title: Establishing pathological cut-offs of brain atrophy rates in multiple sclerosis.
abstract: OBJECTIVE
  To assess whether it is feasible to establish specific cut-off values able to discriminate 'physiological' or 'pathological' brain volume rates in patients with multiple sclerosis (MS).
  
  
  METHODS
  The study was based on the analysis of longitudinal MRI data sets of patients with MS (n=206, 87% relapsing-remitting, 7% secondary progressive and 6% primary progressive) and healthy controls (HC; n=35). Brain atrophy rates were computed over a mean follow-up of 7.5 years (range 1-12) for patients with MS and 6.3 years (range 1-12.5) for HC with the SIENA software and expressed as annualised per cent brain volume change (PBVC/y). A weighted (on the follow-up length) receiver operating characteristic analysis and the area under the curve (AUC) were used for statistics.
  
  
  RESULTS
  The weighted PBVC/y was -0.51±0.27% in patients with MS and -0.27±0.15% in HC (p<0.0001). There was a significant age-related difference in PBVC/y between HC older and younger than 35 years of age (p=0.02), but not in patients with MS (p=0.8). The cut-off of PBVC/y, as measured by SIENA that could maximise the accuracy in discriminating patients with MS from HC, was -0.37%, with 67% sensitivity and 80% specificity. According to the observed distribution, values of PBVC/y as measured by SIENA that could define a pathological range were above -0.52% with 95% specificity, above -0.46% with 90% specificity and above -0.40% with 80% specificity.
  
  
  CONCLUSIONS
  Our evidence-based criteria provide values able to discriminate the presence or absence of 'pathological' brain volume loss in MS with high specificity. Such results could be of great value in a clinical setting, particularly in assessing treatment efficacy in MS.
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: De Stefano
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Stromillo
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Giorgio
authors.affiliation: Neurology Unit, Hospital of Empoli, Empoli, Italy.
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Bartolozzi
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Battaglini
authors.affiliation: Neurology Unit, Hospital of Empoli, Empoli, Italy.
authors.forename: Mariella
authors.initials: M
authors.lastname: Baldini
authors.affiliation: Department of Neurology, University of Florence, Florence, Italy.
authors.forename: Emilio
authors.identifier: http://orcid.org/0000-0002-9662-1762
authors.initials: E
authors.lastname: Portaccio
authors.affiliation: Department of Neurology, University of Florence, Florence, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Amato
authors.affiliation: Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Sormani
mesh_terms: D000328:Adult; D000367:Age Factors; D019540:Area Under Curve; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D018450:Disease Progression; D019317:Evidence-Based Medicine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology / Q000473:pathology* / Q000628:therapy; D012372:ROC Curve; D012015:Reference Standards; D015203:Reproducibility of Results; D055815:Young Adult
keywords: MRI; MULTIPLE SCLEROSIS