Showing posts with label IR. Show all posts
Showing posts with label IR. Show all posts

Thursday, January 31, 2013

[i]nterventional [r]adiology

The alarm went off (not yet quite) bright and early this morning at 6:45 A.M., not even five hours after I had set it when crawling into bed the night before. What kind of crazy insanity would inspire me to get up after so little sleep? Shadowing a physician in interventional radiology (IR). The lack of sleep was no biggie, though. He only had one case on for today, right? I could go and come back with plenty of time to take a nap later on in the day. Well, not exactly. No one mentioned the “one case” was estimated to take 3-5 hours to complete. And then he had an additional case he was going to try to perform after that one.

I walked into angio five minutes before needing to be there, dressed in “business casual” and ready for a quick morning. After meeting with the area manager, she took me to change into scrubs. Not having been told to dress for standing all day (although I had asked), I didn’t have on tennis shoes. Oh, well. She introduced me to Dr. Cooney, and he briefly went over the case he was about to work – a scheduled basilar stent placement and aneurysm coiling. Don’t know what those are? That’s ok. I’m about to give you a brief overview so you can understand what I experienced today. (And by brief I mean a simplistic overview, even though this post appears forever long. Stick with it if you’re curious, though. You won’t be disappointed. Plus, there are pictures to keep your attention. J)

First, let me give you a snapshot of what interventional radiology shadowing involved:

·         Types of procedures typically performed: stents, vertebral biopsies, dialysis catheters, and more.
·         Had to don scrubs, hair net, mask, plastic glasses, shoe covers, and lead apron while in the procedure room.

In the IR attire - scrubs, mask, hair net, glasses, lead apron and shoe covers.
And scrub jacket because it was freezing.

·         By the way, lead aprons weigh a ton; you need to work out just to wear those things! The radiology student in the room advised me I’d be sore tomorrow. I guess I’ll find out soon. However, the lead was so heavy it helped with the next bullet point. Keep reading…
·         Freezing cold, nearly literally. Apparently, the cold temperatures help with keeping germs at bay – think operating room cold. Also, their equipment functions better at cooler temperatures.
·         Sterile field. The doc and his radiology co-worker were suited up in sterile attire (gowns, gloves) working with a sterile field. They even had the monitors covered with sterile plastic so they could navigate the screens.  

[Google image showing IR room, sterile field, and monitors similar to the set-up I saw today]1


·         Persons involved: there are usually 4-5 people on the scene. The doc, the radiology technologist, the “hander” (who grabs any equipment necessary so they don’t have to re-sterilize everything), anesthesia, and the patient.

So, what did I see today? Well, I mentioned the whole stent and coiling deal previously. First, let’s talk about aneurysms so you can follow the procedures.

·         Definition: “An aneurysm is a balloon-like bulge or weakening of an artery wall. As an aneurysm enlarges it becomes thinner and weaker. It also puts pressure on surrounding structures, causing headache or vision problems, and may eventually rupture. A ruptured aneurysm releases blood into the spaces around the brain, called a subarachnoid hemorrhage (SAH) – a life-threatening type of stroke."2
·         Causes: people can be born with them (congenital); some are hereditary; development influenced and  aggravated by methamphetamine and IV drug usage and/or elevated blood pressure;  some proponents suggest smoking contributes to development as well (questionable).
·         If under 4 mm, physicians typically do nothing unless aneurysm is ruptured. Aneurysms of these dimensions are considered small.
·         If over 10 mm (1cm), then aneurysm is considered “giant” in radiology terminology and radiologist must take action - usually placing a stent, although there are other options.

[insert diagram for visual learners like me]2

 This figure illustrates several types of aneurysms:

Anatomy of an aneurysm (top). Different types of aneurysms (bottom).

[back to text]

Now that you have an idea of what aneurysms are and what they look like, let’s move on to the procedure Dr. Cooney performed today.

·         The patient was a 50-ish year old female. Time of aneurysm onset was 1 year ago. Stent placed at that time. During a follow-up appointment, aneurysm displayed significant growth, causing further bulging of blood vessel.
·         Procedure objective: place 2nd stent in left artery and add additional coils to ballooning original aneurysm. Part one’s success was questionable. Part two was a guaranteed occurrence.
·         Patient was prepared:  IV placed for anesthesia, groin shaved and scrubbed.
·         The catheter(s), guide wires(s), and stent first entered the femoral artery in left groin, flowed through the left vertebral artery, and then were guided (taking a backward loop approach) into the right vertebral artery at the basilar junction.

[insert helpful information here] 2

·         Blood supply of the brain: Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries.


