Critical brain regions related to post-stroke aphasia severity identified by early diffusion imaging are not the same when predicting short- and long-term outcome

Objectives: To identify the critical brain regions associated with 7-days, 3 and 6-months aphasia severity using diffusion-weighted imaging (DWI) in acute post-stroke patients. Materials and methods: We performed a voxel-based ADC (Apparent Diffusion Coefficient) analysis to identify the critical brain areas correlated with aphasia at the acute (7-days outcome) and chronic stages (3 and 6-months). The location of these areas was compared with the trajectory of the dorsal (the arcuate fasciculus) and the ventral language pathways (the inferior fronto-occipital and the uncinate fasciculi). Results: Disconnections of the language fasciculi, which were correlated with aphasia outcome, were not the same for the 7-days outcome (disconnection of the ventral stream) and the chronic outcome (3 and 6 months) (disconnection of the dorsal and ventral streams). Conclusion: Routine clinical images can be merged with atlases of anatomical connectivity to provide new insights about the relationship between the lesion location and aphasia severity.