Mr. Michael A. Tao Profile

Michael A. Tao

at US Food and Drug Administration

SPIE Involvement:

Author

Publications (1)

SPIE Journal Paper | 17 April 2023 Open Access

Development of polarization-sensitive optical coherence tomography imaging platform and metrics to quantify electrostimulation-induced peripheral nerve injury in vivo in a small animal model

Guillermo Monroy, Mohsen Erfanzadeh, Michael Tao, Damon DePaoli, Ilyas Saytashev, Ahhyun Stephanie Nam, Harmain Rafi, Kasey Kwong, Katherine Shea, Benjamin Vakoc, Srikanth Vasudevan, Daniel Hammer

NPh, Vol. 10, Issue 02, 025004, (April 2023) https://doi.org/10.1117/12.10.1117/1.NPh.10.2.025004

KEYWORDS: Nerve, Optical coherence tomography, Coherence imaging, Animals, Nervous system, Injuries, Biological imaging, Optical imaging, Image segmentation, Tissue optics

Read Abstract +

SignificanceNeuromodulation devices are rapidly evolving for the treatment of neurological diseases and conditions. Injury from implantation or long-term use without obvious functional losses is often only detectable through terminal histology. New technologies are needed that assess the peripheral nervous system (PNS) under normal and diseased or injured conditions.AimWe aim to demonstrate an imaging and stimulation platform that can elucidate the biological mechanisms and impacts of neurostimulation in the PNS and apply it to the sciatic nerve to extract imaging metrics indicating electrical overstimulation.ApproachA sciatic nerve injury model in a 15-rat cohort was observed using a newly developed imaging and stimulation platform that can detect electrical overstimulation effects with polarization-sensitive optical coherence tomography. The sciatic nerve was electrically stimulated using a custom-developed nerve holder with embedded electrodes for 1 h, followed by a 1-h recovery period, delivered at above-threshold Shannon model k-values in experimental groups: sham control (SC, n = 5, 0.0 mA / 0 Hz), stimulation level 1 (SL1, n = 5, 3.4 mA / 50 Hz, and k = 2.57), and stimulation level 2 (SL2, n = 5, 6.8 mA / 100 Hz, and k = 3.17).ResultsThe stimulation and imaging system successfully captured study data across the cohort. When compared to a SC after a 1-week recovery, the fascicle closest to the stimulation lead showed an average change of +4 % / − 309 % (SL1/SL2) in phase retardation and −79 % / − 148 % in optical attenuation relative to SC. Analysis of immunohistochemistry (IHC) shows a +1 % / − 36 % difference in myelin pixel counts and −13 % / + 29 % difference in axon pixel counts, and an overall increase in cell nuclei pixel count of +20 % / + 35 % . These metrics were consistent with IHC and hematoxylin/eosin tissue section analysis.ConclusionsThe poststimulation changes observed in our study are manifestations of nerve injury and repair, specifically degeneration and angiogenesis. Optical imaging metrics quantify these processes and may help evaluate the safety and efficacy of neuromodulation devices.

DOWNLOAD PAPER

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years