A, Immediate postoperative sagittal T1-weighted image shows a C-shaped flap underlying the operative defect (white arrow). B, Immediate postoperative sagittal T1-weighted image postcontrast with fat suppression shows a C-shaped flap underlying the operative defect (white arrow). C, Follow-up postoperative MR imaging scan sagittal unenhanced T1-weighted MR imaging shows decreased debris and removal of Foley catheter balloon in the sinonasal cavity and a C-shaped configuration of the flap, which is isointense (white arrow). D, Follow-up MR imaging sagittal T1-weighted postcontrast with fat suppression shows robust and thicker enhancement of the flap (white arrow).