Fig 7.

This example is from another data group but illustrates how flaps can be displaced and not adhere to the denuded sinonasal wall. A, Immediate postoperative coronal MR imaging T1-weighted postcontrast with fat suppression shows a defect (white arrowhead) left of the enhancing flap (white arrow). The flap (white arrow) is sloping inferiorly and is not in contact with the denuded sinonasal wall. A Foley catheter balloon is attempting to secure the flap. There is a large anterior skull base defect with herniation of brain parenchyma (white curved arrow). There is fat suppression making the defect (white arrowhead) look larger, which is a potential pitfall. The flap is displaced inferiorly on the left. This patient had a leak. B, Axial T1-weighted 5-mm MR imaging of no fat suppression shows the fat packing in the left defect (black star). This image demonstrates a potential pitfall when there is fat packing in overdiagnosing a defect on the fat-suppressed images.