Advances in F19 MRI: Imaging Drugs in Living Organisms

[gravenewworld]

What kind of advances have been made in this field (since I don't stay on top of it)? If I wanted to image, say, where my fluorinated drug is going within a rat, is it possible? NMR is inherently not a sensitive modality. Hydrogen is vastly more abundant in a living organism than fluorine (typical MRI vs F19 MRI), so given the fact that most therapeutic doses of drugs occur probably in the millimolar to nanomolar range, is it even possible to produce a good image with F19 MRI? Is it practically impossible to produce a decent S/N ratio? What if I incorporated more fluorines into my compound?

 

[Mike H]

I recall people were fiddling around with hyperpolarization schemes in relation to ¹⁹F MRS/MRI at an Experimental NMR Conference a few years back, but they were able to get the model system/proof of concept looking fairly convincing, so you might want to poke around to see if they've made the jump to the clinic (or at least the diagnostic radiology research labs).

Otherwise, more fluorines = more signal. Jeff Bulte at Johns Hopkins has been using extensively fluorinated compounds as contrast agents/tracers that I can also muster up from memory within the last few years. Also, in general, fluorine has some particularly interesting advantages - it's about 80% to 85% as sensitive as ¹H, the only stable isotope is ¹⁹F (in contrast to hydrogen and deuterium), and it's a spin-1/2 nucleus.

 

[gravenewworld]

Thanks for the response. My PI just sent me this paper in which they have a moiety containing a CF3 group complexed with a lanthanide metal

http://onlinelibrary.wiley.com/doi/10.1002/mrm.22881/abstract

Sensitivity for 19F increases by 10,000 fold. Would this work for boron instead of a lanthanide? For example a compound containing a BF2 group? My quantum chemistry is quite rusty (took it almost 10 years ago), so I'm not sure if using boron would also work to decrease relaxation times too.

 

[Mike H]

The most common boron nuclei are quadrupolar, so my initial suspicion is that they would indeed facilitate faster relaxation times. Relative to a comparable lanthanide complex...not sure off the top of my head. I would suspect probably not, although it would depend on which one. I'm mostly thinking that you may find naturally occurring lanthanides to be a mix of isotopes, some of which are themselves quadrupolar (for example - "natural abundance" gadolinium is actually composed of 5 or 6 isotopes, some of which are spin-3/2 nuclei). I think there are some lanthanides which are mostly just spin-1/2 nuclei (thulium, I think, as it's used in the shift reagent TmDOTP), but my rare-earth chemistry is a bit dusty.

 

[LudusRex]

There have been significant advancements in the field of F19 MRI in recent years. F19 MRI, also known as fluorine-19 MRI, is a type of magnetic resonance imaging (MRI) that uses the nucleus of fluorine atoms to produce images. This technique has shown great potential in imaging drugs in living organisms.

One of the major advances in F19 MRI is the development of specialized imaging probes that can be incorporated into drugs. These probes contain a fluorine atom, which can be detected by F19 MRI. This allows for the tracking of the drug in real-time within living organisms. This has greatly improved our understanding of drug distribution and metabolism in the body.

Another important advancement is the improvement in imaging techniques and equipment. F19 MRI has become more sensitive and can now produce high-resolution images, allowing for the detection of even small amounts of the drug in the body. This has made it possible to track drug distribution in living organisms, including rats.

While it is true that hydrogen is more abundant in living organisms than fluorine, F19 MRI has become sensitive enough to detect fluorine at concentrations as low as nanomolar levels. This makes it possible to produce high-quality images of drug distribution in the body, even at therapeutic doses.

Incorporating more fluorines into a drug compound can also improve the sensitivity of F19 MRI. However, this should be done carefully as it can also affect the pharmacokinetics and efficacy of the drug.

In conclusion, significant advances have been made in F19 MRI, making it a valuable tool for imaging drugs in living organisms. With the development of specialized imaging probes and improvements in imaging techniques, it is now possible to produce high-quality images of drug distribution in the body, even at low concentrations. Incorporating more fluorines into drug compounds can further improve the sensitivity of F19 MRI, but it should be done with caution.