Just finishing up, neurolysis and nerve ablation. We talked a little bit about this, but the goal is to permanently disrupt the axons and the myelin sheath. You can do it chemically with alcohol or phenol. But more and more people now are offering
radiofrequency ablation or cryoablation as a more precise way of performing these ablations. Radiofrequency ablation probably has the most data after alcohol and phenol. It's inexpensive and it has a long track record. Cryoablation is now being reported in the literature.
It's easy to see on CT as my colleagues have demonstrated. It's good in soft tissue tumors, but we still have very early data. Some people are actually looking at MR-guided focus ultrasound, very sexy, very expensive technology, very niche.
I don't really see that becoming a major player. I think it's really gonna be RFA and cryoablation,
But I'm really gonna focus on percutaneous ablation because it's particularly well suited to this application, minimally invasive for these potentially frail and elderly patients,
as well as high kill rate with tumors of many different histologies. So when we're choosing, this is the technique, so how do we do it? If we were facing a metastasis in the scapula like this, we can treat it with heat,
radiofrequency, or microwave ablation, or we can treat it with cryoablation, extreme cold temperatures, extreme cold or extreme heat, they'll both kill the tumor. How do we decide? Well, if we compare cryoablation versus microwave ablation
or radiofrequency ablation, ease of use, the heat-based therapies are certainly easier to use. They're generally faster, so the procedure duration is quite a bit shorter, but the energy transmission into bone is better with cryoablation.
It'll go through the cortex, whereas heat is limited in that regard. The predictability of the ablation zone, the cryoablation. As you can see in that scapular picture, we can actually see the edge of the ablation with several different modalities, CTMR and ultrasound.
Our ability to monitor that ablation then and prevent it from escaping into adjacent collateral structures. And then the ablation zone size, we can usually treat a larger area with cryoablation, and patient tolerance, their pain scores are generally less
after a cryoablation than a heat-based therapy. So in general, most of us who are treating for local tumor control would use cryoablation. These factors are a little less true these days where there are newer bipolar radiofrequency devices that are designed specifically for bone
so have better ability to control tumors within these sites.
Why are fast injection rates important? It is important because it allows for optimum enhancement of normal and abnormal structures in the body. It adds quality, value, and extent to the images.
At our institution, the maximum injection rate we currently use is 6 ml per second for CT angiographies. And when we are faced with the issue of image quality versus the risk of extravasation, I always remember what our favorite radiologist
always tells us: Maria, image quality is important, but patient safety comes first. There is a reason why we love him. But also, it depends on who you're talking to. Some radiologists would not even think of that. And here are studies that require fast injection rates
that we usually perform at our institution. And of all these studies, it is the liver and the pancreas studies that make up a large percentage of imaging that we perform at our institution. Now these are images of a CT of the chest
with IV contrast utilizing a one ml per second injection on your left, and a 2.5 ml injection on your right. You can see there is better enhancement, the blood vessels are clearer, the structures are clearer. And I have another slide
that will show us the CT of the abdomen with IV contrast utilizing a one ml per second injection versus a 2.5 ml per second injection. What can you see in the images on the right that you cannot see on the left? Blood vessels, yes, thank you.
You can see very clearly on the right, there are the normal structures, and you have the lesion on the liver, and there's something on the kidney that looks like maybe it's mets, or maybe it's just a cyst, hopefully.
And you see the spleen and the stomach, and there you can see, let me try this, right there, yay, okay, that is the main portal vein, and somewhere here is the hepatic artery, arteries. So having said that,
(laughs) I'm almost done. (Maria and audience laughing) Having said that, these images, oh, sorry, okay, these images clearly demonstrate that fast injection rates are essential
to achieve high quality diagnosis. However, as nurses, and as advocates for our patients, we should always remember that patient safety is still our priority.