Medical Minute 8-17: iMRI Gives Surgeons the Edge

By: Vanessa Welch Email
By: Vanessa Welch Email

A machine may be the key to recovery for some brain tumor patients like 43-year-old April Gillies. In March, doctors removed a tumor from her brain for the third time.

"It's hard to keep your faith, and not wonder why you have to keep going through it," said April Gillies, Brain Tumor Patient.

The tumor was cancerous and growing near an area that controlled fine motor skills. But this time, doctors at Henry Ford Hospital in Detroit have a new tool by their sides -- an intraoperative magnetic resonance imaging machine -- or IMRI.

"We've had surgery and MRI for decades. Now, we're putting them together," said Steven N. Kalkanis, M.D., Co-Director, Hermelin Brain Tumor Center at Henry Ford Hospital in Detroit, MI.

The imaging system is in a special suite connected to the operating room. Patients can be wheeled into the scanner -- giving surgeons a real-time snapshot of the brain. Traditionally, surgeons rely on images taken hours before.

With this surgical set-up, doctors also use the IMRI right after the operation. In April's case, the scanner picked up a tiny area of suspicious cells that were hidden during surgery. Doctor Kalkanis went back in and removed them, increasing her chances of kicking the cancer for good. News that made a huge difference to April, her husband, and their 12-year old son.

That was the one question he asked me at the hospital. 'Did they get it all?' And we were able to tell him yes."

For more information on other series produced by Ivanhoe Broadcast News contact John Cherry at (407) 691-1500, jcherry@ivanhoe.com.

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MEDICAL BREAKTHROUGHS - RESEARCH SUMMARY:

BACKGROUND: The intraoperative Magnetic Resonance Imaging (iMRI) equipment includes a stereotactic targeting device with optimal precision and stability, which allows surgeons to target the exact area of the brain on which they will operate. Once set, the iMRI device projects clear images of the brain to a monitor in the operating room from which the surgeon works. The images function as a map of the brain, and because the map is so precise, the surgeon's work is as accurate as it can possibly be. (SOURCE: http://www.uwhealth.org/neurosurgery/)

THE MACHINE: The system actually is an MRI machine with a 58-cm vertical gap in the center. It is stationary in a lead-shielded OR. The intraoperative MRI allows surgeons to visualize tumors directly, including those that historically have been labeled as inoperable. It permits smaller incisions and smaller bone flap removals because of its location system. This leads to less invasive neurosurgical procedures. Less invasive surgery can be expected to equate to shorter patient recovery time. (SOURCE: www.nortonmri.com)

TUMORS: A recent advancement in treating tumors of the liver is the use of iMRI. Liver tumors often occur next to critical areas of the body, such as the diaphragm, colon, stomach, and gallbladder. Precise, real-time imaging capabilities allow the tumors to be destroyed while the surgeons observe -- literally. The removal of liver tumors had to be done traditionally in open surgery. With the iMRI, the ablation process is carried out using a very thin, minimally-invasive needle instrument. iMRI is especially advantageous in treating recurring liver tumors, including those in patients who have had prior operations. The iMRI can significantly prolong survival. (SOURCE: www.aboutlivertumors.com)

Brain tumor tissue is often difficult to distinguish from normal brain tissue. In iMRI-guided neurosurgery, physicians use real-time imaging from the scanner to distinguish between healthy brain tissue and diseased tissue (the tumor) without compromising the patient's safety and care. Intraoperative MRI is used for the removal of low-grade gliomas -- tumors that typically blend into normal brain tissue. It is also used for pituitary tumor removal surgery, which is performed through a small tube with limited visibility. (SOURCE: www.mayoclinic.com)

FOR MORE INFORMATION, PLEASE CONTACT:
Dwight Angell, Media Relations
Henry Ford Hospital

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Steven N. Kalkanis, MD, Co-Director, Hermelin Brain Tumor Center at Henry Ford Hospital in Detroit talks about a new imaging technique that can be used in the operating room.

