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The reciprocal linear QUEST analysis method facilitates the measurements of chemical exchange rates with CEST MRI
Magnetic resonance imaging (MRI) contrast media that are detected via chemical exchange saturation transfer (CEST) often require an accurate estimation of their chemical exchange rate, kex. A variety of analysis methods have been proposed to estimate kex, including the nonlinear QUEST analysis method that evaluates the CEST amplitude as a function of saturation time. We have derived a linear version of QUEST, termed the Reciprocal Linear QUEST (RL‐QUEST) method. Our simulations and experimental results show that RL‐QUEST performs as well as QUEST, while providing a more simplistic fitting procedure. Although CEST resul...
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: Edward A. Randtke, Liu Qi Chen, Mark D. Pagel Tags: Short Communication Source Type: research

Computed tomography of Lipiodol‐loaded biodegradable pasty polymer for implant visualization
In conclusion, Lipiodol incorporated in P(SA:RA) is visible on CT, and polymer degradation can potentially be monitored noninvasively. This method can be widely applied to follow changes in biodegradable implants. Copyright © 2014 John Wiley & Sons, Ltd. The visibility, shape and degradation of a biodegradable implant incorporating Lipiodol (an X‐ray contrast medium) were evaluated noninvasively using computed tomography. (Source: Contrast Media and Molecular Imaging)
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: Jacob Sosna, Ehud Havivi, Wahid Khan, Liat Appelbaum, Abraham Nyska, Abraham J. Domb Tags: Short Communication Source Type: research

Monitoring hypoxia and vasculature during bevacizumab treatment in a murine colorectal cancer model
The purpose of this study was to assess the effect of bevacizumab on vasculature and hypoxia in a colorectal tumor model. Nude mice with subcutaneous LS174T tumors were treated with bevacizumab or saline. To assess tumor properties, separate groups of mice were imaged using 18F‐Fluoromisonidazole (FMISO) and 18F‐Fluorodeoxyglucose (FDG) positron emission tomography or magnetic resonance imaging before and 2, 6 and 10 days after the start of treatment. Tumors were harvested after imaging to determine hypoxia and vascular density immunohistochemically. The T2* time increased significantly less in the bevacizumab group....
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: L. Heijmen, E. G. W. Voert, C. J. A. Punt, A. Heerschap, W. J. G. Oyen, J. Bussink, C. G. J. Sweep, P. Laverman, P. N. Span, L. F. Geus‐Oei, O. C. Boerman, H. W. M. Laarhoven Tags: Full Paper Source Type: research

USPIO‐loaded red blood cells as a biomimetic MR contrast agent: a relaxometric study
Red blood cells (RBCs) loaded with iron oxide nanoparticles have been proposed as biomimetic constructs with long half‐life (ca. 20 days) in the blood compartment and potentially interesting properties (such as relaxivity) as intravascular contrast agents for magnetic resonance imaging. However, the encapsulation of nanoparticles into RBCs might affect their magnetic properties and relaxivity, which may be significantly different from the native suspension. Here, we present a relaxometric study of P904, a novel ultra small iron oxide nanoparticle developed by Guerbet, enclosed in human RBCs. We measured longitudinal (r...
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: Adriano Boni, Davide Ceratti, Antonella Antonelli, Carla Sfara, Mauro Magnani, Elisabetta Manuali, Sonia Salamida, Alessandro Gozzi, Angelo Bifone Tags: Full Paper Source Type: research

Liposome‐encapsulated superoxide dismutase mimetic: theranostic potential of an MR detectable and neuroprotective agent
Endogenous manganese based superoxide dismutase (Mn–SOD) provides the primary defense against excess production of potentially toxic superoxide anion (O2–). M40401 is a synthetic enzyme mimetic that has a catalytic activity rate exceeding that of the native SOD enzymes. The presence of a paramagnetic Mn(II) cation in M40401 suggests that the delivery and spatial distribution of this enzyme mimetic in vivo may be directly detectible using magnetic resonance imaging (MRI); however, the cardiotoxicity of Mn(II) severely limits the use of free M40401 in living systems. To deliver M40401 in vivo in amounts sufficient for MR...
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: Mohammed Salman Shazeeb, Giancarlo Feula, Alexei Bogdanov Tags: Full Paper Source Type: research

Generation and characterization of nanobodies targeting PSMA for molecular imaging of prostate cancer
Nanobodies show attractive characteristics for tumor targeting in cancer diagnosis and therapy. A radiolabeled nanobody binding the prostate‐specific membrane antigen (PSMA) could offer a noninvasive strategy to select prostate cancer patients eligible for PSMA‐targeted therapies. We here describe the generation, production and in vivo evaluation of anti‐PSMA nanobodies. Nanobodies were derived from heavy‐chain‐only antibodies, raised in immunized dromedaries. Binding characteristics were evaluated through ELISA and flow cytometry. Selected nanobodies were radiolabeled with 99mTc at their hexahistidine tail, afte...
Source: Contrast Media and Molecular Imaging - March 6, 2014 Category: Radiology Authors: Mehdi Evazalipour, Matthias D'Huyvetter, Bahram Soltani Tehrani, Mohsen Abolhassani, Kobra Omidfar, Shahriyar Abdoli, Roghaye Arezumand, Hamid Morovvati, Tony Lahoutte, Serge Muyldermans, Nick Devoogdt Tags: Full Paper Source Type: research

Issue Information
No abstract is available for this article. (Source: Contrast Media and Molecular Imaging)
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Tags: Issue Information Source Type: research

Quantitation of a spin polarization‐induced nuclear Overhauser effect (SPINOE) between a hyperpolarized 13C‐labeled cell metabolite and water protons
The spin polarization‐induced nuclear Overhauser effect (SPINOE) describes the enhancement of spin polarization of solvent nuclei by the hyperpolarized spins of a solute. In this communication we demonstrate that SPINOEs can be observed between [1,4‐13C2]fumarate, hyperpolarized using the dissolution dynamic nuclear polarization technique, and solvent water protons. We derive a theoretical expression for the expected enhancement and demonstrate that this fits well with experimental measurements. Although the magnitude of the effect is relatively small (around 2% measured here), the SPINOE increases at lower field stren...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Irene Marco‐Rius, Sarah E. Bohndiek, Mikko I. Kettunen, Timothy J. Larkin, Meer Basharat, Colm Seeley, Kevin M. Brindle Tags: Short Communication Source Type: research

Sensitivity‐enhanced chemical exchange saturation transfer (CEST) MRI with least squares optimization of Carr Purcell Meiboom Gill multi‐echo echo planar imaging
Chemical exchange saturation transfer (CEST) imaging is a novel MRI technique that is sensitive to biomolecules, local pH and temperature, and offers considerable advantages for in vivo applications. However, the magnitude of CEST effect for dilute CEST agents undergoing slow or intermediate chemical exchange is typically small, requiring the use of signal averaging to enhance its sensitivity. Given that T2‐induced signal loss can be normalized by asymmetry analysis, the magnitude of CEST effect is independent of echo time. Therefore, CEST MRI with multi‐echo echo planar imaging (EPI) readout should yield the same CEST...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Phillip Zhe Sun, Yu Wang, Jie Lu Tags: Short Communication Source Type: research

In vitro Gd‐DTPA relaxometry studies in oxygenated venous human blood and aqueous solution at 3 and 7 T
In vitro T1 and T2* relaxivities (r1 and r2*) of Gd‐DTPA (GaD) in oxygenated human venous blood (OVB) and aqueous solution (AS) at 3 and 7 T were calculated. GaD concentrations ([GaD]) in OVB and AS were prepared in the range 0‐5 mM. All measurements were acquired at 37 ± 2 °C. At both 3 and 7 T, a linear relationship was observed between [GaD] and R1 in both AS and OVB. At 7 T, r1 in AS decreased by 7.5% (p = 0.045) while there was a negligible change in OVB. With respect to R2*, a linear relationship with [GaD] was only observed in AS, while a more complex relationship was observed in OVB; quadrat...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Chaitanya Kalavagunta, Shalom Michaeli, Gregory J. Metzger Tags: Full Paper Source Type: research

Anatomical and functional imaging of myocardial infarction in mice using micro‐CT and eXIA 160 contrast agent
Noninvasive small animal imaging techniques are essential for evaluation of cardiac disease and potential therapeutics. A novel preclinical iodinated contrast agent called eXIA 160 has recently been developed, which has been evaluated for micro‐CT cardiac imaging. eXIA 160 creates strong contrast between blood and tissue immediately after its injection and is subsequently taken up by the myocardium and other metabolically active tissues over time. We focus on these properties of eXIA and show its use in imaging myocardial infarction in mice. Five C57BL/6 mice were imaged ~2 weeks after left anterior descending coronary...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Jeffrey R. Ashton, Nicholas Befera, Darin Clark, Yi Qi, Lan Mao, Howard A. Rockman, G. Allan Johnson, Cristian T. Badea Tags: Full Paper Source Type: research

