title: Linear longitudinal decline in fractional anisotropy in patients with amyotrophic lateral sclerosis: preliminary results.
abstract: OBJECTIVE
  As potential therapies aimed at halting or slowing the decline in upper motor neuron function in patients with amyotrophic lateral sclerosis (ALS) or primary lateral sclerosis (PLS) are developed, a quantitative method for monitoring response will be necessary. Measurement of fractional anisotropy (FA) using diffusion tensor imaging (DTI) over time should parallel functional decline from upper motor neuron degeneration in these patients.
  
  
  METHODS
  Two patients with definite ALS were imaged at 3.0 T and FA values were obtained in the corticospinal tract every 3 months for 1 year. The FA values were compared to normal age-matched controls.
  
  
  RESULTS
  Both patients showed linear decreases in FA values over time with R(2) values ranging from 0.93 to 0.99. The decline became statistically significant over the course of the study. Qualitative decreases in anisotropy were also evident on FA maps.
  
  
  CONCLUSIONS
  If these trends can be validated in greater numbers of patients, DTI may serve as an objective quantitative biomarker for disease progression in patients with upper motor neuron disease.
authors.affiliation: Department of Radiology, Fletcher Allen Healthcare/The University of Vermont, 111 Colchester Ave., Burlington, VT 05401, USA. Joshua.Nickerson@vtmednet.org
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Nickerson
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Koski
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Boyer
authors.forename: Heather N
authors.initials: HN
authors.lastname: Burbank
authors.forename: Rup
authors.initials: R
authors.lastname: Tandan
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Filippi
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D018450:Disease Progression; D005207:Fasciculation / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000000981:diagnostic imaging / Q000473:pathology; D011712:Pyramidal Tracts / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D013997:Time Factors