Figure 1.
Schematic overview of the performed measures.
Figure 2.
Whole brain cortical thickness.
Whole brain cortical thickness measurements in patients with ALS compared to healthy controls. Cortical areas with (uncorrected) p-values <0.01 are marked. The threshold for this illustration was set at 0.2 mm cortical thickness reduction in ALS.
Figure 3.
Overview of motor network measures.
a) Cortical thickness in patients with ALS versus controls in the precentral gyrus in mm (p = 0.04), corrected for age and whole brain cortical thickness; b) Fractional anisotropy (FA) values along the corticospinal tract and the corpus callosum in patients with ALS and controls (** p<0.01; * p<0.05); c) Number of functional connections, corrected for age (threshold 0.40); p = 0.14, CT = cortical thickness. PCG = precentral gyrus. FA = fractional anisotropy.
Figure 4.
Correlation of imaging parameters with clinical measures.
Correlation of ALSFRS-R score and progression rate with; a) cortical thickness in the precentral gyrus (CT PCG) of the clinically most affected side. Cortical thickness is corrected for average whole brain cortical thickness and age; b) FA in the -rostral part of the- corticospinal tract (CST) and FA in the corpus callosum (CC); c) Gamma - or local connectedness - corrected for the number of functional connections and age (threshold 0.30). * p<0.05, ALSFRS-R = ALS Functional Rating Scale Revisited. FA = fractional anisotropy. CST = corticospinal tract. CC = corpus callosum.
Table 1.
Study population characteristics.
Figure 5.
Selection of corticospinal tract (CST) and corpus callosum (CC) fibers.
First, all fibres were tracked. Secondly, the left precentral gyrus was selected as region of interest (ROI 1) and the fibres touching this ROI were selected. Thirdly, the brainstem was selected as second ROI (ROI 2a). The left CST was defined by all fibres touching both ROI 1 and ROI 2a. Finally, a third ROI (ROI 2b) was defined as the right precentral gyrus. The CC was defined by all fibres touching both ROI 1 and ROI 2b. The tracts of the right CST were defined in a similar manner. ROI = region of interest. PCG = precentral gyrus. CST = corticospinal tract. CC = corpus callosum.