scholarly journals Intravascular (blood pool) MRI contrast agents

2013 ◽  
Author(s):  
Andrew Murphy ◽  
J. Ballinger

2012 ◽  
Vol 2012 (12) ◽  
pp. 1924-1933 ◽  
Author(s):  
Gang Ho Lee ◽  
Yongmin Chang ◽  
Tae-Jeong Kim


1998 ◽  
Vol 40 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Kevin M. Johnson ◽  
Jing Zang Tao ◽  
Richard P. Kennan ◽  
John C. Gore


2003 ◽  
Vol 2 (1) ◽  
pp. 153535002003031 ◽  
Author(s):  
Hisataka Kobayashi ◽  
Martin W. Brechbiel

Numerous macromolecular MRI contrast agents prepared employing relatively simple chemistry may be readily available that can provide sufficient enhancement for multiple applications. These agents operate using a ~100-fold lower concentration of gadolinium ions in comparison to the necessary concentration of iodine employed in CT imaging. Herein, we describe some of the general potential directions of macromolecular MRI contrast agents using our recently reported families of dendrimer-based agents as examples. Changes in molecular size altered the route of excretion. Smaller-sized contrast agents less than 60 kDa molecular weight were excreted through the kidney resulting in these agents being potentially suitable as functional renal contrast agents. Hydrophilic and larger-sized contrast agents were found better suited for use as blood pool contrast agents. Hydrophobic variants formed with polypropylenimine diaminobutane dendrimer cores created liver contrast agents. Larger hydrophilic agents are useful for lymphatic imaging. Finally, contrast agents conjugated with either monoclonal antibodies or with avidin are able to function as tumor-specific contrast agents, which also might be employed as therapeutic drugs for either gadolinium neutron capture therapy or in conjunction with radioimmunotherapy.



Author(s):  
Joel Garcia ◽  
Stephen Z. Liu ◽  
Angelique Y. Louie

No discussion of challenges for chemistry in molecular imaging would be complete without addressing the elephant in the room—which is that the purest of chemical compounds needs to interact with a biological system in a manner that does not perturb normal biology while still providing efficacious feedback to assist in diagnosis of disease. In the past decade, magnetic resonance imaging (MRI) agents long considered inert have produced adverse effects in certain patient populations under certain treatment regimens. More recently, inert blood pool agents have been found to deposit in the brain. Release of free metal is often suspected as the culprit but that hypothesis has yet to be validated. In addition, even innocuous agents can cause painful side effects during injection in some patients. In this brief review, we summarize known biological effects for gadolinium- and iron-based MRI contrast agents, and discuss some of the potential mechanisms for the observed biological effects, including the potential role of phosphorus imbalance, related to kidney disease or cancer, in destabilizing gadolinium-based chelates and precipitating free gadolinium. This article is part of the themed issue ‘Challenges for chemistry in molecular imaging’.



ChemInform ◽  
2012 ◽  
Vol 43 (29) ◽  
pp. no-no
Author(s):  
Gang Ho Lee ◽  
Yongmin Chang ◽  
Tae-Jeong Kim


2007 ◽  
Vol 232 (8) ◽  
pp. 1081-1089 ◽  
Author(s):  
Rongzuo Xu ◽  
Yanli Wang ◽  
Xuli Wang ◽  
Eun-Kee Jeong ◽  
Dennis L. Parker ◽  
...  

Macromolecular Gd(III) chelates are superior magnetic resonance imaging (MRI) contrast agents for blood pool and tumor imaging. However, their clinical development is limited by the safety concerns related to the slow excretion and long-term gadolinium tissue accumulation. A generation 6 PAMAM Gd(III) chelate conjugate with a cleavable disulfide spacer, PAMAM-G6-cystamine-(Gd-DO3A), was prepared as a biodegradable macromolecular MRI contrast agent with rapid excretion from the body. T1 and T2 relaxivities of the contrast agent were 11.6 and 13.3 m M−1sec−1 at 3T, respectively. Blood pool and tumor contrast enhancement of the agent were evaluated in female nude mice bearing MDA-MB-231 human breast carcinoma xenografts with a nondegradable conjugate PAMAM-G6-(Gd-DO3A) as a control. PAMAM-G6-cystamine-(Gd-DO3A) resulted in significant contrast enhancement in the blood for about 5 mins, and Gd-DO3A was released from the conjugate and rapidly excreted via renal filtration after the disulfide spacer was cleaved. The nondegradable control had much longer blood circulation and excreted more slowly from the body. PAMAM-G6-cystamine-(Gd-DO3A) also resulted in more prominent tumor contrast enhancement than the control. However, PAMAM-G6-cystamine-(Gd-DO3A) demonstrated high toxicity due to the intrinsic toxicity of PAMAM dendrimers. In conclusion, although PAMAM-G6-cystamine-(Gd-DO3A) showed some advantages compared with the nondegradable control, PAMAM dendrimers are not suitable carriers for biodegradable macromolecular MRI contrast agents, due to their high toxicity.



2010 ◽  
Vol 6 (2) ◽  
pp. 61-68 ◽  
Author(s):  
Wenlian Zhu ◽  
Dmitri Artemov


2003 ◽  
Vol 49 (3) ◽  
pp. 586-590 ◽  
Author(s):  
Kofi Adzamli ◽  
Dmitriy A. Yablonskiy ◽  
Michael R. Chicoine ◽  
Eun Kyung Won ◽  
Karen P. Galen ◽  
...  


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