Functional Ultrasound Imaging Shows Promise as a Safe Bedside Brain Monitor for Neonates
Device uses ultrafast Doppler ultrasound to map blood flow changes in small brain vessels.
U.S. Navy photo by Jacob Sippel
One of the best techniques for studying human brain function is magnetic resonance imaging, which can measure and map brain activity noninvasively and without ionizing radiation. However, using MRI to study the newborn brain remains challenging—motion artifacts are typical without sedation, and volume estimates of specific brain structures may not always be accurate for such a small head size.
As an alternative to functional MRI, a team of researchers from Inserm and the Assistance Publique–Hôpitaux de Paris explored the feasibility of real-time functional ultrasound imaging in human neonates, which they call fUSI. The device employs ultrafast Doppler ultrasound imaging to obtain maps of blood flow changes in small brain vessels and provide a window into brain activity. They published the study Oct. 11 in Science Translational Medicine.
A lightweight ultrasound probe was secured to the head of late preterm neonates during sleep and measurements occurred without adverse events or visible discomfort. Simultaneous continuous video-electroencephalography recordings accompanied fSUI to characterize different sleep states. From quiet to active sleep, the authors saw a threefold increase in peak-to-peak amplitude of cerebral blood volume.
Next, they measured two neonates with congenital abnormal cortical development associated with repeated drug-resistant seizures. A highly significant increase in the average intensity of relative ultrasound signals was observed in regions of cortical dysplasia during seizure, whereas no change was seen in contralateral regions.
As a bedside monitor for neonates, the fUSI device shows promise due to its portability, low cost, and continuous measurement of blood flow changes. However, unlike MRI, fUSI is restricted to 2-D plane acquisition of images instead of the full 3-D brain volume.