title: Quantitative susceptibility mapping of the motor cortex in amyotrophic lateral sclerosis and primary lateral sclerosis.
abstract: OBJECTIVE
  The diagnosis of amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) is often difficult because of a lack of disease biomarkers. The purpose of this study was to investigate quantitative susceptibility mapping (QSM) of the motor cortex as a potential quantitative biomarker for the diagnosis of ALS and PLS.
  
  
  METHODS
  From a retrospective database, QSM images of 16 patients with upper motor neuron disease (nine men [56%], seven women; mean age, 56.3 years; 12 with ALS, four with PLS) and 23 control patients (13 men [56%], 10 women; mean age, 56.6 years) were reviewed. Two neuroradiologists, blinded to diagnosis, qualitatively assessed QSM, T2- and T2*-weighted, and T2-weighted FLAIR images. Relative motor cortex susceptibility was calculated by subtraction of adjacent white matter and CSF signal intensity from mean motor cortex susceptibility on the axial image most representative of the right- or left-hand lobule, and ROC analysis was performed. The Fisher exact and Student t tests were used to evaluate for statistical differences between the groups.
  
  
  RESULTS
  Qualitatively, QSM had greater diagnostic accuracy than T2-weighted, T2*-weighted, or T2-weighted FLAIR imaging for the diagnosis of ALS and PLS. Quantitatively, relative motor cortex susceptibility was found to be significantly greater in patients with motor neuron disease than in control patients (46.0 and 35.0 ppb; p < 0.001). ROC analysis showed an AUC of 0.88 (p < 0.0001) and an optimal cutoff value of 40.5 ppb for differentiating control patients from patients with ALS or PLS (sensitivity, 87.5%; specificity, 87.0%).
  
  
  CONCLUSIONS
  QSM is a sensitive and specific quantitative biomarker of iron deposition in the motor cortex in ALS and PLS.
authors.affiliation: 1 Department of Radiology, New York-Presbyterian Hospital, Weill-Cornell Medical Center, 525 E 68th St, Starr 630-C, New York, NY 10065.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Schweitzer
authors.forename: Tian
authors.initials: T
authors.lastname: Liu
authors.forename: Ajay
authors.initials: A
authors.lastname: Gupta
authors.forename: Karen
authors.initials: K
authors.lastname: Zheng
authors.forename: Stephen
authors.initials: S
authors.lastname: Seedial
authors.forename: Alexander
authors.initials: A
authors.lastname: Shtilbans
authors.forename: Mona
authors.initials: M
authors.lastname: Shahbazi
authors.forename: Dale
authors.initials: D
authors.lastname: Lange
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: A John
authors.initials: AJ
authors.lastname: Tsiouris
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology*; D016472:Motor Neuron Disease / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
keywords: amyotrophic lateral sclerosis; motor neuron disease; primary lateral sclerosis; quantitative susceptibility mapping