MR EVALUATION OF FRONTAL-SINUS OSTEOPLASTIC FLAPS WITH AUTOGENOUS FATGRAFTS

PURPOSE: To investigate the MR findings in patients who have had osteo plastic frontal sinus flaps placed for inflammatory sinonasal disease. METHODS: The MR images of 13 patients who had improvement of symptoms after osteoplastic frontal sinus flap placement with fat autograft we re prospectively evaluated for the presence of high intensity on T2-we ighted scans, contrast enhancement, and replacement of frontal sinus f at by lower-signal soft tissue. All studies were performed on a 1.5-T unit using a 5-in round surface coil placed over the nasion. Sagittal Tl-weighted, axial and coronal fast spin-echo T2-weighted, and precont rast and postcontrast axial and coronal T1-weighted images were obtain ed through the operative bed. The T2-weighted and postgadolinium seque nces were done with a fat-suppression technique. RESULTS: Hyperintensi ty within the frontal sinuses on T2-weighted images and enhancement (p eripherally and/or centrally where fat was replaced with soft tissue) were found to some degree in all patients. The degree of replacement o f frontal sinus fat with soft tissue ranged from 4% to 85% (mean, 43%) . Five patients with persistent symptoms had no distinguishing MR feat ures when compared with asymptomatic patients. CONCLUSIONS: Although i ncreased T2-weighted intensity, fat replacement, and enhancement are f indings compatible with inflammation, these changes may be seen in pat ients who are asymptomatic after placement of osteoplastic frontal sin us flaps; they may represent the normal granulation process. MR findin gs after flap placement are nonspecific and have limited utility in di stinguishing symptomatic patients with recurrent inflammatory disease from asymptomatic patients whose imaging findings are related to posto perative scar tissue.