title: Diffusion tensor imaging of the anterior cruciate ligament graft after reconstruction: repeatability and diffusion tensor imaging metrics.
abstract: OBJECTIVE
  The purpose of the study was to explore the feasibility and repeatability of diffusion tensor imaging and diffusion tractography on the anterior cruciate ligament graft after reconstruction and determine the fractional anisotropy and mean apparent diffusion coefficient values.
  
  
  METHODS
  Twenty-two patients who underwent anterior cruciate ligament reconstruction operation were scanned at 3-T clinical magnetic resonance scanner. The fiber tracking and other postprocessing steps were carried out twice by a radiologist on the workstation and repeated by another radiologist. Diffusion tensor metrics of different parts of the grafts were determined with region of interest- and fiber tractography-based measurements, and the intraobserver and interobserver measurement variances were calculated.
  
  
  RESULTS
  Tractography illustrated nicely the 3-dimensional courses of the graft in all 22 cases. The mean fractional anisotropy value of the intratunnel part was significantly higher than that of the intra-articular part, whereas the mean apparent diffusion coefficient value of the intratunnel part was lower when compared with that of the intra-articular part. According to the 2-sided paired samples Student t test, the intraobserver and interobserver measurements correlated well.
  
  
  CONCLUSIONS
  Diffusion tensor imaging and diffusion tractography can be used to visualize the anterior cruciate ligament grafts and can provide additional information over standard morphologic magnetic resonance imaging.
authors.affiliation: From the Departments of *Radiology, and †Orthopedic Surgery, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, People's Republic of China.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Yang
authors.forename: Dongyang
authors.initials: D
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Dongquan
authors.initials: D
authors.lastname: Shi
authors.forename: Bin
authors.initials: B
authors.lastname: Zhu
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology* / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult