Figure 15b. Mucosal polyp (normal epithelium). (a) Endoluminal 3D view from CT colonography that simulates a retroflexed rectal view at colonoscopy shows a tiny 3-mm polyp (arrow). Note tip of a rectal catheter. Almost all mucosal polyps are diminutive and therefore will not influence management. (b) Digital photograph from optical colonoscopy shows measurement of the diminutive 3-mm lesion with the calibrated wire.