While improving MRI machines is one way of making the clinical images look better, another is improving the injectable contrast agents that are compatible with magnetic resonance. Gadolinium-based MRI contrast agents are the most commonly used now, but they carry safety concerns and they don’t have alternatives for some tests. Rice University researchers have been working on developing a contrast agent that is not only safer, but that also helps to produce higher resolution images in so-called T1 scans that currently rely almost exclusively on gadolinium chelates.
While iron chelates are common for T2 scans, they have been assumed to be nearly impossible to employ for T1 scans. The Rice University researchers have now shown that with a bit of nanoengineering it is possible to do so.
The Rice team loaded an iron-based contrast into tiny shells of silica, which they call nanomatryoshka because of the similarity wooden Russian dolls that fit into each other. The shells help to constrain the iron and provide the necessary physical quality to appear well under T2 weighted MRI scans.
Moreover, this new contrast agent is a lot more stable. “All fluorescent dyes are subject to photo bleaching, which means they fade over time and eventually won’t give off a measureable signal,” said Luke Henderson, lead author of the study. “Even if you freeze them, which slows down bleaching, they typically don’t last more than a couple of weeks. I was looking at an old sample of nanomatryoshkas that had been in the fridge for months, and I found they were still fluorescing quite well. When we looked more closely at this we found the dyes were about 23 times more stable when they were inside the nanomatryoshkas.”
Via: Rice University…