Functional NIRS imaging holds the potential to become a versatile, economical, and compact tool for the study of the detailed dynamics of the vascular response to neuroactivation. While steady progress has been made in hardware development, lagging has been the availability of a software environment that provides for accurate reconstructions on a fast time scale and versatile phantoms well suited to explore the wide range of complex behavior inherent to neuroactivation. Building on significant progress made during Phase I, we have developed a fast and stable image enhancement scheme that can significantly improve the image accuracy of first order reconstructions. Independently, by adopting principles from liquid crystal technology, we have developed programmable dynamic phantoms that mimic complex hemodynamic events with high accuracy, precision and speed. The proposed investigation will combine these two innovations to allow for the systematic optimization and quantitative examination by which dynamic NIRS imaging can explore complex neurovascular states. These efforts complement a broader seven-year technology development plan that has already produced an imaging system now in use at ten leading national and international research centers. The proposed study considers an in-depth optimization of user controllable factors (e.g., optimal selection of illuminating wavelengths, improvements in accuracy of reconstructred images, fine tuning of the image enhancement scheme) so as to determine the underlying accuracy and stability of the integrated technology as a function of a range of parameters intrinsic to the brain. The end point of these studies will be a ground truth validation of the fidelity and accuracy of the NIRS imaging approach developed by our company. Through careful optimization of the principal system components, we are confident that the combination of new technologies, and innovative improvements to our software environment will lead to the broad acceptance of NIRS imaging as a versatile and accurate neuroimaging tool. The systematic testing and integration of a new image enhancement scheme for functional NIRS imaging and its ground truth validation using an innovative and versatile assessment modality is proposed for the purpose overcoming the key technology barriers preventing the wide acceptance of functional NIRS imaging. ? ? ?
