Fig. 4
Rectal cancer in a 65-year-old woman. a Axial T2-weighted image demonstrated a rectal mass deeply extending to the mesorectal fat (white arrow). b Perfusion fraction (f), apparent kurtosis diffusion (Kapp), and the curve of signal intensity decay in diffusion pretherapy. Note that this curve showed a marked attenuation of signal intensity at low b values (red arrow) due to the influence of tumor perfusion on diffusion. c Following therapy, there are reduction of both f and Kapp and dissapearance of the fast attenuation of the signal intensity at low b values, related to tumor response with reducer perfusion on IVIM model