Fig. 4

Growth pattern of tumor and the measurement of maximal extramural depth. A: on oblique axial HRT2WI, the rectal tumor invaded the entire rectal wall, showing a complete annular shape. The maximal extramural depth was the distance between the attachment in the two muscularis propria breakthroughs and the outermost boundary of the tumor (1.11 cm). B: a local mass appeared in the right wall of the rectum (white dotted circle), with less than one-half of the invaded rectal wall