FIGURE 3. A 44-y-old woman with NPC 9 mo after intensity-modulated radiation therapy. (A) Coronal contrast-enhanced T1-weighted MR image shows an asymmetric mucosal thickening (arrow) in the left nasopharynx. (B) However, the negative ¹⁸F-FDG PET findings are false, for histopathologic examination showed a recurrent NPC.