Updated: Mar 11, 2019
CTA, Cone Beam CTA, and digital subtraction angiography (DSA) are equally viable options for pre-procedure imaging of the prostatic arteries. Prostatic artery embolization (PAE) experts Dr. Ari Isaacson and Dr. Sandeep Bagla debate their preferred modalities, and discuss what imaging techniques helped them get started with PAE.
The BackTable Brief
When first performing prostatic artery embolization (PAE) procedures, CTA can be useful for understanding the unique anatomy of the prostate, determining the origin of the prostatic artery, and planning your approach.
Having started with CTA, Dr. Isaacson now uses Cone Beam CTA as it allows him to image patients and plan his approach on the same day of the procedure, thereby cutting costs and making the procedure more convenient for his patients.
Dr. Sandeep Bagla prefers to use digital subtraction angiography (DSA). DSA has the advantage of allowing the operator to visualize flow dynamics and collaterals that may not be emphasized in static CTA images.
Disclaimer: The opinions expressed by the participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
Getting Started with CTA in Prostatic Artery Embolization
For preprocedure CTA, which kind of patients are you still doing these for?
Let me give you a little history on this, and I'll tell you where I'm at with it.
Initially, I got CT in everybody. That's just cause when you're starting out with PAE, one of the biggest challenges is the anatomy, and determining where the origin of the prostatic artery is. I'm not the smartest guy, I'll just put it that way. So, I wanted to give myself the best opportunity to figure out what was going on. That meant having images the night before, looking at them, studying them, figuring out what approaches I was going to use. I was pretty meticulous in doing that, in that I would create 3D rendered images, and I would figure out what angle with the eye I wanted to see the origin of the prostatic artery the best. I'd create kind of a map for myself.
Additional Advantages of Cone Beam CTA
As I started to grow in confidence, with more volume of PAEs, I tried to make the experience a little more convenient for the patients. Since most of them, at that time, were coming from out of town ... I have to say, I give credit to Sonny, this was Sonny's idea. I don't know if he remembers, but way back, he said, "Why don't you just do a Cone Beam CTA?", and I said, "Alright. Let's see what we can do with that.", so we came up with a Cone Beam CTA protocol. What that allowed us to do, is basically get the same CTA information, but do it on the table prior to the actual procedure. That prevented the need for the patient to come the day before, and get a CTA. It reduced some added expense.
That's kind of my practice these days. I'm just doing Cone Beam CTAs ahead of time, unless there's a patient I'm particularly concerned about. If I think they have bad atherosterotic disease for some reason, or if there's some other vascular issue that I'm concerned about, I will get a CTA. But, the majority of the patients, I'm doing Cone Beam CTA on the table prior to the procedure.
Do both modalities tend to give fairly equivalent anatomic information? Can you see shunts, for example, in both modalities?
It's funny you ask that, Mike. We have a paper coming out in January, shortly. Yes, thank you very much. We did a comparison between our conventional CTAs, and our Cone Beam CTAs. We looked at it two ways, objectively, and subjectively.
Objectively, we're looking at the degree of enhancement within the vessels. Subjectively, we had a couple reviewers look at if they could determine the prostatic arteries, and we had a grading scale for it.
The way it came out, was the objective measurements were better for Cone Beam CTA, believe it or not. But the subjective measurements, there was no significant difference, although, in my opinion, I think you do see the arteries better on the Cone Beam CTAs. What you lose on Cone Beam CTAs are some of the soft tissue information.
Cone Beam CTA vs. Digital Subtraction Angiography (DSA)
It's funny. In listening, back to Ari's conversation. Evolution, from going from the preoperative CT, to CTA, he told that story really well. I still to this day, find myself identifying certain shunts, depending on how hard I even inject the prostatic artery, with the microcatheter, and the syringe.
I find that there's so much variability in day to day PAE practice, that it's very hard scientifically to prove what we will see better with certain techniques, versus others. As you probably know, and I mentioned to Aaron not too long ago, just the other day, actually, was that I don't firmly believe Cone Beam is a significant value.
It takes a lot to say that, I'll be honest, because over the years, having sat on panels, where my colleagues have said, "You know, you should just tell everybody that it's great to use in the beginning. You have to use it." I'm a pretty traditional diagnostic angiography type of person, and maybe that's just being simple minded, of looking at, there are six, seven, eight arteries you need to be able to identify. When I feel really comfortable with a good digital subtraction angiography, I can not only identify the prostate, but also identify much of the flow dynamics and collaterals that I don't feel like I will get during a static image, per se, like a Cone Beam CTA or Cone Beam CT.
We published, a number of years ago, the Cobalt Cone Beam CT does improve your confidence level in identifying other collateral vessels. It also does lead to a significant number of false positives, so I think, taking in mind the good and bad with Cone Beam CT, overall, if I had to start over ... we did do this in the very beginning. We just did the procedure with good DSA, and we used the Cone Beam to confirm. But really, relied mostly on the subtraction and angiography.
Sonny, I'm interested to hear if you use Cone Beam in the same way as Ari. My vast experience of one day with Ari, what really blew me away, was how he was able to take the images obtained on Cone Beam CT, and create these immaculate rotating roadmaps, that allowed very easy identification, and the proper obliquity to catheterize the prostatic artery. That's where I wasted a lot of my time in the past. Are you doing the same thing?
No. For a number of reasons. One, is I think that while they do produce great images, I think that one of the things you get from a selective run, for example, the hypogastric artery, is that dynamic image. That dynamic image is very important for flow dynamics.
Oftentimes, I think if you get a roadmap, for example, which is not dynamic, and you try to go all the way from position A to position Z, sometimes the problem is you can overlook, or bypass, another vessel, which may have a different flow dynamic than the targeted vessel you've identified.
So, we don't do that. Although, I do appreciate the pretty images, and I do use many of Ari's images for my lectures, cause they're always good show stoppers. We don't tend to do that. We tend to just focus on subtraction.
Dr. Sandeep Bagla is a practicing interventional radiologist with the Vascular Institute of Virginia.
Dr. Ari Isaacson is a practicing interventional radiologist with the UNC Department of Radiology in North Carolina.
Dr. Michael Barraza is a practicing interventional radiologist with Radiology Alliance in Nashville.
Cite this podcast:
BackTable, LLC (Producer). (2017, November 27). Ep 17 – Prostate Artery Embolizations [Audio podcast]. Retrieved from https://www.backtable.com/podcasts
The Materials available on the BackTable Blog are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients.