Data from: A prospective harmonized multicentre DTI study of cerebral white matter degeneration in ALS

Objective: To evaluate progressive white matter (WM) degeneration in ALS.
Methods: Sixty-six patients with ALS and 43 healthy controls were enrolled
in a prospective, longitudinal, multicentre study in the Canadian ALS
Neuroimaging Consortium (CALSNIC). Participants underwent a harmonized
neuroimaging protocol across 4 centres including diffusion tensor imaging
(DTI) for assessment of WM integrity. Three visits were accompanied by
clinical assessments of disability (ALSFRS-R) and upper motor neuron (UMN)
function. Voxel-wise whole brain and quantitative tractwise DTI
assessments were done at baseline and longitudinally. Correction for site
variance incorporated data from healthy controls and from healthy
volunteers that underwent the DTI protocol at each centre. Results: ALS
patients had a mean progressive decline in fractional anisotropy (FA) of
the corticospinal tract (CST) and frontal lobes. Tractwise analysis
revealed reduced FA in the CST, corticopontine/corticorubral and
corticostriatal tracts. CST FA correlated with UMN function and frontal
lobe FA with the ALSFRS-R. A progressive decline in CST FA correlated with
a decline in the ALSFRS-R and worsening UMN signs. Patients with fast vs
slow progression had a greater reduction in FA of the CST and upper
frontal lobe. Conclusions: Progressive WM degeneration in ALS is most
prominent in the CST and frontal lobes, and to a lesser degree in the
corticopontine/corticorubral tracts and the corticostriatal pathways. With
the use of a harmonized imaging protocol and incorporation of analytical
methods to address site-related variances, this study is an important
milestone towards developing DTI biomarkers for cerebral degeneration in
ALS.