title: Longitudinal measurements of syrinx size in a rat model of posttraumatic syringomyelia.
abstract: OBJECTIVE Syringomyelia pathophysiology is commonly studied using rodent models. However, in vivo studies of posttraumatic syringomyelia have been limited by the size of animals and lack of reliable noninvasive evaluation techniques. Imaging the rat spinal cord is particularly challenging because the spinal cord diameter is approximately 1-3 mm, and pathological lesions within the spinal cord parenchyma are even smaller. The standard technique has been histological evaluation, but this has its limitations. The aim of the present study was to determine whether syrinx size could be reliably measured using a preclinical high-field MRI animal system in a rat model of posttraumatic syringomyelia. METHODS The authors used an existing rat model of posttraumatic syringomyelia, which was created using a controlled pneumatic compression device to produce the initial spinal cord injury, followed by a subarachnoid injection of kaolin to produce arachnoiditis. T2-weighted MRI was performed on each animal using a 9.4-T scanner at 7, 10, and 13 weeks after injury. Animals were killed and syrinx sizes were calculated from in vivo MRI and histological studies. RESULTS MRI measurements of syrinx volume and length were closely correlated to histological measurements across all time points (Pearson product moment correlation coefficient r = ± 0.93 and 0.79, respectively). CONCLUSIONS This study demonstrates that high-field T2-weighted MRI can be used to measure syrinx size, and data correlate well with syrinx size measured using histological methods. Preclinical MRI may be a valuable noninvasive technique for tracking syrinx formation and enlargement in animal models of syringomyelia.
authors.affiliation: Faculty of Medicine and Health Sciences and.
authors.forename: Elmira
authors.initials: E
authors.lastname: Najafi
authors.affiliation: Neuroscience Research Australia, and.|Prince of Wales Clinical School, University of New South Wales Medicine, Randwick, New South Wales, Australia.
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Bilston
authors.affiliation: Faculty of Medicine and Health Sciences and.
authors.forename: Xin
authors.initials: X
authors.lastname: Song
authors.affiliation: Lowy Cancer Research Centre, University of New South Wales, Sydney; and.
authors.forename: Andre
authors.initials: A
authors.lastname: Bongers
authors.affiliation: Faculty of Medicine and Health Sciences and.
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Stoodley
authors.affiliation: Faculty of Science and Engineering, Macquarie University.
authors.forename: Shaokoon
authors.initials: S
authors.lastname: Cheng
authors.affiliation: Faculty of Medicine and Health Sciences and.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Hemley
mesh_terms: D000818:Animals; D001100:Arachnoiditis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D003560:Cysts / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D018450:Disease Progression; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted; D007616:Kaolin; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009929:Organ Size; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D013595:Syringomyelia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors
chemical_list: D007616:Kaolin
keywords: ADC = apparent diffusion coefficient; MRI; RARE = rapid acquisition with relaxation enhancement; posttraumatic syringomyelia; spinal cord injury; syrinx