Enhanced gadolinium

Magnetic resonance imaging (MRI)-enhancing gadolinium compounds... 

Remonda L, Held O, Schroth G. Carotid artery stenosis, occlusion, and pseudoocclusion first-pass, gadolinium-enhanced, three-dimensional MR angiography— preliminary study. Radiology 1998 209 95-102 [see comment]. 

Motexafin gadolinium is being developed under the name XCYTRIN for the enhancement of A -radiation. www.pcyc.com. 

A water-solubilized texaphyrin based on gadolinium(III) (XCYTRIN ) is under current testing in a new Phase III clinical trial with the role to enhance the effects of radiation therapy for... 

Fig. 11. Tensor-valued elasticity parameters in a human breast in vivo. A dotted circle symbolizes a carcinoma previously localized using gadolinium-enhanced Ti-weighted imaging. Eigenvalues Ei, E2, and E3 of the elasticity tensor are shown in (a), (b), and (c) respectively. Also shown in (d) is the isotropic elasticity...

Collidge TA, Thomson PC, Mark PB, Traynor JP, Jardine AG, Morris ST, Simpson K, Roditi GH (2007) Gadolinium-enhanced MR imaging and nephrogenic systemic fibrosis retrospective study of a renal replacement therapy cohort. Radiology 245 168-175. 

Attempts were made to investigate the relaxivity enhancement produced by an MFI-type zeolite with framework-incorporated gadolinium (84). A relaxivity less than 3 s mM was found at room temperature and at 40 MHz. This indicates that the accessibility of gadolinium to water plays a very important role, and that the outer sphere effect might be very small. 

The enhancement of the fluorescent yield of terbium, europium, and gadolinium in heavy-water solutions was studied by Kropp and Windsor (105). They observed substantial increases in emission intensities for both terbium and europium compounds when ordinary water was replaced by deuterated water. No appreciable increase was observed for gadolinium, however. For terbium they also obtained the fluorescent lifetimes of the 5D4 state. 

The relaxivity induced by gadolinium chelates due to inner-sphere water molecules, riIS, is well understood on the microscopic scale as can be seen from the above discussion. The contribution to the overall relaxation enhancement due to all other water molecules is normally summed up in the term r, generally called the outer-sphere contribution. The interaction between the water proton nuclear spin I and the gadolinium electron spin S is supposed to be a dipolar intermolecular interaction whose fluctuations are governed by random translational motion. The corresponding relaxation rate, l/Tly for unlike spins is given by Eq. (23) [88-90]... 

Increasing the molecular weight of a gadolinium chelate does indeed provide a contrast agent with enhanced relaxivity, provided that free rotation at the metal ion is sufficiently hindered. It is not however the only way to improve the efficacy of a contrast agent as described later (see smart contrast agents). 

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