Significant progress over three and a half years of support on the three proposed aims has enabled: 1) in-depth cognitive function studies (over 2,000 studies) with seven high school subjects in Year 3. The preferred prefrontal imaging modality was developed and tested in Year 2 (600 validation studies) with the result that maximal optical signals in fruitful prefrontal voxels are sharply imaged when the """"""""difficulty matches ability"""""""" in anagram solutions using a time multiplex pulsed light system (ACTM). This provides a fast, safe, and economical brain function NIR imager. 2) Quantitative brain oximetry requires measures of tissue optical properties for which the IQ oximeter has been tested on piglet models and the brain oxygen tissue value is found to be near the average of arterial and venous values. 3) Thick hair oximetry has been solved by higher laser power (FDA Class 3) and by intercalculating light fibers inserted through ferrules in a rigid helmet. This progress affords a sound basis for the design of a wearable, portable brain function imager which will be constructed and tested on various age groups to further validate difficulty/ability match and to extrapolate to younger groups where testing is more difficulty due to disattention. Quantitative brain tissue oximetry will now output arterial and venous values and, in animal models, wifi be correlated with corresponding localized 3-D images of the mitochondrial redox state in hypoxia, in order to correlate critical desaturation of hemoglobin and mitochondrial hypoxia in the piglet brain model and serve as a warning signal in evaluating stroke-induced hypoxias in neonates. In order to explore the time range of optical signals beyond vasomotor and metabolic effects, a fast (15 Hz) high localized (approximately 1 mm3) phased array system with sequential lock-in?s will provide very sensitive phase measurements. This frequency domain system will be used to evaluate the feasibility of detection of light scattering changes due to iterated visual responses in the occipital region with a go/no-go point in Year 3. These projects represent logical continuations of current activities into new and related researches.
| Tian, Fenghua; Chance, Britton; Liu, Hanli (2009) Investigation of the prefrontal cortex in response to duration-variable anagram tasks using functional near-infrared spectroscopy. J Biomed Opt 14:054016 |
| Chance, Britton; Nioka, Shoko; Zhao, Zhongyao (2007) A wearable brain imager. IEEE Eng Med Biol Mag 26:30-7 |
| Intes, Xavier; Chance, Britton (2005) Non-PET functional imaging techniques: optical. Radiol Clin North Am 43:221-34, xii |
| Chance, Britton; Nioka, Shoko; Sadi, Sajid et al. (2003) Oxygenation and blood concentration changes in human subject prefrontal activation by anagram solutions. Adv Exp Med Biol 510:397-401 |
| Ntziachristos, V; Kohl, M; Ma, H et al. (2000) Oximetry based on diffuse photon density wave differentials. Med Phys 27:410-21 |
