May 08, 2017
Magnetic resonance fingerprinting technology developed in Cleveland shows promise in adult brain tumors
Advanced magnetic resonance imaging techniques abound. But traditional MR techniques are qualitiative or subjective rather than quantitative. As a result, interpretation of MR images varies according to the machine that was used and the skills of the radiologist.
“When the decision is to treat or not to treat, to operate or not to operate, the decision is more subjective than most of us would like it to be,” says Andrew Sloan, MD, Director, Neuro-Oncology Center, University Hospitals Seidman Cancer Center, Vice Chairman, Department of Neurological Surgery, UH Cleveland Medical Center; Professor of Neurosurgery, Case Western Reserve University School of Medicine. “We’ve always wanted to be objective, and part of that is getting quantitative, objective data.”
Fortunately, Dr. Sloan and colleagues are part of a study testing a new imaging technology that provides such data. Known as magnetic resonance fingerprinting (MRF), which was developed at Case Western Reserve University and UH, it provides absolute values for T1 and T2 for each voxel in the image.
“Once you have these values, you can establish the normal range for white matter, gray matter and cerebrospinal fluid,” Dr. Sloan says. “And then when you have an unknown, you can measure the T1 and T2 to see if it matches with known parameters.”
In a proof-of-concept study published recently in the American Journal of Neuroradiology, UH radiologists Chaitra Badve, MD, Neuroradiologist, UH Cleveland Medical Center; Clinical Assistant Professor of Radiology, Case Western Reserve University School of Medicine, and Vikas Gulani, MD, PhD, collaborating with Dr. Sloan, demonstrated that MRF could distinguish between the solid tumor regions of primary brain tumors (gliomas) and brain metastases. These distinctions, of course, are pivotal variables to consider in making treatment decisions.
“If a patient has a brain metastasis, we treat it with radiosurgery, which is about 90 percent effective in controlling local disease. You don’t need a biopsy to do that,” Dr. Sloan says. “On the other hand, if you have a primary tumor of the same size, you need to biopsy it or take it out. Even though it may look the same, we treat it very differently.”
“We are really excited about these early results,” adds Dr. Badve, a neuroradiologist at UH and the first author on the MRF publication.
“Ongoing technological innovation means that the latest version of MRF now allows us to capture the quantitative T1 and T2 data from whole tumor volume and peritumoral white matter with a 3D acquisition. We intend to validate our high-resolution 3D MRF results with targeted biopsy sampling before moving on to multi-center validation. MRF has the potential to be a crucial imaging biomarker with applications in tumor diagnosis and treatment monitoring.”
Dr. Sloan says he’s also encouraged by MRF’s ability to differentiate radiation necrosis or tumor pseudoprogression, from tumor recurrence — a major challenge in caring for brain tumor patients since uncertainty about diagnosis may lead to clinical indecision or unnecessary and invasive biopsies.
“Part of the modern treatment of gliomas is temozolamide, an alkylating agent that tends to cause an inflammatory response in the brain,” he says. “This inflammatory response, or “pseudoprogression” is actually associated with tumor killing, but on routine MRI, pseudoprogression and tumor recurrence look much the same and there are no definitive ways to tell them apart. In contrast, early MRF data appear to differentiate these two conditions by calculating T1 and T2 values.”
Going forward, Dr. Sloan says he expects MRF to be most useful for monitoring treatment response among patients treated for brain tumors, possibly of changing the standard of care in the near future.
“Another clinically significant application of MRF is we could better follow the course of treatment,” he says. “What’s really a game-changer is how it could help the patient who comes back six months after surgery, radiation and chemotherapy and has a new enhancement. Today, we say we’re not sure what it is, but in the future, we will be able to say “let’s do fingerprinting and we’ll figure it out.” If we see something that looks like tumor but is really pseudoprogression, then we just follow it. On the other hand, if we see something that looks like pseudoprogression but is really tumor, then we know we need to change drugs, add radiation or maybe operate. Thus MRF in this setting would be highly impactful.”
For more information on MRF or other aspects of the Brain Tumor and Neuro-Oncology Center at UH Seidman Cancer Center, email Cancer.Innovations@UHhospitals.org.