title: Clinical significance of atrophy and white matter mean diffusivity within the thalamus of multiple sclerosis patients.
abstract: BACKGROUND
  Gray-matter (GM) atrophy is strongly predictive of cognitive impairment in multiple sclerosis (MS) patients. The thalamus is the region where the atrophy/cognition correlation is most robust. However, few studies have assessed diffusion tensor imaging (DTI) metrics within the thalamus.
  
  
  OBJECTIVE
  This study was designed to determine if thalamus white matter DTI predicts cognitive impairment after accounting for the effects of volume loss.
  
  
  METHODS
  We enrolled 75 MS patients and 18 healthy controls undergoing 3T brain magnetic resonance imaging (MRI). Thalamus volumes were calculated on 3D T1 images. Voxelwise analyses of DTI metrics were performed within the thalamic white matter tracts. Neuropsychological (NP) testing, acquired using consensus standard methods, contributed measures of memory, cognitive processing speed and executive function.
  
  
  RESULTS
  All cognitive tests were significantly predicted (R (2) =0.31, p<0.001) by thalamus volume after accounting for influence of demographics. Mean diffusivity was retained in regression models predicting all cognitive tests, adding from 7-13% of additional explained variance (p<0.02) after accounting for thalamus volume.
  
  
  CONCLUSIONS
  We confirm the significant role of thalamus atrophy in MS-associated cognitive disorder, and further report that subtle thalamus pathology as detected by DTI adds incremental explained variance in predicting cognitive impairment.
authors: Department of Neurology, SUNY Buffalo School of Medicine, USA.
authors: Ralph Hb
authors: RH
authors: Benedict
authors: Hanneke E
authors: HE
authors: Hulst
authors: Niels
authors: N
authors: Bergsland
authors: Menno M
authors: MM
authors: Schoonheim
authors: Michael G
authors: MG
authors: Dwyer
authors: Bianca
authors: B
authors: Weinstock-Guttman
authors: Jeroen Jg
authors: JJ
authors: Geurts
authors: Robert
authors: R
authors: Zivadinov
mesh_terms: D000328:Adult; D000368:Aged; D001284:Atrophy; D003072:Cognition Disorders / Q000209:etiology* / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology* / Q000523:psychology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D013788:Thalamus / Q000473:pathology*
keywords: Multiple sclerosis; cognitive impairment; diffusion tensor imaging; mean diffusivity; thalamus