So needle guidance is one of the main tools that we use. This is basically a straight line overlay.
Distinct starting and ending points. We draw this again on cross sectional imaging. Automatically, you can align the C-arm to the, to kind of align with the path that you've drawn, in either a bullseye line of sight orientation, or also a kind of tangential view.
And really you can use this for anything that has straight line geometry. Bone trocars, cement cannulae, ablation probes, screws, temperature probes, hydrodissection needles, anything that more or less is straight line geometry. Just a couple examples of this.
On the right side you can see an example of bullseye needle guidance orientation, and then a more tangential view from the side of the same pathway, so that you can have real time kind of overlay guidance of needle placement as you rotate the II, with a detector,
back and forth real time. And one of the benefits of this is to be able to achieve placements within narrow corridors. Example on the left is placing a screw through a scapular body, which
you know, is pretty thin with a narrow corridor, but this really facilitates placement in this circumstance.
Point overlay is pretty simple. Again drawn on cross sectional imaging. These are just specific points. Can mark bone cortex.
You can mark kind of ablation probe stations if you're doing multiple overlapping ablation zones. Again this can be very helpful when, perhaps in a tumor case where there's been some bone destruction, you don't have good bony fluoroscopic landmarks that you might have in a normal patient.
Polyline overlay is kind of a similar technique. It's basically drawing a curvilinear line, again on a cross sectional imaging. And this is for more curvilinear structures such as perhaps marking nerves or neuroforamina. Estimating ablation zones,
marking out portal veins or other targets that you might use for even non MSK procedures. These are just a couple examples of this. You can kind of see a schematic representation on the left of what an ablations zone might look like. Also, some examples on the right of marking out a
sciatic nerve particularly, and then down on the right side, it's a little bit hard to see, but some green kind of cross hair point marks, just in terms of where you're gonna pull back your ablation probe along the path.
There just kinda different ways that you can utilize these, you know, these tools. These are examples again of the kind of curvilinear marking of neuroforamina. Whether it's ablation or cementation or such. That these are maybe structures
that you wanna know where they are under fluoro and stay away from.
Segmentation or volumetric overlay is basically overlaying either a shaded volume or a contour of a volume. The edges of the overlay volume can kind of be tangential to whichever orientation of the detector,
as it changes in real time. Again, drawn on the cross sectional CT data, using kind of segmentation type software. The use of this is really to mark a volume, or kind of a curvilinear surface. So you can either use this as to mark target volumes
that you're intending to ablate or cavities that you're intending to fill with cement. But you can also mark areas that you want to stay away from. Particularly in say the joint space, or the acetabulum or such. So this is an example, kind of on the left,
of you know, two different areas, volumetric areas kind of segmented out on the cross sectional data and how this looks on the three dimensional volumetric model on the right. So the yellow would be kinda this area of tumor, and destruction in the bone that we're intending to fill,
and the red being the actual joint space itself, that we wanna stay out of.
And you kinda see in, in real time, in fluoro, this is at the same point and time, but from different projections
that these different contours actually project differently based on how the detector is rotated, so that you can kind of have, in a real time feedback as to where the edges of your intended ablation or cement fill are.
And sometimes again, and this can be very hard to tell, using just fluoroscopy in a pelvis or a bone that's had extensive destruction. Where you don't have good cortico kind of markers under fluoroscopy. Registration is really a key to all this,
and a big part of where the technologist come into play. This is really the process of aligning one data set with another. There's different ways you can do this. Two dimensional, three dimensional,
or three dimensional, three dimensional registration. What this allows you to do is potentially draw those objects of overlays on a separate 3D data set, so maybe a pre-procedural imaging study that has contrast, where you can actually see your targets a little bit clearer.
And then be able to fuse or register this with you know, real time, time of procedure, cone-beam CT. So that you can kind of then stack and fuse those objects that you've drawn on a more detailed study before.
But it's really key to pay attention during
you know, your procedure. Patient movement during the procedure leads to misregistration of the overlay objects. And inaccurate needle placement. And so you really have to kind of periodically verify this registration and alignment.
This an example just from a case where you can see that the overlay is off from the actual fluoroscopic image. Which means that all of the objects that are tied to that overlay are also gonna be off.
And so while the needle guidance and the advanced imaging can be helpful, you do have to kind of pay attention as a proceduralist to what you're doing, and whether it makes sense fluoroscopically. So you can see here that this
bullseye orientation needle guidance placement is really not exactly where it needs to be. It really should be shifted over a little bit more, into this AP corridor. So registration becomes kind of a iterative process during cases.
And it's a big case where, or a big example where the technologist can add a lot of value and help out a lot. So just a case example that kind of ties together. This was a 53 year old male. He's doing pretty good, except he kinda had
some progressive right hip pain for a few months, but was still walking and able to kind of do most things. Was diagnosed with myeloma. And this was his CT scan, kind of a coronal projection. You can see this large lytic destructive lesion
over his right acetabulum. With extensive kind of bony dehiscence and thinning of the cortex throughout. And so this was the plan to stabilize this. And help his pain from kind of a combined augmented screw, cement and screw approach.
These were the needle paths, and the screw paths that we used on pre-procedural imaging. You can kind of see representations of these here. So again it gives you a good idea of where these screws are gonna go, and in the case of the bottom right image
through a narrow corridor, this really allows us to achieve that. Using this live kind of overlay needle guidance. Several of these screws were placed. Again, up on the I guess top left, you can see this narrow ramus corridor,
that this kind of allows us to find. So again, just kind of more examples of how this case progressed. Registration is a key part again. This was the segmentation that I showed you earlier. And then kind of used this in real time
as we filled this entire area with cement. Again, given the bony destruction, at least the kind of posterior aspect of it was extremely difficult to see. Just under fluoroscopy, and I think without this nice contouring of our target lesion,
in cases that we've had, you know, previously, we would have stopped a lot earlier, thinking that we'd filled it. Whereas here we have kind of that confidence that there's a little bit more to go, a little bit more to fill.
So you can kinda see it, as this goes on, we are able to fill most of the target volume. And this was kind of the completion, you can kinda see that these are screws, and then the cement area here, kind of reforming almost the acetabulum roof.
So he did well, so this was all done percutaneously. He basically had three Band-aids from his three different screw entry sites. And was weight bearing within two hours. Afterwards, he underwent radiation therapy. He was on systemic therapy.
He's starting a Zometa for his kind of overall bone health, and he really doesn't have any specific right hip pain. And the biggest thing for him was that he was able to kind of move on to his systemic therapy and radiation therapy almost immediately afterwards. So a really good outcome, and one that I think that
without a lot of these advanced imaging techniques, we either wouldn't have been able to accomplish or probably would not have been able to provide as much structural reinforcement as we were.
So in conclusion, recent fluoroscopic software advances enable these various forms of,
ends up kind of being augmented fluoroscopy. The points, lines, volumes, really you can apply these in a lot of different creative ways. Dataset registration, verification is critical. Advanced imaging ends up being trusting the computer. And so a knowledgeable technologist is really invaluable
in terms of making sure that things are done correctly from the workstation standpoint and the registration as a case kind of goes along. So, thanks for your attention.
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