title: Chronic T2 Lesions in Multiple Sclerosis are Heterogeneous Regarding Phase MR Imaging.
abstract: OBJECTIVE
  Phase imaging provides additional information on multiple sclerosis (MS) lesions and may in combination with mean diffusivity (MD) and magnetization transfer ratio (MTR) help differentiating heterogeneity of MS lesion pathology.
  
  
  METHODS
  Magnetic resonance imaging (MRI) was performed in 23 MS patients including diffusion tensor imaging (DTI), magnetization transfer imaging (MTI), and SWI. Mean values (MTR, MD, and homodyne filtered phase) from 138 chronic MS lesions and normal appearing white matter (NAWM) were obtained and correlations examined. For explorative analysis, a divisive hierarchical clustering algorithm was applied.
  
  
  RESULTS
  Phase characteristics were an independent characteristic of chronic T2 lesions, as MTR and MD were not correlated with phase values (R = - 0.23, R = - 0.18). Dependent on MTR, MD, and phase, cluster analysis led to five lesion groups. Of the two groups with phase values close to NAWM, one presented with highest MD and most severe MTR decrease (p  =  0.01), the other with slight MD increase and MTR decrease. Two lesion groups with highest phase values (p  =  0.01) displayed slightly increased MD and moderate decrease in MTR. Clinical data including EDSS, disease duration, and age did not differ significantly between groups.
  
  
  CONCLUSIONS
  Increased phase is predominantly detectable in lesions with clear MTR decrease but only moderate MD increase. Phase images seem to represent an independent parameter for MS lesion characterization and may provide additional information on MS lesion heterogeneity.
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany. s.siemonsen@uke.uni-hamburg.de.
authors.forename: S
authors.initials: S
authors.lastname: Siemonsen
authors.affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: K L
authors.initials: KL
authors.lastname: Young
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bester
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Sedlacik
authors.affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Heesen
authors.affiliation: Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Fiehler
authors.affiliation: Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: J-P
authors.initials: JP
authors.lastname: Stellmann
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging* / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Diffusion tensor imaging; Magnetic resonance imaging; Magnetization transfer contrast imaging; Multiple sclerosis; Susceptibility weighted imaging