High-resolution, multiplexed experiments are a staple in cellular imaging. Analogous experiments in animals are challenging, however, due to substantial scattering and autofluorescence in tissue at ...visible (350-700 nm) and near-infrared (700-1,000 nm) wavelengths. Here, we enable real-time, non-invasive multicolour imaging experiments in animals through the design of optical contrast agents for the shortwave infrared (SWIR, 1,000-2,000 nm) region and complementary advances in imaging technologies. We developed tunable, SWIR-emissive flavylium polymethine dyes and established relationships between structure and photophysical properties for this class of bright SWIR contrast agents. In parallel, we designed an imaging system with variable near-infrared/SWIR excitation and single-channel detection, facilitating video-rate multicolour SWIR imaging for optically guided surgery and imaging of awake and moving mice with multiplexed detection. Optimized dyes matched to 980 nm and 1,064 nm lasers, combined with the clinically approved indocyanine green, enabled real-time, three-colour imaging with high temporal and spatial resolutions.
Purpose
The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN).
Areas covered
...Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic measures used to reduce the incidence of CIN, and the management of patients receiving metformin.
Key Points
• Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed.
• CIN risk is lower with intravenous than intra-arterial iodinated contrast medium.
• eGFR of 45 ml/min/1.73 m
2
is CIN risk threshold for intravenous contrast medium.
• Hydration with either saline or sodium bicarbonate reduces CIN incidence.
• Patients with eGFR ≥60 ml/min/1.73 m
2
receiving contrast medium can continue metformin normally.
This review focuses on the trends in contrast media (CM) research published in Acta Radiologica during the last 100 years, since the first edition in 1921. The main topics covered are the ...developments of iodine- and gadolinium-based CM. Other topics include manganese-based CM for magnetic resonance imaging (MRI) and barium for the investigation of the alimentary tract. From a historic point of view, special CM for use in cholegraphy and myelography are addressed in the review. Today, these imaging procedures are obsolete due to the development of computed tomography, MRI, and ultrasound. The historical use of radioactive thorium-based CM for angiography is also addressed. Furthermore, publications on adverse reactions to CM are reviewed.
Magnetic resonance imaging (MRI) contrast agents are categorised according to the following specific features: chemical composition including the presence or absence of metal atoms, route of ...administration, magnetic properties, effect on the magnetic resonance image, biodistribution and imaging applications. The majority of these agents are either paramagnetic ion complexes or superparamagnetic magnetite particles and contain lanthanide elements such as gadolinium (Gd3+) or transition metal manganese (Mn2+). These elements shorten the T1 or T2 relaxation time, thereby causing increased signal intensity on T1-weighted images or reduced signal intensity on T2-weighted images. Most paramagnetic contrast agents are positive agents. These agents shorten the T1, so the enhanced parts appear bright on T1-weighted images. Dysprosium, superparamagnetic agents and ferromagnetic agents are negative contrast agents. The enhanced parts appear darker on T2-weighted images. MRI contrast agents incorporating chelating agents reduces storage in the human body, enhances excretion and reduces toxicity. MRI contrast agents may be administered orally or intravenously. According to biodistribution and applications, MRI contrast agents may be categorised into three types: extracellular fluid, blood pool and target/organ-specific agents. A number of contrast agents have been developed to selectively distinguish liver pathologies. Some agents are also capable of targeting other organs, inflammation as well as specific tumors.
Key Points
CI‐AKI is an iatrogenic renal damage that can occur in patients undergoing percutaneous procedures with the use of contrast media.
This article tested the efficacy and safety of the new ...DyeVert system, demonstrating a significant reduction in CM volume injected and in the incidence of post‐procedural CI‐AKI.
Future researches will be needed to confirm these results and identify the specific type of patient in which a reduction in CM volume would impact in clinical outcomes.
Contrast-Associated Acute Kidney Injury Mehran, Roxana; Dangas, George D; Weisbord, Steven D
The New England journal of medicine,
05/2019, Letnik:
380, Številka:
22
Journal Article
Recenzirano
This review summarizes the pathophysiology and definition of contrast-associated acute kidney injury, as well as risk stratification. The authors discuss controversies regarding the incidence of this ...condition and highlight studies providing the evidence for preventive care.
ABSTRACTThe established class of intravenous contrast media for magnetic resonance imaging is the gadolinium chelates, more generally referred to as the gadolinium-based contrast agents (GBCAs). ...These can be differentiated on the basis of stability in vivo, with safety and tolerability of the GBCAs dependent upon chemical and biologic inertness. This review discusses first the background in terms of development of these agents and safety discussions therein, and second their relative stability based both on in vitro studies and clinical observations before and including the advent of nephrogenic systemic fibrosis. This sets the stage for the subsequent focus of the review, the current knowledge regarding accumulation of gadolinium in the brain and specifically the dentate nucleus after intravenous administration of the GBCAs and differentiation among agents on this basis. The information available to date, from the initial conception of these agents in 1981 to the latest reports concerning safety, demonstrates a significant difference between the macrocyclic and linear chelates. The review concludes with a discussion of the predictable future, which includes, importantly, a reassessment of the use of the linear GBCAs or a subset thereof.
Purpose
The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury ...(PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers.
Areas covered in part 1
Topics reviewed include the terminology used, the best way to measure eGFR, the definition of PC-AKI, and the risk factors for PC-AKI, including whether the risk with intravenous and intra-arterial contrast medium differs.
Key Points
•
PC-AKI is the preferred term for renal function deterioration after contrast medium
.
•
PC-AKI has many possible causes
.
•
The risk of AKI caused by intravascular contrast medium has been overstated
.
•
Important patient risk factors for PC-AKI are CKD and dehydration
.
Magnetic nanoparticle clusters composed of primary magnetic nanoparticles can not only significantly enhance the magnetic properties of the assembly but also retain the superparamagnetic properties ...of the individual primary nanoparticle, which is of great significance for promoting the development of multifunctional advanced materials. Herein, water-soluble biocompatible and superparamagnetic europium-doped iron oxide nanoparticle clusters (EuIO NCs) were directly synthesized by a simple one-pot method. The obtained EuIO NCs have excellent water solubility, colloidal stability, and biocompatibility. Europium doping significantly improved the contrast enhancement effect of EuIO NCs in T 1-weighted MR imaging. In addition, EuIO NCs can be functionalized by active molecules, and the rhodamine123-functionalized EuIO NCs have long circulation time and excellent fluorescence imaging performance in vivo. This study provides a simple strategy for the design and construction of a novel multifunctional magnetic nanoplatform and provides solutions for the development of multimodal imaging probes and the diagnosis of disease.
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