title: Corticospinal tract integrity is related to primary motor cortex thinning in relapsing-remitting multiple sclerosis.
abstract: BACKGROUND
  The relationship between white matter injury and cortical atrophy development in relapsing-remitting multiple sclerosis (RRMS) remains unclear.
  
  
  OBJECTIVE
  To investigate the associations between corticospinal tract integrity and cortical morphology measures of the primary motor cortex in RRMS patients and healthy controls.
  
  
  METHODS
  51 RRMS patients and 30 healthy controls underwent MRI examination for cortical reconstruction and assessment of corticospinal tract integrity. Partial correlation and multiple linear regression analyses were used to investigate the associations of focal and normal appearing white matter (NAWM) injury of the corticospinal tract with thickness and surface area measures of the primary motor cortex. Relationships between MRI measures and clinical disability as assessed by the Expanded Disability Status Scale and disease duration were also investigated.
  
  
  RESULTS
  In patients only, decreased cortical thickness was related to increased corticospinal tract NAWM mean, axial and radial diffusivities in addition to corticospinal tract lesion volume. The final multiple linear regression model for PMC thickness retained only NAWM axial diffusivity as a significant predictor (adjusted R(2)= 0.270, p= 0.001). Clinical measures were associated with NAWM corticospinal tract integrity measures.
  
  
  CONCLUSIONS
  Primary motor cortex thinning in RRMS is related to alterations in connected white matter and is best explained by decreased NAWM integrity.
authors: MR Research Laboratory, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy/Buffalo Neuroimaging Analysis Center, Department of Neurology, University at Buffalo SUNY, USA/Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy nbergsland@dongnocchi.it.
authors: Niels
authors: N
authors: Bergsland
authors: MR Research Laboratory, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy.
authors: Maria Marcella
authors: MM
authors: Laganà
authors: Unit of Motor Neurorehabilitation, Multiple Sclerosis Centre, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy.
authors: Eleonora
authors: E
authors: Tavazzi
authors: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors: Matteo
authors: M
authors: Caffini
authors: Unit of Motor Neurorehabilitation, Multiple Sclerosis Centre, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy.
authors: Paola
authors: P
authors: Tortorella
authors: MR Research Laboratory, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy.
authors: Francesca
authors: F
authors: Baglio
authors: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors: Giuseppe
authors: G
authors: Baselli
authors: Unit of Motor Neurorehabilitation, Multiple Sclerosis Centre, IRCCS, Don Gnocchi Foundation ONLUS, Milan, Italy.
authors: Marco
authors: M
authors: Rovaris
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000473:pathology*; D011712:Pyramidal Tracts / Q000473:pathology*; D012720:Severity of Illness Index; D066127:White Matter / Q000473:pathology*
keywords: MRI; Multiple sclerosis; brain atrophy; cortical atrophy; corticospinal tract; diffusion tensor imaging