(NACA) Some porphyrin (e.g. Gadophrin-2) and non-porphyrin (e.g. CEIII-60) paramagnetic chelates are able to specifically accumulate in nonviable tissues and can be applied as a MRIcontrast agent for acute myocardial infarction and therapeutic necrosis. This function of necrosis avid contrast agents is a unique pathological targetability. These agents can also be exploited for multipurpose applications, because NACAs also bear other common properties including early systemic distribution, albumin binding, hepatocellular uptake and renal elimination.
Blood pool MRIcontrast agents with their longer intravascular circulation can be designed to be targeted to necrotic myocardium, to assess myocardial viability, or tumor directed to provide better diagnostic information for various tumors.
A disadvantage of the use of blood pool agents for MRA is that the separation of arteries and veins is more difficult because they are present in both and the overlapping of those vessels is disturbing. This can be solved by e.g. different MIP segmentation algorithms.
A contrast medium (or contrast agent) is a chemical substance introduced to the anatomical or functional region being imaged, to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times.
The chemical composition of the contrast media determines the specific usage. Similar to nuclear imaging is the intention in development of MR contrast media a high affinity to different organs or even tumors (e.g. necrosis avid contrast agent).
In 'contrast' to nuclear imaging contrast agents MR contrast media do not contain radiopharmaceuticals and the concentrations are about 100 times higher. Nuclear imaging contrast agents are direct contrast agents;; they are directly visible caused by their radioactivity. MR contrast agents affect the targeted tissue; they are indirect contrast agents.
See also Contrast Agents, the info sheet gives an overview and more in-depth information about different types of MRIcontrast medium.
Short name: ECIII-60, central moiety: Gd3+
A non-porphyrin paramagnetic chelate with capabilities as a multipurpose T1-relaxivity necrosis avid MRIcontrast agent.