Fig. 7.

Example of problematic signal value changes between the BL and FU FLAIR scans: the images in (a) visualize the BL and FU scan with the same level-windows settings for both scans. This shows that the contrast and the signal value distribution between the two scans changed. If the window-level-setting are adjusted (b) to create a similar visual impression between the images, it becomes obvious that the lesion in this image slide has already be present in the BL scan. The CNN-based method correctly identified this lesion as old lesion tissue while the LST-method (c) detected a false positive (FP) new lesion. In the whole MR scan LST found 13 FP while our CNN method found no FP.