THE MAGNETIC-PROPERTIES OF SOME MATERIALS AFFECTING MR IMAGES

We have compared the magnetic properties of various types of materials known to affect MR images. The materials compared were: (i) MR contrast agents based on chelates of paramagnetic metals (Gd‐DTPA, Dy‐DTPA); (ii) biological forms of iron (horse spleen ferritin and deoxyhemoglobin); and (iii) a superparamagnetic iron oxide (AMI‐25). The properties compared were the magnetic susceptibility and the magnetization. The magnetization and susceptibility of superparamagnetic AMI‐25 are far larger than that of ferritin or low molecular weight, paramagnetic chelates. Superparamagnetic iron oxide colloids, like AMI‐25, are a uniquely powerful class of magnetic materials. © 1991 Academic Press, Inc. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company