Northwestern Medicine researchers have developed a new imaging approach to more accurately assess blood flow in the spinal cord, a method that could be used to better inform the treatment of neurological diseases and injuries, as described in a recent study published in Scientific Reports.
“We’ve taken MRI methods that we’ve firmly established in the brain, and with a lot of attention to detail and a lot of small improvements, we’ve made this critical leap to using them in the spinal cord, and I find it pretty exciting,” said Molly Bright, Ph.D., assistant professor of Physical Therapy and Human Movement Sciences and of Biomedical Engineering in the McCormick School of Engineering, who was the lead author of the study.
Impaired vascular function in the spinal cord contributes to many neurological diseases, including traumatic spinal cord injury and degenerative cervical myelopathy, a condition in which age-related damage to the spinal discs compresses the spinal cord, which can cause progressive weakness, numbness, and difficulty with coordination.
Measuring changes in blood supply to spinal cord tissue is essential to guide preventative care measures and treatment. However, existing methods have yet to measure these changes accurately, Bright said.
To address this gap, Bright and his team developed a functional magnetic resonance imaging (fMRI)-based approach to map spinal cord vascular reactivity, or how well blood vessels can dilate to increase blood flow to spinal cord tissue. FMRI is most commonly used to map neural activity by measuring changes in blood flow and is therefore an excellent imaging tool to study blood supply directly, Bright said.
“For most of my career I have used fMRI to not only look at neural activity, but also to look at the plumbing and how the vascular system supports the nervous system. This is important for many neurodegenerative diseases because neural and vascular health are so interconnected,” Bright said.
To validate their approach, study participants underwent a series of fMRI scans. During the scans, participants were asked to repeatedly hold their breath for short periods, which causes carbon dioxide to build up and causes blood vessels to dilate, increasing blood flow.
From these imaging scans, scientists were able to create maps of vascular function in the spinal cord, which revealed that certain regions of the spinal cord responded at different times.
“This was actually very consistent across people,” Bright said. “We didn’t really know to look for this beforehand, but it could be that we are looking at the circulation patterns of different arteries that supply blood to the spinal cord, which I don’t think have been mapped before.”
Overall, the approach can provide more detailed information about the vascular health of the spinal cord, which can help guide treatment strategies for spinal cord injuries and diseases, Bright said.
“For spinal cord injuries, we could use this type of vascular mapping, as well as some of the more traditional fMRI neural mapping, to understand whether interventions are improving function in a damaged part of the cord,” Bright said.
Bright added that the approach could also help improve preventive care for patients with degenerative cervical myelopathy.
“If we can detect that vascular supply is impaired in the area of umbilical cord compression in certain older adults with degenerative disc disease, then we can potentially identify who needs further follow-up or early intervention,” Bright said.
Co-authors of the study include Milap Sandhu, PhD, assistant professor of Physical Medicine and Rehabilitation, and Todd Parrish, PhD, professor of Radiology and Biomedical Engineering in the McCormick School of Engineering.
Kimberley Hemmerling, PhD, a former graduate student in Northwestern’s Biomedical Engineering program, was the lead author of the study.
This work was supported by the Northwestern University Translational Imaging Center and Craig H. Neilsen Foundation grant 595499.