 [back to the story]

·         One of the guide wires had a radio opaque tip, so it was more noticeable on the monitor. Contrast was also used periodically to visualize blood flow through the arteries of the brain.
·         The technologist would occasionally take x-ray shots of the contrast (fluoroscopy) images so that they could overlay that screen shot over what was presently taking place (shown via regular x-ray imaging).
·         It took over 2.5 hours to complete part one. After trying multiple times to guide the wire where it needed to be, the doc finally got it. He, himself, admitted it was a “miracle” exclaiming “Thank God” when he finally succeeded. Just goes to show that success is not dependent on skill alone but on God’s grace and intervention.
·         There were eight monitors stacked in sets of two connected in a big rectangle to each other. It was moveable, and it was what everyone relied on to view the images. Throughout this procedure, they only used 4-6 of the 8 monitors at a time.
·         After stent placement, they performed a CT to make sure there was no hemorrhaging caused by the guide wire poking around trying to follow the flow in the vessels. On a CT involving a hemorrhage, the blood shows up as white. There was no hemorrhage in this patient’s case.
·         With the brain hemorrhage free, the doc proceeded with part two: filling the original aneurysm with more coil to protect it from further ballooning.
·         This process involved threading catheter wires into the aneurysm, gradually decreasing in diameter size. As the wires were threaded, they coiled into themselves, filling the space from the top of the aneurysm down toward the first stent.

[insert webpage information and diagram for clarity] 2, 3

·         Endovascular coiling: In contrast to surgery, another form of treatment is endovascular coiling.In a coiling procedure, a catheter is inserted into an artery in the groin and then passed through the blood vessels to the aneurysm. The doctor guides the catheter through the bloodstream while watching a fluoroscopy (a type of x-ray) monitor. Through the catheter, the aneurysm is packed with material, either platinum coils or balloons, that prevents blood flow into the aneurysm (Fig. 6).

The aneurysm is packed with platinum coils by way of a small catheter.
The arrow indicates bloodflow through the artery, but not the aneurysm.

Aneurysm Coil Embolization

[back to procedure one]

·         Catheter tidbits:
o   Metal wires have “memory” and will retain shape: circular, square, etc.
o   Begin with catheter size just smaller than the size of the aneurysm. For example, if aneurysm is 10mm, then use a 9 mm catheter to begin. Gradually decrease catheter size. Dr. Cooney compared the process to the opposite of Russian stacking dolls, starting with largest to smallest size.
·         In total, they used 14+ catheters to fill the aneurysm.
·         Patient was taken to PACU (recovery room part of surgery) after procedure, and would then be transferred to a bed in the hospital to be monitored.

Other Angio Tidbits
·         There are three layers of blood vessels: tunica intima (inner), tunica media (middle), tunica adventitia (exterior).
·         Stents bend like bananas – possible to thread a second stent through first to create a “y”-shaped double stent placement formation.  If stunts placed side by side, stent placement called a double barrel formation.

The procedure was scheduled to begin at 8:00 A.M. We started at 9:25 A.M. and ended around 1:30 P.M. After the first procedure, we took a quick break and grabbed lunch. When we returned from the doctor’s lounge, the second patient was being readied. He was an elderly male. His procedure: a biopsy and cementing of fractures of the T11 vertebra (lower back). Fortunately, in comparison to the first procedure, this one only lasted about 35 minutes.

·         The patient was placed stomach-down, sedated, and anesthetized locally. Sterile technique was used in this procedure as well.

[insert another Google image illustration]4

Patient positioning for vertebroplasty. Padding flattens the spinal curvature while maximizing patient comfort.

 [back to text]

·         I didn’t catch the terminology as well on this procedure since it was so short. In addition, it was at the end of Dr. Cooney’s work day and everyone was tired by this point.
·         The doc identified the vertebra of interest, hammered a hollow metal tube into the body of the vertebra, and used a biopsy needle to aspirate a sample, which was placed in a dry specimen cup.

[insert additional Google image illustrations]4, 5

PMSB : Ostycut needle, penetration performed with surgical hammer

Disassembled components of a standard needle/trocar unit used in vertebroplasty. 14-gauge biopsy needle set

The x-rays of the procedure looked like this:

(B) Posteroanterior and (C) lateral fluoroscopic images during vertebroplasty.

[back to procedure]

·         Then he repeated this procedure on the other side of the vertebra body, so that in the end, there were two metal tubes symmetrically sticking out of the man’s back. A 2nd sample was obtained and placed in a fluid-filled specimen cup. 
·         Cement was squeezed into the hollow tubes using the aspiration needle and a syringe.
·         Then the tubes were removed and the procedure was officially finished. 

[another view thanks to Google images]6

Puncture surgical hammer.

Puncture.

Vertebral body biopsy.


This was my second shift shadowing in radiology. The first time was in musculoskeletal (MSK), and interventional radiology was different in many ways. For one, there was quite a bit of hands-on work as well as interaction with patients. In contrast to just looking at images and dictating findings, IR had a tactile component or placing or removing something in the body using radiology images to aid the procedure. I'm headed back to angiography tomorrow to view neuro radiology. But that's all for now...

1. http://www.bendbulletin.com/article/20110817/NEWS0107/108170408/
2. http://www.mayfieldclinic.com/PE-AneurUn.htm
3. https://neurosciences.beaumont.edu/aneurysm-coil-embolization
4. http://www.sciencedirect.com/science/article/pii/S0033838908000663
5. http://www.openradiology.org/zosirws/survey/biopsies/bonepen
6. http://www.openradiology.org/zosirws/survey/vertebroplasty/technique/puncture