Noninvasive optical imaging of localized absorption and scattering changes during functional activation of the human brain: an evaluation and feasibility study

In the present study we evaluated a new 50 MHz single wavelength multi-source detector imaging system for noninvasive optical imaging of human brain function. The system is based on phase resolved technology and allows measurements in remission mode of changes in phase shift and light intensity in the phased array approach and the conventional phase modulation approach. To evaluate the potentials and limitations of the system with respect to functional brain imaging we assessed the sensitivity of imaging based on photon migration pattern and absorption changes in the two different approaches as a function of object depth in a homogeneous brian model under controlled conditions. Furthermore first results using this technique for noninvasive optical imaging of functional brain activation in human subjects are presented and discussed with respect to potentials and limitations of the respective parameter.