DOT Sheds Light on Infant Brains
15-Feb-2007
Researchers at Washington University in St. Louis are developing an optical scanning system that assesses the functional status of infants' brains. Now, with the help of $500,000 funding from investment firm Allied Minds Inc., the university is spinning out a new company to commercialize this technology.
The company is Cephalogics and its technology is diffuse optical tomography (DOT) – a non-invasive computational imaging technique. Cephalogics' system uses a small cap containing multiple sources and detectors to monitor near-infrared (NIR) light transmitted through the patient's head and image blood flow within the brain.
Oxyhaemoglobin and deoxyhaemoglobin in blood exhibit different NIR absorption spectra. Thus, by recording the absorption spectra at several wavelengths, the system can continually monitor both the blood volume and the level of blood oxygenation in the brain. Changes in these factors can be indicative of neuronal activity.
"Cerebral oxygenation is a good indicator of the health of the tissue," Joseph Culver, assistant professor of radiology at the university's School of Medicine and inventor of the brain-imaging system, told medicalphysicsweb. "If you have a patient in an intensive-care unit and the cerebral oxygenation decreases over a particular area, that indicates that cerebral perfusion is too low in that region and something needs to be done."
The DOT system can indicate areas of brain injury as well as monitor the brain's response to interventions, which should help clinicians to diagnose and treat any problems with brain development or function at an early stage. Culver sees the technology as having maximum impact for neonates – premature babies, in particular – intensive care units.
"This group is highly susceptible to brain injury, and early intervention is very important," Culver explained. "Any brain injury at that time can impact upon a person for the rest of their life."
The Next Stage
While the idea of using NIR spectroscopy to monitor brain function is not new, the big step forward has been the development of systems that can create tomographic images. "We are working on an imaging system that has a high density of source-detector arrays," said Culver. "Higher-density arrays allow us to get better image quality and better discrimination of cerebral signals."
Culver reckons that there's a big gap in commercial neonatal neurological imaging equipment. While commercial cerebral oximeters are available, those that have been employed within clinics are non-imaging systems that just measure cerebral oxygenation at one particular position. He adds that such NIR spectroscopy systems can also suffer from motion artefacts, poor coverage and contamination of the brain signal by those arising from the scalp and skull.
"We are trying to develop a system that's really got the performance needed to be a useful clinical tool," Culver explained. "We believe that this market could grow quickly and be adopted broadly worldwide, initially for neonates, and then extending into other areas," added Chris Silva, CEO of Allied Minds.
Cephalogics' initial technology development will take place at Washington University. "We're looking to develop a prototype within a year and do some pilot trials in a clinical setting shortly thereafter," said Silva. "Once we have the prototype, we'll have to make a decision on where to actually do the production." Allied Minds' initial investment will cover this prototype development and preliminary testing, with further funding slated to follow as the technology progresses.
About the author
Tami Freeman is industry editor on medicalphysicsweb.
