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FIG 4. A case of postoperative changes. Patient 6 was referred because of the presence of a polypoid mass in right maxillary sinus wall. This patient had a right nasal fossa and maxillary sinus IP that was treated initially with en bloc excision via lateral rhinotomy-medial maxillectomy 9 months before the study was conducted.
A, The conventional images are presented in the same order as those shown in figure 3A. The T1-weighted image shows isointensity to muscle. The T2-weighted image shows a region of inhomogeneous hyperintensity in right maxillary sinus wall; the signal intensity of most areas (arrows) in this region is hypointense to CSF and hyperintense to muscle. Postcontrast studies with fat saturation show inhomogeneous, moderate enhancement as compared with enhanced mucosa. The diagnosis of the conventional images is "recurrence."
B, ROI analysis shows a color-coded zone suggestive of postoperative changes.
C, The A and Tc of the pixels corresponding to the ROI are shown.
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