Abstract 2021 Poster Session II, Sunday, 5/2 (poster 217)

Changes in regional brain blood flow and hemoglobin oxygen saturation occur in the human cortex in response to neural activation. These changes can create a signal that can be imaged and quantitated using various methods. Functional MRI (fMRI) and positron emission tomography (PET) have both been used as methods for mapping functional brain blood flow and oxygenation patterns, however, these approaches do not allow for continuous, portable measurements. Using our time-of-flight and absorbance (TOFA) near-infrared medical optical imaging and spectroscopy device, we have previously reported optical functional images of the adult motor cortex during hand movement which showed good spatial agreement with fMRI. We now present brain functional images of ill, premature infants during passive movement of the forearm using a new system, the Boston Diffusion Optical Tomography System (DOTS). The DOTS is a portable continuous-wave diffuse optical tomography system which uses lasers at 780 nm and 830 nm, and allows for real-time, non-invasive bedside assessments. For these studies, custom-made soft flexible probes embedded with the fiberoptic emitter-detector array were placed on extremely ill, mechanically ventilated 24 week premature infants. Specific passive movements of the left arm resulted in focal, contralateral and reproducible changes in cerebral absorption, indicating an increase in regional blood flow and oxygenation. Further bedside, real-time functional imaging studies are now being undertaken to continue to explore the spatiotemporal relationship between neural activation and vascular response in the brain. In the intensive care setting, these bedside, continuous and non-invasive optical methods of functional imaging could be critically important and may provide a tool to prospectively identify patients at high risk for brain injury.

Supported by United Cerebral Palsy Foundation, GCRC (MO1 RR 00070), ONR N-00014-94-1024, Spectros Co. (equity held by DA Benaron).