Progressive and short-interval changes observed in the corticospinal tract and corpus callosum of ALS patients: A texture analysis study.

Background and purpose: Diffusion magnetic resonance imaging (MRI) measures indicative of white matter integrity have consistently been shown to be altered in the state of the corticospinal tract and corpus callosum of patients with amyotrophic lateral sclerosis (ALS). However, diffusion MRI acquisitions are not routinely collected as part of the standard medical imaging of ALS patients. T1-weighted MRI scans are commonly available in the clinical assessment of most ALS patients. While visual inspection of these scans reveals little about the cerebral pathology of ALS, analysis of their textural patterns has identified disease-related abnormalities in patients at various stages of the disease. The present study aimed to examine the spatial and temporal profile of corticospinal tract and corpus callosum degeneration in ALS patients using texture analysis of T1-weighted MRI scans obtained at baseline and at four-and eight-month follow-ups.

Materials and methods: The study involved data from 64 ALS patients and 83 healthy controls who participated in the multicenter Canadian ALS Neuroimaging Consortium (CALSNIC) project. The texture feature "autocorrelation" was quantified along the superior-inferior course of the corticospinal tract and along the anterior-posterior direction of the corpus callosum of participants.

Results: Progressive textural changes were observed within the bilateral corticospinal tract, particularly in the primary motor cortex region, posterior limb of the internal capsule, and the cerebral peduncle. As the disease progressed, significant textural changes developed in the middle and anterior parts of the corpus callosum. Autocorrelation values in these regions correlated with the degree of upper motor neuron dysfunction on neurological examination.

Conclusions: Progressive corticospinal tract and corpus callosum degeneration was characterized in ALS using a novel imaging texture analysis approach, with changes observed over an interval of 4 months.

Abbreviations: ALS＝ Amyotrophic lateral sclerosis; CST＝ corticospinal tract; CC = corpus callosum; ALSFRS-R= ALS functional rating scale-revised; CALSNIC = Canadian ALS Neuroimaging Consortium; DPR = disease progression rate; ECAS = Edinburgh Cognitive and Behavioral ALS Screen; HC = healthy control; FDR = false discovery rate; UMN = upper motor neurons.