This video shows motion correction of 3D images of a human fetus’s brain using the UW’s reconstruction techniques. Credit: Studholme Lab/UWMC
Because there’s no way to make a squirmy fetus in a mother’s uterus hold still, the researchers developed a method that creates a four-dimensional reconstruction of brain activity.
Led by Colin Studholme, UW joint professor of pediatrics and bioengineering, the team published its work in two papers last fall in Human Brain Mapping (online August 2016) and Magnetic Resonance in Medicine (online October 2016).
When using MRI to measure brain function, estimating the intensity of the imaging signal is critical. As part of the brain activates, blood vessels in the area react and supply those brain cells with more oxygen, which causes slight changes in intensity in the MRI image. But if the subject moves, this intensity change can be corrupted and its location in the brain is lost.
“To get around some of the motion problems in fetal imaging, we acquire multiple echoes, each from a different perspective, at each location and time point, and then we use those different echoes to calculate a quantitative map of the tissue activity within the brain,” Dr. Studholme says. Using the physical measurements, the team was able to calculate the activation signals over a few minutes, accommodating the baby’s movement.
The method allows the mapping of the brain’s default mode network and other regions that are active when the brain is at rest, daydreaming or not concentrating on a specific task.