Magnetic contrast media

Other imaging techniques such as magnetic resonance and ultrasound have opened up avenues of tremendous potential for contrast medium enhancement (123). Ultrasound contrast media developments have centered around encapsulated air micro-bubbles. Magnetic resonance contrast agents iavolve metal—ligand complexes and have evolved from ionic to nonionic species, much as radiopaques have. 

In a different way, metallic-core nanoparticles [346-349] (prepared cf. Section 3.10) equipped with biocompatible coats such as L-cysteine or dextrane may be exploited for highly efficient and cell-specific cancer cell targeting, i.e., for improving diagnosis and therapy of human cancer. In a recent proof-of-principle experiment an unexpectedly low toxicity of the L-cysteine-covered cobalt nanoparticles was demonstrated [433] For diagnostic purposes, it is expected to use the advantageous magnetic properties of the metallic-core nanoparticles to obtain a contrast medium for MRI with considerably increased sensitivity, capable to detect micro-metastases in the environment of healthy tissues [434 37]. 

Fig. 22. Magnetic resonance imaging (MRI) without contrast medium showed wedge-shaped contrast enhancement in some patients (Patient 16 TR3600, TE138)...

In the patients with ALPE, plain CT of the kidney (delayed CT) a few hours, 24 h, and 48 h after the administration of 40 ml contrast medium showed wedge-shaped contrast enhancement. When physicians hesitate to administer a contrast medium, patchy accumulation can be sometimes detected by magnetic resonance imaging (MRI) with gadolinium-diethylenetriaminopentoacetic acid (Gd-DTPA), bone scan with MDP, or ultrasonography with Levovist. 

Stehling MK, Niedermeyer M, Laub G (1997) [Contrast medium enhanced magnetic resonance angiography. Theory, technique and practical implementation], Radio-loge 37 501-507... 

Dewey, M., Kaufels, N., Laule, M., et al. (2004) Assessment of myocardial infarction in pigs using a rapid clearance blood pool contrast medium. Magnetic Resonance in Medicine, 51, 703—709. 

Rodrigues de Miranda JF, Flilbers ON. A nuclear magnetic resonance study ofthe kinetics ofthe binding ofthe renal contrast medium acetrizoate to albumin. Mol Pharmacol 1976 12 279-290. 

Fig. 23.4. A wire-frame outline of the total stomach volume after ingestion of a soup meal serving as contrast medium. The images used for 3D reconstruction are acquired by ordinary 2D ultrasonography and magnetic scanhead tracking enables precise acquisition and reconstruction of the organ...

Isotope Investigations, Computerized Tomography, and Intravenous Pyelography 426 Use of Contrast Medium 426 Voiding Cystourethrography 426 Magnetic Resonance Imaging 426... 

Thomsen HS, Marckmann P, Logager VB (2007) Enhanced computed tomography or magnetic resonance imaging a choice between contrast medium-induced nephropathy and nephrogenic systemic fibrosis Acta Radiol 48 593-596... 

Coreless furnaces derive their name from the fact that the coil encircles the metal charge but, in contrast to the channel inductor described later, the cod does not encircle a magnetic core. Figure 8 shows a cross section of a typical medium sized furnace. The cod provides support for the refractory that contains the metal being heated and, therefore, it must be designed to accept the mechanical loads as well as the conducted thermal power from the load. 

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