What is Intraoperative Magnetic Resonance Imaging (iMRI)? Purpose, Procedure & Results

Intraoperative MRI (iMRI) is a specialized imaging technique that allows surgeons to take detailed brain scans while you're still in the operating room during surgery. Think of it as having a window into your brain that helps your surgical team see exactly what's happening in real-time, ensuring they can make the most precise decisions for your care.

This advanced technology combines the power of MRI scanning with ongoing surgery, giving your medical team the ability to check their progress and make adjustments as needed. It's particularly valuable for complex brain surgeries where millimeter-level precision can make all the difference in your outcome and recovery.

What is intraoperative MRI?

Intraoperative MRI is essentially a regular MRI scanner that's been specially designed to work inside an operating room. The key difference is that instead of having your scan done before or after surgery, this happens while your surgery is actively taking place.

During your procedure, your surgeon can pause the operation and take detailed images of your brain to see exactly what they've accomplished so far. This real-time feedback helps them determine if they need to remove more tissue, if they've achieved their surgical goals, or if any adjustments are needed before closing up.

The technology works by using powerful magnets and radio waves to create incredibly detailed pictures of your brain's soft tissues. What makes iMRI special is that it can show the difference between healthy brain tissue and abnormal areas like tumors, even when they look very similar to the naked eye.

Why is intraoperative MRI done?

Your doctor might recommend iMRI to ensure the most complete and safe removal of brain tumors or other abnormal tissue. The main goal is to maximize the amount of problematic tissue that gets removed while protecting the healthy parts of your brain that control important functions like speech, movement, and memory.

Brain surgery presents unique challenges because your brain doesn't have clear visual boundaries between healthy and diseased tissue. Sometimes what looks normal to the surgeon might actually contain microscopic tumor cells, while areas that appear abnormal might just be swelling or scar tissue.

Here are the main reasons your surgical team might use iMRI during your procedure:

• To confirm complete tumor removal and check for any remaining abnormal tissue
• To verify that critical brain areas responsible for speech, movement, or cognition remain undamaged
• To guide the placement of surgical instruments in deep or hard-to-reach areas of the brain
• To monitor for any unexpected complications like bleeding or swelling during surgery
• To ensure that any implanted devices or electrodes are positioned correctly

This technology is particularly valuable for treating aggressive brain tumors like glioblastoma, where removing every possible cancer cell significantly improves your long-term outlook. It's also helpful for surgeries near eloquent brain areas that control essential functions you need for daily life.

What is the procedure for intraoperative MRI?

Your iMRI procedure begins much like any other brain surgery, with careful preparation and positioning in a specially designed operating room. The main difference is that this operating room contains an MRI scanner, which looks like a large tube or tunnel positioned near the surgical table.

Before your surgery starts, you'll receive general anesthesia so you're completely unconscious and comfortable throughout the entire procedure. Your surgical team will then position you on a special table that can move smoothly between the surgical area and the MRI scanner when needed.

Here's what typically happens during your iMRI procedure:

1. Your surgeon begins the operation using traditional surgical techniques and tools
2. At predetermined points, the surgical team pauses and moves you into the MRI scanner
3. The scanner takes detailed images of your brain to show the current surgical progress
4. Your surgeon reviews these images to determine the next steps
5. You're moved back to the surgical position, and the operation continues
6. This process may repeat several times until your surgeon is satisfied with the results

The entire procedure typically takes longer than traditional brain surgery because of the time needed for imaging and analysis. However, this extra time often leads to better outcomes and may actually reduce your need for additional surgeries later.

How to prepare for your intraoperative MRI?

Preparing for iMRI surgery involves the same general steps as any major brain surgery, with a few additional considerations related to the MRI technology. Your medical team will provide you with detailed instructions specific to your situation, but here are the common preparation steps.

Several days before your surgery, you'll meet with your surgical team to discuss the procedure and complete pre-operative testing. This might include blood work, additional imaging studies, and consultations with anesthesia specialists who understand the unique requirements of iMRI procedures.

You'll need to remove all metal objects from your body before the procedure, since the MRI uses powerful magnets. Your surgical team will carefully review any medical devices you have, such as pacemakers, cochlear implants, or metal plates, to ensure they're compatible with the MRI environment.

On the day of your surgery, you'll typically need to avoid eating or drinking for at least eight hours beforehand. Your medical team may also ask you to stop certain medications temporarily, particularly blood-thinning drugs that could increase bleeding risk during surgery.

It's completely normal to feel anxious about this type of surgery, and your medical team understands this. Don't hesitate to ask questions or share your concerns with your healthcare providers, as they're there to support you through this process.

How to read your intraoperative MRI results?

Your iMRI results are interpreted in real-time by your surgical team rather than being delivered to you as a separate report. During your surgery, specialized radiologists and neurosurgeons work together to analyze each set of images as they're taken, making immediate decisions about how to proceed.

The images show different types of brain tissue in various shades of gray, white, and black. Your surgical team looks for specific patterns that indicate healthy brain tissue versus abnormal areas like tumors, swelling, or bleeding.

What your surgical team evaluates during iMRI includes:

• The extent of tumor removal and whether any abnormal tissue remains
• The condition of healthy brain tissue surrounding the surgical area
• Any signs of bleeding, swelling, or other complications
• The position of critical brain structures that control important functions
• The overall success of the surgical objectives

After your surgery, your doctor will explain what the iMRI showed and how it influenced your treatment. They'll discuss whether the surgical goals were achieved and what the images revealed about your specific condition.

What are the benefits of intraoperative MRI?

The primary benefit of iMRI is that it significantly improves the precision and completeness of brain tumor removal. Studies show that patients who undergo iMRI-guided surgery often have more complete tumor removal compared to traditional surgery alone.

This technology also reduces the likelihood that you'll need additional surgeries later. When surgeons can see exactly what they've accomplished during the initial procedure, they can address any remaining issues right away rather than discovering them weeks or months later.

Here are the key advantages iMRI offers for your care:

• More complete tumor removal, which can improve your long-term prognosis
• Better preservation of healthy brain tissue and important neurological functions
• Reduced risk of needing repeat surgeries
• Immediate detection and correction of any surgical complications
• More precise placement of any implanted devices or treatment materials

Many patients also find comfort knowing that their surgical team has this additional tool to ensure the best possible outcome. The real-time feedback helps create a more confident and thorough surgical approach.

What are the risks and limitations of intraoperative MRI?

While iMRI is generally very safe, it does add some complexity to your surgery that can increase certain risks. The procedure takes longer than traditional brain surgery, which means you'll be under anesthesia for an extended period.

The specialized equipment and operating room setup also require your surgical team to use MRI-compatible instruments, which can sometimes limit their surgical options compared to traditional tools.

Here are the potential risks and limitations to be aware of:

• Longer surgery time increases anesthesia-related risks
• Risk of infection may be slightly higher due to extended procedure time
• Limited availability, as not all hospitals have iMRI capabilities
• Higher cost compared to traditional brain surgery
• Potential for technical difficulties that could interrupt the procedure

Rare but serious complications can include unexpected reactions to prolonged anesthesia, equipment malfunction, or complications related to moving you between the surgical area and MRI scanner during the procedure.

Your surgical team will carefully weigh these risks against the potential benefits for your specific situation. For most patients with complex brain tumors, the advantages of iMRI significantly outweigh the additional risks.

When should you consider intraoperative MRI?

Your doctor might recommend iMRI if you have a brain tumor that's particularly challenging to remove completely using traditional surgical techniques. This is especially true for tumors located near critical brain areas or those that don't have clear boundaries between healthy and diseased tissue.

The decision to use iMRI depends on several factors related to your specific condition and overall health. Your surgical team will consider the location, size, and type of tumor, as well as your individual risk factors and treatment goals.

Common situations where iMRI might be recommended include:

• High-grade gliomas or other aggressive brain tumors
• Tumors located near areas that control speech, movement, or other critical functions
• Recurrent tumors that have grown back after previous surgery
• Complex vascular malformations or other structural brain abnormalities
• Cases where maximizing tumor removal is crucial for your treatment plan

Your neurosurgeon will discuss whether iMRI is appropriate for your situation during your consultation. They'll explain how this technology might improve your specific outcomes and whether the potential benefits justify the additional complexity and time involved.