Fig. 2

Patterns of fibrosis. Examples of the pre-CRT (a–c) and corresponding post-CRT (d–f) T2-weighted images of three male patients with low to mid-rectal tumors. The first patient has a well-defined, almost circular tumor mass (a). After CRT (d), the tumor has undergone fibrotic transformation that follows the shape of the primary tumor, resulting in a full thickness (semi) circular fibrotic wall thickening. The second patient has a relatively small, semicircular tumor (b). After CRT, only a small focal area of fibrosis remains visible that is confined to the rectal wall (e). The third patient has an irregularly shaped, spiculated tumor (c). After CRT, the fibrosis also has an irregular aspect with persistent spiculations (f)