Please explain the procedure, it’s probably something our viewers are not familiar with.
Steven Kalkanis: In my opinion the intraoperative MRI has really revolutionized the way we take out brain tumors and it allows us in real time to visualize any remnants of the tumor that may be left behind and to take them out fully so we can prevent the cancer cells from growing and from recurring. And so for the patient that means that they are in a special intraoperative MRI surgical suite that is essentially an operating room that’s connected through very special doors that open and close during periods of the case where we can wheel the patient seamlessly back and forth to an MR scanner that’s dedicated to the operating suite. And so the surgery goes on as planned and the surgeon will typically remove as much of the tumor as possible and I’ll give you an example from even just a few days ago. We had quite a large tumor that was invading deep in to the area that controlled the speech center of the brain. I thought that I had removed essentially everything, at least everything that I could see but at a certain point in the case when it’s time to check that patient then gets wheeled in to the intraoperative MRI scanner and we can do a real time image. And what I mean by real time is that this is actually a snapshot of what is happening in surgery. Typically the tools that we use for navigation are based on yesterdays scan or images that were done before we even had the surgical site open so it doesn’t account for things like brain shift or swelling or partial removal of the tumor and so forth. So in that example of a case where this very large tumor was taken out in fact there was a very tiny remnant that was left behind and these ruminants are invisible to the naked eye. You can’t even see them under a microscope but the MRI was able to pick it up. So this little remnant was then targeted our navigational tools beamed this imaging apparatus back in to the operating room, I have a wand that’s a wireless wand that we actually sterilely stick inside the brain and find where that remnant is based on that intraoperative MRI imaging that was just done and we can remove it. And once we were able to do that we could actually say that we got one hundred percent of the tumor out and that makes a huge difference for patients. Literally the difference between perhaps doubling, tripling their life expectancy even from having the presence of a few cancer cells left. So I really think it’s a major advance for this dreaded disease.
Without this technology what would have happened? There would have been a couple of cells and you felt confident you got it all?
Steven Kalkanis: Typically and for all the years that this surgery has been going on before this technology surgeons remove as much as they feel they can safely and often times there are little remnants that are left over that simply can’t be seen and they’re treated with radiation and chemotherapy. And patients do reasonably well but we know, and we know from extensive data that’s been published that the more tumor that you’re able to remove the better patients do. If you have a low grade tumor such as a low grade glioma you can actually get essentially a surgical cure if you’re able to remove it where survival is in the twenty, twenty five year range. But if you leave a chunk of it behind because it simply doesn’t enhance and you can’t see it on any other modality when you’re in the operating room it’s very hard to achieve that resection. With this intraoperative MRI it’s standard now to take the whole thing out. And on the other side of the spectrum if you have a very highly malignant tumor and you leave even just a few cells behind those are the seeds for recurrence for cancer for those patients. And no matter clinical trials, chemotherapy, radiation we know that all of those things work best when they are no actually tumor remnants left behind. And so for those patients their life expectancy is significantly increased.
Tell me how this helps you preserve some of the critical areas?
Steven Kalkanis: That’s actually one of the most exciting parts to this whole endeavor because the intraoperative MRI allows us to plan a trajectory that’s safest for the patient so that we can identify for instance where the motor strip is or where the language or the speech center is located in relationship to their tumor. So as we’re removing the tumor and we’re worried that a particular remnant is sitting right next to or in a critical area once we get that scan and the intraoperative MRI we can fuse all of our other imaging modalities that we’ve done previously. Such as a functional test that we previously may have done to find out where the speech center is lighting up or where the motor strip is so that we know if we can come from in front or behind or from the side to avoid those critical areas. So we’re able to plan the trajectory better and that allows for a much safer resection.
Describe again how this is different than the standard brain surgeries would have been done even six months ago.
Steven Kalkanis: Without the intraoperative MRI a patient would come in to the operating room and the surgery would go on basically to the extent to where the surgeon felt that all the tumor was removed. But that definition would be based on imaging studies that were done let’s say the day before, before the skull was even opened, before accounting for any fluid shifts or swelling or for changes in the way the brain moved in relation to the surgery that had just been going on. So it would be very difficult to locate with that old technology where these remnants are. And in addition often times these remnants are so small and so hidden that it really can’t be seen even under a microscope or with our surgical loops and it often looks very much like normal brain. So you need these special sequences that the intraoperative MRI has to allow these abnormal cells to light up. And so we’re able to do this now and target these potential seeds of tumor recurrence.
It seems like common sense to have these images that are the freshest, why has it taken so long to get to this point?
Steven Kalkanis: Well technology that’s deliverable and reproducible and that can be made in a situation where it’s kept sterile in an operating room setting doesn’t happen overnight. And we are blessed I think in this country to have state of the art technology, we’re leaders of the world in that regard but the classic MRI technology that’s used to help diagnose and treat these tumors is really meant as a standalone diagnostic unit, it really wasn’t built or interpreted in its infancy to be used in the operating room setting. And so you can imagine that while you’re operating you have to have special tools that aren’t magnetized so that they wouldn’t fly in to the scanner. You have people that are trained specifically to count every last, you can’t imagine, the instruments and even the smallest threads that potentially might be magnetized. Even the surgical sponges that have slight implants in them so that they show up on x-ray can’t be used in this sort of thing. So it really requires an entire revamping of the way that we think about doing this surgery. To answer your question specifically about why has it taken this there’s a huge expense involved. You know Henry Ford and the Hermelin Brain Tumor Center spent multiple millions of dollars not only for the equipment but the entire OR had to be reconstructed. The walls needed to be reinforced, we had to take the roof off of a section of the hospital and drop it in with a crane and build it with reinforced steel because of the power of the magnet and everything it entailed. So it’s not a small endeavor but we think in the end it really is the right thing to do for patients.
