MRI, molecular

Sosnovik DE, Weissleder R. Emerging concepts in molecular MRI. Curr. Opin. Biotechnol. 2007 18 4-10. 

S. Langereis, T. Geelen, H. Gruell, G. J. Strijkers and K. Nicolay, Paramagnetic Liposomes for Molecular MRI and MRI-Guided Drug Delivery, NMR Biomed., 2013, 26, 728. 

Most disease-specific molecular and cellular processes involve low concentrations and have low capacities. Therefore, molecular imaging requires highly sensitive imaging modalities to detect and quantify the imaging probes as it is done with short-lived radioisotopes. Optical imaging and ultrasound are next in sensitivity. MRI would require too high contrast agent concentrations... 

Toth E, Hehn L, Merbach AE (2002) Relaxivity of MRI Contrast Agents. 221 61-101 Tovar GEM, Krauter I, Gruber C (2003) Molecularly Imprinted Polymer Nanospheres as Fully Affinity Receptors. 227 125-144... 

NMR spectroscopy is one of the most widely used analytical tools for the study of molecular structure and dynamics. Spin relaxation and diffusion have been used to characterize protein dynamics [1, 2], polymer systems[3, 4], porous media [5-8], and heterogeneous fluids such as crude oils [9-12]. There has been a growing body of work to extend NMR to other areas of applications, such as material science [13] and the petroleum industry [11, 14—16]. NMR and MRI have been used extensively for research in food science and in production quality control [17-20]. For example, NMR is used to determine moisture content and solid fat fraction [20]. Multi-component analysis techniques, such as chemometrics as used by Brown et al. [21], are often employed to distinguish the components, e.g., oil and water. 

The sensitivity of Magnetic Resonance (MR) to the local concentration, molecular dynamics and molecular environment of these nuclei make it well suited for the study of deterioration processes in concrete materials. Hydrogen (water), lithium, sodium, chlorine and potassium are all MR sensitive nuclei and play an important role in cement chemistry. The ability of MRI to spatially resolve and non-destructively examine test samples as a function of treatment or exposure has the potential to provide new insight to better understand deterioration mechanisms and mass transport properties of concrete materials. 

Dextrans are also attractive as macromolecular carriers of paramagnetic chelates because of their hydrophilicity, the different available molecular weights with narrow polydispersity, and the versatility of activation methods applicable. Several DTPA- or DOTA-loaded carboxymethyl dextran (CMD) derivatives have been prepared and tested in blood pool MRI.136-139 The relaxivities reported for these compounds are, however, relatively moderate. 

Targeted contrast agents are specific and directed to a specific molecular or cellular target with an appropriate targeting ligand molecule. Recombinant high density lipoprotein (HDL)-like nanoparticles, a specific contrast agent for MRI of atherosclerotic plaques, has been reported [86] (Fig. 25). 

Flacke S, Fischer S, Scott MJ, Fuhrhop RJ, Allen JS, McLean M, Winter P, Sicard GA, Gaffney PJ, Wickline SA, Lanza GM (2001) Novel MRI contrast agent for molecular imaging of fibrin implications for detecting vulnerable plaques. Circulation 104 1280-1285... 

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