Quantification of spinal cord injury through optical coherence tomography

Abstract

Recently, several treatment solutions for spinal cord injury (SCI) patient are introduced such as wireless electrical stimulation and stem cell therapy. To check the effect of treatment, monitoring spinal cord healing process is required, but MRI and CT cannot resolve small tissue level SCI. As an alternative non-destructive imaging tool, optical coherence tomography (OCT) was demonstrated to monitor and quantify SCI. OCT can visualize cross section information of biological samples with sub-micron resolution. Conventional OCT utilizes infra-red laser as a light source and screen flat focal plane through 2D scanner. However, if sample is curved or uneven structure, it is hard to acquire images where sample position is out of flat focal plane. To acquire entire information of curved sample, we present circular scanning optical coherence tomography. Like computed tomography (CT), scanning laser is guided to the sample omnidirectionally through specially designed metal coated mirror. Due to the perpendicular reflection at mirror, cylindrical focal plane around sample can be obtained, providing clear cross section information of spinal cord. To quantify SCI, we applied circular scanning OCT to spinal cord of mouse model ex vivo and segmented injury region through image processing. In addition, circular scanning OCT can detach white matter and gray matter. It gives possibility to monitor SCI healing process through quantifying area or volume of wound and time.