title: Anatomical brain connectivity can assess cognitive dysfunction in multiple sclerosis.
abstract: BACKGROUND
  Brain disconnection plays a major role in determining cognitive disabilities in multiple sclerosis (MS). We recently developed a novel diffusion-weighted magnetic resonance imaging (DW-MRI) tractography approach, namely anatomical connectivitity mapping (ACM), that quantifies structural brain connectivity.
  
  
  OBJECTIVE
  Use of ACM to assess structural connectivity modifications in MS brains and ascertain their relationship with the patients' Paced-Auditory-Serial-Addition-Test (PASAT) scores.
  
  
  METHODS
  Relapsing-remitting MS (RRMS) patients (n = 25) and controls (n = 25) underwent MRI at 3T, including conventional images, T1-weighted volumes and DW-MRI. Volumetric scans were coregistered to fractional anisotropy (FA) images, to obtain parenchymal FA maps for both white and grey matter. We initiated probabilistic tractography from all parenchymal voxels, obtaining ACM maps by counting the number of streamlines passing through each voxel, then normalizing by the total number of streamlines initiated. The ACM maps were transformed into standard space, for statistical use.
  
  
  RESULTS
  RRMS patients had reduced grey matter volume and FA, consistent with previous literature. Also, we showed reduced ACM in the thalamus and in the head of the caudate nucleus, bilaterally. In our RRMS patients, ACM was associated with PASAT scores in the corpus callosum, right hippocampus and cerebellum.
  
  
  CONCLUSIONS
  ACM opens a new perspective, clarifying the contribution of anatomical brain disconnection to clinical disabilities in MS.
authors: Santa Lucia Foundation, Rome, Italy. m.bozzali@hsantalucia.it
authors: M
authors: M
authors: Bozzali
authors: B
authors: B
authors: Spanò
authors: G J M
authors: GJ
authors: Parker
authors: G
authors: G
authors: Giulietti
authors: M
authors: M
authors: Castelli
authors: B
authors: B
authors: Basile
authors: S
authors: S
authors: Rossi
authors: L
authors: L
authors: Serra
authors: G
authors: G
authors: Magnani
authors: U
authors: U
authors: Nocentini
authors: C
authors: C
authors: Caltagirone
authors: D
authors: D
authors: Centonze
authors: M
authors: M
authors: Cercignani
mesh_terms: D000328:Adult; D016880:Anisotropy; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests
keywords: Anatomical connectivity mapping; cognitive dysfunction; diffusion imaging; fractional anisotropy; magnetic resonance imaging; paced auditory serial addition test; relapsing–remitting multiple sclerosis