The MR imaging appearance of the vascular pedicle nasoseptal flap.

BACKGROUND AND PURPOSE Recently, surgeons have used an expanded endonasal surgical approach (EENS) to access skull base lesions not previously accessible by minimally invasive techniques. Reconstruction of the large skull base defects created during EENS is necessary to prevent postoperative CSF leaks. A vascular pedicle nasoseptal mucoperiosteal flap based on the nasoseptal artery, (Hadad-Bassagasteguy flap) is becoming a common reconstructive technique. The purpose of this study was to review the expected MR imaging appearance of these flaps and to discuss variations in the appearance that may suggest potential flap failure. MATERIALS AND METHODS We retrospectively reviewed 10 patients who underwent EENS for resection of sellar lesions with skull base reconstruction by multilayered reconstruction including the Hadad-Bassagasteguy flap. All patients had preoperative, immediate, and delayed postoperative MR imaging scans. Flap features that were evaluated included flap configuration, signal intensity characteristics on T1-weighted and T2-weighted images, enhancement patterns, location, and flap thickness. RESULTS All patients had detectable postoperative skull base defects. All patients had C-shaped configuration flaps within the operative defect, which were isointense on T1-weighted and T2-weighted images on both immediate and delayed postoperative MR imaging scans. On the immediate scans, 8 of 10 patients had enhancing flaps and 2 of 10 had minimal to no enhancement. There were 9 of 10 patients who had enhancing flaps on delayed scans, and 2 of 10 patients had flaps that increased in enhancing coverage on the delayed scans. CONCLUSIONS Vascular pedicle nasoseptal flaps have a characteristic MR imaging appearance. It is important for the radiologist to recognize this appearance and to evaluate for variations that may suggest potential flap failure.