Cortico-Efferent Tract Involvement in Primary Lateral Sclerosis and Amyotrophic Lateral Sclerosis: A Two-Center Tract of Interest-Based DTI Analysis
28 Pages Posted: 1 Aug 2018 First Look: Under Review
Background: After the demonstration of a corticoefferent propagation pattern in amyotrophic lateral sclerosis (ALS) by neuropathological studies, this concept has been used for in vivo staging of individual patients by diffusion tensor imaging (DTI) techniques, both in `classical` ALS and in restricted phenotypes such as primary lateral sclerosis (PLS). Objective: The study was designed to identify microstructural changes according to the neuropathologically defined ALS affectation pattern in PLS patients compared with ´classical´ ALS patients and healthy controls. Methods: Tractwise analysis of fractional anisotropy (FA) maps according to the ALS-staging pattern was applied to DTI data (pooled from two ALS centers) of 88 PLS patients and 88 ALS patients with a 'classical' phenotype in comparison to 88 matched controls in order to identify white matter integrity alterations.
Results: In the tract-specific analysis, alterations were identical for PLS and ALS in the tract systems corresponding to the ALS staging pattern, independent of the subject samples and the data acquisition parameters. The individual categorization into ALS stages did not differ between PLS and ALS patients.
Conclusions: This DTI study in a two-center setting demonstrated that the neuropathological stages can be mapped in vivo in PLS with high reproducibility and that PLS-associated cerebral propagation, although showing the same corticofugal patterns as ALS, might have a different time course.
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