Fig. 7
a Three-dimensional view of the ascending colon showing a longitudinal luminal defect along a semi-lunar fold (black arrow): flat lesion? b, c The corresponding axial and sagittal views show a subtle stair step artefact on the abdominal wall (white arrowheads) and a doubled or “twin fold” aspect of the semilunar fold explaining the small longitudinal defect as a subtle breathing artefact