title: Relapsing neuromyelitis optica and relapsing-remitting multiple sclerosis: differentiation at diffusion-tensor MR imaging of corpus callosum.
abstract: OBJECTIVE
  To prospectively assess sensitivity and specificity of diffusion indexes of the corpus callosum (CC) for differentiating relapsing neuromyelitis optica (RNMO) from relapsing-remitting multiple sclerosis (RRMS), by using final clinical diagnosis as the reference standard.
  
  
  METHODS
  Participants provided informed consent; the study was approved by the institutional review board. Forty-six consecutive patients with RRMS (18 men, 28 women; mean age, 37.7 years; range, 18-58 years) and 26 consecutive patients with RNMO (two men, 24 women; mean age, 38.6 years; range, 19-59 years) underwent diffusion-tensor magnetic resonance imaging. Mean diffusivity (MD) and fractional anisotropy (FA) of the region of interest (ROI) of the CC in the midsagittal plane were measured and used as discriminative indexes. Bayesian classification with leave-one-out cross-validation was used to determine diagnostic accuracy. Differences in diffusion indexes of ROIs among groups were evaluated by using the Kruskal-Wallis test, followed by the Mann-Whitney U test for multiple comparisons and Bonferroni correction.
  
  
  RESULTS
  Mean MD (8.48 x 10(-4) mm(2)/sec) and FA (0.729) of the ROI in patients with RNMO were significantly (P<.001) different from those (MD=10.64 x 10(-4) mm(2)/sec, FA=0.599) in patients with RRMS. Sensitivity and specificity for differentiation were 92.3% (24 of 26 patients with RNMO) and 93.5% (43 of 46 patients with RRMS) for FA and 88.5% (23 of 26 patients with RNMO) and 89.1% (41 of 46 patients with RRMS) for MD, respectively.
  
  
  CONCLUSIONS
  Measurement of diffusion indexes of the CC may be useful for distinguishing patients with RNMO from those with RRMS.
authors.affiliation: Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053, People's Republic of China.
authors.forename: Chun Shui
authors.initials: CS
authors.lastname: Yu
authors.forename: Chao Zhe
authors.initials: CZ
authors.lastname: Zhu
authors.forename: Kun Cheng
authors.initials: KC
authors.lastname: Li
authors.forename: Yun
authors.initials: Y
authors.lastname: Xuan
authors.forename: Wen
authors.initials: W
authors.lastname: Qin
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.forename: Piu
authors.initials: P
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D001499:Bayes Theorem; D003337:Corpus Callosum / Q000473:pathology*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000473:pathology; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000473:pathology; D011446:Prospective Studies; D012008:Recurrence; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric