New Surgical Suite Allows for Accurate Imaging During Neurosurgery
This article reprinted courtesy of GE Healthcare and SignaPULSE, its magnetic resonance (MR) magazine.
Madison - University of Wisconsin Hospital and Clinics, part of UW Health, recently completed the first installation in the US of a GE 1.5T wide bore MR Surgical Suite.
Anchored by the Optima* MR450w, the suite has two connected rooms - an operating room (OR) and magnetic resonance (MR) room separated by double doors that enable movement from one sterile environment to another. This innovative set up allows clinicians and staff to image patients during tumor resections and deep brain stimulation (DBS) procedures, while also preserving the ability of both rooms to serve surgical and imaging procedures independent of one another.
MR Diagnosis in Real Time
Within the context of surgical cases, the Optima MR450w from GE Healthcare is used for imaging tumor resections and performing DBS. According to Karl Vigen, PhD, MRI physicist, Department of Radiology, the 70-cm bore on the Optima MR450w is ideal for the iMRI suite.
"The wider bore is very important for flexibility in patient positioning," he says.
Additionally, Dr. Vigen is very impressed with the pulse sequences on the scanner. He notes it is crucial to have the capability to quickly acquire an entire volume of data with the appropriate image contrast for both conventional and intraoperative procedures.
"Our two most important sequences are T1 weighted volumetric imaging with BRAVO and T2 volumetric imaging with Cube," Dr. Vigen adds. "With ARC (parallel imaging) and the 6-channel Neuro Flex coil, we can achieve good coil positioning to obtain the acceleration factors needed (for speed) and generate high-quality images."
The Flex coil, he says, is easy for the MR technologists to position for quality imaging.
For Howard Rowley, MD, Chief of Neuroradiology, having another tool that enables surgeons and radiologists to view tumor resections and DBS in real time - at a time where they can go back and modify the procedure - is a true game-changer.
"We can determine while the patient is in surgery if the tumor has been completely resected," he says. "In cases of DBS, we can directly visualize the passage and position of electrodes when implanting devices. This is an exciting new tool that we use in patients with Parkinson's disease."
While it is too early to know the full impact on patient care, Dr. Rowley cites a recent study that found that 96 percent of patients who undergo glioma tumor section in conjunction with MR imaging actually have more complete resections. This is compared to 68 percent of patients who had more complete resection using traditional surgery without an MR scan.
Initial results suggest better long-term outcomes. "Removing more tumor translates to better patient survival, that's really the bottom line," he adds.
Both Dr. Vigen and Dr. Rowley are very pleased with the imaging performance of the Optima MR450w.
"High image quality has been one of the most pleasant aspects of this entire process," says Dr. Rowley.
It is superb when compared to the low-field systems he has seen in other operating room environments. And, there is the full flexibility to run a range of 3-D sequences such as Cube and BRAVO, while taking advantage of parallel imaging. PROPELLER 3.0-based diffusion-weighted imaging is another useful technique that helps combat susceptibility artifacts, Dr. Rowley adds.
In tumor resections, patient outcomes are dependent upon the success of removing the tumor during surgery. However, the completeness of the resection may not be evident at the time of surgery, explains Robert J. Dempsey, MD, Professor and Chairman of Neurological Surgery at UW Health.
"In real time, iMRI can help identify additional lesions and also, any intraoperative shift in the lesion location. It changes our intraoperative approach to surgery and may potentially provide a greater safety margin and higher degree of certainty that we've completely resectioned the tumor."
During the perioperative imaging, a neuroradiologist - such as Dr. Rowley - is in the MR control room for real-time diagnosis of the MR images. This can help avoid potential complications and the need to take the patient back to surgery.
John S. Kuo, MD, PhD, Assistant Professor and Director, Comprehensive Brain Tumor Program at UW Health explains that, "The pituitary region is a small yet important area deep within the head and is difficult to image. High-field MR is one of the safest, most effective imaging techniques for this area."
