Fig. 2
From: Deep learning to identify stroke within 4.5 h using DWI and FLAIR in a prospective multicenter study
Critical regions for onset-time classification using Grad-CAM. Grad-CAM was applied to the lesion images extracted from the b1000 volumes of the diffusion-weighted imaging (DWI) or fluid-attenuated inversion recovery (FLAIR) images. Lesion regions marked with higher values, closer to red on the map, indicate a greater contribution to onset-time classification. (A) The Grad-CAM results are indicated for the stroke-onset time of 2.3 h (< 4.5 h). (B) The Grad-CAM results are indicated for the stroke-onset time of 5.8 h (> 4.5 h). (C) The Grad-CAM results are indicated for the stroke-onset time of 18.7 h (> 4.5 h). Grad-CAM, gradient-weighted class activation mapping; hrs, hours; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery.
