title: Application of fiber tractography and diffusion tensor imaging to evaluate spinal cord diseases in dogs.
abstract: Fiber tractography is a technique capable of depicting the three-dimensional structure and connectivity of nerve fibers using serial magnetic resonance diffusion tensor imaging (DTI). To establish fiber tractography and DTI methods in veterinary clinical medicine, we evaluated fiber tractography and DTI parameters: apparent diffusion coefficient (ADC) values and fractional anisotropy (FA) values, in various spinal cord diseases. Spinal cord DTI was examined in 28 dogs with spinal cord diseases. The ADC and FA values were measured at lesion sites and cranial normal sites on spinal cords, and both values of lesion sites were compared with normal sites. In thoracolumbar intervertebral disk herniation (IVDH) cases, depending on their neurologic grades, fiber tractography indicated rupture of fiber trajectories, loss of neuronal bundles and disorder of fiber directions. In these cases, the average ADC values at lesion sites significantly decreased compared with normal sites (P=0.016). In the progressive myelomalacia case, the average ADC and FA values of hyperintense swollen regions in T2WI decreased compared to both values in other disease cases. Finally, in the meningioma case, the continuity of fiber trajectories improved after the administration of an anticancer agent. This study suggests that fiber tractography and DTI are useful in the diagnosis and prognosis of veterinary spinal cord diseases.
authors.affiliation: Laboratory of Veterinary Clinical Radiology, Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Konishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Satoh
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Kuroiwa
authors.forename: Mizuki
authors.initials: M
authors.lastname: Kusaka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamashita
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Asada
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Asanuma
mesh_terms: D000818:Animals; D056324:Diffusion Tensor Imaging / Q000662:veterinary*; D004283:Dog Diseases / Q000000981:diagnostic imaging*; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging / Q000662:veterinary; D009412:Nerve Fibers; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000662:veterinary*