Optical brain imaging noninvasively measures small perfusion changes caused by visual stimulation

In a recent study, Cephalogics (Boston, MA) demonstrated that its high-density diffuse optical tomography (HD-DOT) system can measure and monitor very small, focal changes in cortical perfusion resulting from visual stimulation in healthy volunteers. The company's noninvasive, portable brain perfusion imaging system is being designed to provide continuous bedside monitoring of regional brain oxygenation in patients suffering from stroke or traumatic brain injury.

Related: Imaging distributed function and networks in the human brain

Retinotopic mapping of visual cortex activation has been widely used and accepted in early evaluations of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) because of its ability to generate small focal changes in perfusion. Using a typical retinotopic stimulation experiment, the company's fiber optic-free HD-DOT system demonstrated the ability to image retinotopic visual stimuli consistent with earlier studies using standard PET and fMRI. The study results replicate the previous work of Joseph P. Culver, Ph.D., at Washington University St. Louis (WUSTL; St. Louis, MO), who is a pioneer of HD-DOT.

The changes in cortical perfusion measured by the company's HD-DOT system in this study are significantly smaller than the typical perfusion changes associated with brain injury patients. Similarly, the area of cortical tissue that changes in response to the visual stimuli used in this study is much smaller than the spatial extent of the perfusion deficits typically expected with brain injuries. The ability to measure perfusion changes in cortical tissue of such small magnitude and in such focal areas demonstrates that the system should have the ability to reach the necessary sensitivity and spatial resolution for imaging cerebral perfusion. Giving clinicians easy access to continuous imaging and perfusion measures at the bedside can help them identify and treat perfusion deficits to avoid ischemia and its associated adverse outcomes.

The results were presented on June 29, 2016, at the Human Brain Mapping conference in Geneva, Switzerland.

For more information, please visit www.cephalogics.com.