Fig. 4

Comparison of baseline and follow-up MRI in three patients with Crohn’s disease. A1–A4 Axial and coronal T2-weighted images of a 22-year-old male from the high activity group, in which a high-signal perianal fistula is visible in baseline images (A1, A2), and after 15 months of treatment with adalimumab, the corresponding lesion disappeared in follow-up images (A3, A4); B1–B4 Axial and sagittal T2-weighted images of a 29-year-old male from the low-activity group, where the high T2 signal lesion in baseline images (B1, B2) was significantly reduced in extent in follow-up images (B3, B4) after 3 months of treatment with vedolizumab; C1, C2 Axial T2-weighted images of a 34-year-old male from the low-activity group, where a high T2 signal fistula in baseline image (C1) became significantly more extensive in follow-up image (C2) and an additional lesion was present