Fig 3.

Involved circumferential resection margin predicted by magnetic resonance imaging. Oblique axial thin section imaging and corresponding gross tissue slice. The scan depicts an intermediate signal intensity (grey) mid-third rectal tumour (outlined in white). The mesorectal fascia is shown as a thin low signal intensity dark line enveloping the mesorectum (red line). The scan shows a tongue of tumour lying against the mesorectal fascia (arrow). The potential circumferential margin is defined as affected on the preoperative magnetic resonance imaging because the distance to the mesorectal fascia is <1 mm. The tissue slice shows tumour affecting the surgical circumferential margin. The margin is therefore affected as predicted by magnetic resonance imaging