title: Combined structural and neurochemical evaluation of the corticospinal tract in amyotrophic lateral sclerosis.
abstract: Our objective was to characterize the structural and metabolic changes of the corticospinal tract (CST) in ALS patients using combined diffusion tensor imaging (DTI) and magnetic resonance spectroscopic imaging (MRSI). Fourteen patients (male:female, 6:8; mean age, 54 years) and 14 controls (male:female, 8:6; mean age, 53 years) underwent imaging. Four regions of the CST were evaluated: precentral gyrus, corona radiata, posterior limb of the internal capsule, and cerebral peduncle. DTI and MRSI indices tested included fractional anisotropy (FA), apparent diffusion coefficient (ADC), and the ratio of N-acetylaspartate to choline (NAA/Cho) and creatine (NAA/Cr). In the precentral gyrus, NAA/Cho was reduced 18% (p<0.001), NAA/Cr was reduced 9% (p=0.01), and FA was reduced 3% (p=0.02). NAA/Cho and NAA/Cr were reduced in the corona radiata (p<0.001). Reduced NAA/Cho in the precentral gyrus correlated with shorter symptom duration (r=0.66, p=0.02) and faster disease progression (r=-0.65, p=0.008). Increased spasticity correlated with higher ADC in the precentral gyrus (R=0.52, p=0.005). In conclusion, both MRSI and DTI provided in vivo evidence of intracranial degeneration of the CST in ALS that was most prominent rostrally in the precentral gyrus.
authors.affiliation: Department of Medicine, The University of Alberta, Canada.
authors.forename: Timothy
authors.initials: T
authors.lastname: Pyra
authors.forename: Benjamin
authors.initials: B
authors.lastname: Hui
authors.forename: Chris
authors.initials: C
authors.lastname: Hanstock
authors.forename: Luis
authors.initials: L
authors.lastname: Concha
authors.forename: John C T
authors.initials: JC
authors.lastname: Wong
authors.forename: Christian
authors.initials: C
authors.lastname: Beaulieu
authors.forename: Wendy
authors.initials: W
authors.lastname: Johnston
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kalra
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000473:pathology*; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D056324:Diffusion Tensor Imaging; D018450:Disease Progression; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000378:metabolism / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000378:metabolism / Q000473:pathology; D011712:Pyramidal Tracts / Q000378:metabolism* / Q000473:pathology*; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline