SLIDES & TRANSCRIPTS
Tuesday, June 19

Imaging Section--Fine Needle Aspiration

David Yankelevitz, MD

Traditionally, much of the work that has been done with biopsy has been done on lesions that are in this size range, 2 centimeter lesions. Most of our experience talks about this kind of abnormality, and how we go about performing biopsy on this.
However, we are really in a new domain now. This new domain is small size, and this other category of abnormalities, which has been referred to as ground glass opacity, I think the term that we are starting to prefer using now is non-solid nodules or part solid nodules as opposed to sort of solid nodules. The terminology is certainly developing.

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When I talk about small nodules, I don't really know what a small nodule is. If you listen to people in this room, it's quite interesting what the word "small" means.

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Slide 4: Small Solid Nodule

I think this probably is a small nodule. But I don't really know how to define it. Some of the biopsy literature talks about 1.5 centimeters being small, some talks about under a centimeter. In my mind it's somewhere around five or six millimeters where I start to think of a small nodule.

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This is certainly what I would call a non-solid nodule, the so-called ground glass opacity, no solid elements, just vessels that you can see through it.

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And this is part solid nodule, where there are some ground glass components in the periphery, but centrally you can see the very solid element.

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Now I put this slide up to show this is what pathologists are looking at when they get material. And we have heard a lot about imaging techniques, and how much we can get. But when you look at what the pathologists are seeing, they are looking at individual cells. And no matter how good these imaging techniques are, and where they might be heading, when you think about the pathologists are seeing compared to what the radiologists are seeing, you are talking about orders of a 1 million to 1.

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So for example, if this represents the highest resolution you can possibly see on a single element in a CT scanner, this is what a cell might look like. So this is what the pathologists are looking at, and this is what radiologists are looking at, and trying to sort of make predictions or diagnoses. So it's really just a tremendous order of magnitude of information difference as to what you can get from the pathologic information.

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Now this is a nodule that was seen on a screening CT. I show this case, because it demonstrates some of the image processing techniques, as well as what you can do with biopsy. This is a small nodule seen on a screening CT.

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Here is it, that nodule on a high resolution image. We waited some period of time, because we weren't sure what to do with this.

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Here we see it again, and it looks a little bigger.

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Here we get some 3-D techniques, and you can see it looks like it has grown from time one to time two.

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And in fact, when you look at it in a different plane, you can see that this is a funny shaped nodule. This is not that sort of round nodule that you get from the two dimensional image. It's got a three dimensional shape to it. In fact, you might even start to guess, maybe this is something a little unusual.

Well, we biopsy that nodule here. This is in a prone position, so the nodule is on the other side, and we biopsy it. It turns out that in fact this was a very unusual nodule.

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We got all this lymphoid tissue. In fact this was within a lymph node, this material. So you can see what kind of information you can get.

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These are some of the ways we can get tissue: bronchoscopy, FNA, VATS, thoracotomy, and I'm sure some others will speak about the benefits of these other procedures. I will focus on transthoracic needle biopsy.

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There are basically two types of needles that we use, aspiration needles, which come in these various sizes, as large as about 16 gauge, down to 25 gauge, and cutting needles. And these are various types of the cutting needles. There are these side slotted cutting needles, and these spring loaded guns, which really take out a chunk of tissue, and you can go down to 14 gauge with them. They come in single needles or coaxial techniques. I prefer to use the smaller needles, about 22 gauge.

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At our institution, these are the personnel. We do all our biopsies under CT guidance. I have a CT tech, a dedicated biopsy nurse, an on-site cytologist. And I cannot stress enough how important it is to do these procedures, to have the on-site cytologist to give you the information right away.
I do about 8-10 per day, two days a week, 45 minutes per case. The next patient is on the table, and recovery is usually about two hours.

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The first question is what are we really trying to learn with biopsies. This is not such an easy question. Certainly, we are trying to make a diagnosis. When you think of that, how much tissue do you need? And then how do you get it?

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What about a case like this, where you have this ground glass opacity?

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There is a big mass. I get this cytology. As far as diagnosis goes, this is pretty straightforward.

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Do I even need the histology? Does this add a whole lot in terms of making a diagnosis of adenocarcinoma? I don't think so.

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You do a biopsy of it, and you get cells like this on cytology. Well, this is a little tougher. You show this to a couple of cytologists, you are going to get a lot of struggling. Is this hyperplasia? Is this early BAC? The cells are kind of uniform. It's much more difficult to make a diagnosis here.

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Do you need histology? Well, that's a problem too. You show this kind of slide to a pathologist, there is going to be some struggling. I've seen some pathologists really struggle with some of these cases as to what this kind of lesion is. And I suspect that at least in cases like this, there is going to be a very, very important role for biomarkers in terms of distinguishing what these lesions are, and what the idea of their progression is going to be.

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And here is another case of a 5 millimeter nodule, and I show you that sometimes you can put the needle in, and it's like a heat seeking missile, it goes straight for it, and you can get a diagnosis. But sometimes this is really not the case.

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Here is a needle in it.

