Dual-contrast photon-counting micro-CT using iodine and a novel bismuth-based contrast agent.

To characterize for the first timea novel bismuth-based nanoparticular contrast agent developed for preclinical applications. Then, to design and testa multi-contrast protocol for functional cardiac imaging using the new bismuth nanoparticles and a well-established iodine-based contrast agent.A micro-computed tomography scanner was assembled and equipped with a photon-counting detector.

Features Found in Indocyanine Green-Based Fluorescence Optical Imaging of Inflammatory Diseases of the Hands.

Rheumatologists in Europe and the USA increasingly rely on fluorescence optical imaging (FOI, Xiralite) for the diagnosis of inflammatory diseases. Those include rheumatoid arthritis, psoriatic arthritis, and osteoarthritis, among others. Indocyanine green (ICG)-based FOI allows visualization of impaired microcirculation caused by inflammation in both hands in one examination.

Multifunctional Rare-Earth Element Nanocrystals for Cell Labeling and Multimodal Imaging.

In this work, we describe a simple solvothermal route for the synthesis of Eu-doped gadolinium orthovanadate nanocrystals (Eu:GdVO-PAA) functionalized with poly(acrylic)acid (PAA), that are applicable as cell labeling probes for multimodal cellular imaging. The Eu doping of the vanadate matrix provides optical functionality, due to red photoluminescence after illumination with UV light. The Gd ions of the nanocrystals reduce the T1 relaxation time of surrounding water protons, allowing these nanocrystals to act as a positive MRI contrast agent with a r1 relaxivity of 1.

Quantification of Myocardial Infarction in Mice Using Micro-CT and a Novel Blood Pool Agent.

We herein developed a micro-CT method using the innovative contrast agent ExiTron™ MyoC 8000 to longitudinally monitor cardiac processes in small animals. Experiments were performed on healthy mice and mice with myocardial infarction inflicted by ligation of the left anterior descending artery. Time-dependent signal enhancement in different tissues of healthy mice was measured and various contrast agent doses were investigated so as to determine the minimum required dose for imaging of the myocardium.

Measurement of R1 dynamics using sliding window-DESPOT.

Purpose: To measure longitudinal relaxation rate (R1) changes during contrast agent studies using a driven equilibrium single pulse observation of T1 (DESPOT) method with a sliding window (sw) acquisition.

Materials And Methods: A sw-DESPOT technique was implemented that uses several three-dimensional (3D) image data sets to calculate R1 with a temporal resolution of only a single data set. Different sources of systematic errors were studied in simulations, and the technique was tested in a tumor-bearing mouse using an intravascular contrast agent.

Stabilization of indocyanine green by encapsulation within micellar systems.

Indocyanine green (ICG) is a fluorescence dye that is widely used for near-infrared imaging. Application of this dye is limited by its numerous disadvantageous properties in aqueous solution, including its concentration-dependent aggregation, poor aqueous stability in vitro and low quantum yield. Additionally, ICG is highly bound to nonspecific plasma proteins, leading to rapid elimination from the body with a half-life of 3-4 min.

Characterization of superparamagnetic iron oxide nanoparticles by asymmetrical flow-field-flow-fractionation.

Aims: The further development of diagnostic and therapeutic nanomedicines in research and their translation into clinical practice require appropriate characterization methods to ensure a reproducible quality and performance. However, many methods are insufficient for a detailed analysis of the particle size. The primary aim of the present work is to evaluate the application of asymmetrical flow-field-flow-fractionation (AF4) coupled with multiangle laser and dynamic light scattering (DLS) for the characterization of superparamagnetic iron oxide (SPIO) particles.

The in vitro stability of air-filled polybutylcyanoacrylate microparticles.

Different methods of manufacturing permitted the production of air-filled PBCA microparticles (af-pbca-mp) with different physical properties such as size and wall thickness. These differences led to distinctions with respect to mechanical stability and, at the same time, to different levels of biochemical stability when incubated in biofluids. Microparticles, designed as they are to be mechanically more stable (composed of larger nanoparticles resulting in thicker shell wall, no surface hydrolysis), persist longer under in vitro conditions in biofluids such as serum, plasma and whole blood than do the more fragile ones.

In vivo molecular imaging of adhesion molecules in experimental autoimmune encephalomyelitis (EAE).

The infiltration of autoreactive T cells into the central nervous system (CNS) requires a complex molecular interplay between immune cells and the blood-brain barrier (BBB), especially involving adhesion molecules like intercellular adhesion molecule (ICAM)-1. Here we study the molecular expression at the BBB during adoptively transferred (AT) myelin basic protein (MBP)-experimental autoimmune encephalomyelitis (EAE) in vivo by sensitive particle acoustic quantification (SPAQ)-enhanced ultrasound after intravenous application of specific gas-filled MP (MP) targeted against ICAM-1 (ICAM-MP) as contrast agent. Our results reveal a clear periventricular and cerebellar upregulation of ICAM-1 expression at the disease maximum of AT-EAE.

Sensitive particle acoustic quantification (SPAQ): a new ultrasound-based approach for the quantification of ultrasound contrast media in high concentrations.

Rationale And Objectives: Ultrasound contrast media (USCM) consisting of gas-filled microparticles (MPs) can be detected in tissue in extremely small amounts using the stimulated acoustic emission effect (SAE), which occurs after the destruction of MPs in an acoustic field. Limited by the spatial resolution of ultrasound devices, the displayed size of individual MPs/SAEs is in the range of millimeters rather than micrometers. Thus, more than approximately 1000 microparticles per milliliter led to complete SAE saturation in the image and cannot be quantified.

A real-time in vitro assay for studying functional characteristics of target-specific ultrasound contrast agents.

Purpose: To develop an in vitro assay for studying the feasibility of specific targeting of ultrasound contrast agents (USCAs) for ultrasound diagnostics by employing the parallel plate flow chamber, which provides an environment that mimics some aspects of the in vivo conditions like shear rate and flow effects.

Methods: USCAs based on air-filled microparticles (MP) were functionalized with specific antibodies using carbodiimide coupling chemistry and characterized by fluorescence activated cell sorter (FACS). The binding experiments were done by subjecting the MP to shear stress as they interact with the target-coated surface of the flow chamber.

Molecular targeting of lymph nodes with L-selectin ligand-specific US contrast agent: a feasibility study in mice and dogs.

Purpose: To evaluate the feasibility of using intravenously administered L-selectin ligand-specific polymer-stabilized air-filled microparticles (MPs) for active targeting of peripheral lymph nodes under normal conditions in animal models.

Materials And Methods: L-selectin ligand-specific MPs and two control substances (immunoglobulin M-isotype MPs and native MPs) were each administered in three conscious mice as a single intravenous bolus injection (1.4 x 10(7) MPs/kg).