Prior to installation of the iMRI system, patients had to wait for a follow-up MR scan to ensure maximal resection. Now, Dr. Kuo has immediate visualization and sometimes even where he cannot visualize portions of the tumor using endoscopy, he knows that iMRI will provide a timely surgical roadmap. As importantly, he can provide patients and families immediate feedback on the surgery success.
"Instead of, 'I think the maximal safe resection was done,' I can immediately show them what was accomplished." Dr. Kuo foresees many additional uses for real-time, perioperative MR imaging in tumor surgeries. "For many complex cases, such as brain tumors near important areas of brain function, a patient will benefit from the immediate feedback of an MR scan."
He anticipates the ability to conduct more complex surgeries in a safer manner, and believes extending use of the suite to other neurosurgery applications will contribute to better care and more comprehensive research. In addition to pituitary tumors, UW Health is using iMRI for DBS on Parkinson's patients.
"Perhaps as few as 20 percent of patients with Parkinson's disease who may benefit from DBS undergo the procedure and concerns with awake surgery have been cited as a significant factor in the decision for some patients to consent to DBS," says Karl A. Sillay, MD, Assistant Professor of Neurological Surgery and Director of Adult Functional and Stereotactic Neurological Surgery at UW Health.
Unfortunately, many patients are reluctant to undergo this procedure that can help to treat the symptoms of Parkinson's disease because they must be awake during the entire procedure, which often takes up to six hours. Between April and September 2011, Dr. Sillay performed DBS on four patients. The first had waited for the opportunity to have the surgery while asleep under general anesthesia.
"There is a segment of the population who has anxiety and fear of being awake during the surgery," he explains.
If using iMRI becomes a standard of care, Dr. Sillay adds, the hospital has removed a significant barrier to patients consenting to a procedure that may help them. There are additional benefits to performing DBS in the iMRI suite. For example, the patient does not have to be off medication as they do before and during the awake surgery. According to Dr. Sillay, it is easier to identify brain signals when the patient is off Parkinson's medication; yet many patients don't want to do this either. Also, certain steps in the treatment are eliminated and the workflow is significantly streamlined: There is no need to perform pre-op CT scans with the stereotactic frame in place and an MR scan for surgical planning.
"We can perform the high-resolution imaging for electrode placement during the procedure," Dr. Sillay says. "The reality is that the iMRI DBS surgery will sell itself to the patient who would otherwise elect to avoid awake brain surgery."
Two Departments Share One Vision
"One of the key requirements in setting up the suite was that the MR room had the diagnostic capability and capacity to also image inpatients and outpatients," says Matt Henry, MBA, Radiology Manager - MRI, CT and Research at UW Health. Room utilization is currently on par with the other four MR scanners at the hospital. "From a financial standpoint, there are many imaging benefits with this particular magnet and we have scanned more patients because of it," he adds.
Not only is it used for routine MR imaging, but the wide-bore and 500-pound rated table accommodate larger-sized and claustrophobic patients. "Each week since we installed the system, there have been a handful of patients who weigh 400-plus pounds and without the wide bore scanner, we would not have been able to image them."
The same can be said for the OR suite. Denise Dillon, RN, BSN, CNOR, Surgical Services Supervisor, Neurosurgery, says, "The value of this additional OR room for our department is a huge plus, as our volumes are increasing at the moment. Having this OR room independent from the MR room enables us to serve more patients and perform more cases than we otherwise would have been able to accommodate."
It's All in the Planning
Having two independent rooms was always part of the plan for UW Health. Throughout the planning stages, it was apparent that to achieve financial stability in addition to clinical success, each room had to maximize the volume of patients and procedures. Yet, planning for an intraoperative MR suite was the first challenge this team faced.
The journey began with meetings that included all stakeholders - radiology, nursing, neurosurgery, housekeeping, infection control, facilities management and medical physics. Jordan Henry, RN, BSN, Neurosurgery Care Team Leader and a key facilitator throughout the planning stage also notes that the team conducted several site visits to similar OR/MR configurations.
