title: [Imaging analysis of ossification of ligamentum flavum associated with dural adhesions].
abstract: OBJECTIVE
  To summarize the characteristic imaging signs of ossification of the ligamentum flavum (OLF) associated with dural adhesions by analyzing retrospectively the imaging signs of OLF associated with dural adhesions.
  
  
  METHODS
  A retrospective analysis was made on clinical data of 85 patients undergoing OLF surgery between January 2010 and September 2012. The patients were assigned into the study group and the control group according to the preoperative imaging signs. Of 85 patients, 34 had both "tram track sign" and "jagged line sign" as the study group and 51 had either "tram track sign" or "jagged line sign" and neither of them as the control group. Adherence between dura mater and ligamentum flavum was observed during operation as the "gold standard" for the diagnosis of dural adhesion. The imaging information of CT and MRI in sagittal and axial planes was analyzed. The typical characteristics of dural adhesions were found. Then the sensitivity, specificity, and positive likelihood ratio of the preoperative imaging examinations were calculated to estimate the reference value and diagnostic value (> 5 having reference value, and > 10 having diagnostic value).
  
  
  RESULTS
  In the study group, dural adhesion was observed in 26 patients (10 males and 16 females), and the other 8 patients (6 males and 2 females) had no dural adhesion. In the control group, dural adhesion was found in 2 female patients who had "jagged line sign", and 49 patients had no dural adhesion (14 males and 35 females). In patients having both "tram track sign" and "jagged line sign", the sensitivity was 92.9%; the specificity was 86.0%; and the positive likelihood ratio was 6.6. In patients having "tram track sign", the sensitivity was 92.9%; the specificity was 64.9%; and the positive likelihood ratio was 2.6. In patients having "jagged line sign", the sensitivity was 100%; the specificity was 77.2%; and the positive likelihood ratio was 4.4.
  
  
  CONCLUSIONS
  For patients with OLF having both "tram track sign" and "jagged line sign", preoperative CT and MRI have a reference value for diagnoses of the OLF associated with dural adhesions.
authors.affiliation: Graduate School of Tianjin Medical University, Tianjin, 300070, P.R.China.
authors.forename: Xingqin
authors.initials: X
authors.lastname: Shen
authors.forename: Tianwei
authors.initials: T
authors.lastname: Sun
authors.forename: Zhao
authors.initials: Z
authors.lastname: Fang
authors.forename: Defu
authors.initials: D
authors.lastname: Meng
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Xueli
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004388:Dura Mater / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D011300:Preoperative Care; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013904:Thoracic Vertebrae; D000267:Tissue Adhesions; D014057:Tomography, X-Ray Computed