A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339

https://mriquestions.com/uploads/3/4/5/7/34572113/lauffer_1999_review.pdf

Gadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and Applications

Magnetic nanoparticles have attracted attention because of their current and potential usefulness as contrast agents for magnetic resonance imaging (MRI) or colloidal mediators for cancer magnetic hyperthermia. This review examines these in vivo applications through an understanding of the involved problems and the current and future possibilities for resolving them. A special emphasis is made on magnetic nanoparticle requirements from a physical viewpoint (e.g. relaxivity for MRI and specific absorption rate for hyperthermia), the factors affecting their biodistribution (e.g. size, surface hydrophobic/hydrophilic balance, etc.) and the solutions envisaged for enhancing their half-life in the blood compartment and targeting tumour cells.

http://konsys-t.tanger.cz/files/proceedings/nanocon_11/lists/papers/1094.pdf

Magnetic nanoparticle design for medical diagnosis and therapy

Rationale and Objectives:To characterize and compare commercially available contrast media (CM) for magnetic resonance imaging (MRI) in terms of their relaxivity at magnetic field strengths ranging from 0.47 T to 4.7 T at physiological temperatures in water and in plasma. Relaxivities also were quan

Comparison of magnetic properties of MRI contrast media solutions at different magnetic field strengths.

Recent advances in iron oxide nanocrystal technology for medical imaging

Gadolinium(III) complexes are often used in clinical MRI to increase contrast by selectively relaxing the water molecules near the complex. There is a desire to improve the sensitivity (relaxivity) of these contrast agents in order to detect molecular targets. This tutorial review describes the molecular factors that contribute to relaxivity and illustrates with recent examples how these can be optimized. It may be of interest to senior undergraduates and more advanced researchers interested in lanthanide chemistry, biophysics, and/or molecular imaging.

Strategies for increasing the sensitivity of gadolinium based MRI contrast agents.

Objectives:Assessment of the complex stability and Gd3+ dissociation rate of all marketed gadolinium-based MRI contrast agents (GBCA) in human serum at pH 7.4 and 37°C.Methods and Results:The kinetic profiles of Gd3+ dissociation of GBCAs were determined by incubation for 15 days in human serum from

Stability of Gadolinium-Based Magnetic Resonance Imaging Contrast Agents in Human Serum at 37°C

Tissue-specific MR contrast agents

Background—Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. Methods and Results—Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. ΔR1 ratio (ΔR1myocardium/ΔR1blood) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20±0.15) than in normal myocardium (0.47±0.05, P<0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA–enhanced region on day 2 was larger (32.8±0.9%) than true infarction as demonstrated by triphenyltetrazolium chl...

Magnetic Resonance Characterization of the Peri-Infarction Zone of Reperfused Myocardial Infarction With Necrosis-Specific and Extracellular Nonspecific Contrast Media

Objectives:Several recent publications have suggested an association between the administration of gadolinium (Gd)-based contrast agents and the occurrence of Nephrogenic Systemic Fibrosis (NSF), an acquired disorder marked by skin thickening and fibrosis occurring in patients with severe renal dysf

Hanns-Joachim Weinmann

Papers

Comparison of magnetic properties of MRI contrast media solutions at different magnetic field strengths.

Stability of Gadolinium-Based Magnetic Resonance Imaging Contrast Agents in Human Serum at 37°C

Tissue-specific MR contrast agents

Magnetic Resonance Characterization of the Peri-Infarction Zone of Reperfused Myocardial Infarction With Necrosis-Specific and Extracellular Nonspecific Contrast Media

A Preclinical Study to Investigate the Development of Nephrogenic Systemic Fibrosis: A Possible Role for Gadolinium-Based Contrast Media