During a 2016 brain workshop, Foundation staff asked several research groups to participate in a “volumetric thermometry challenge” to develop and propose novel MRI sequences that could expand the volume of temperature data captured during focused ultrasound brain treatments. As part of his remote research fellowship, Will Grissom, PhD, Associate Professor of Biomedical Engineering at Vanderbilt University, compared and analyzed the submitted sequences to determine which method best met the technical and clinical requirements established at the workshop.
The three groups that submitted ideas to the challenge were Vanderbilt University, the University of Utah, and the University of Virginia (UVA). Kim Butts Pauly, PhD, at Stanford University, also advised on the project. The teams developed and compared three novel MRI sequences for capturing a large volume of temperature data during brain treatments. The sequences were called:
- Echo-planar data sampling (grid pattern) from Utah.
- Stack of spirals data sampling (vinyl record pattern) from UVA.
- Stack of stars data sampling (spoked wheel pattern) from Vanderbilt.
Because the sequences were originally developed on different MRI systems, they could not be directly compared, so Dr. Grissom set out to harmonize the parameters and evaluate the sequences on the same scanner to allow direct comparison. He used special software at the UVA Focused Ultrasound Center to test each of the data sampling patterns. Ultimately, all three groups worked together to collaborate on the project. Steven Allen, PhD, at UVA also assisted with data analysis and precision calculations.
“What was nice was that the project created a reasonable collection of methods that all work,” said John Snell, PhD, the Foundation’s Brain Program Director. “Dr. Grissom’s project was to load the sequences onto the same system and compare them to try to determine which method best met the clinical and technical requirements that the group established at the start of the project when they initially met in 2016.”
Target parameters outlined acquisition time, desired resolution, volume of tissue sampled, and temperature precision. In the end, the stack of spirals (vinyl record pattern) achieved the most technical and clinical goals.
“No method was sufficient to cover the entire brain,” said Grissom. “We need to do more work, but ultimately the “stack of spirals” sequence submitted by Craig Meyer’s group at UVA allowed us to cover a larger region around the focus, and this can make treatments more efficient.”
The teams plan to move forward with transferring the “stack of spirals” sequence to companies that might be able to use it to improve patient care.
Anyone interested in obtaining the project results can contact Dr. Grissom.
Transferring the Technology to Patients
Grissom would like to see these new and improved ideas available to patients. “I don’t want the ideas to just sit there,” he said. “Insightec could evaluate the adoption of these new methods and then work with MRI vendors to incorporate the sequences into the MRI scanners.” Unfortunately, transferring the team’s ideas directly to patients is a slow process because it requires collaboration between several stakeholders, and regulatory requirements are mandated for even relatively small changes.