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And I show this diagram just to sort of demonstrate just how difficult it is to really biopsy something like a 5 millimeter nodule. Let's say this is the skin surface of the patient. Here is a 5 millimeter nodule. Let's say it's about 10 centimeters to it. If I start to put this needle in, and I'm off by one single degree in my angulation of that needle when I start, and I advance, I'll miss. I will be deviated by over 2 millimeters or 3 millimeters.
So that it tells you that it's virtually impossible to line the needle up accurately enough to make the needle go to it. So you've got to be able to do something. There have got to be ways of adjusting that needle. And to me that's the critical area that needs development. How do you guide these needles? How do you make them move?

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Well, at least the technique that I have been using, and this takes a fair amount of experience, but I'll show you the basic idea. This is a typical biopsy needle with a beveled edge. I tried to push this needle through this apple. This is a radiograph of it. It doesn't go in a straight line. It bends away from the bevel. The bevel acts almost as a force that the tissue pushes down, and it doesn't travel in a straight line. It bends. Now this is an apple, and it's certainly firmer than lung.

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Well, what about lung? Well, we took a cadaver lung, and we inflated it with air, and we tried to push this needle through. And you can see this is where the needle should go if we followed this straight line. You can see again even in the lung, it deviates away, because of the bevel. So the needle moves.

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Now you can use that to your advantage. Here is a nodule. Here is my needle going in, and you can see I miss. What we do is we pull the needle back. We turn the bevel away from the needle. I torque on the needle, and then I reinsert, and I can push it, and make the needle move. That's the way you can compensate, because as I say, you can't get to the nodule accurately by just aiming precisely. It's impossible. You can't get that accurate, so you have to be able to make adjustments.

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And here is an example of a case, and I'll show several of these cases. These are all cases I'm going to show now that were done within the last month. Here is a case I thought I was right on target. I advanced the needle. I was off a little bit. Now I say I've got to adjust it. Now I don't know how much I can adjust it.

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So I pull back a little bit. I reinsert, and I'm off on the other side. But you can get an idea of how much I'm able to move that needle already. I moved it over a centimeter, a centimeter and a half.

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Then I said, okay, I don't need to make that much of an adjustment. I adjusted a little bit less going the other direction, and I'm back in.

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Another case. This is more subtle now. Here I am just at the side of the lesion, and now I make a minor adjustment, and I'm in.

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Another case, as I'm advancing, you can see I'm just to the side of the small nodule. And you can move it over.

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Now some cases are a little bit more difficult. Here is a small nodule, a 6 millimeter nodule you can see here.

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I take the next image, I see that I'm just underneath the nodule.

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I readjust. I angle it upwards. I'm on the medial side of it.

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I adjust again, and I'm on the lateral side of it. This nodule was also pretty hard.

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Then I adjust one more time, and you can just see that the tip is getting right in there. This turned out to be a small hamartoma, which was detected on CT. So you've got to be able to go through this. You've got to be able to make these multiple adjustments. I just say from this slide that there is really no place in the lung you can't biopsy. I don't think there is any spot in the lung that is not reachable by percutaneous procedure -- apices near the heart, the high lung, in the posterior sulcus. It's amazing how accurate people can hold their breath when they are given a little bit of coaching, and how they can move their diaphragm back to this same spot.

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In addition, CT fluoroscopy I think is a wonderful technique for being able particularly to do these kind of posterior sulcus lesions.

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And the same thing goes with these ground glass opacities. You can biopsy them as well. There is no trick.

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This shows you one of the advantages for the image processing techniques. This is the same nodule, and you can see it's sort of a ground glass looking thing, or a non-solid nodule.

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And here with the image processing I see that there is a solid element, and I can separate them. And here is the non-solid portion. Here is the solid portion. And when you do these biopsies, it's very important that you aim for the solid component, because that tends to be where the aggressive tumor is, if it's going to be there. So you really want to aim for this portion of it, and in fact it's fairly easy to do that.

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And you can biopsy just the solid component right in the center. This turned out to be an adenocarcinoma.

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Here is another example of a non-solid nodule. This is small, and this is one of the things that you have to be aware of when you do these procedures.

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Right as I started this procedure, you can see I'm starting to develop a small pneumothorax.

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Slide 51: Increasing Pneumothorax

Then it becomes a large pneumothorax. Now I'm the middle of a procedure, and I'm in trouble. You really have to be able to be aggressive with these cases. You've got to be able to treat the pneumothorax while the patient is still on the table, and continue.

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That's what we do here. I put a small tube in. I put it in from the back, a one piece tube, a thoracic vent, and then I continue the procedure, and I put the needle in. So you can do these procedures. You've got to be willing to be persistent, and move the needle around.
And as I say, in my mind the important thing is being able to steer that needle. I would say in my practice somewhere around overall, 20 or 30% of my nodules are under a centimeter. And the screening population of screen detected cases, it's a much higher percentage.

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So in conclusion, I would just say that needle maneuverability is critical for success of this procedure. And I think this is where industry has to really help us with developing needles that are going to be steerable. As I say, moving that needle around is not so easy. It takes a lot of practice to get that needle to move, and to get these small nodules. I think that needles can be built that are going to be much better for this.
The amount of tissue that's going to be necessary, I don't know. I think there are people in this room that are much more qualified to answer that, but I think that's a critical question in terms of how much tissue we want to get, in terms of both making a diagnosis, as well as deciding what treatment is necessary.
Thank you.

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