title: Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.
abstract: Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention.
authors.affiliation: Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow G4 0NW, United Kingdom.
authors.forename: Mario E
authors.initials: ME
authors.lastname: Giardini
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council (CNR), Via Fratelli Cervi 93, 20090 Segrate (Milan), Italy.
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Zippo
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council (CNR), Via Fratelli Cervi 93, 20090 Segrate (Milan), Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Valente
authors.affiliation: CMOS Sensors Group, Integrated Micro & Nano Systems, School of Engineering, University of Edinburgh, The King's Buildings, Edinburgh EH9 3JL, United Kingdom.
authors.forename: Nikola
authors.initials: N
authors.lastname: Krstajic
authors.affiliation: Institute of Molecular Bioimaging and Physiology, National Research Council (CNR), Via Fratelli Cervi 93, 20090 Segrate (Milan), Italy.
authors.forename: Gabriele E M
authors.initials: GE
authors.lastname: Biella
mesh_terms: D000818:Animals; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000503:physiopathology* / Q000601:surgery; D041623:Tomography, Optical Coherence