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

Fourier transform pulsed-gradient spin-echo studies of molecular diffusion

We present the results of new and previously published 17O NMR, EPR, and NMRD studies of aqueous solutions of the Gd3+ octaaqua ion and the commercial MRI contrast agents [Gd(DTPA)(H2O)]2- (MAGNEVIST, Schering AG, DTPA = 1,1,4,7,7-pentakis(carboxymethyl)-1,4,7-triazaheptane), [Gd(DTPA-BMA)(H2O)] (OMNISCAN, Sanofi Nycomed, DTPA-BMA = 1,7-bis[(N-methylcarbamoyl)methyl]-1,4,7-tris(carboxymethyl)-1,4,7-triazaheptane), and [Gd(DOTA)(H2O)]- (DOTAREM, Guerbet, DOTA = 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane). High-field EPR measurements at different concentrations give evidence of an intermolecular dipole−dipole electronic relaxation mechanism that has not previously been described for Gd3+ complexes. For the first time, the experimental data from the three techniques for each complex have been treated using a self-consistent theoretical model in a simultaneous multiple parameter least-squares fitting procedure. The lower quality of the fits compared to separate fits of the data for each o...

Structural and Dynamic Parameters Obtained from 17O NMR, EPR, and NMRD Studies of Monomeric and Dimeric Gd3+ Complexes of Interest in Magnetic Resonance Imaging: An Integrated and Theoretically Self-Consistent Approach1

Magnetism in medicine has had a long and interesting history In the 10 th century AD, Egyptian physician and philosopher Avicenna prescribed a grain of magnetite dissolved in milk for the accidental swallowing of rust reasoning that magnetite would render the poisonous iron inert by attracting it and accelerating its excretion through the intestine1 A thousand years later on July 3, 1977, “Indomitable”, the little machine that could, labored for five hours to produce one image, an event that used magnetism to change the landscape of modern medicine 2 Looking at the homemade superconducting magnet constructed from 30 miles of niobiumtitanium wire that now resides in its rightful place at the Smithsonian Institution, it is incredible to comprehend how in a mere 30 years magnetic resonance imaging (MRI) has gone from its crude, almost ugly, human scan to where physicians can now regularly order MRIs off their menu of diagnostic tools because of its exquisite anatomical resolution, routinely down to 05 to 1 mm When the field was first reviewed in this journal in 1987, 3 only 39 papers were found in Medline with keywords “gado-“ and “MRI” 4 Today, this same search on PubMed pulls out over 250,000 records, of which a significant component has been development of MR contrast agents The human body is essentially a super-sized water bottle, with about two-thirds of its weight consisting of water Water's hydrogen atoms are able to act as microscopic compass needles that stand “at attention” when placed in a strong magnetic field When submitted to pulses of radio waves, their magnetic alignment is disrupted and the differences in how they relax to the previous state are used to generate images Contrast agents can act to catalyze the process of the return to the ground relaxed state Now commonplace in the clinic, paramagnetic or superparamagnetic metal ions are administered in 40–50% of the 7–10 million MR examinations per year 5 These image-enhancing contrast agents add significant morphological and functional information to unenhanced MR images, allowing for enhanced tissue contrast, characterization of lesions, and evaluation of perfusion and flow-related abnormalities In this review, we will introduce small molecule agents, but focus primarily on macromolecular MR contrast agents, particularly those containing gadolinium (Gd 3+ ) that are assembled or based in part on these same small molecules A brief discussion on iron oxide and manganese (Mn 2+ ) agents is also provided

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Macromolecules, Dendrimers, and Nanomaterials in Magnetic Resonance Imaging: The Interplay between Size, Function, and Pharmacokinetics

Field-Cycling NMR Relaxometry

Theory of nuclear spin relaxation in paramagnetic systems in solution

A theory of nuclear spin relaxation in paramagnetic systems, allowing for the electron spin relaxation to be in the slow motion regime, is presented. The formulation is general and can, for example, be used to derive formally the modified Solomon-Bloembergen equations. The theory is applied to the specific problem of nuclear spin lattice relaxation caused by the dipole-dipole interaction between the nuclear spin and an electron spin (S = 1). The lattice is described in terms of the electron Zeeman interaction, a zero field splitting of cylindrical symmetry and isotropic rotational diffusion. The resulting equations are solved numerically for a range of parameter values of practical interest and limiting cases are discussed. In the slow motion regime for the electron spin relaxation (that is, where the zero field splitting is larger than the rotational diffusion constant), the behaviour of the nuclear spin-lattice relaxation rate predicted using the present formalism differs qualitatively from the predicti...

Nuclear spin relaxation in paramagnetic systems

NMR lineshapes of I = 52 and I = 72 nuclei. Chemical exchange effects and dynamic shifts

Proton spin-lattice relaxation in aqueous solution of the nickel(II) ion

Nuclear spin-lattice and spin-spin relaxation in paramagnetic systems in the slow-motion regime for the electron spin. III: Dipole-dipole and scalar spin-spin interaction for S=3/2 and S=5/2

P.-O Westlund

Papers

Theory of nuclear spin relaxation in paramagnetic systems in solution

Nuclear spin relaxation in paramagnetic systems

NMR lineshapes of I = 52 and I = 72 nuclei. Chemical exchange effects and dynamic shifts

Proton spin-lattice relaxation in aqueous solution of the nickel(II) ion

Nuclear spin-lattice and spin-spin relaxation in paramagnetic systems in the slow-motion regime for the electron spin. III: Dipole-dipole and scalar spin-spin interaction for S=3/2 and S=5/2