Influence of paramagnetic melanin on the MRI contrast in melanoma: a combined high‐field (11.7 T) MRI and EPR study
Melanoma is the most dangerous form of skin cancer and its incidence is rising each year. Because the current methods of diagnosis based on the visual aspect of the tumor show limitations, several new techniques are emerging to help in this diagnosis, amongst which are magnetic resonance imaging (MRI) and electron paramagnetic resonance (EPR). The origin of the typical contrast pattern observable in melanoma in T1‐ and T2‐weighted images remains to be elucidated and is a source of controversy. In addition, melanin could create sufficient magnetic inhomogeneities to allow its visualization on T2*‐weighted images using...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Q. Godechal, L. Mignion, O. Karroum, J. Magat, P. Danhier, R. Morandini, G. E. Ghanem, P. Leveque, B. Gallez Tags: Full Paper Source Type: research

Multimodal cell tracking of a spontaneous metastasis model: comparison between MRI, electron paramagnetic resonance and bioluminescence
In conclusion, EPR is well adapted to ex vivo analysis of tissues after cell tracking experiments and allows short‐term monitoring of metastasizing cells. MRI is a suitable tool for checking labelled cells at their injection site, but dilution of the iron oxides owing to cell division remains a major limitation. BLI remains the most suitable technique for long‐term monitoring of metastatic cells. Copyright © 2014 John Wiley & Sons, Ltd. Ex vivo electron paramagnetic resonance allows short‐term cell tracking of iron oxide‐labeled metastatic cancer cells whereas bioluminescence imaging allows long‐term monitor...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Pierre Danhier, Géraldine De Preter, Julie Magat, Quentin Godechal, Paolo E. Porporato, Bénédicte F. Jordan, Olivier Feron, Pierre Sonveaux, Bernard Gallez Tags: Full Paper Source Type: research

In vivo near‐infrared fluorescence targeting of T cells: comparison of nanobodies and conventional monoclonal antibodies
The large size of conventional antibodies impedes tissue penetration and renal elimination, resulting in suboptimal in vivo targeting. Here we assess the utility of nanobodies and nanobody‐Fc‐fusion proteins as alternatives to monoclonal antibodies as theranostics, using T cell ADP–ribosyltransferase 2 (ART2) as a model antigen for specific targeting of lymph nodes. ART2‐specific monovalent nanobody s + 16a (17 kDa), a bivalent Fc‐fusion protein of s + 16a (s + 16‐mFc, 82 kDa), and conventional antibody Nika102 (150 kDa) were labeled with AlexaFluor680. In vitro binding and inhibitory properti...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Peter Bannas, Lennart Well, Alexander Lenz, Björn Rissiek, Friedrich Haag, Joanna Schmid, Katja Hochgräfe, Martin Trepel, Gerhard Adam, Harald Ittrich, Friedrich Koch‐Nolte Tags: Full Paper Source Type: research

A fast tumor‐targeting near‐infrared fluorescent probe based on bombesin analog for in vivo tumor imaging
In this study, a near‐infrared fluorescent dye (MPA) and polyethylene glycol (PEG) were conjugated to BBN analog to form BBN[7–14]–MPA and BBN[7–14]–SA–PEG–MPA. The successful synthesis of the two probes was proved by the characterization via sodium dodecylsulfate–polyacrylamide gel electrophoresis, infrared and optical spectra. Cellular uptakes studies indicated that BBN‐based probes were mediated by gastrin‐releasing peptide receptors (GRPR) on tumor cells and the PEG modified probe had higher affinity. The dynamic distribution and clearance investigations showed that the BBN‐based probes were elimi...
Source: Contrast Media and Molecular Imaging - February 12, 2014 Category: Radiology Authors: Haiyan Chen, Shunan Wan, Fenxia Zhu, Chuan Wang, Sisi Cui, Changli Du, Yuxiang Ma, Yueqing Gu Tags: Full Paper Source Type: research