OCT News 2013 Student Paper Awarded to Carissa Reynolds from University of California Riverside
Carissa Reynolds from University of California Riverside was a winner of the 2013 OCT News Student Paper Award for her submission “Using Optical Coherence Tomography to Detect Cerebral Edema.” Below is a summary of her work:
Cerebral edema, an increase in brain water content, is responsible for significant morbidity and mortality among patients suffering from neurological disorders such as traumatic brain injury, stroke, brain tumor and infection. Cerebral edema develops in response to these conditions and leads to further clinical deterioration by, for example, raising the intracranial pressure (ICP), disrupting blood flow to the brain and/or causing brain herniation. These types of secondary injuries caused by cerebral edema could be avoided by early detection of the condition [1,2] which currently is not possible, despite its prevalence. Instead, ICP is measured to indirectly determine the net change in brain volume due to excess water. This method however, does not provide an accurate measure of edema [3,4].
Together with Dr. Hyle Park and Dr. Devin K. Binder, I am working to develop a new cerebral edema detection method using optical coherence tomography (OCT). Optical detection will provide a more direct measure of cerebral edema compared with ICP detection since light scattering is directly affected by the amount of water in the brain . Furthermore, the multi-functional nature of OCT allows for both the edematous region to be spatially located relative to known brain structures and for local changes in blood flow to be determined.
In our initial studies, a mouse model of cerebral edema, prepared with a thinned-skull cortical window , was imaged using a spectral-domain OCT system centered at 1300 nm. Images were acquired continuously over twenty minutes of baseline followed by approximately one hour of cerebral edema, until the animal expired. This condition was induced in the animal by an intraperitoneal (IP) injection of water given twenty minutes into the experiment. The average OCT intensity within the cerebral cortex showed a decreasing trend over time after the IP injection was given. Furthermore, local analysis of phase variance in regions initially showing flow demonstrated a decrease in blood flow during late-stage edema. These results are consistent with blood vessel compression known to occur during severe edema . Phase variance volumetric data from a separate TBI mouse model has also demonstrated the ability of OCT to spatially resolve a local injury site. These results taken together provide preliminary evidence for the ability of OCT to detect cerebral edema.
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 L. C. Padayachy, A. A. Figaji, and M. R. Bullock, Childs Nerv Syst 26, 441-52 (2010).
 M. Czosnyka and J. D. Pickard, J of Neurol, Neurosurg Psychiatry 75, 813-821 (2004).
 A. S. Gill, K. F. Rajneesh, C. M. Owen, J. Yeh, M. Hsu, and D. K. Binder, J Neurosurg 114, 470-7 (2011).
 J. I. Szu, M. M. Eberle, C. L. Reynolds, et al., J. Vis. Exp. (69), e50053, doi:10.3791/50053 (2012).