New PET technique spots 'smoldering' changes not visible on MRI in the brains of MS patients
With the help of a specialized radiotracer, PET scans could explain why patients with multiple sclerosis are not responding well to treatment when MRI exams don’t reveal the cause.
Using a new imaging technique known as 18F-PBR06-PET, experts recently discovered hidden inflammation on the PET brain scans of patients with MS, who despite undergoing extensive treatment for the condition, had worsening symptoms. The inflammation, which researchers described as “smoldering” due to its slow and steady progression, could not be seen on the patients’ MRI exams.
“One of the perplexing challenges for clinicians treating patients with MS is after a certain amount of time, patients continue to get worse while their MRIs don’t change,” lead author Tarun Singhal, MD, director of the PET Imaging Program in the Ann Romney Center for Neurologic Diseases, said in a release. “This is a new approach that is potentially going to be very helpful for the field, for research and hopefully for clinical use.”
The special technique utilizes a radiotracer that binds to immune cells in the brain known as microglia. These cells are believed to be linked to the progression of MS but cannot be ably visualized on MRI exams.
The radiotracer essentially lights up microglial activity. Increased activity of these cells can result in atrophy of the gray matter in the brain which, in turn, affects cognition and fine motor skills—something MS patients can often struggle with.
On imaging, experts observed a direct association between increased inflammation in the brain due to microglia with the level of fatigue and disability reported by participants.
The team was also able to compare inflammation between groups of patients receiving different levels of treatment. Compared to participants undergoing lower efficacy treatments, those receiving higher efficacy treatments displayed less inflammation on imaging but still showed worsening symptoms. This, experts explained, could suggest that even when a reduction in inflammation is achieved through treatment, the disease will continue to slowly progress.
Study co-author Rohit Bakshi, MD, with the department of neurology at Brigham and Women’s Hospital, said that although current treatments are effective for patients with MS, there is still room for improvement.
“Our therapies are excellent in that we’ve definitely improved MS patients’ lives,” Bakshi said. “There’s no doubt about that, but we’re still not at the finish line. This study tells us something new about the disease and may be giving us an important clue as to what is driving disease progression in patients.”
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.