title: Histogram analysis of diffusion measures in clinically isolated syndromes and relapsing-remitting multiple sclerosis.
abstract: OBJECTIVE
  The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases.
  
  
  METHODS
  DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T(2)WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients.
  
  
  RESULTS
  Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS.
  
  
  CONCLUSIONS
  Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.
authors.affiliation: Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing, China.
authors.forename: Chun Shui
authors.initials: CS
authors.lastname: Yu
authors.forename: Fu Chun
authors.initials: FC
authors.lastname: Lin
authors.forename: Yaou
authors.initials: Y
authors.lastname: Liu
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Duan
authors.forename: Hao
authors.initials: H
authors.lastname: Lei
authors.forename: Kun Cheng
authors.initials: KC
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016880:Anisotropy; D016022:Case-Control Studies; D003711:Demyelinating Diseases / Q000473:pathology*; 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 / Q000473:pathology*; D011446:Prospective Studies; D018709:Statistics, Nonparametric