International Innovation talks to the Martinos Center's Anna-Liisa Brownell about her work with PET imaging and the insights it provides into neurodegenerative disease
Neuroimage celebrates 20 years of functional near-infrared spectroscopy
In 1993, four different groups reported a novel noninvasive technique with which to image hemodynamics in the brain. The technique - functional near-infrared spectroscopy (fNIRS) - enables study of both healthy brain development and a range of diseases and disorders by monitoring changes in cerebral hemoglobin concentrations, based on changes in optical absorption obtained by shining near-infrared light on the scalp and measuring the amount of light that reaches a detector a few centimeters away.
fNIRS was - and is - attractive as a research and clinical tool because it is safe, portable and relatively inexpensive, and because it offers high temporal resolution. For these reasons, it can be applied in populations and for procedures where use of other imaging modalities is often constrained: in children, for example, or in the operating room or intensive care unit.
It's not surprising, then, that interest in the technique has grown considerably in the two decades since its introduction. The number of publications has doubled every 3.5 years - passing the 200 mark in 2012 - reflecting the increasing number of researchers and clinicians adopting it for a host of applications, both established and newly realized.
Now, the journal Neuroimage is set to publish a special issue devoted to fNIRS, with papers reporting the latest advances and the spectrum of possible applications. Ahead-of-print versions of papers are available online, here.
"Functional near-infrared spectroscopy has now reached a tipping point," said Martinos Center researcher David Boas, a pioneer in the development of the technique and one of the editors of the special issue. "Advances both in the technology and in signal processing have brought us to a point where users are exploring its potential for a range of health science and clinical applications, as well as for the research applications in the brain. We are tremendously excited to see where it takes us next."
Growing interest in the technique has also spurred a biennial conference - the third of which will be held in October 2014 - and the formation of a new society. See fNIRS.org for further information.
Image courtesy of Ippeita Dan and Daisuke Tsuzuki. Tsuzuki, D., Dan, I., 2014. Spatial Registration for Functional Near-infrared Spectroscopy: From Channel Position on the Scalp to Cortical Location in Individual and Group Analyses. Neuroimage 85, 92–103.