title: Localization of nerve fiber bundles by polarization-sensitive optical coherence tomography.
abstract: Diagnostic modalities that can distinguish brain tumors from eloquent cortices or nerve fiber bundles are important for neurosurgery. For identifying nerve fiber bundles, various techniques such as diffusion tensor imaging and subcortical stimulation mapping have been used. In this article, we propose localization of nerve fiber bundles by polarization-sensitive optical coherence tomography (PS-OCT) for the first time. PS-OCT performs tomographic imaging by measuring the travel distance and the change in polarization of the backscattered light from the tissue at different traverse positions, enabling selective visualization of birefringent tissues such as nerve fiber bundles. We examined the imaging of nerve fiber bundles in blocks of fixed rat brains. Nerve fiber bundles in internal and external capsules of the rat brains appearing on the surfaces of the coronal, horizontal, and sagittal planes were identified as to their locations and orientations. The nerve fiber bundles were clearly visualized by PS-OCT. The image penetration depth of the PS-OCT images was about 1.0mm in gray matter and about 0.5mm in white matter, so the refractive indices of gray and white matters were assumed to be 1.4.
authors.affiliation: Department of Advanced Biomedical Engineering and Science, Graduate School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, Japan. hnakaji@abmes.twmu.ac.jp
authors.forename: Haruo
authors.initials: H
authors.lastname: Nakaji
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kouyama
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Muragaki
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iseki
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology; D001931:Brain Mapping / Q000295:instrumentation* / Q000379:methods*; D020772:Internal Capsule / Q000033:anatomy & histology / Q000502:physiology; D008027:Light; D008029:Lighting / Q000295:instrumentation / Q000379:methods; D008859:Microscopy, Polarization / Q000295:instrumentation / Q000379:methods; D009413:Nerve Fibers, Myelinated / Q000502:physiology / Q000648:ultrastructure*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*