What is the challenge of having this technology? Is that the biggest challenges?
Steven Kalkanis: Well I think the challenge and the promise is really utilizing it to its full potential. I think that this will spark hopefully several studies that we’ll be able to run showing and proving really that extent of resection based on intraoperative MRI technology makes a difference for patients. It will help inform what sorts of radiation therapy or chemotherapy or clinical trials that are done. And I think the real challenge is having it made more available not just that a few select centers around the country and around the world like we have now but deploying this technology so that more people have access to it. But quite frankly I think that if I had a brain tumor or if I had a loved one with a brain tumor I would want them to be at a place that had this sort of technology.
Go through the differences technically, is there a scan first that everything is based on?
Steven Kalkanis: There are several points throughout the case where the intraoperative MRI is used. The patient is brought in to the operating room they get put under general anesthetic and they’re put in a special head frame that fixes the head in place but it’s an MRI compatible head frame. The patient is then wheeled directly in to the MRI suite for what we call registration images. These are the images that we plan our navigation and our trajectory for the initial section of the surgery. We then proceed with the surgery we remove as much of it as we feel that we can safely do and then we check our work essentially. The MRI door is opened the patient is wheeled from the operating table to the MRI table which is really just a few feet away but it’s all done very sterilely and with a very specific checklist to make sure that there’s no metal objects or tools or surgical instruments that are anywhere near the patient at that point. And then that intraoperative MRI imaging tells us either did we get a hundred percent of the tumor out or is there a tiny part remaining and if so where is that tiny remnant and thirdly where is that remnant in relation to critical structures. So we can superimpose images from functional MRI testing and from other modalities that can tell us about where the language center is lighting up for instance or where the motor center is. So that when we go back to the operating room a second time if we need to go after that remnant we can plan our path to that tumor remnant in the safest way possible.
We talked about the metal, what is the concern with having this MRI?
Steven Kalkanis: Even a small surgical tool that’s made of metal will immediately get sucked in to the scanner. It acts as a projectile, a missile if you will and obviously if there’s a patient in the scanner or nursing staff and physicians and anesthesiologist and so forth in the room you want to maintain the safety of everyone involved. So it’s a very critically important step.
Is it because of the way the MRI is based on magnetic imaging?
Steven Kalkanis: MRI stands for magnetic resonance imaging and it basically creates a very, very powerful magnetic field that simulates and accesses water content in the cells which then gets translated in to these very complex images. But because of that magnetic field anything that’s magnetized will essentially be drawn in to that field as well. So we have to take great precaution because of that.
Is there any doubt in your mind that this is lifesaving?
Steven Kalkanis: No doubt at all. I think that this will make a very huge difference for patients in terms of their life expectancy and quality of life quite frankly because I think it will make surgery safer in addition to more complete. Because we have the ability to stop midway before we get too aggressive and perhaps endanger critical areas so that we can get that intraoperative scan and redirect our approach if necessary to preserve normal brain function.
Can you tell us a little bit about your patient?
Steven Kalkanis: She had a very, very interesting situation. She originally presented with a benign tumor and it was removed and unfortunately the tumor grew back and it actually happened a couple of times. But this third time it grew back in a different location so she has a syndrome that makes her prone to these sorts of tumors. Unfortunately when it grew back this third time it was no longer completely benign it had some more aggressive features to it. And so it started to have these finger like projections deeper in to the brain where we needed to be sure that we got every last bit of it out. And the second important caveat in her is that this tumor was nestled right between the part of the brain that controls motor power and the part of the brain that controls sensation. And so it was in probably the most critical portion of her entire brain cortex which meant that we needed everything at our disposal to number one, make sure that we had removed everything completely so it didn’t grow back yet again but also to plan our approach so that we very gingerly danced between the tightrope of the motor strip and the sensory strip. And in her we previously had obtained functional imaging so we knew where her motor function was lighting up, we knew where her sensory function was lighting up, language and so forth. All of that was incorporated in to our intraoperative MRI scanning sequence and so we could plan for a more complete surgery. And I’m thrilled to say that it worked, we got everything out completely and she’s done quite well.
We will see her about a week after surgery so what is your prognosis?
Steven Kalkanis: I think her prognosis is excellent. I think that because we were able to get a hundred percent of the tumor out I think that we basically can monitor it now with serial imaging studies, perhaps a little bit of radiation as a precaution but it’s unlikely it will recur. Most patients after this kind of surgery are significantly weak on the opposite side of the body and she’s actually already recovered a significant amount of strength where she can walk on her own, her hand and grip strength is normal. She’s got a little bit of residual weakness in her upper arm but already in the last few days that’s improved since right after surgery. So she’s definitely moving in the right direction.
Five or ten years ago the prognosis would not have been as good without the technology you have?
Steven Kalkanis: I think the prognosis would have been dramatically different because we wouldn’t have had the tools to A, get every last remnant out but B get it out in the trajectory and in a manner that preserved those critical functions on either side. So this machine really made the difference.

Detroit, MI
dangell1@hfhs.org


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