title: In vivo evaluation of rabbit sciatic nerve regeneration with diffusion tensor imaging (DTI): correlations with histology and behavior.
abstract: Diffusion tensor imaging (DTI) is widely used in the study of the central nervous system. DTI represents a potential diagnostic tool for the peripheral nerve. However, more detailed information is needed for application of DTI in the clinical setting. In this study, peripheral degeneration and regeneration were evaluated using DTI-based analyses in a rabbit model. The changes in DTI parameters were compared to histological and functional changes after nerve injury. We used a high magnetic field (7.04T) MRI system. Japanese white male rabbits were used as the model of sciatic nerve crush injury. MR images were obtained before injury and at 2, 4, 6 and 8 weeks post-injury. The DTI parameters of fractional anisotropy (FA), axial diffusivity (λ||), and radial diffusivity (λ⊥) were calculated. Our results showed decreased FA and increased λ⊥ during the degenerative phase after sciatic nerve injury. In contrast, increased FA and decreased λ⊥ were observed during the regenerative phase. FA changes were correlated with axon number and with motor function recovery, assessed with the toe-spreading index. This study clearly demonstrates the validity of applying DTI parameters to the in vivo evaluation of peripheral nerve regeneration. Furthermore, results suggest that DTI can be a potent tool for predicting the extent of functional recovery after peripheral nerve injury.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yamasaki
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan. Electronic address: roda@koto.kpu-m.ac.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Oda
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mikami
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Ikeda
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Masateru
authors.initials: M
authors.lastname: Nagae
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Shirai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Morisaki
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ikoma
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Miwako
authors.initials: M
authors.lastname: Masugi-Tokita
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawata
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D016880:Anisotropy; D001369:Axons / Q000473:pathology; D001522:Behavior, Animal; D056324:Diffusion Tensor Imaging; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D009416:Nerve Regeneration / Q000502:physiology*; D059348:Peripheral Nerve Injuries / Q000473:pathology; D011817:Rabbits; D012584:Sciatic Nerve / Q000293:injuries / Q000473:pathology*
keywords: Diffusion tenor imaging; Fractional anisotropy; Peripheral nerve; Rabbit; Regeneration; Toe-spreading reflex