Contrast Agents for Image Guided Surgery

    PubMed Central

    Njiojob, Costyl N.; Owens, Eric A.; Narayana, Lakshminarayana; Hyun, Hoon; Choi, Hak Soo; Henary, Maged

    2015-01-01

    The success of near-infrared (NIR) fluorescence to be employed for intraoperative imaging relies on the ability to develop a highly stable, NIR fluorescent, nontoxic, biocompatible, and highly excreted compound that retains a reactive functionality for conjugation to a cancer-recognizing peptide. Herein, systematic modifications to previously detailed fluorophore ZW800-1 are explored. Specific modifications, including the isosteric replacement of the O atom of ZW800-1, include nucleophilic amine and sulfur species attached to the heptamethine core. These novel compounds have shown similar satisfactory results in biodistribution and clearance while also expressing increased stability in serum. Most importantly, all of the synthesized and evaluated compounds display a reactive functionality (either a free amino group or carboxylic acid moiety) for further bioconjugation. The results obtained from the newly prepared derivatives demonstrate that the central substitution with the studied linking agents retains the ultralow background in vivo performance of the fluorophores regardless of the total net charge. PMID:25711712

  8. Contrasting actions of pressor agents in severe autonomic failure

    NASA Technical Reports Server (NTRS)

    Jordan, J.; Shannon, J. R.; Biaggioni, I.; Norman, R.; Black, B. K.; Robertson, D.

    1998-01-01

    BACKGROUND: Orthostatic hypotension is the most disabling symptom of autonomic failure. The choice of a pressor agent is largely empiric, and it would be of great value to define predictors of a response. PATIENTS AND METHODS: In 35 patients with severe orthostatic hypotension due to multiple system atrophy or pure autonomic failure, we determined the effect on seated systolic blood pressure (SBP) of placebo, phenylpropanolamine (12.5 mg and 25 mg), yohimbine (5.4 mg), indomethacin (50 mg), ibuprofen (600 mg), caffeine (250 mg), and methylphenidate (5 mg). In a subgroup of patients, we compared the pressor effect of midodrine (5 mg) with the effect of phenylpropanolamine (12.5 mg). RESULTS: There were no significant differences in the pressor responses between patients with multiple system atrophy or pure autonomic failure. When compared with placebo, the pressor response was significant for phenylpropanolamine, yohimbine, and indomethacin. In a subgroup of patients, we confirmed that this pressor effect of phenylpropanolamine, yohimbine, and indomethacin corresponded to a significant increase in standing SBP. The pressor responses to ibuprofen, caffeine, and methylphenidate were not significantly different from placebo. Phenylpropanolamine and midodrine elicited similar pressor responses. There were no significant associations between drug response and autonomic function testing, postprandial hypotension, or plasma catecholamine levels. CONCLUSIONS: We conclude that significant increases in systolic blood pressure can be obtained in patients with orthostatic hypotension due to primary autonomic failure with phenylpropanolamine in low doses or yohimbine or indomethacin in moderate doses. The response to a pressor agent cannot be predicted by autonomic function testing or plasma catecholamines. Therefore, empiric testing with a sequence of medications, based on the risk of side effects in the individual patient and the probability of a response, is a useful approach.

  9. Superparamagnetic And Paramagnetic MRI Contrast Agents: Application Of Rapid Magnetic Resonance Imaging To Assess Renal Function

    NASA Astrophysics Data System (ADS)

    Carvlin, Mark J.; Renshaw, Perry F.; Arger, Peter; Kundel, Harold L.; Dougherty, Larry; Axel, Leon; Kassab, Eleanor; Moore, Bethanne

    1988-06-01

    The paramagnetic chelate complex, gadolinium-diethylene-triamine-pentaacetic acid, Gd-DTPA, and superparamagnetic particles, such as those composed of dextran coated magnetite, function as magnetic resonance contrast agents by changing the relaxation rates, 1/T1 and 1/T2. The effects that these agents have upon MR signal intensity are determined by: the inherent biophysical properties of the tissue being imaged, the concentration of the contrast agent and the data acquisition scheme (pulse sequence parameters) employed. Following the time course of MR signal change in the first minutes after the injection of contrast agent(s) allows a dynamic assessment of organ functions in a manner analogous to certain nuclear medicine studies. In order to study renal function, sequential MR fast scan images, gradient echo (TR=35/TE=7 msec, flip angle=25 degrees), were acquired, one every 12 seconds, after intravenous injection of Gd-DTPA and/or dextran-magnetite. Gd-DTPA, which is freely filtered at the glomerulus and is neither secreted nor reabsorbed, provides information concerning renal perfusion, glomerular filtration and tubular concentrating ability. Dextran-magnetite (200 A diameter), which is primarily contained within the intravascular space shortly after injection, provides information on blood flow to and distribution within the kidney. The MR signal change observed after administration of contrast agents varied dramatically depending upon the agents injected and the imaging parameters used. Hence a broad range of physiolgic processes may be described using these techniques, i.e. contrast agent enhanced functional MR examinations.

  10. Design Principles of Nanoparticles as Contrast Agents for Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Shan, Liang; Gu, Xinbin; Wang, Paul

    2013-09-01

    Molecular imaging is an emerging field that introduces molecular agents into traditional imaging techniques, enabling visualization, characterization and measurement of biological processes at the molecular and cellular levels in humans and other living systems. The promise of molecular imaging lies in its potential for selective potency by targeting biomarkers or molecular targets and the imaging agents serve as reporters for the selectivity of targeting. Development of an efficient molecular imaging agent depends on well-controlled high-quality experiment design involving target selection, agent synthesis, in vitro characterization, and in vivo animal characterization before it is applied in humans. According to the analysis from the Molecular Imaging and Contrast Agent Database (MICAD, ), more than 6000 molecular imaging agents with sufficient preclinical evaluation have been reported to date in the literature and this number increases by 250-300 novel agents each year. The majority of these agents are radionuclides, which are developed for positron emission tomography (PET) and single photon emission computed tomography (SPECT). Contrast agents for magnetic resonance imaging (MRI) account for only a small part. This is largely due to the fact that MRI is currently not a fully quantitative imaging technique and is less sensitive than PET and SPECT. However, because of the superior ability to simultaneously extract molecular and anatomic information, molecular MRI is attracting significant interest and various targeted nanoparticle contrast agents have been synthesized for MRI. The first and one of the most critical steps in developing a targeted nanoparticle contrast agent is target selection, which plays the central role and forms the basis for success of molecular imaging. This chapter discusses the design principles of targeted contrast agents in the emerging frontiers of molecular MRI.