Room planning was perhaps the most important consideration for the OR. Henry had to consider new obstacles, such as losing one wall where the doors open to the MR suite for hanging and placing surgical equipment. He utilized a structural column in the middle of the OR as a place to hang surgical equipment and ensured that all electrical outlets are accessible to the surgical area to keep clear walkways for the surgeons and nurses. And, since the OR is in radiology and not near the other surgical suites, a storage area had to be included in the planning.
"This suite is very different from what we're accustomed to in a typical OR," Henry says.
It also took planning to ensure that images from the MR scanner and PACS could be delivered into the OR suite in near real time or on an as-needed basis to help guide the neurosurgeons during the procedure.
"Another huge challenge was getting all the equipment to work together in a useable workflow that we could sustain," Henry adds. "The other aspect, operating in a magnetic field, was different from anything we'd ever experienced."
Key concerns were patient and staff safety, in particular ensuring that no ferrous materials enter the MR room during patient transport, and that the MR suite is sterile when used in conjunction with the OR. Henry and Dillon, along with the MR team, set up protocols with safety checks for patient and staff movement into the MR room from the OR. Stainless steel surgical tools were replaced with titanium tools and the typical fixed base OR table was replaced with a moveable base table. There is also redundancy in the safety sweeps performed by the surgeon, surgical technologist, nurse, and MR technologist.
In fact, the protocol stipulates that OR staff be MR compatible even when entering the OR room, notes Tammy Heydle, RT(MR), Senior MRI Technologist.
"We adapted MR safety to the surgical environment with non-ferrous OR equipment, such as MR-safe monitoring equipment, that can move from the OR to the MR without disconnecting from the patient," she says.
Also, a handheld magnet is swept over the OR table prior to patient transport. Just as the OR room had to adopt MR safety policies, so too did MR workflow and policies change to accommodate patient surgeries.
"The MR room had to meet OR requirements, including air handling and the ability to clean the room with solid surfaces," says Dr. Vigen.
Tom McKinlay, RT (MR), Senior MRI Technologist, adds that the new MR workflow is designed to handle outpatient imaging at the same time as a tumor resection. "Once the surgeon needs the MR, we bring the patient over and are able to determine if the tumor was entirely removed. After they take the patient back into the OR suite, we open the MR back up to outpatients until it is needed again by the surgeon."
For McKinlay, the most rewarding aspect of his job in the iMRI suite is seeing how the patient benefits from this collaboration. "Not only are we resecting a tumor in one suite, but we are transporting the patient to the MR scanner to determine if the tumor was completely resected or if there is some left. That can only benefit the patient."
Collaboration Breeds Success
Across all team members - surgeons, radiologists, nurses, technologists and administrators - one theme continued to surface: the collaboration of different UW Health departments and team members with GE Healthcare. In their opinion, not only is the Optima MR450w an excellent system for an iMRI suite (due to its 70-cm bore and ability of the MR table to move out of the bore for greater access to the patient), GE Healthcare is the ideal collaborator for venturing into relatively unknown territory. In fact, with the successful implementation of the DBS and tumor resection neurosurgical procedures in the iMRI, UW Health is planning to add other specialty surgeries to the suite in the near future.
"We spent years developing this concept for the iMRI suite," says Dr. Dempsey, "but I told the hospital, 'Not yet,' until I had a chance to see this system. What we have with this system is remarkable ease of use, an extremely high-quality magnet, some of the best sequences available, and a solid implementation and service team to back it up."
Dr. Rowley agrees with Dr. Dempsey's assessment of the system, adding, "We can accommodate more types of patients and we have more flexibility with positioning surgical patients in the wider bore."
While there were challenges along the way, M. Henry credits GE Healthcare with finding solutions and resolving issues. "GE has been a strategic collaborator for us, including the research and development that we perform with the company. Yet, the ability to bring in a new wide bore MR system in the context of an interventional suite has really been unique for us - together we've created something new and exciting that, at the end of day, will positively impact patient outcomes. And that's really the most important aspect of this project."
*Trademark of General Electric Company
Date Published: 12/09/2011